U.S. patent application number 13/602990 was filed with the patent office on 2013-04-04 for system and method for selective measurement of fiber optic instrument sensors.
This patent application is currently assigned to KONINKLIJKE PHILIPS ELECTRONICS N.V.. The applicant listed for this patent is Bhaskar S. Ramamurthy, Randall L. Schlesinger, Neal A. Tanner, Robert G. Younge. Invention is credited to Bhaskar S. Ramamurthy, Randall L. Schlesinger, Neal A. Tanner, Robert G. Younge.
Application Number | 20130085331 13/602990 |
Document ID | / |
Family ID | 40193882 |
Filed Date | 2013-04-04 |
United States Patent
Application |
20130085331 |
Kind Code |
A1 |
Ramamurthy; Bhaskar S. ; et
al. |
April 4, 2013 |
SYSTEM AND METHOD FOR SELECTIVE MEASUREMENT OF FIBER OPTIC
INSTRUMENT SENSORS
Abstract
An instrument system that includes an elongate body, an optical
fiber, and a controller is provided. The optical fiber is
operatively coupled to the elongate body and has a plurality of
strain sensors provided on the optical fiber. The controller is
operatively coupled to the optical fiber and adapted to obtain
signals from one of the plurality of strain sensors more frequently
than from another of the plurality of strain sensors and to
determine a position of the elongate body based on the obtained
signals from the one of the plurality of strain sensors.
Inventors: |
Ramamurthy; Bhaskar S.; (Los
Altos, CA) ; Tanner; Neal A.; (Mountain View, CA)
; Younge; Robert G.; (Portola Valley, CA) ;
Schlesinger; Randall L.; (San Mateo, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ramamurthy; Bhaskar S.
Tanner; Neal A.
Younge; Robert G.
Schlesinger; Randall L. |
Los Altos
Mountain View
Portola Valley
San Mateo |
CA
CA
CA
CA |
US
US
US
US |
|
|
Assignee: |
KONINKLIJKE PHILIPS ELECTRONICS
N.V.
Eindhoven
NL
|
Family ID: |
40193882 |
Appl. No.: |
13/602990 |
Filed: |
September 4, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12192033 |
Aug 14, 2008 |
|
|
|
13602990 |
|
|
|
|
60964773 |
Aug 14, 2007 |
|
|
|
Current U.S.
Class: |
600/117 |
Current CPC
Class: |
A61B 6/12 20130101; A61B
2034/301 20160201; A61B 2034/741 20160201; A61B 18/1492 20130101;
A61B 34/77 20160201; A61B 90/96 20160201; A61B 5/066 20130101; A61B
1/00057 20130101; A61B 34/37 20160201; A61B 1/00045 20130101; A61B
2090/376 20160201; A61B 1/00004 20130101; A61B 2017/00699 20130101;
G01B 11/165 20130101; A61B 90/39 20160201; A61B 2017/00725
20130101; A61B 1/00165 20130101; A61B 5/06 20130101; A61B 34/30
20160201; A61B 2034/2061 20160201; A61B 5/0059 20130101; A61B 8/48
20130101; A61B 2034/715 20160201; A61B 1/0017 20130101; A61B 5/4887
20130101; A61B 5/7285 20130101; A61B 8/00 20130101; A61B 2090/374
20160201; A61B 34/20 20160201; A61B 1/00013 20130101; A61B 5/065
20130101; A61B 2090/378 20160201; A61B 90/98 20160201; G01B 11/16
20130101; G01L 1/242 20130101; A61B 5/0064 20130101; A61B 34/71
20160201; A61M 2025/0166 20130101; A61B 18/082 20130101 |
Class at
Publication: |
600/117 |
International
Class: |
A61B 1/00 20060101
A61B001/00 |
Claims
1. An instrument system, comprising: an elongate body; an optical
fiber operatively coupled to the elongate body and having a
plurality of strain sensors provided on the optical fiber; and a
controller operatively coupled to the optical fiber and adapted to:
obtain signals from one of the plurality of strain sensors more
frequently than from another of the plurality of strain sensors;
and determine a position of the elongate body based on the obtained
signals from the one of the plurality of strain sensors.
2. The instrument system of claim 1, wherein the optical fiber
comprises a proximal portion. and a distal portion, and wherein the
one of the plurality of strain sensors is located on the distal
portion and the another of the plurality of strain sensors is
located on the proximal portion.
3. The instrument system of claim 1, wherein the controller is
adapted to obtain the signals by selecting, based on movement of
the elongate body, the one of the plurality of strain sensors to be
sampled more frequently.
4. The instrument system of claim 1, wherein the optical fiber
comprises a first proximal portion and a second proximal portion,
wherein the second proximal portion is more proximal than the first
proximal portion, and wherein the controller is adapted to select,
based on an increase in signal amplitude of signals from the first
proximal portion relative to signals from the second proximal
portion, the first proximal portion to be sampled more
frequently.
5. The instrument system of claim 1, wherein the plurality of
strain sensors comprise a plurality of axially-spaced Bragg
gratings.
6. The instrument system of claim 5, wherein the plurality of
axially-spaced Bragg gratings are substantially continuous along
the optical fiber.
7. An instrument system, comprising: an elongate body; an optical
fiber operatively coupled to the elongate body and having a
plurality of strain sensors provided on the optical fiber; and a
controller operatively coupled to the optical fiber and adapted to:
select a reference strain sensor from among the plurality of strain
sensors; receive signals from the plurality of optical fibers; and
determine, based on the signals received from the plurality of
strain sensors, a position of the elongate body relative to a
position of reference strain sensor.
8. The instrument system of claim 7, wherein one of the plurality
of strain sensors is most proximal to the controller, and wherein
the selected reference strain sensor is not the one of the
plurality of strain sensors.
9. The instrument system of claim 8, wherein the selected reference
strain sensor is adjacent to the one of the plurality of strain
sensors.
10. The instrument system of claim 7, wherein the reference strain
sensor is a first strain sensor, and wherein the controller is
adapted to select a second reference strain sensor from among the
plurality of strain sensors.
11. The instrument system of claim 10, wherein the controller is
adapted to determine a position of the first strain sensor relative
to a position of the second reference strain sensor.
12. The instrument system of claim 7, further comprising a
localization sensor operatively coupled to the elongate body,
wherein the controller is adapted to determine a position of the
reference strain sensor relative to a position of the localization
sensor.
13. The instrument system of claim 7, wherein the instrument system
is adapted to prevent the reference strain sensor from moving.
14. The instrument system of claim 7, wherein the plurality of
strain sensors comprises a plurality of Bragg gratings that are
substantially continuous or overlapping.
15. An instrument system, comprising: an elongate body; an optical
fiber operatively coupled to the elongate body and having a
plurality strain sensors provided on the optical fiber; and a
controller operatively coupled to the optical fiber and adapted to:
select a measurement strain sensor from among the plurality of
strain sensors; receive a signal from the measurement strain
sensor; and determine, based on the signal, a position of a portion
of the elongate body at which the measurement strain sensor is
located.
16. The instrument system of claim 15, wherein the measurement
strain sensor comprises a Braga grating, and wherein the controller
is configured to receive the signal by measuring only a portion of
the Bragg grating, Wherein a length of the portion of the Braga
grating is less than a length of the Bragg grating.
17. The instrument system of claim 16, wherein the plurality of
Bragg gratings are overlapping.
18. The instrument system of claim 15, wherein the controller is
further configured to select a reference strain sensor from among
the plurality of strain sensors, and wherein the controller is
configured to determine the position of the portion of the elongate
body relative to a position of the reference strain sensor.
19. The instrument system of claim 18, wherein the selected
reference strain sensor is adjacent to the selected measurement
strain sensor.
20. The instrument system of claim 15, wherein one of the plurality
of strain sensors is most proximal to the controller, and wherein
the selected measurement strain sensor is not the one of the
plurality of strain sensors.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a divisional of U.S. patent
application Ser. No. 12/192,033 filed on Aug. 14, 2008, which
claims the benefit under 35 U.S.C. .sctn.119 to U.S. Provisional
Application No. 60/964,773, filed on Aug. 14, 2007, the contents of
which is incorporated herein by reference as though set forth in
full.
[0002] The present application may also be related to subject
matter disclosed in the following applications, the contents of
which are also incorporated herein by reference as though set forth
in full: U.S. patent application Ser. No. 10/923,660, entitled
"System and Method for 3-D Imaging", filed Aug. 20, 2004; U.S.
patent application Ser. No. 10/949,032, entitled "Balloon
Visualization for Transversing a Tissue Wall", filed Sep. 24, 2005;
U.S. patent application Ser. No. 11/073,363, entitled "Robotic
Catheter System", filed Mar. 4, 2005; U.S. patent application Ser.
No. 11/173,812, entitled "Support Assembly for Robotic Catheter
Assembly", filed Jul. 1, 2005; U.S. patent application Ser. No.
11/176,954, entitled "Instrument Driver for Robotic Catheter
System", filed Jul. 6, 2005; U.S. patent application Ser. No.
11/179,007, entitled "Methods Using A Robotic Catheter System",
filed Jul. 6, 2005; U.S. patent application Ser. No. 11/185,432,
entitled "System and method for denaturing and fixing collagenous
tissue", filed Jul. 19, 2005; U.S. patent application Ser. No.
11/202,925, entitled "Robotically Controlled Intravascular Tissue
Injection System", filed Aug. 12, 2005; U.S. patent application
Ser. No. 11/331,576, entitled "Robotic Catheter System", filed Jan.
13, 2006; U.S. patent application Ser. No. 11/418,398, entitled
"Robotic Catheter System", filed May 3, 2006; U.S. patent
application Ser. No. 11/481,433, entitled "Robotic Catheter System
and Methods", filed Jul. 3, 2006; U.S. patent application Ser. No.
11/637,951, entitled "Robotic Catheter System and Methods", filed.
Dec. 11, 2006; U.S. patent application Ser. No. 11/640,099,
entitled "Robotic Catheter System and Methods", filed Dec. 14,
2006; U.S. patent application Ser. No. 11/678,001, entitled
Apparatus for Measuring Distal Forces on a Working Instrument,
filed Feb. 22, 2007; U.S. patent application Ser. No. 11/678,016,
entitled Method of Sensing Forces on a Working Instrument, filed
Feb. 22, 2007; U.S. patent application Ser. No. 11/690,116,
entitled Fiber Optic Instrument Sensing System, filed Mar. 22,
2007; U.S. patent application Ser. No. 12/032,622, entitled
Instrument Driver Haying Independently Rotatable Carriages, filed
Feb. 15, 2008; U.S. patent application Ser. No. 12/032,634,
entitled Support Structure :for Robotic Medical Instrument filed
Feb. 15, 2008; U.S. patent application Ser. No. 12/032,626,
entitled Instrument Assembly for Robotic Instrument System, filed
Feb. 15, 2008; U.S. patent application Ser. No. 12/032,639,
entitled Flexible Catheter Instruments and Methods, filed Feb. 15,
2008; U.S. application Ser. No. 12/106,254, entitled Optical Fiber
Shape Sensing Systems, filed on Apr. 18, 2008; and U.S. application
Ser. No. 12/114,720, entitled Apparatus, Systems and Methods for
I-Twining a Working Platform of a Robotic instrument System by
Manipulation of Components Having Controllable Rigidity," filed on
May 2, 2008.
[0003] The present application may also be related to subject
matter disclosed in the following provisional applications, the
contents of which are also incorporated herein by reference as
though set forth in full: U.S. Provisional Patent Application No.
60/550,961, entitled "Robotic Catheter System," filed Mar. 5, 2004;
U.S. Provisional Patent Application No. 60/750,590, entitled
"Robotic Catheter System and Methods", filed Dec. 14, 2005; U.S.
Provisional Patent Application No. 60/756,136, entitled "Robotic
Catheter System and Methods", filed Jan. 3, 2006; U.S. Provisional
Patent Application No. 60/776,065, entitled "Force Sensing for
Medical Instruments", filed Feb. 22, 2006; U.S. Provisional Patent
Application No. 60/785,001, entitled "Fiberoptic Bragg Grating
Medical instrument", filed Mar. 22, 2006; U.S. Provisional Patent
Application No. 60/788,176, entitled "Fiberoptic Bragg Grating
Medical Instrument", filed Mar. 31, 2006; U.S. Provisional Patent
Application No. 60/801,355, entitled "Sheath and Guide Catheter
Apparatuses For A Robotic Catheter System With Force Sensing",
filed May 17, 2006; U.S. Provisional Patent Application No.
60/801,546, entitled "Robotic Catheter System and Methods", filed
May 17, 2006; U.S. Provisional Patent Application No. 60/801,945,
entitled "Robotic Catheter System and Methods", filed May 18, 2006;
U.S. Provisional Patent Application No. 60/833,624, entitled
"Robotic Catheter System and Methods", filed Jul. 26, 2006; U.S.
Provisional Patent Application No. 60/835,592, entitled "Robotic
Catheter System and Methods", filed Aug. 3, 2006; U.S. Provisional
Patent Application No. 60/838,075, entitled "Robotic Catheter
System and Methods", filed Aug. 15, 2006; U.S. Provisional Patent
Application No. 60/840,331, entitled "Robotic Catheter System and
Methods", filed Aug. 24, 2006; U.S. Provisional Patent Application
No. 60/843,274, entitled "Robotic Catheter System and Methods",
filed Sep. 8, 2006; U.S. Provisional Patent Application No.
60/873,901, entitled "Robotic Catheter System and Methods", filed
Dec. 8, 2006; U.S. Provisional Patent Application No. 60/879,911,
entitled "Robotic Catheter System and Methods", filed Jan. 10,
2007; U.S. Provisional Patent Application No. 60/899,048, entitled
"Robotic Catheter System", filed Feb. 8, 2007; U.S. Provisional
Patent Application No. 60/900,584, entitled "Robotic Catheter
System and Methods", filed Feb. 8, 2007; U.S. Provisional Patent
Application No. 60/902,144, entitled, Flexible Catheter Instruments
and Methods, filed on Feb. 15, 2007; U.S. Provisional Patent
Application No. 60/925,449, entitled Optical Fiber Shape Sensing
Systems, filed Apr. 20, 2007; and U.S. Provisional Patent
Application No. 60/925,472, entitled Systems and Methods for
Processing Shape Sensing Data, filed Apr. 20, 2007.
FIELD OF INVENTION
[0004] The invention relates generally to robotically controlled
systems such as telerobotic surgical systems.
BACKGROUND
[0005] Robotic interventional al systems and devices are well
suited for use in performing minimally invasive medical procedures
as opposed. to conventional procedures that involve opening the
patient's body to permit the surgeon's hands to access internal
organs. Traditionally, surgery utilizing conventional procedures
meant significant pain, long recovery times, lengthy work absences,
and visible scarring. However, advances in technology have led to
significant changes in the field of medical surgery such that less
invasive surgical procedures are increasingly popular, in
particular, minimally invasive surgery (MIS). A "minimally invasive
medical procedure" is generally considered a procedure that is
performed by entering the body through the skin, a body cavity, or
an anatomical opening utilizing small incisions rather than larger,
more invasive open incisions in the body.
[0006] Various medical procedures are considered to be minimally
invasive including, for example, mitral and tricuspid valve
procedures, patent formen ovale, atrial septal defect surgery,
colon and rectal surgery, laparoscopic appendectomy, laparoscopic
esophagectomy, laparoscopic hysterectomies, carotid angioplasty,
vertebroplasty, endoscopic sinus surgery, thoracic surgery, donor
nephrectomy, hypodermic injection, air-pressure injection,
subdermal implants, endoscopy, percutaneous surgery, laparoscopic
surgery, arthroscopic surgery, cryosurgery, microsurgery, biopsies,
videoscope procedures, keyhole surgery, endovascular surgery,
coronary catheterization, permanent spinal and brain electrodes,
stereotactic surgery, and radioactivity-based medical imaging
methods. With MIS, it is possible to achieve less operative trauma
for the patient, reduced hospitalization time, less pain and
scarring, reduced incidence of complications related to surgical
trauma, lower costs, and a speedier recovery.
[0007] Special medical equipment may be used to perform MIS
procedures. Typically, a surgeon inserts small tubes or ports into
a patient and uses endoscopes or laparoscopes having a fiber optic
camera, light source, or miniaturized surgical instruments. Without
a traditional large and invasive incision, the surgeon is not able
to see directly into the patient. Thus, the video camera serves as
the surgeon's eyes. Images of the body interior are transmitted to
an external video monitor to allow a surgeon to analyze the images,
make a diagnosis, visually identify internal features, and perform
surgical procedures based on the images presented on the
monitor.
[0008] MIS procedures may involve minor surgery as well as more
complex operations. Such operations may involve robotic and
computer technologies, which have led to improved visual
magnification, electromechanical stabilization and reduced number
of incisions. The integration of robotic technologies with surgeon
skill into surgical robotics enables surgeons to perform surgical
procedures in new and more effective ways.
[0009] Although MIS techniques have advanced, physical limitations
of certain types of medical equipment still have shortcomings and
can be improved. For example, during a MIS procedure, catheters
(e.g., a sheath catheter, a guide catheter, an ablation catheter,
etc.), endoscopes or laparoscopes may be inserted into a body
cavity duct or vessel. A catheter is an elongated tube that may,
for example, allow for drainage or injection of fluids or provide a
path for delivery of working or surgical instruments to a surgical
or treatment site. In known robotic instrument systems, however,
the ability to control and manipulate system components such as
catheters and associated working instruments may be limited due, in
part, to a surgeon not having direct access to the target site and
not being able to directly handle or control the working instrument
at the target site.
[0010] More particularly, MIS diagnostic and interventional
operations require the surgeon to remotely approach and address the
operation or target site by using instruments that are guided,
manipulated and advanced through a natural body orifice such as a
blood vessel, esophagus, trachea., small intestine, large
intestine, urethra, or a small incision in the body of the patient.
In some situations, the surgeon may approach the target site
through both a natural body orifice as well as a small incision in
the body.
[0011] For example, one or more catheters and other surgical
instruments used to treat cardiac arrhythmias such as atrial
fibrillation (AR are inserted through an incision at the femoral
vein near the thigh or pelvic region of the patient, which is at
some distance away from the operation or target site. In this
example, the operation or target site for performing cardiac
ablation is in the left atrium of the heart. Catheters are guided
(e.g., by a guide wire, etc.) manipulated, and advanced toward the
target site by way of the femoral vein to the inferior vena cava
into the right atrium through the interatrial septum to the left
atrium of the heart. The catheters may be used to apply cardiac
ablation therapy to the left atrium of the heart to restore normal
heart function.
[0012] However, controlling one or more catheters that are advanced
through naturally-occurring pathways such as blood vessels or other
lumens via surgically-created wounds of minimal size, or both, can
be a difficult task. Remotely controlling distal portions of one or
more catheters to precisely position system components to treat
tissue that may lie deep within a patient, e.g., the left atrium of
the heart, can also be difficult. These difficulties are due in
part to limited control of movement and articulation of system
components, associated limitations on imaging and diagnosis of
target tissue, and limited abilities and difficulties of accurately
determining the shape and/or position of system components and
distal portions thereof within the patient. These limitations can
complicate or limit the effectiveness of surgical procedures
performed using minimally invasive robotic instrument systems.
[0013] For example, referring to FIG. 1, a typical field of view or
display 10 of a catheter includes a representation 12 of a catheter
and an image 14 of a catheter. The catheter representation 12 is in
the form of "cartoon object" that is created based on a position of
the catheter determined according to a kinematics model. The image
14 is generated using an imaging modality such as fluoroscopy.
[0014] A kinematics model is related to the motion and shape of an
instrument, without consideration of forces on the instrument that
bring about that motion. In other words, a kinematics model is
based on geometric parameters and how a position of the instrument
changes relative to a pre-determined or reference position or set
of coordinates. One example of a kinematics model that may be used
in non-invasive robotic applications receives as an input a desired
or selected position of the instrument, e.g., a position of a
distal portion of the instrument within a portion of the heart, and
outputs a corresponding shape or configuration of the instrument,
e.g., with reference to a current or known shape or configuration,
that results in positioning of the instrument according to the
input.
[0015] A fluoroscopic system may be utilized to image, or
"visualize", the elongate instrument or a portion thereof. A
drawback of known fluoroscopic imaging systems is that it they are
projection based such that depth information is lost. As a result,
true three-dimensional location of objects such as an elongate
instrument in the field of view of the fluoroscope is lost as a
result of generating a two-dimensional fluoroscopic image. Thus,
even if it is possible to obtain accurate x-y or two-dimensional
data, it may be difficult or impossible to accurately determine the
location of a catheter in three-dimensional space. Examples of
fluoroscopy instruments and associated methods are described in
further detail in U.S. application Ser. No. 11/637,951, the
contents of which were previously incorporated by reference.
[0016] In the example illustrated in FIG. 1, the shapes of the
representation 12 and image 14 are generally consistent, but in
some applications, the position and/or shape of a catheter or
elongate instrument may differ and inaccurately reflect the shape
and/or position of the instrument, which may result in
complications during surgical procedures. Such mismatches may be
interpreted as a problem associated with the kinematics model or
controls or sensing algorithms, or as a result of contact between
the subject instrument and a nearby object, such as tissue or
another instrument.
[0017] A process called "registration" may be performed to
spatially associate the two coordinate systems in three dimensions.
Registration involves moving the elongate instrument to one or more
positions, imaging the instrument with one or more positions of the
fluoroscopic imaging device (e.g., the C-arm), and analyzing the
images to deduce the coordinate system of the elongate instrument
in relation to the coordinate system of the fluoroscopic imaging
device. This process, however, can be tedious, and it is relatively
easy for the elongate instrument to go out of alignment relative to
the other pertinent coordinate systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present disclosure will be readily understood by the
following detailed description, taken in conjunction with
accompanying drawings, illustrating by way of examples the
principles of the present disclosure. The drawings illustrate the
design and utility of preferred embodiments of the present
disclosure, in which like elements are referred to by like
reference symbols or numerals. The objects and elements in the
drawings are not necessarily drawn to scale, proportion or precise
positional relationship; instead emphasis is focused on
illustrating the principles of the present disclosure.
[0019] FIG. 1 generally illustrates a field of view or display that
includes a representation of a catheter generated using a
kinematics model and an image of a catheter;
[0020] FIG. 2A illustrates a surgical apparatus constructed
according to one embodiment includes an optical fiber sensor
attached to or integral with an elongate surgical instrument;
[0021] FIG. 2B is a cross-sectional view of an elongate instrument
constructed according to one embodiment and that defines a central
lumen and a lumen defined through a wall of the catheter in which
an optical fiber sensor may be positioned;
[0022] FIG. 3A schematically illustrates a system for use with
optical fiber sensors having one or more Fiber Bragg Gratings
written or formed therein and that are coupled to or integral with
one or more components of a robotic surgical system;
[0023] FIG. 3B illustrates a core of an optical fiber sensor
constructed according to one embodiment including multiple, axially
spaced Fiber Bragg Gratings;
[0024] FIG. 3C illustrates a core of an optical fiber sensor
constructed according to another embodiment that includes sets of
Fiber Bragg Gratings having different reflectivities;
[0025] FIGS. 4A-D illustrate different optical fiber configurations
or shapes that may interface with a portion of an elongate
instrument or catheter to prevent twisting of the fiber, and FIG.
4E illustrates another configuration of an optical fiber sensor
that includes off-center core;
[0026] FIG. 5 generally depicts a mismatch between a shape of a
representation of a catheter generated by a kinematics model and a
shape of an image of a catheter acquired using an imaging modality
that can be addressed or prevented with use of optical fiber sensor
embodiments;
[0027] FIG. 6 generally depicts how optical fiber sensor
embodiments may be utilized to provide a more accurate x-y-z
position data of a two-dimensional image of a catheter;
[0028] FIG. 7 generally depicts how optical fiber sensor
embodiments may be utilized to provide more accurate x-y-z position
data and orientation, roll or twist data of a two-dimensional image
of a catheter;
[0029] FIG. 8 is a flow chart of a method of generating and
displaying a representation of an instrument body according to one
embodiment;
[0030] FIG. 9 is a flow chart of a method of controlling movement
of a component of a robotic surgical system based on shape and
location information received or derived from light reflected by an
optical fiber sensor according to another embodiment;
[0031] FIG. 10 is a flow chart of a method of generating a
structural map of a tissue surface utilizing an optical fiber
sensor according to another embodiment;
[0032] FIG. 11 illustrates an embodiment in which multiple fibers
are coupled to or integral with respective robotically controllable
catheters that carry different types of catheters;
[0033] FIG. 12 illustrates another embodiment of a system in which
an optical fiber sensor is coupled to or integral with a controller
or instrument driver of an elongate instrument;
[0034] FIG. 13 illustrates an embodiment in which optical fiber
sensors are coupled to or integral with respective controllers or
instrument drivers of respective robotically controllable catheters
and coupled to or integral with respective controllable
catheters;
[0035] FIG. 14 illustrates another embodiment in which optical
fiber sensors are coupled to or integral with elongate instrument
bodies such as a catheter and an image capture device;
[0036] FIG. 15 illustrates another embodiment of a system in which
an optical fiber sensor is attached or affixed to a patient;
[0037] FIG. 16 is a flow chart of a method of performing a
calibration procedure utilizing an optical fiber sensor according
to one embodiment;
[0038] FIG. 17 is a flow chart of a method of performing a
diagnostic or therapeutic procedure using an instrument calibrated
as shown in FIG. 16;
[0039] FIG. 18 illustrates one embodiment of a test fixture
suitable for calibration procedures involving an optical fiber
sensor;
[0040] FIG. 19 illustrates one embodiment directed to establishing
a reference grating or sensor;
[0041] FIG. 20 illustrates one embodiment of a connector for
providing slack and a grating or sensor reference;
[0042] FIG. 21 illustrates an apparatus constructed according to
another embodiment that is configured to accommodate a grating
having a portion of which that is within a sleeve and a portion of
which is outside of the sleeve;
[0043] FIGS. 22A-F illustrate a robotic instrument or surgical
system in which embodiments of the invention may be implemented,
wherein FIG. 22A illustrates a robotic medical instrument system,
FIG. 22B illustrates an operator workstation including a master
input device and data gloves, FIG. 22C is a block diagram of a
system architecture of a robotic medical instrument system in which
embodiments may be implemented or with which embodiments may be
utilized, FIG. 22D illustrates a setup joint or support assembly of
a robotic instrument system with which embodiments may be utilized,
FIG. 22E is a rear perspective view of a flexible catheter assembly
of a robotic instrument system with which embodiments may be
utilized, and FIG. 22F illustrates an instrument driver to which
the flexible catheter assembly illustrated in FIG. 22E may be
attached and to which an optical fiber sensor may be coupled;
[0044] FIGS. 23A-C are different views of a multi-a sheath catheter
having an optical fiber sensor coupled thereto according to on
embodiment;
[0045] FIGS. 24A-D are different views of a rotatable apparatus
that interfaces with the sheath catheter illustrated in FIGS.
23A-C;
[0046] FIGS. 25A-F are different views of an orientation platform
or interface for a working instrument with which rotational
apparatus embodiments as shown in FIGS. 24A-D can be utilized;
[0047] FIGS. 26A-B illustrate other configurations of a robotic
instrument system in which embodiments may be utilized, wherein
FIG. 26A illustrates an embodiment including three multi-segment
sheath catheters, each of which has an optical fiber sensor coupled
thereto, and FIG. 26B shows the configuration shown in FIG. 26A
with an additional optical fiber sensor coupled to an image capture
device that extends through the master sheath;
[0048] FIGS. 27-43 illustrate aspects of a control schema,
kinematics, actuation coordinates for kinematics, and a block
diagram of a system with which embodiments may be implemented or
utilized, a sample flowchart of transforming a position vector to a
haptic signal, and a block diagram of a system including haptics
capability of robotic surgical systems in which embodiments of the
invention may be implemented; and
[0049] FIGS. 44-49 illustrate a system and system configuration for
visualization of tissue by overlaying images, a schematic for
overlaying objects to the display, a distributed system.
architecture and hardware and software interfaces of robotic
surgical systems which embodiments may be implemented.
SUMMARY OF THE INVENTION
[0050] In accordance with one embodiment, an instrument system that
includes an elongate body, an optical fiber, and a controller is
provided. The optical fiber is operatively coupled to the elongate
body and has a plurality of strain sensors provided on the optical
fiber. The controller is operatively coupled to the optical fiber
and adapted to obtain signals from one of the plurality of strain
sensors more frequently than from another of the plurality of
strain sensors and to determine a position of the elongate body
based on the obtained signals from the one of the plurality of
strain sensors.
[0051] According to another embodiment, an instrument system that
includes an elongate body, an optical fiber, and a controller is
provided. The optical fiber is operatively coupled to the elongate
body and has a plurality of strain sensors provided on the optical
fiber. The controller is operatively coupled to the optical fiber
and adapted to select a reference strain sensor from among the
plurality of strain sensors, to receive signals from the plurality
of optical fibers and to determine, based on the signals received
from the plurality of strain sensors, a position of the elongate
body relative to a position of the reference strain sensor.
[0052] According to yet another embodiment, an instrument system
that includes an elongate body, an optical fiber, and a controller
is provided. The optical fiber is operatively coupled to the
elongate body and has a plurality of strain sensors provided on the
optical fiber. The controller is operatively coupled to the optical
fiber and adapted to select a measurement strain sensor from among
the plurality of strain sensors, to receive a signal from the
measurement strain sensor, and to determine, based on the signal, a
position of a portion of the elongate body at which the measurement
strain sensor is located.
[0053] These and other aspects of the present disclosure, as well
as the methods of operation and functions of the related elements
of structure and the combination of parts and economies of
manufacture, will become more apparent upon consideration of the
following description and the appended claims with reference to the
accompanying drawings, all of which form a part of this
specification, wherein like reference numerals designate
corresponding parts in the various figures. In one embodiment, the
structural components illustrated can be considered are drawn to
scale. It is to be expressly understood, however, that the drawings
are for the purpose of illustration and description only and are
not intended as a definition of the limits of the present
disclosure. It shall also be appreciated that the features of one
embodiment disclosed herein can be used in other embodiments
disclosed herein. As used in the specification and in the claims,
the singular form of "a", "an", and "the" include plural referents
unless the context clearly dictates otherwise.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0054] Embodiments of the invention are related to systems,
apparatus and methods including or involving the use of optical
fiber sensors, e.g., Fiber-Bragg sensors, which may be used to
provide accurate shape and/or position data of an elongate
instrument.
[0055] Referring to FIG. 2A, according to one embodiment, one or
more components of a robotically controlled instrument 200 of a
robotic surgical system include an optical fiber or fiber sensor
215 (referred to as optical fiber sensor or fiber 215), which is
coupled to, or an integral part of, an elongate instrument body
210. Data based on light reflected by gratings of the fiber 215 may
be used to determine the shape and/or position of the elongate
instrument, which may be a catheter, such as a guide catheter. In
the illustrated embodiment, the elongate instrument or catheter 210
is a part of a robotically controlled instrument 200 that it
utilized to position a bendable distal end portion 211 of the
catheter 210 and one or more working instruments 240 at a target
site within a patient. The particular working instrument 240
employed may depend on the target tissue and manner in which the
instrument 200 is inserted or advanced into the patient.
[0056] The optical fiber sensor 215 can be attached or coupled to
an elongate instrument or catheter 210 in various ways. Referring
to FIG. 2B, in one embodiment, the optical fiber sensor 215 extends
through a central or other lumen 217 defined by the catheter 210.
According to another embodiment, the optical fiber sensor 215
extends through a lumen 213 defined through a wall of the catheter
210, i.e., through a lumen 213 defined between an inner wall 214
and an outer wall 216 of the catheter 210. FIG. 2B illustrates a
single lumen 213 defined within a catheter 210 wall to accommodate
a single optical fiber sensor 215 and a single lumen 217, but in
other embodiments, multiple lumens 213, 217 may be defined, and an
optical fiber sensor 215 may extend through some or all of the
multiple lumens 213, 217. In other embodiments, the optical fiber
sensors 215 can be coupled, bonded or attached to the inner wall
214 or to the outer wall 215 as appropriate. The inner wall 214 may
also define a groove in which a fiber 215 may be positioned. In yet
other embodiments, an optical fiber sensor 215 can be coupled to or
integral with an outer surface 216 using, for example, a suitable
adhesive or bonding agent and/or the fiber 215 may be positioned
within an aperture or groove that is formed within the outer wall
216. Further, the optical fiber 215 can be coupled to a catheter or
other instrument 210 in such a manner that a portion of the optical
fiber 215 is coupled at a known reference location on the proximal
potion of the instrument 210.
[0057] For ease of explanation, this specification refers to an
optical fiber sensor 215 that is coupled to or integral with a
catheter 210 or other system component in a non-limiting manner.
Thus, while certain figures may illustrate an optical fiber sensor
215 extending along a surface of a catheter 210 for ease of
illustration, it should be understood that in practice, one or
multiple optical fiber sensors 215 may extend through one or more
lumens 213, 217 of one or more instruments depending on the
configuration employed.
[0058] Referring again to FIG. 2A, one manner in which robotic
intravascular systems including an elongate instrument 210 having
an optical fiber sensor 215 coupled thereto or integral therewith
may be utilized is to position the catheter 210 or other working
instrument 240 within the heart 230, e.g., to diagnose, treat or
ablate endocardial tissue. In the illustrated application, a
robotically controlled instrument 200 including a catheter or guide
instrument 210 and a sheath instrument 220 is positioned within the
heart 230. FIG. 2A depicts delivery of the instrument 200 utilizing
a standard atrial approach in which the robotically controlled
catheter 210 and sheath 220 pass through the inferior vena cava and
into the right atrium. An image capture device (not illustrated in
FIG. 2), such as an endoscope or intracardiac echo ("ICE")
sonography catheter (not shown in FIG. 1), may be advanced into the
right atrium to provide a field of view upon the interatrial
septum. The catheter 210 may be driven to the septum wall 132, and
the septum 132 may be crossed using a conventional technique of
first puncturing the fossa ovalis location with a sharpened device,
such as a needle or wire, passed through a working lumen of the
catheter 110, then passing a dilator or other working instrument
240 over the sharpened device and withdrawing the sharpened device
to leave the dilator 240, over which the catheter 210 may be
advanced.
[0059] Various working instruments 240 (not shown in FIG. 1) may be
delivered through the lumen of the catheter 210 as necessary and
depending on the surgical application. For example, for treatment
of atrial fibrillation, the working instrument 240 may be an
ablation catheter that delivers targeted radio frequency (RF)
energy to selected endocardial tissue. Further aspects of such
systems, devices and applications are described in U.S. application
Ser. No. 11/176,598, the contents of which were previously
incorporated herein by reference.
[0060] An optical fiber sensor 215 may be used in various
applications and may be coupled to or integral with various
instruments and surgical system components, and even a patient. For
example, in one embodiment, the optical fiber sensor 215 serves as
a localization sensor, Which may be used to "localize" or monitor
the position and/or orientation of various objects or system
components involved in a surgical procedure. The optical fiber
sensor 215 may also be utilized in other applications involving
registration, calibration, force calculation and feedback, improved
accuracy, mechanical interfacing or "connectorization," and
fiber-based diagnostics. Further aspects of embodiments of the
invention and systems in which embodiments may be utilized are
described in further detail with reference to FIGS. 3A-49.
[0061] Referring to FIG. 3A, an optical fiber sensor 215
constructed according to one embodiment includes a fiber core 304
surrounded by a cladding 306. The core 304 includes a distributed
Bragg reflector, such as one or more Fiber Bragg gratings or FBGs
302 (generally referred to as FBGs or gratings 302), which are
formed within or written into the core 304. FBGs 302 can be
inscribed or written into the core 304 of a fiber 215, e.g., in a
periodic manner, using various known methods and devices. For
example, an ultraviolet (UV) laser may be used to "write" a
periodic variation of refractive index (n) into the core 304 of a
photosensitive germanium-doped silica fiber. Various types and
arrangements of FBGs 302 may also be utilized in embodiments
including, for example, uniform, chirped, tilted, superstructure,
uniform positive-only, Gaussian-Apodized Index FBGs. For ease of
explanation, this specification refers generally to one or more
FBGs 302 generally, but it should be understood that different
numbers, types and arrangements of FBGs 302 may be utilized in
embodiments, and that various system components may include fibers
215 so configured.
[0062] FIG. 3A illustrates a single fiber 215 and a single FBG 302
written on or within the core 304. In other embodiments (e.g., as
generally illustrated in FIGS. 3B-C), an optical fiber sensor 215
may have a fiber core 304 that includes multiple FBGs 302 or sets
thereof that are axially distributed along the core 304. In certain
embodiments, the FBGs 302 may be continuous, overlapping or
partially overlapping.
[0063] In one embodiment, as illustrated in FIG. 3C, a core 304 may
include different sets 361-362 of FBGs 302 that have different
reflectivities. Although FIG. 3C illustrates sets 361, 362 having
three FBGs 302 for purposes of illustration, it should be
understood that different numbers of gratings may be utilized, and
the number of gratings 302 in each set 361, 362 may be the same or
different. For example, in the illustrated embodiment, the
reflectivity of the first set 361 of FBGs 302 may be configured to
have relatively low reflectivity, whereas another set 362 has
slightly higher reflectivity. In one embodiment, a first fiber 215
may include gratings of a first reflectivity, and a second fiber
215 may include gratings of a second, different reflectivity.
[0064] In another embodiment, a single fiber 215 has FBGs 302 of
different reflectivities, which may be suitable for use with both
optical frequency domain reflectometry (ODFR) and wavelength
division multiplexing (WDM) processors that are operably coupled to
the same fiber 215. En this manner, embodiments combine the
advantages of two different processing systems. OFDR is suited for
low reflectively gratings 302 of the same wavelength and is
beneficial since it may be able to handle a larger number of
gratings per length of fiber 215 compared to WDM, whereas WDM is
suited for high reflectivity gratings 302 of different wavelengths,
and can achieve high signal-to-noise rations. Thus, embodiments may
advantageously utilize both OFDR and WDM on the same fiber 215.
Further aspects of OFDR and WDM processing are described in U.S.
application Ser. No. 12/106,254, the contents of which were
previously incorporated herein by reference.
[0065] Thus, various figures, including FIGS. 3A-C, are provided as
examples of how FBGs 302 may be arranged, and it should be
understood that various numbers and arrangements of FBGs 302 may be
utilized, that the FBGs 302 may have the same or different
reflectivities. Further, while FIG. 3A illustrates a fiber 215
having a cylindrical shape, other fiber 215 configurations and
shapes can be utilized, and the outer surfaces of fibers 215 may be
configured or have structural attributes (shapes or other
structural features) to interface with an inner surface or
corresponding structural attribute of a catheter 210 or other
instrument to form a key-like arrangement that limits or prevents
twisting or rotational movement of the fiber 215 within the
catheter 210.
[0066] For example, referring to FIG. 4A, in one embodiment, an
optical fiber sensor 215 has an oval-shaped outer surface 402. An
inner surface of a catheter 210 may have a corresponding oval shape
to mechanically limit or prevent twisting of the fiber sensor 215
within the catheter 210. According to another embodiment, referring
to FIG. 4B, a fiber sensor 215 is configured such that it includes
an arcuate or cylindrical outer surface 404 and a linear or flat
outer surface, segment or beveled edge 406. Although one flat
segment 406 is illustrated, a fiber sensor 215 may include other
numbers of segments, which may be arranged symmetrically or
asymmetrically. An inner surface of a catheter 210 may have a shape
corresponding to the surface shown in FIG. 4B to limit or prevent
rotation of the fiber sensor 215. Referring to FIG. 4C, in a
further embodiment, an optical fiber sensor 215 may also comprise
multiple fibers, e.g., two fibers 215a, 215b, which have mating
faces 406a, 406b and respective cylindrical surfaces 404a, 404b to
form a shape that resembles the number 8. Although FIG. 4C
illustrates two fibers 215a, 215b, other numbers of fibers 215 may
be configured to interface with each other with corresponding faces
or edges 406 or other interfacing surfaces resulting in other
shapes. An inner surface of a catheter 210 may have a shape
corresponding to this outer surface to prevent or limit twisting or
rotation of the fibers 215a, 215b. Referring to FIG. 4D, according
to another embodiment, an optical fiber sensor 215 may have an edge
406 (as shown in FIG. 4B) and a deeper groove 408 formed therein.
An inner surface of a catheter 210 may have a corresponding segment
or protrusion configured to mate with the groove 408 to avoid
twisting or rolling between the fiber 215 and the catheter 210.
Although the groove 408 is shown as having a rectangular shape,
other shapes may also be utilized, e.g., V-shaped grooves and other
shaped grooves. Further, while embodiments are described with
reference to an optical fiber 215 being disposed within an
instrument such as a catheter 210, embodiments may also he applied
to a fiber that is coupled to an outer surface of an
instrument.
[0067] Additionally, each fiber 215 may contain a single core or
comprise multiple sub-cores. In a further embodiment, referring to
FIG. 4E, the optical fiber sensor 215 may include an "off-center"
single core 304, which may he beneficial since the shape of the
fiber 215 having one core 304 can be calculated under constrained
conditions knowing the roll orientation axial strain on the
catheter 210.
[0068] Further, while figures illustrate certain core 304 and FBG
302 configurations and arrangements, embodiments may utilize a
single optical fiber 215 having one FBG 302, a single optical fiber
215 including a multiple FBGs 302 distributed along the core 304,
multiple fibers 215, each of Which includes one FBG 302, multiple
fibers 215, each of which includes multiple FBGs 302 distributed
along respective cores 304, or multiple fibers 215, some of Which
have only one FBG 302, and others that include multiple FBGs 302,
and the FBGs may have the same or different reflectivities.
[0069] Certain fibers 215 may also be different sizes. According to
one embodiment, the diameter of a fiber 215 configured for
insertion into a patient is smaller than the diameter of a fiber
215 that is utilized externally of the patient. For example, the
diameter of a fiber 215 intended for insertion into a patient may
have a diameter of about 150 microns, and a diameter of a fiber 215
intended for use outside of the patient may have a diameter of
about 200 microns or greater, e.g. about 500 microns.
[0070] Embodiments utilizing a fiber core 304 having a distribution
of axially-spaced Bragg gratings 302, which may, for example, be
continuous or substantially continuous FBGs 302 written on the at
least one fiber core 304, provide for various control options. In
one embodiment, a controller 340 of the output unit or readout
system 300, or a controller or computer of the robotic surgical
system, or combination thereof, is configured to sample the
respective FBGs 302 while selected gratings 302 are sampled more
frequently than others. For example, gratings 302 that are sampled
more frequently may be located on a portion of the Bragg sensor
optical fiber 325 coupled to a distal end portion of the instrument
210. Further, the controller 340 can be configured to actively
change which Bragg gratings 302 are selected for more frequent
sampling based upon, for example, movement of the instrument 210.
In yet another embodiment, the controller 340 may be configured to
identify a most proximal Bragg grating 302 that is selected for
more frequent sampling based on a detected increase in signal
amplitude from the respective grating 302 as compared to more
proximal gratings 302.
[0071] Additionally, embodiments may involve instruments 210 having
multiple optical fiber sensors 215, each of which has cores 304
having axially-spaced Bragg gratings 302. The controller 340 may be
configured to sample respective sensor gratings 302 on the fiber
cores 304, and to conduct common mode error analysis by comparing
signals received from respective corresponding gratings 302
thereon. As an example of common mode analysis, first and second
Bragg sensor optical fibers 215 may be attached to the same
elongate instrument 210 in an identical manner except that the
fibers 215 may be attached at different locations. For example, the
first and second fibers 215 may be attached diametrically opposite
each other of an elongate instrument 210 that has the shape of a
cylinder. In this example, through analysis of the signals 236
reflected from each fiber 215, the location of the tip of the
cylinder can be determined. The signals 236 from both fibers 215
can be averaged together taking into account that the fibers 215
are a known distance away from each other, and noise in the
measurement can thus be reduced in this manner.
[0072] Referring again to FIG. 3A, in the illustrated system
configuration, light emitted 322 by a light source 320, such a
laser, is directed into the fiber core 304 through one or more
suitable interfaces, couplers or connectors (generally illustrated
as 328), and transmitted through the fiber core 304 to one or more
FBGs 302. Light 322 may be partially transmitted 324 through the
one or more FBGs 302, and partially reflected 326. Reflected light
326 propagates in the opposite direction through the core 304,
through one or more suitable interfaces, couplers or connectors
328, and is detected by a detector 330 of an output or read out
unit (generally identified as 300). The connectors 328 are
configured to serve as interfaces between one or more fibers 215
and one or more output or read out units 300.
[0073] As shown in FIG. 3A, a control element 340 is located in the
output unit 300. In another embodiment, a controller 340 is located
in controller or computer of a robotic surgical system (e.g. as
shown in FIGS. 22A-C). The output unit 300 may also be integrated
within or a part of a controller or computer of a robotic surgical
system. In a further embodiment, a controller 340 includes
components of the output unit 300 and another computer or
controller of a robotic surgical system that are operably coupled
together. For ease of explanation, reference is made generally to a
controller 340, but it should be understood that the controller may
be a standalone component or multiple components that are operably
coupled together.
[0074] In certain embodiments, the controller 340 is configured for
applications involving shape, position and/or orientation of
robotic surgical system components, calibration, therapeutic,
diagnostic and localization procedures. The controller be
implemented as hardware, software or a combination thereof, and may
be processor, a micro-controller, or a computer, which is part of,
or associated with, the read out unit 300 or a robotic surgical
system. The controller may process reflected light 326 and issue
controls in response thereto, e.g., to adjust the shape or
reposition of an instrument of a robotic surgical system (as
generally illustrated in FIG. 3A), or generate representations of
system components on a display.
[0075] It should be understood that the system configuration
illustrated in FIG. 3A is provided to generally illustrate system
components and how they may be generally configured, and that other
components and configurations may be utilized. For example,
although FIG. 3A illustrates a single fiber sensor 215, multiple
fiber sensors 215 may also be utilized together with additional
system components as necessary. Further, each fiber sensor 215 may
have a dedicated detector or output unit 330 or fibers 215 may
share a detector or output unit 330. Further, although FIG. 3A
illustrates a separate light source 320 and output or read out unit
300, the light source 320 may also be a part of the output unit 300
(represented by dotted line). Other system configurations and/or
components may be utilized, examples of which are described in
further detail in U.S. patent application Ser. Nos. 11/678,001,
11/678,016 and 11/690,116 and U.S. Provisional Application Nos.
60/785,001 and 60/788,176, the contents of which were previously
incorporated by reference. Accordingly, FIG. 3A is provided to
generally illustrate system components and how they may be
implemented in a robotic surgical system, but other numbers and
configurations and components ay be utilized as necessary.
[0076] FIG. 5 illustrates one example of a situation that
embodiments an optical fiber sensor 215 and related systems and
methods are capable of addressing or preventing. As shown in FIG.
5, a mismatch between a shape of a representation 12 of a catheter
210, which may be generated using a kinematics model, and a shape
of an image 14 of the catheter 210, which may be generated using
fluoroscopy, is displayed 10. Embodiments of an optical fiber
sensor 215 are coupled to or integral with a catheter 120 and
address or prevent these types of mismatches by providing accurate
catheter 210 shape data, thereby allowing for accurate manipulation
and positioning of the distal portion 211 of the catheter 210.
Embodiments may also be utilized to provide accurate position
data.
[0077] For example, referring to FIG. 6, according to one
embodiment, an optical fiber sensor 215 including one or more FBGs
302 as described previously is coupled to or integral with a
catheter 210 and used as a localization sensing device to determine
and display position of a given point upon an instrument 210 on a
display 350. In the illustrated embodiment, a two-dimensional image
14 is generated using fluoroscopy and displayed 350. The image 14
may be shown independently (as shown in FIG. 6), or together with
other representations and/or images. In one embodiment, the image
14 is displayed together with the virtual catheter representation
12 or "cartoon object" that is generated according to a kinematics
model (as described with reference to FIG. 1).
[0078] As shown in FIG. 6, embodiments are used as a localization
sensing device to generate three-dimensional position data or
spatial coordinates (x-y-z) 602 of a given point on the catheter
210. In this manner, the image 14 is presented with more accurate
x-y data, and z data is also generated such that a location of the
catheter 210 or distal portion 211 thereof can be accurately
determined or extracted from the optical fiber sensor 215 data. In
this manner, a user or surgeon can know precisely where the distal
portion 211 or tip of the catheter 210 relative to surrounding
tissue.
[0079] Referring to FIG. 7, in another embodiment, in addition to
the accurate x-y-z data 602 (as described with reference to FIG.
6), orientation, roll or "twist" angle data (.alpha., .beta.) 702
may also be determined or extracted from the optical fiber sensor
215. In this manner, embodiments may be used to provide position
(x, y, z) 602 and orientation (.alpha., .beta.) data 702, which may
be particularly beneficial when the distal tip of the instrument
210 is at or adjacent to a target area or tissue.
[0080] Thus, referring to FIG. 8, one embodiment is directed to a
method 800 of generating and displaying a representation of an
instrument body 210 and includes positioning the instrument body
210 within the patient at stage 805, and directing light 322
through an optical fiber sensor 215 attached thereto or integral
therewith at stage 810. At stage 815, light 326 is reflected by,
e.g., a FBG 302, that is formed within a core 304 of the optical
fiber sensor 215. At stage 820, reflected light 326 is sensed or
detected by a detector 330, which may, for example, be a part of or
operably coupled to a controller or output unit 300. At stage 825,
a controller 340 or other suitable control element operably coupled
to the detector 330 or read out unit 800 is configured to process
data associated with the reflected light 326 to generate data such
as spatial position and/or orientation data. At stage 830, an image
14 and/or other representation 12 of the instrument body 210 is
generated and displayed 350. The shape and/or position of the
instrument 210 is accurately depicted in, for example, an image 14,
based on data determined or derived from the light reflected 326 by
FBGs 302 of the optical fiber sensor 215. Embodiments may also be
utilized for other methods and may involve generating of an image
14 and another representation 12.
[0081] Given the number of points along a given instrument 210 that
may be sensed with a Bragg grating fiber 215, embodiments
advantageously allow for accurate sensing of the shape and/or
position of the instrument 210. Shape recognition algorithms, which
may be configured to detect the position of radioopaque markers
positioned upon the elongate instrument 210, for example, may also
be utilized to detect the position of the instrument 210 in space
automatically. in the event of a mismatch between the Bragg grating
fiber 215 based cartoon object 12 and the fluoroscopic images 14
(e.g., depending on the accuracy of the Bragg gating fiber 215
positioned along the elongate instrument 210 and the accuracy of
shape recognition, or marker recognition algorithms), a procedure
may be interpreted. For example, a robotic drive motor may be
deactivated automatically, or subsequent to a notification
(audible, visual, etc.) to the operator that a mismatch exists.
[0082] The position and/or orientation of other components may also
be displayed, and they may be displayed 350 together with a
representation 12 generated according to a kinematic model (as
discussed above) and/or with other representations or images, e.g.,
together with an indicator of an orientation of an image capture
device, such as an actual or virtual camera, ultrasound image
capture device, optical or infrared imaging chip, etc. In the
illustrated embodiment, the orientation of an image capture device
is represented as an arrow object 710. The arrow object 710
indicates the origin position and vector of the orientation of the
image capture device relative to other objects presented upon the
same display in two or three dimensions. In other embodiments, the
display element depicting roll can be a display of roll angle, or
another arrow, a horizon indicator, etc. Thus, it should be
understood that additional "cartoon" objects or representations
showing the position and/or orientation of different types of
system components can be displayed together with the representation
510 of an instrument 210 based upon localization information.
[0083] Further, other localization sensors can be used to determine
the shape, position and/or orientation of one or more points of an
elongate instrument, such as a catheter 210, in space--and such
points may be utilized to construct and display a cartoon or
representation of such instrument 210 relative to other images of
the same object, generated based upon fluoroscopy, other models,
etc. For example, other localization sensors may be coupled to an
instrument body such as a catheter 210 and/or coupled to a fiber
215. Thus, a catheter 210 may include an attached fiber 215 and
localization sensor, or the localization sensor may be coupled to
the fiber 215 instead. Suitable localization sensors that may be
used for this purpose include, for example, electromagnetic coils
(such. as those available from Biosense Webster or Ascension
Technology), potential difference sensing devices (such as those
available from St. Jude Medical), and ultrasound sensors. Further
aspects of such devices are described in further detail in U.S.
application Ser. No. 11/637,951, the contents of which were
previously incorporated reference.
[0084] Thus, embodiments of optical fiber sensors 215 can be used
to "localize" or monitor the positions and/or orientations of
various objects or system components involved in a particular
procedure. For example, not only is it useful to localize
instruments, e.g., a catheter 210, configured and utilized for
endocorporeal use in a given procedure, but also it is useful to
localize other associated objects and components, such as
structures utilized to present the operational instruments 210 into
the body, structures utilized to stabilize the body, the body
itself or portions thereof. Further, depending upon the
capabilities (for example bus and processing capabilities; certain
localization systems are only capable of sensing a small number of
sensors in parallel; Bragg Grating sensors 215, on the other hand,
may be utilized to gather at least positional information regarding
many points along a given structure or multiple structures,
depending upon the particular signal processing configuration) of
the localization system utilized, multiple mechanically-associated
objects may be localized simultaneously. For example, the
instrument 200 shown in FIG. 2A includes three coaxially associated
instruments--an outer sheath catheter 220, an inner
coaxially-associated catheter 210 such as a guide catheter, and a
working instrument 240 such as a guidewire, a pusher wire, an
ablation catheter, a laser ablation fiber, a grasper, a collapsible
basket tool, etc., which is positioned within the working lumen
defined by the inner catheter 210, and all of which may be
localized simultaneously with embodiments for maximum operator
feedback and system control.
[0085] An instrument or component of a robotic surgical system
having an optical fiber sensor 215 can also be used in other
methods, and with external structures, such as instrument driver
structures, proximal instrument block structures, instrument driver
setup structures, fluoroscopy gun and/or arm structures, etc. With
embodiments, these other system components may also be localized
and monitored.
[0086] Optical fiber sensors 215 can also be coupled or attached to
a patient, e.g., to a patient's chest. With this configuration, the
position of the patient's chest may be localized to provide the
system and operator with the ability to understand changes in
position and, for example, gate or pause activities during deep
breaths or body movements, simply warn the operator with visual,
audible, and/or haptic feedback, or facilitate recalibration of
relative positioning between instruments and the patient, for
example. Such techniques may be utilized to present an operator
with pertinent information regarding the position and/or
orientation of one or multiple instruments.
[0087] For example, it may be useful to present such information
for two or more robotic arms or robotic catheters being utilized in
a given operational theatre. Further, it may be useful to present
such information for one or more imaging device, such as an
ultrasound catheter. Further, such techniques are highly useful in
not only electromechanically-driven instrument scenarios, such as
with robotic arms or robotic catheters, but also in
manually-actuated instrument scenarios, where handles and other
components are utilized to operate instruments.
[0088] Referring to FIG. 9, another embodiment is directed to a
method 900 of controlling an instrument or elongate body, such as
the catheter 210, based on the shape and/or orientation of the
catheter 210 that is expected versus the shape and/or orientation
actually achieved or measured using an optical fiber sensor 215.
The method 900 includes receiving a user command associated with a
new or desired location of the catheter 210 at stage 905, and
allowing the catheter 210 to move at stage 910 according to the
command issued or received at stage 905. At stage 915, a
determination is made whether the measured location of the catheter
210 changed as expected based on the shape and location information
received from the optical fiber sensor 215 coupled thereto or
integrated therein at stage 920. If so, then at stage 925, a
further determination is made whether the catheter 210 has reached
or is positioned at the commanded or final destination, position or
orientation. If so, the method is successful and complete at stage
930. Otherwise. the catheter 210 can be moved further at stage 915
and method steps can be repeated as necessary until the final
destination has been reached. However, movement of the catheter 210
may also result in stage 920 resulting in a determination that the
measured location changed in an unexpected way, in which case a
warning may be issued and/or catheter 210 movement can be limited
or aborted at stage 935.
[0089] Referring to FIG. 10, other embodiments are directed to a
method 1000 of generating a structural map of an internal body
tissue, such as endocardial tissue. The method includes maneuvering
a distal end portion 211 of an elongate flexible instrument or
catheter 210, which includes an optical fiber sensor 215, within an
anatomical workspace in a body at stage 1005, and detecting When a
distal end 211 of the instrument 210 contacts a tissue surface in
the workspace at stage 1010. At stage 1015, a geometric
configuration of the distal end portion 211 of the instrument 210
is determined when the distal end 211 contacts the tissue surface,
e.g., based on light reflected 226 by one or more FBGs 302. At
stage 1020, position data is generated and indicative of a position
of the instrument distal end portion 211 based upon the determined
geometric configuration of the instrument distal end portion 211
when the distal end portion 211 of the instrument 210 contacts the
tissue surface. At stage 1025, one or more or all of the previous
stages can be repeated as necessary in order to generate sufficient
position data to generate a structural map of the tissue
surface.
[0090] Referring to FIG. 11, in another embodiment, multiple
robotically controlled catheter instruments 210a,b may have
respective optical fiber sensors 215a,b coupled thereto (e.g.,
extending through a lumen 213 or 217). In the illustrated
embodiment, one robotically controllable catheter 210a has an
optical fiber sensor 215a coupled thereto and carries or supports
an imaging device or imaging catheter 1102. Another robotically
controllable catheter 210b includes an optical fiber sensor 215b
and carries or supports a mapping catheter 1104, which is used to
map electrical signals within the heart 330, With this
configuration, embodiments advantageously allow the shape and
location of multiple catheters 210a,b that are used for different
purposes to be determined by use of light reflected by FBGs 302 of
respective optical fiber sensors 215a,b.
[0091] Yet other embodiments are directed to methods involving
system components other than elongate instruments or catheters. For
example, referring to FIG. 12, other systems and associated methods
may involve determining one or more position and/or orientation
variables of an instrument driver 1200 that includes one or more
motors 1205 that can be actuated to controllably manipulate a
bendable distal end portion 211 of an elongate instrument or
catheter 210 (which may also have an optical fiber sensor 215
coupled thereto as illustrated) based on detected reflected light
signals 326 received from the respective FBGs 302 on the optical
fibers 215. FIG. 12 generally illustrates an output or readout
unit/controller 300/340 for ease of illustration, but may include
components such as a light source, detector, etc., as discussed
with reference to FIG. 3A and FIGS. 22A-C.
[0092] Referring to FIG. 13, in a further embodiment, optical fiber
sensors 215a,b are coupled to respective robotically controlled
catheter instruments 210a,b, which may carry or support other
devices or catheters such as an imaging device or imaging catheter
1102 and mapping catheter as discussed with reference to FIG. 11.
Additionally, in the illustrated embodiment, additional optical
fiber sensors 215c,d are coupled to controllers, anus or instrument
drivers 1200a,b that are used to control or manipulate the
respective catheters 210a,b. The arms, instrument drivers or
controllers 1200a,b are typically located outside of the patient's
body and, in one embodiment, the fiber sensors 215 are larger than
the fiber sensors 215 that are coupled to catheters or elongate
instruments 210a,b and advanced into the patient's body. For
example, fibers 215c,d that are located outside of a patient can
have a diameter of greater than 200 microns, e.g. about 500
microns, whereas fibers 215a,b for use within a patient may have a
diameter of about 150 microns. With this configuration, larger
diameter fibers 215c,d. can then have the individual cores spread
further apart which, may be utilized to increase the accuracy of
the measurements by increasing the difference in signal produced by
cross-sectionally opposing fibers. The larger diameter fibers
215c,d can accurately measure the location of the arm or driver
1200a,b, and the smaller diameter fibers 215a,b can measure from a
point where the larger diameter fiber 215c,d ends.
[0093] In another embodiment, referring to FIG. 14, other systems
and associated methods are directed to determining one or more
position and/or orientation variables of an image capture device
1400 based on light reflected 226 by Bragg gratings 302 on a Bragg
sensor optical fibers 215b coupled to or integral with the image
capture device 1400. Examples of image capture devices 1400 include
a fluoroscope, an optical camera, an infrared camera, an ultrasound
imager, a magnetic resonance imager, and a computer tomography
imager. In the illustrated embodiment, the catheter 210 and the
image capture device 1400 are advanced through an outer sheath 220
and include respective optical fiber sensors 215a,b, but other
system configurations may be utilized. A controller 340 may be
configured to determine one or more position and/or orientation
variables of the image capture device 1400 based on signals 326
received from Bragg gratings 302 on a fiber 215.
[0094] Referring to FIG. 15, other methods and systems are directed
to an optical fiber sensor 215 that is attached to a patient's body
1500, e.g. the chest 1505 of a patient 1500, using a patch or other
suitable adhesive. For example, a fiber sensor 215 may be coupled
to the patch that is applied to a patient 1502. Such embodiments
are useful for determining one or more position and/or orientation
variables of the patient's body 1500 to which an optical fiber
sensor 215 is attached based on signals reflected 226 by one or
more Bragg gratings 302.
[0095] This configuration allows for detection of an unexpected
movement of a patient 1500 based on signals received from the
respective FBGs 302, in response to which an output can be
generated for the system operator to allow the system operator to
adjust the catheter 210 within the patient 1500 as necessary,
temporarily suspend the procedure, or halt the procedure. Further,
such embodiments area also useful for generating an image of the
patient 1500 or such that an image of a patients body 1500 that is
displayed can be moved or adjusted according to the movement sensed
using the optical fiber sensor 215. Other methods may involve
coordinating diagnostic and/or therapeutic procedures on the
patient with the patient's respiration as determined by light
reflected 226 by one or more FBGs 302.
[0096] More particularly, as described above, it is desirable to
know where the patient 1500 and the anatomy are located in relation
to the catheters or elongate instruments 210. For example, if the
patient 1500 unexpectedly moves, a warning may be generated to
reposition the catheter 210 or other components. Thus an automatic,
semi-automatic or a manual feedback loop may be created based on
the position of the patient 1500. Embodiments provide for using a
shape and location measurement fiber 215 for patient 1500
monitoring. A key advantage of embodiments is that a single
technology (in this example a Bragg-grating fiber 215) may be used
for locating all the essential components of the environment,
although other localization technologies, such as electromagnetic
and potential-difference based localization technologies, may also
be used, depending upon the capabilities of the particular system
employed.
[0097] When navigating, or "driving", in static image-based
(preoperative or intraoperative) models, such as those created
utilizing modalities such as MRI and/or CT, it is advantageous to
register the model to the distal tip 211 of the elongate instrument
210; after such registration has been accomplished, if the patient
1500 moves, the registration relationship may be significantly
altered, requiring another registration unless embodiments as
illustrated in FIG. 15 are utilized. With embodiments, a patient
localization device which in one embodiment is an optical fiber
sensor 215 is used to understand the relative geometric/spatial
relationships of the instrument 210 components and patient 1500 in
real, or near-real, time, in which scenario registration may be
updated manually or automatically.
[0098] There are several ways to attach the optical fiber sensor
215 to the human body 1500. One method involves wrapping fiber
sensor 215 around the chest 1505 of the patient 1500. As discussed
above, another technique is to attach the fiber sensor 215 to a
patient patch, and applying the patient patch to the chest 1505 of
the patient 1500. As the fiber sensors 215 are very thin, the
images of the fibers 215 viewed via an image capture device 1400
such as a fluoroscope generally are not objectionable. Further, the
fiber sensor 215 may be attached to a radio-opaque marker (net
illustrated in FIG. 15) such that it is possible to see the markers
and associated fiber sensor 215 clearly in a fluoroscopic image. As
the exact location of the marker can also be determined by the
location measurement system of the fiber sensor 215, the location
of the marker can thus be known in two coordinate systems--the
coordinate system of the fluoroscopic imaging system 1400 and the
coordinate system of the shape and location measurement fiber
sensor 215. This permits a way to spatially associate the
coordinate system of the fiber sensor 215 with the coordinate
system of the imaging system 1400.
[0099] More particularly, in one embodiment, referring again to
FIG. 14, a shape and location measurement fiber 215 is coupled to
an external imaging device 1400 such as a fluoroscope. The
knowledge of the location of the fluoroscope 1400 is advantageous
for the combination display of the fluoroscopic image and the
virtual catheters and for aligning the coordinate systems of the
imaging system 1400, the fiber sensor 215 based device and the
robot or other control mechanism 1200. This is particularly true in
the embodiment wherein one has a fluoroscopy display driving to be
instructive to the operator.
[0100] Patient 1500 respiration may also he monitored with the
fiber 215 based measurement system. As the patient's chest 1505
moves with breathing, the optical fiber sensor 215 attached.
thereto also moves. These movements can be monitored, and this
information can then be fed back into the robotic navigation system
and may be used, for example, to accurately deliver therapy.
Elaborating on this example, in the situation in which the catheter
210 holds or supports an ablation catheter, ablation energy can be
delivered at the same point in the respiratory cycle or the
respiratory and cardiac cycle. This may improve the accuracy and
effectiveness of ablations.
[0101] Monitoring patient 1500 respiration and. movement can lead
to yet another advantage. In many electrophysiology procedures,
models of the inside of the heart 230 are built by various methods.
These models are quite distinct from images as a model is a
parametric representation of the heart 230. These models are often
stationary in that they do not contain any information about the
dynamics of the heart 230 or the dynamics of the patient 1500 such
as due to respiration. These models are used for navigation
purposes for example to navigate a catheter 210 inside of the heart
320. The availability of patient 1500 movement data such as via
respiration) though the use of a fiber sensor 215 or other
localization technique, advantageously enables compensation or
adjustment of the model.
[0102] Embodiments can also be utilized for purposes of
registration, or for spatial association of Objects and/or images.
Such registration may be continuous or semi-continuous, based on a
common reference or connected by a defined relationship. References
may also be connected by a defined relationship or associated
utilizing other imaging modalities.
[0103] As discussed above, in known minimally invasive procedures,
an elongate instrument 120 may be inserted within the body and an
imaging device such as a fluoroscopic system may be utilized to
image, or "visualize", the elongate instrument 120 or a portion
thereof, but a drawback of known fluoroscopic imaging systems is
that they are projection based--the depth information is lost and
therefore true three-dimensional location of objects such as an
elongate instrument in the field of view of the fluoroscope is
lost. However, with embodiments, an elongate instrument 210 has a
shape and location measuring fiber or optical fiber sensor 215 that
provides the three-dimensional location of specific locations in a
continuous or semi-continuous manner, thus allowing for automatic
registration. Locations of interest may be visualized with the
fluoroscope and spatially analyzed utilizing techniques such as
pattern, geometry, shape, movement, and/or marker recognition
(preferably with the help of radioopaque markers positioned upon
portions of the subject instrument, beacon transducers placed upon
the instrument for ultrasound pinging localization, or other
techniques to localize with fluoroscopy); such results then may be
processed in conjunction with the location information obtained
about these same locations from the fiber sensor 215 based
measurement device. Image information from the two techniques may
be utilized to make the images produced by each appropriately and
accurately associated with the other in three-dimensional
space.
[0104] A Bragg grating fiber sensor 215 based shape and
localization measuring device may be attached to one or more or all
of the key elements in an operating room environment including, for
example, a catheter 210 or other elongate instrument, to
controllers or instrument drivers 1200 that control the location of
the catheter 210, to the bed supporting the patient 1500, to the
patient 1500, and to an image capture device 1400 such as an
external imaging system, one example of which is a fluoroscopic
system. it is advantageous if all of the fiber sensors 215 in this
embodiment have a single common reference point or reference
coordinate system, preferably located as distally as possible
without compromising the mechanical behavior of the system (to
increase the effectiveness of common-mode error rejection analysis,
which may be applied, to light or data moving through the system of
localization fibers 215). This ensures that the coordinate system
for the devices and instruments and objects to which the fiber 215
based system is coupled are all similarly and precisely spatially
associated during registration.
[0105] Each fiber 215 may have its own reference point, and each
reference point may refer to a single coordinate system for
coordination. Different instruments may each have a fiber 215, and
in this case, and the relationship between different instruments
can be determined based on a fixed spatial relationship between
instruments, or if there is not a fixed spatial relationship, then
each fiber on each instrument may refer to the same coordinate
system, and data from the fibers can be used for an necessary
adjustments. Thus, with embodiments, the position and/or
orientation variables of a plurality of elongate instruments, each
of which includes an elongate instrument body having a Bragg sensor
optical fiber 215 coupled thereto, may be determined and registered
in a single reference coordinate system. The instrument bodies may
be coupled to a same or different structure in a known spatial
relationship, or coupled to a same or different structure in an
unknown spatial relationship. In the latter case, registration of
the instrument position and/or orientation variables of respective
instruments in a single reference coordinate system is accomplished
by maintaining a fixed distance between respective locations on the
instrument bodies.
[0106] Even if the references for all of the fiber sensors 215 are
not the same, in one embodiment there is a defined relationship
between the different references such that the relationship between
the different coordinate systems is accurately defined and may be
utilized to analyze the spatial relationships between coordinate
systems. For example, two references may be utilized for two fibers
215 attached to two devices, with the two references connected by a
stiff structural rod or member (or another device that prevents
relative movement between the reference points, or with other
devices to predictably understand the geometric/spatial
relationship between the two references) to prevent relative motion
between the references.
[0107] Other technologies such as an electromagnetic or
potential-difference-based localization, lasers or ultrasound (for
beaconing, shape/marker/pattern/etc. recognition, and/or
time-of-flight analysis to determine relative spatial positioning)
may be used to establish the absolute positions of each reference.
For example, an electromagnetic localization sensor may be placed
on each Bragg fiber 215 to obtain the three-dimensional coordinates
relative to a coordinate system established by the electromagnetic
localization system. The measurements provided by each fiber 215
all are consistent with each other as they all are referenced back
to a common reference.
[0108] Embodiments may also be utilized in procedures for
calibration instruments and tools in which the instrument or tool
includes an optical fiber sensor 215. While certain techniques for
calibration are known, embodiments provide apparatus and methods
for calibrating a robotically controlled elongate instrument
attached to one or more shape and location measuring fibers
215.
[0109] Initial calibration information can be Obtained utilizing
several techniques. In one method, measurement or observation of
properties and/or behaviors of the instrument having an optical
fiber sensor 215 and being calibrated are observed. Other methods
involve obtaining information from the design of the
localization/shape-sensing fiber 215, the elongate instrument 210,
or both. Yet other methods involve use of calibration or test
fixtures adapted for an instrument that includes an optical fiber
sensor 215.
[0110] Referring to FIG. 16, a calibration procedure 1600 according
to one embodiment includes positioning an instrument or tool in a
known geometric configuration at stage 1605. At stage 1610, a
sensed geometric configuration is determined based on signals or
light 326 received from the one or more Bragg gratings 302 of a
fiber sensor 215 while the instrument body 210 is in the known
geometric configuration. At stage 1615, the sensed geometric
configuration is compared with the known geometric configuration.
At stage 1620, if necessary, data representative of the comparison
is stored on a storage medium associated with instrument 210. The
storage medium may be, for example, a programmable device, a bar
code, a "RED" device, or a memory dongle, which may be positioned
within or coupled to the elongate instrument 210, a software of a
system component associated with the elongate instrument 210, or an
external device such as an external server, in which case retrieval
can be performed via a computer network. Thus, in one embodiment,
calibration of an instrument 210 that has an optical fiber position
sensor 215 includes performing a predetermined task with the
instrument 210, acquiring measurements or recording relevant
information, storing such information or derived information, and
retrieving such information for use in normal operation.
[0111] Referring to FIG. 17, a diagnostic or therapeutic procedure
11700 may be performed using the instrument calibrated as shown in
FIG. 16. At stage 1705, the instrument so calibrated is maneuvered
within a patient's body. At stage 1710, one or more sensed position
and/or orientation variables of the instrument are determined based
on signals received from the one or more FBGs 302 while the
instrument is in the patient's body. At stage 1715, the sensed
position and/or orientation variables are adjusted based on
calibration data, which may be stored in a storage medium.
[0112] The types of information that can be stored (for example,
upon a memory chip associated with or coupled to the elongate
instrument) as part of calibration include but are not limited to,
a diameter of a fiber 215 or fiber core 304, a position of a core
304 within a fiber 215, a position of fibers 215 within or coupled
to an elongate instrument 210 or other system component, a position
of each FBG 302 formed within the core 304, a reflectivity of each
FBG 302, thermal characteristics of the fiber 215, mechanical
properties of the fiber 215 including stiffness, offsets and gain,
and mechanical properties of the combination of the catheter 210
and fiber 215 coupled thereto, such as stiffness and position or
orientation dependent properties. Calibration information can be
stored in various places and devices including but not limited to,
a programmable device within or coupled to the elongate instrument
210, software of a system component associated with the elongate
instrument 210, an external device such as an external server in
which case retrieval can be via a computer network, a bar code, a
"RFID" device, or a memory dongle.
[0113] Initial calibration information for use in embodiments can
be obtained utilizing several methods. In one embodiment,
calibration of an elongate instrument 210 that includes an optical
fiber position sensor 215 coupled to a distal portion or tip 211
thereof involves driving the elongate instrument 210 to a known
position in a well-defined and characterized geometric fixture or
test structure. The operator then compares the reading from the
sensor 215 to the known position. The reading can thus be equated
to the known position.
[0114] FIG. 18 illustrates one embodiment of a test fixture 1800
and associated method that may be used during calibration
procedures in the illustrated embodiment, the test fixture 1800 is
made from a rigid material such as glass, plastic or another
material in which a calibration groove 1802 can be formed. In the
illustrated embodiment, the groove 1802 spans a quarter of a circle
or has a bend of about 90 degrees. The groove 1802 is configured to
accommodate a catheter 210 and an optical fiber sensor 215 coupled
thereto or integral therewith to ensure that the combination of the
catheter 210 and optical fiber sensor 215 can both bend with the
groove 1802, e.g., at about 90 degrees. The measurements from the
fiber 215 may be read for this section and any error may be
calibrated out,
[0115] In another embodiment, the rigid structure 1800 may define a
linear or straight groove rather than a groove 1802 at about a 90
degree bend as illustrated in FIG. 18. With this configuration,
similar to the embodiment described above, the linear groove is
configured to accommodate the catheter 210 and the optical fiber
sensor 215. During use, the combination of the catheter 210 and
fiber sensor 215 is positioned within the linear groove, and
readings from each FBG 302 are obtained using a detector or fiber
readout unit 330. This establishes a "zero" reading for the
combination of the catheter 210 and the optical fiber sensor 215
and corresponds to a linear or straight shape. Any other shape will
be measured relative to a zero shape.
[0116] However, a zero shape does not have to be a straight shape.
A zero shape could be any predefined arbitrary shape. A
non-straight zero shape may be desirable if, for example, a fiber
is integrated to a pre-bent catheter 210 (i.e., the natural shape
or the "home" shape of the catheter is not straight but bent).
[0117] Thus, a calibration process may involve placing the catheter
210 and localization/shape-sensing fiber 215 in a well-defined
rigid structure 1800 with a groove, sending light 322 Or other
appropriate energy) through the fiber 215, detecting light 226
reflected by one or more FBGs 302 within the fiber core 304,
obtaining strain values and calculating shape, storing the strain
values or some derived values in a storage device identifying this
as a "zero" shape.
[0118] Calibration procedures and related data can be based on each
individual device or a group of devices. For example, if it is
known that a certain group of elongate instruments 210 or fibers
215 has a certain type of property that effected the measurements
in certain ways, this information can become part of the
calibration information. From group to group, this information may
be different. When the catheter 210 is installed, the system can
read the serial number of the catheter 210 or some other form of
identification and the correct calibration values can be
utilized.
[0119] Embodiments may also be utilized in force calculation and
feedback applications. Various techniques may be utilized to
calculate force at the distal tip of the catheter 210 or other
instrument. One such method is described in U.S. patent application
Ser. No. 11/678,016, "Method of Sensing Forces on a Working
Instrument", filed Feb. 22, 2007, previously incorporated by
reference herein. A force applied upon an instrument may be
calculated by understanding the shape of the instrument with a load
applied and utilizing kinematic relationships of the instrument to
back out the presumed load applied to the instrument. The
calculated load may then be utilized for force feedback to the
operator techniques, such as haptics, on-screen displays, warnings
to the operator, etc. For example, in one embodiment, if the force
exceeds a certain value, then a warning message may he displayed or
other actions may be taken to prevent patient injury; yet another
alternative to this scheme is that the level when warnings or other
actions are initiated may he anatomy specific; for example, in the
ventricles where the walls are thicker, higher forces may be
applied without triggering an alarm or response.
[0120] As described in the incorporated references regarding
fiber-based Bragg diffraction localization, the location
measurement at the tip of the location measurement fiber 215
depends on component measurements obtained from each grating 302.
In practice, each grating 302 will contribute a finite amount of
error in measurement. The error at the tip is the sum of all
errors, i.e., errors are cumulative. It is thus advantageous to
maintain length from the tip to the origin, or the reference, or
from where the measurement must be taken, as small as possible.
However, the cores 304 of the optical fibers 215 may have numerous
gratings 302, and the number of gratings 302 may be more than what
is required between the tip and the origin. Thus, in one
embodiment, it is not necessary to include all of the gratings 302
for location measurements at the tip.
[0121] Referring to FIG. 19, in one embodiment, a data acquisition
and analysis software, which may, for example, reside in a
controller or associated memory of a computer, MID controller,
electronics rack or other suitable controller of a robotic
instrument system illustrated in FIGS. 22A-C), is configured to
pass over, disregard or ignore the first number N gratings 1902,
thereby placing the reference 1904 at the location of the
N+1.sup.th grating 302. In the illustrated embodiment, the first
two FBGs 302 are ignored, thereby placing the reference 1904 at the
third FBG 302, which is also at the beginning or proximal end of
catheter 210. This method will provide shapes and location
measurements relative to the location of the reference grating.
[0122] In other embodiments, systems and methods are directed to
using software executed by a controller 340 to select a reference
FBG 302, a measurement FBG 302 and/or a length or window of a FBG
302 to be measured or analyzed. For example, in one embodiment, the
location of a reference FBG 302 is fixed at a proximal end of a
catheter 210 as described above, and the location where the
measurement is to be performed, or the measurement FBG 302 to be
selected, is flexibly controlled via software such that the
selected measurement FBG 302 may change during the analysis.
Further, whichever FBG 302 is selected at a given time for
measurement, the controller 340 software can also be executed to
select the length of a selected measurement FBG over which the
measurement is to be performed. In this regard, the length or
window can be the entire length of a selected measurement FBG 302,
or the length or window may be a portion or segment thereof. For
example, about half of a measurement FBG 302 may he selected. for
measurement rather than the entire FBG 302. Embodiments may be
implemented using continuous, overlapping or partially overlapping
gratings 302.
[0123] If absolute location of the tip is needed, and if the first
N FBGs 1902 sensors are ignored as shown in FIG. 19, then another
independent method can be used to obtain the absolute or relative
position of the reference 1904. This independent method may be
another fiber 215 which has it tip at the location of the
N+1.sup.th FBG 302 on the first fiber 215 is, or it may be an EM
based sensor attached on the location of the N+1.sup.th FBG 302 or
some other device. In all of these cases, the absolute location of
the N+1.sup.th FBG 302 is measured or its relative location with
another absolute reference is measured.
[0124] Various systems and components may be utilized to implement
embodiments, and selection of a FBG 302 as a reference grating or a
measurement may be performed using hardware, software or a
combination thereof. Examples of systems and. components thereof
that may be used with or to implement embodiments are described in
further detail in U.S. Provisional Application Nos. 60/925,449 and
60/925,472, filed on Apr. 20, 2007, and U.S. application Ser. No.
12/106,254, filed on Apr. 18, 2008, the contents of which were
previously incorporated herein by reference.
[0125] Two fibers may be used for measuring twist, e.g. as
described in U.S. Patent Application No. 60/925,449, "Optical Fiber
Shape Sensing System", filed Apr. 20, 2007, previously incorporated
herein by reference. Two or more fibers 215, each of which has a
single core or multiple cores, may also be used to improve location
accuracy. If the geometric or spatial relationship between the
fibers 215 is known and invariant, then the independent location
measurements from each fiber 215 can be averaged together resulting
in improved signal to noise ratio and thereby result in improved
accuracy. This technique of improving accuracy works if the noise
in each measurement is independent of the noise in the other
measurements. However, for any measurement system such as the fiber
based measurement system, independent noise will exist. Invariance
in the location of the two fibers 215 may be obtained through
suitable design.
[0126] In many minimally invasive interventional systems, such as
those made by Hansen Medical, Mountain View, Calif., there exists a
disposable component (for example, a catheter) Which typically
enters a human body, and a non-disposable piece, which may, for
example, house the mechanisms to control the disposable component.
It may be through these controls that navigation of the disposable
component is achieved within the body. As described above,
according to one embodiment, the instrument 210 or may be coupled
to a shape and location measuring fiber 215. Consequently, the
connector(s) between the disposable and non-disposable components
are configured to accommodate the catheter 210 and the fiber
215.
[0127] Embodiments address mechanical aspects associated with use
of an optical fiber sensor 215 in robotic surgical components
including at the coupling point or interface prior to the fiber 215
exiting the instrument and allows for movement of a fiber 215
within the instrument. This is achieved by providing slack at the
proximal end since the distal end is typically positioned within
the body, and the fiber 215 would probably be constrained in some
fashion at the distal end. In this manner, embodiments address
connection issues involving the catheter or elongate instrument 210
flexing or bending by providing slack to the fiber 215 to prevent
breaking or excessive straining of the fiber 215. Such slack or
"service loop" can be introduced in various ways.
[0128] For example, referring to FIG. 20, in one embodiment, a
fiber 215 is shown entering a splayer 2000 through a wall or side
2005 and traversing a path through the splayer 2000 that provides
slack 2010. For ease of illustration and explanation, FIG. 20 is a
top view of the interior of a splayer 2000, and the catheter 120 is
not shown, but would be positioned to the left of the splayer 2000.
If the catheter 210 and fiber 215 move outwardly to the left, some
of this slack 2010 will be taken up or reduced. Slack 2010 may also
be provided in other ways and may be outside of the splayer
2000.
[0129] Embodiments address another issue related to the position of
the splayer 2000 in relation to the location of a FBG 302 (FBGs are
not illustrated in FIG. 20 for ease of illustration), e.g., a first
FBG 302(1), although not necessarily the first FBG 302, which
serves as a reference FBG 2020. In this embodiment, the reference
FBG 2020 is positioned such that its location is precisely known.
In this manner, the location of the reference FBG 2020 can be
precisely known and is suitable for fiber based location
measurement devices that depend on various small measurements that
start from or based on the reference. For example, the location of
a second. grating 302 is measured in relation to the first grating
302, the location of the third grating 302 is measured in relation
to the second grating 302, and so on. Thus if the absolute location
of the reference grating 2020 is not known in relation to some
coordinate system, then the absolute position of a second grating
302 or the position of a third grating 302 or any grating 302 that
is beyond the reference grating 2020 is not known.
[0130] In some cases, it may not be necessary to know the absolute
positions of the gratings 302; it may be only necessary to know the
relative location of the second, third and other gratings 302 in
relation to the reference grating 2020. in both of these cases
where the absolute position or the relative position is required,
it still is necessary to ensure that the reference grating 2020
does not move, or if it does move, that some adjustment or
accommodation is utilized to know the location of the reference
grating 2020.
[0131] As shown in FIG. 20, a fiber 215 is attached to a wall of
the splayer 2000, and a grating 302, e.g. a first grating, is
placed within the fiber 215 at this "reference" location. This
ensures that the reference grating 2020, the first grating in this
example, does not move relative to the wall of the splayer 2000.
Since the splayer 2000 is a rigid component, the location of the
reference grating 2020 is precisely known.
[0132] In an alternative embodiment, referring to FIG, 21, a long
first grating 2102 is provided. A portion of the grating 2102 is in
a rigidly placed sleeve 2104 (which is also rigid). A portion of
the grating 2102 is positioned within the sleeve 2104, and a
portion is positioned outside of the sleeve 2104. In certain
embodiments, a multi-core fiber 215 has multiple cores 304 that are
spaced around the neutral axis of the fiber 210. This arrangement
ensures that sections of the fiber cores 304 outside of the sleeve
2104 that are bent will experience a different strain compared to
sections of the cores 304 that are inside of the sleeve 2104 and
that are linear or straight. Reflected light 226 from this grating
2102 contains two peaks. A first peak occurs at a frequency
corresponding to the strain experienced by the portion of the
grating 2102 that is located outside of the sleeve 2104, and a
second peak occurs at a frequency corresponding to the strain
experienced by the portions of the grating 2102 that are located
inside of the sleeve 2104. The relative locations and the width of
the grating 2104 can be used to determine the exact position of the
reference sensor 2020.
[0133] Yet other embodiments involve apparatus and methods for
determining the position of the reference sensor or grating 2020.
External sensors, such as precision linear encoders,
electromagnetic localization sensors, or potential-difference-based
localization sensors may be attached at the location of the
reference sensor 2020. These sensors may then be utilized to
provide the location of the reference sensor 2020.
[0134] As described above, minimally-invasive interventional and/or
diagnostic systems often involve both disposable components (such
as a splayer 2000) and non-disposable components (such as a light
source or instrument driver). In such a system, the integrity of
the connection between the disposable component and a
non-disposable component should be high. For this purpose, an
integrity test can be performed by emitting light or a test signal
into the disposable component and analyzing the light reflected
there from. For example, the received signal 226 from each grating
302, particularly the first or reference grating 2020 may be
analyzed for various parameters, particularly for intensity. If the
intensity is low, then the connector may be bad or the connection
may not have been made properly. A warning can then be generated to
warn the operator to check the connection.
[0135] In a robotic surgical system that controls a minimally
invasive elongate instrument or catheter 210, it is important to
maintain the structural integrity of the instrument 210. If for
example, mechanisms that control the navigation of the elongate
instrument 210 break, then the controllability of the system lay be
compromised. To address these issues, in one embodiment, a fiber
215 is attached to an elongate instrument or catheter 210 to
monitor such mechanical breakages. As the fiber 210 based shape and
location measurement device is attached to the elongate instrument
or catheter 210, the shape of the instrument or catheter 210 can be
monitored. If the shape is anomalous in some way indicating a
breakage, then a warning is generated for the operator and the
procedure may be stopped manually or automatically.
[0136] Having described various apparatus and method embodiments in
detail, further details of a robotic surgical systems and
components thereof in which embodiments of the invention may be
implemented are described with reference to FIGS. 22A-26B, and
FIGS. 23A-B and 26A-B illustrate how embodiments of th.e invention
can be implemented and including various components of the robotic
surgical system described. A description a system and methods for
utilizing localization data for closed-loop control of a robotic
catheter system in which embodiments may be implemented is provided
with reference to FIGS. 22A-25F.
[0137] Referring to FIGS. 22A-F, one example of a robotic surgical
system 2200 in which embodiments of the invention that utilize an
optical fiber sensor 215 may be implemented includes an operator
work or control station 2205, which may be configured as, or
include control, processor or computer software and/or hardware,
which may perform various data processing functions on data from an
optical fiber sensor 215 and execute various processing and control
functions in response thereto.
[0138] The workstation 2205 is located remotely from an operating
table 2207, an electronics rack 2210, a setup joint mounting brace
2215, and motor-driven controller 1200 in the form an instrument
driver 2220. A surgeon or operator 2225 seated at the operator
workstation 2205 monitors a surgical procedure, patient 1500
vitals, and controls one or more flexible catheter assemblies that
may include a coaxially-associated instruments of an outer sheath
catheter 220, an inner axially-associated catheter 210 such as a
guide catheter, and a working instrument 240 such as a guidewire, a
pusher ablation catheter, a laser ablation fiber, a grasper, a
collapsible basket tool, etc., which is positioned within the
working lumen defined by the inner catheter 210.
[0139] Although the various components of the system 2200 are
illustrated in close proximity to each other, components may also
be separated from each other, e.g., in separate rooms. For example,
the instrument driver 2220, the operating table 2207 and a bedside
electronics box may be located in the surgical area, whereas the
operator workstation 2205 and the electronics rack 2210 may be
located outside of the surgical area behind a shielded partition.
System 2200 components may communicate with other components via a
network, thus allowing for remote surgery such that the surgeon
2225 may be in the same or different building or hospital site. For
this purpose, a communication link may be provided to transfer
signals between the operator control station 2205 and the
instrument driver 2220. Components may be coupled together via
cables 2230 as necessary for data communication. Wireless
communications may also be utilized.
[0140] Referring to FIG. 22B, one suitable operator workstation
2205 includes a console having one or more display screens 2232,
which r ay serve as display 340, a master input device (MID) 2234
and other components such as a touchscreen user interface 2236, and
data glove input devices 2238. The MID 2234 may be a
multi-degree-of-freedom device that includes multiple joints and
associated encoders. MID 2234 software may be a proprietary module
packaged with an off-the-shelf master input device system, such as
the Phantom.RTM. from SensAble Technologies, Inc., which is
configured to communicate with the Phantom.RTM. Haptic Device
hardware at a relatively high frequency as prescribed by the
manufacturer. Other suitable MIDs 2234 are available from suppliers
such as Force Dimension of Lausanne, Switzerland. The MID 2234 may
also have haptics capability to facilitate feedback to the
operator, and software modules pertinent to such functionality may
be operated on the master computer. An example of data glove
software 2244 is a device driver or software model such as a driver
for the 5DT Data Glove. In other embodiments, software support for
the data glove master input device is provided through application
drivers such as Kaydara MOCAP, Discreet 3D Studio Max, Alias Maya,
and SoftImage|XSI.
[0141] The instrument driver 2220 and associated flexible catheter
assembly and working instruments may be controlled by an operator
2225 via the manipulation of the MID 2234, data gloves 2238, or a
combination of thereof. During use, the operator 2225 manipulates a
pendant and MID 2234 to cause the instrument driver 2220 to
remotely control flexible catheters that are mounted thereon.
Inputs to the operator workstation 2205 to control the flexible
catheter assembly can entered using the MID 2223 and one or more
data gloves 2238. The MID 2234 and data gloves 2238, which may be
wireless, serve as user interfaces through which the operator 2225
may control the operation of the instrument driver 2220 and any
instruments attached thereto. It should be understood that While an
operator 2225 may robotically control one or more flexible catheter
devices via an inputs device, a computer or other controller 340 of
the robotic catheter system 2200 may be activated to automatically
position a catheter instrument 210 and/or its distal extremity 211
inside of a patient 1500 or to automatically navigate the patient
anatomy to a designated surgical site or region of interest.
[0142] Referring to FIG. 22C, a system architecture of a robotic
catheter system 2200 includes a controller 340 in the form of a
master computer 2241 that manages operation of the system 2200. The
master computer 2241 is coupled to receive user input from hardware
input devices such as a data glove input device 2238 and a haptic
MID 2234. The master computer 2241 may execute MID hardware or
software 2243, data glove software 2244 and other software such as
visualization software, instrument localization software, and
software to interface with operator control station buttons and/or
switches. Data glove software 2244 processes data from the data
glove input device 2238, and MID hardware/software 2243 processes
data from the haptic MID 2234. The master computer 2241 or another
computer or controller may also receive data from an optical fiber
sensor 215.
[0143] For example, in one embodiment, in response to the processed
inputs, e.g., in response to the data or analysis of such data of
detected reflected light signals 326 from the optical fiber sensor
215, the master computer 2241 processes instructions to instrument
driver computer 2242 to activate the appropriate mechanical
response from the associated motors and mechanical components of
the driver 2220 to achieve the desired response from the flexible
catheter assembly including a sheath 220 and catheter or elongate
instrument 210.
[0144] Further, in another embodiment, the master computer 2241 or
other suitable computer or controller may control actuation of the
at least one servo motor to activate the appropriate mechanical
response from the associated motors and mechanical components of
the driver 2220 to achieve the desired response from the flexible
catheter assembly including a sheath 220 and catheter or elongate
instrument 210 based at least in part upon a comparison of an
actual position the instrument derived from the localization data
to a projected position of the instrument derived from a kinematic
model of the instrument.
[0145] As a further example, in one embodiment, the master computer
2241 or another suitable computer may be configured to determine
patient respiration based on signals 326 received from respective
Bragg gratings 302 on the one or more Bragg sensor optical fibers
215. Thus, the master computer 2241 can coordinate control of one
or more instruments, such as a catheter, monitor one or more
instruments, and/or monitor a patient. For example, a controller or
computer 340 may be configured to determine one or more position
and/or orientation variables of an instrument driver 2220, an
instrument such as a catheter 210, and a patient's body based on
detected reflected light signals 326 received from the respective
Bragg gratings 302 on the different fibers 215.
[0146] In yet another embodiment, in response to the data or
analysis of such data of detected reflected light signals 326 from
the optical fiber sensor 215, a controller 340 or master computer
2241 may generate and display a graphical representation of an
instrument body such as a catheter 210 by depicting one or more
position and/or orientation variables thereof based. upon reflected
light signals 326 received from the one or more Bragg gratings
302.
[0147] Referring to FIG. 22D, an example of a setup joint,
instrument mounting brace or support assembly 2250 (generally
referred to as a support assembly 2250) that supports the
instrument driver 2220 above the operating table 2207 is an
arcuate-shaped structure configured. to position the instrument
driver 2220 above a patient 1500 lying on the table 2207 for
convenient access to desired locations relative to the patient
1500. The support assembly 2250 may also be configured to lock the
instrument driver 2220 into position. In this example, the support
assembly 2250 is mounted to the edge of a patient bed 2207 such
that an assembly including a catheter 210 mounted on the instrument
driver 2220 can be positioned for insertion into a patient 1500 and
to allow for any necessary movement of the instrument driver 2220
in order to maneuver the catheter assembly during a surgical
procedure.
[0148] As shown in FIGS. 22A, 22D, 22E and 22F, and as illustrated
in FIG. 2A, a flexible catheter assembly for use in embodiments
includes three coaxially-associated instruments including an outer
sheath catheter 220, an inner coaxially-associated catheter or
guide catheter 210, and a working instrument (not illustrated in
FIGS. 22A, 22D, 22E-F) such as a guidewire, pusher wire, ablation
catheter, laser ablation fiber, grasper, collapsible basket tool,
etc.--a myriad of small working tools may be utilized and
localized) positioned through the working lumen formed by the inner
catheter 210.
[0149] In the illustrated example, a splayer 2261 having one or
more control elements or pull wires and a flexible sheath member
220 having a central lumen. Similarly, a splayer 2262 located
proximally of the splayer 2261 for the catheter 210 has one or more
control elements or pull wires. The catheter instrument 210 has a
central lumen configured for passage of a working element or
instrument 240. Prior to use, the catheter 210 is inserted into the
sheath 220 such that these components are coaxially positioned.
Both splayers 2261, 2262 are mounted to respective mounting plates
on the instrument driver 2220, and the splayers 2261, 2262 are
controlled to manipulate the catheter and sheath instruments 210,
220.
[0150] In one embodiment, a system includes an elongate instrument
or catheter 210 having one or more control elements or pull wires
operatively coupled to at least one servo motor of the instrument
driver 2220 (e.g. as generally illustrated in FIGS. 12 and 13) such
that the instrument 210 moves in response to actuation of the at
least one servo motor. The optical fiber sensor 215 supplies
localization data indicative of a spatial position of at least a
portion of the instrument 210, and the controller 340 or other
system control element controls actuation of the at least one servo
motor in order to control movement of the instrument 210 based at
least in part upon a comparison of an actual position the
instrument 210 derived from the localization data to a projected
position of the instrument derived from, for example, a kinematic
model of the instrument 210.
[0151] As shown in various system figures, optical fiber sensors
215 can be coupled to or integral with various system components.
In certain embodiments, an optical fiber sensor 215 is coupled to
or integral with a catheter or elongate instrument 210 (e.g.,
within a lumen 213 or lumen 217), a sheath 220, the instrument
driver 2220, the patient's bed 2207, and/or attached to the patient
1500. For example, FIG. 22A illustrates an embodiment in which
optical fiber sensors 215 are coupled to two system components
(instrument driver 2200 and a bed or table 2207) and the patient
1500, and a catheter or other elongate instrument 210 may also
include an optical fiber sensor 215. For ease of illustration,
various figures Show an optical fiber sensor 215 and its associated
system component without associated connectors, etc.
[0152] FIGS. 23A-C illustrate an elongate catheter 210 in the form
of a sheath catheter 2302 through which another instrument such as
a guide catheter 2304 may extend. According to embodiments, optical
fiber sensors 215 can be coupled to or integral with the sheath
catheter 2302 and/or the guide catheter 2304, e.g., positioned
within a suitable lumen or extending through a wall of an
instrument. In the illustrated embodiment, the sheath catheter
includes multiple segments 2310(a-n) (generally segment 2310). Each
segment 2310 may be generally the same shape, e.g. round ring-like
structures, but may differ to some degree. Segments 2310 can also
be other shapes, e.g., square, rectangular, triangular, pentagonal,
hexagonal, octagonal, circular, spherical, elliptical, star, etc.
Pull wires 2320 are operably coupled to each segment 2310 and
extend through aligned passages, apertures or channels 2314 defined
by a wall of each segment 2310. For example, a pull wire 2320 may
be coupled to a distal most segment 2310 such that placing the pull
wire 2320 in tension also places more proximal segments 2310 in
tension. In another embodiment, the pull wires 2320 can be attached
to some or all of the segments 2310, e.g., attached to an exterior
surface of a segment 2310.
[0153] In certain embodiments, the wall of each segment 2310 can
also define an aperture 213 (as illustrated in FIG. 2) for an
optical fiber sensor 215. In this manner, control elements or pull
wires 2320 and optical fiber sensors 215 are advantageously routed
through the body or wall of segments 2320 rather than through an
inner or central lumen defined by a collection of segments 2320. In
this manner, embodiments advantageously reduce the components
extending through the inner or central lumen, thereby providing
more space through which other instruments and devices, such as a
guide catheter 2304 and/or working instrument 240 may be inserted.
Instruments can also be advanced through the sheath catheter 2302
more easily since the control elements 2320 and optical fiber
sensor 215 do not interfere with these components. In an
alternative embodiment, an optical fiber sensor 215 extends through
an inner or central lumen defined by the collection of segments
2320.
[0154] Individual segments 2320 of a sheath catheter 2302 having
shaped, interlocking top and bottom surfaces that allow segment
2320 to matingly engage adjacent segments 2320. In the illustrated
embodiment, each segment 2320 includes mating teeth or protrusions
2326 and notches or grooves 2328 that matingly engagement each
other such that interlocking segments 2320 are not rotatable
relative to each other. In this manner, aligned interlocking
segments 2320 collectively define a catheter or elongate body
structure 120 that defines a lumen that extends through the
plurality of segment 2320 bodies. While the figures illustrate a
structural configuration of one embodiment of a segment 2320, other
numbers and arrangements of teeth or protrusions 2326, notches or
grooves 2328 and apertures 2314, 213 for control elements 2320 and
optical fiber sensors 215 may be utilized. Further, individual
segments 2320 may have different numbers of teeth or protrusions
and notches depending on the need to provide additional stability,
support, and rigidity to the sheath catheter 2302 when the sheath
catheter 2302 is deployed.
[0155] With the sheath 2302 configuration illustrated, segments
2320 and be placed in tension to place the group of segments 2320
in tension or a rigid state, or placed in a relaxed, low tension or
flexible state. Thus, one embodiment of a catheter or elongate
instrument 120 in the form of a sheath catheter 2302 that may
include an optical fiber sensor has controllable rigidity and can
form a platform from which other instruments can extend and be
controlled and provide rigidity and resistance to twisting or
rotational loads on the sheath catheter 2302.
[0156] In addition to having an optical fiber sensor 215 as shown
in FIG. 23A, a reference sensor may also be coupled to the sheath
2302 proximate the distal end opening. With this configuration, one
or more position and/or orientation variables of the distal end
portions of the respective instrument bodies are determined
relative to the reference sensor.
[0157] With continuing reference to FIG. 23A, and with further
reference to FIGS. 24A-D, a rotatable apparatus 2330 is coupled to
the sheath catheter 2302 and provides greater degrees of freedom
and movement of a guide catheter 2304, an orientation platform 2340
and/or working instrument 240 coupled thereto or associated
therewith. A rotatable apparatus 2330 may include an interface or
wire guide apparatus 2331 and a rotatable collar, tool base or wire
receive apparatus 2332 which are rotatably coupled together. Thus,
a tool or other system component may be rotatably coupled to a
distal end portion of a medical instrument, such as a sheath or
guide catheter 2302, by manipulation of one or more control
elements 207 that extend through grooves formed within rotatable
apparatus 2330 to rotate the collar component 2332 clockwise (FIG.
24C) and counter-clockwise (FIG. 24D).
[0158] As shown in FIGS. 24A-D, outer surfaces of the interface and
collar components 2331, 2332 defines one or more guides, channels
or grooves 2402 that serve to guide, direct or route control
element 2320 (two control elements 2320a,b are illustrated). In the
illustrated embodiment, control elements 2302 wrap around a
substantial portion of the rotatable collar 2331 such that
manipulation of control elements 207 results in rotation of the
rotatable collar 2332. FIG. 23C further illustrates how various
control elements 207 may extend through a sheath catheter 2302 are
connected to different components. Thus, pulling or placing tension
on the control element 2320 rotates the collar 2332 and associated
instruments such as a guide catheter 2304 and working instrument
240, thereby advantageously providing rotational control as well as
articulation control of system components.
[0159] Referring to FIG. 23A, and with further reference to FIGS.
25A-F, an orientation platform 2340 of a robotic instrument system
is configured to control a working instrument 240 (one example of
which is illustrated) coupled to a distal end of a catheter
instrument 2304 or other instrument of a robotic medical system,
e.g., a sheath 220 covered catheter 210. In the illustrated,
example, the interface or platform 2340 includes a base member or
socket plate 2502 configured for coupling to a distal end of
catheter instrument member, a spacer element 2504 and another
socket plate or platform member 2506. The spacer element 2504 is
retained or interposed between, and separates, the base member 2502
and the platform member 2506. The platform member 2506 is movable
relative to the base member 2502 about the spacer element 2504. The
interface or platform 2506 also includes a control element 2320,
such as a pull wire, that extends through the catheter member,
through an aperture defined by the base member 2502, and
terminating at the platform member 2506. The platform 2340 may be
used to control an orientation of the platform ember 2506 and an
orientation of the working instrument 240 are controllably
adjustable by manipulation of the control member 2320.
[0160] Further aspects of system components illustrated in FIGS.
23A-25F are described in various applications previously
incorporated by reference.
[0161] FIG. 26A illustrates another manner in which embodiments may
be implemented in which multiple optical fiber sensors 215 are
coupled to or integral with multiple catheters coupled to
respective rotatable apparatus and orientation apparatus components
described above, and which are advanced through an outer or master
sheath 2600.
[0162] In the illustrated embodiment, each sheath catheter 2302 or
a sub-portion thereof is localized utilizing an optical fiber
sensor 215 which may be a Fiber Bragg Grating localization sensor.
Other system components, such as an image capture device 1400 (as
shown in FIG. 26B) may also be localized with an optical fiber
sensor 215. Further, similar to other embodiments discussed above,
other system components, such as an instrument driver 2220 and
patient bed 1500 may also have optical fiber sensors 215. With this
configuration, embodiments enable the entire environment (image
capture device, each flexible arm, the main proximal arm, etc.) to
be well characterized in near-real time, and the images from the
image capture device 1400, such as a fluoroscopy device, may be
appropriately associated with representations, cartoons and images
produced from the depicted devices. Thus, embodiments provide
apparatus and methods for combining or fusing a shape and
localization measuring fiber 215 and robotic surgical system
components.
[0163] Additionally, similar to apparatus and method embodiments
discussed above, optical fiber sensors 215 coupled to each system
component may provide for determining and displaying the
orientation and the roll of the tip of the elongate instruments.
This is particularly useful when planning surgery or placing
leads.
[0164] Further, as shown in FIGS. 26A-B, a common reference device,
or "control ring" 2602 is provided at the distal end of the master
sheath 2600 or sheath like structure that carries the elongate
instruments including sheath catheters 2302 and guide catheters
2304. This control ring 2602 can be used as a common reference for
all the fibers 215 on elongate instruments, image capture devices,
and the like which may extend distally from the control ring 2602
location. This common reference establishes a common coordinate
frame for all the fibers 215 such that the shape and location of
the fibers 215 may be measured in relation to the control ring
2602. This arrangement is particularly advantageous because the
accuracy at the tip will be high due to the short length of the
fiber 215 run, the twist and roll of the elongate instruments may
result in smaller errors since the distance between the control
ring 2602 and the tip is short, and the elongate instruments are
all in the same coordinate frame, which also improves accuracy
compared to use of different coordinate frames.
[0165] The location of the control ring 2602 may be localized in
the world coordinate system by a separate fiber 215 (single or
multiple core), which is helpful if elongate instruments, such as
catheters 2302, 2304, image capture device 1400 platforms, and the
like, which extend distally beyond the control ring 2602, are
coordinated with other external medical imaging or data processing
systems, such as fluoroscopy systems, magnetic resonance imaging
systems, or geometric and/or electronic mappings and datasets.
[0166] For embodiments in which multiple elongate instruments 2302
and/or 2304 carry single tools, a single elongate instrument
carries multiple tools, or multiple elongate instruments each carry
multiple tools, fiber based shape and location measurement devices
215 may be mechanically associated with each tool or each elongate
instrument or to both. It is not necessary that all tools or
elongate instruments have a fiber 215 attached or coupled thereto.
Each fiber 215 could be a single core Bragg grating sensor fiber or
a multiple core fiber Bragg grating sensor. More than one fiber may
be used per tool or per elongate instrument or catheter.
[0167] Accordingly, FIGS. 23A-C and 26A-B are provided to
illustrate different ways embodiments can be implemented. It should
he understood that an instrument may include other numbers of
sheath catheters 2302, other numbers of guide catheters 2304, and
that each catheter 210 having an optical fiber sensor 215 coupled
thereto may have fibers of various lengths, positions and
configurations.
[0168] Additionally, embodiments described above can be utilized
with various manually or robotically steerable instruments, various
localization systems and rendering of images to assist an operator,
including those systems and methods described in the aforementioned
patent application, U.S. application Ser. No. 11/637,951, the
contents of which were previously incorporated herein by reference.
FIGS. 27-43 are provided for reference and illustrate one example
of a localization system that utilizes localization data for
closed-loop control of a robotic catheter system in which
embodiments of the invention may be implemented, and FIGS. 44-49
are provided for reference and illustrate one example of user
interface presentation of captured or "cartoon" rendered images
that are used to assist the operator in controlling a robotic
catheter system or the like. Additional details regarding these
systems are omitted for clarity and described in further detail in
application Ser. No. 11/637,951. Embodiments may also utilize other
known localization and user interface presentation systems, and the
systems and related methods shown in FIGS. 27-43 are provided as
illustrative examples that may be used with embodiments.
[0169] FIGS. 27-37 depict various aspects of one embodiment of a
SimuLink.RTM. software control schema for an embodiment of a
physical system, with particular attention to an embodiment of a
"master following mode." In this system, an instrument is driven by
following instructions from a MID, and a motor servo loop
embodiment, which comprises key operational functionality for
executing upon commands delivered from the master following mode to
actuate the instrument.
[0170] FIG. 27 depicts a high-level view of an embodiment wherein
any one of three modes may be toggled to operate the primary servo
loop 2702. In idle mode 2704, the default mode when the system is
started up, all of the motors are commanded via the motor servo
block 2706 to servo about their current positions, their positions
being monitored with digital encoders associated with the motors.
In other words, idle mode 2704 deactivates the motors, while the
remaining system stays active. Thus, when the operator leaves idle
mode, the system knows the position of the relative components. In
auto home mode 2708, cable loops within an associated instrument
driver, such as the instrument driver 2220, are centered within
their cable loop range to ensure substantially equivalent range of
motion of an associated instrument, such as a catheter, in both
directions for a various degree of freedom, such as + and -
directions of pitch or yaw, when loaded upon the instrument driver.
This is a setup mode for preparing an instrument driver before an
instrument is engaged.
[0171] In master following mode 2710, the control system receives
signals from the master input device, and in a closed loop
embodiment from both a master input device and a localization
system, and forwards drive signals to the primary servo loop 2702
to actuate the instrument in accordance with the forwarded
commands. Aspects of this embodiment of the master following mode
2710 are depicted in further detail in FIGS. 32-37. Aspects of the
primary servo loop and motor servo block 2706 are depicted in
further detail in FIGS. 28-31.
[0172] Referring to FIG. 32, a more detailed functional diagram of
an embodiment of master following mode 2710 is depicted. As shown
in FIG. 32, the inputs to functional block 3202 are XYZ position of
the master input device in the coordinate system of the master
input device which, per a setting in the software of the master
input device may be aligned to have the same coordinate system as
the catheter, and localization XYZ position of the distal tip of
the instrument as measured by the localization system in the same
coordinate system as the master input device and catheter.
Referring to FIG. 33, for a more detailed view of functional block
3202 of FIG. 32, a switch 3302 is provided at block to allow
switching between master inputs for desired catheter position, to
an input interface 3304 through which an operator may command that
the instrument go to a particular XYZ location in space. Various
controls features may also utilize this interface to provide an
operator with, for example, a menu of destinations to which the
system should automatically drive an instrument, etc. Also depicted
in FIG. 33 is a master scaling functional block 3306 which is
utilized to scale the inputs coming from the master input device
with a ratio selectable by the operator. The command switch 3302
functionality includes a low pass filter to weight commands
switching between the master input device and the input interface
3304, to ensure a smooth transition between these modes.
[0173] Referring back to FIG. 32, desired position data in XYZ
terms is passed to the inverse kinematics block 3206 for conversion
to pitch, yaw, and extension (or "insertion") terms in accordance
with the predicted mechanics of materials relationships inherent in
the mechanical design of the instrument.
[0174] The kinematic relationships for many catheter instrument
embodiments may be modeled by applying conventional mechanics
relationships, in summary, a control-element-steered catheter
instrument is controlled through a set of actuated inputs. In a
four-control-element catheter instrument, for example, there are
two degrees of motion actuation, pitch and yaw, which both have +
and - directions. Other motorized tension relationships may drive
other instruments, active tensioning, or insertion or roll of the
catheter instrument. The relationship t, between actuated inputs
and the catheter's end point position as a function of the actuated
inputs is referred to as the "kinematics" of the catheter.
[0175] Referring to FIG. 38, the "forward kinematics" expresses the
catheter's end-point position as a function of the actuated inputs
while the "inverse kinematics" expresses the actuated inputs as a
function of the desired end-point position. Accurate mathematical
models of the forward and inverse kinematics are essential for the
control of a robotically controlled catheter system. For clarity,
the kinematics equations are further refined to separate out common
elements, as shown in FIG. 38. The basic kinematics describes the
relationship between. the task coordinates and the joint
coordinates. In such case, the task coordinates refer to the
position of the catheter end-point while the joint coordinates
refer to the bending (pitch and yaw, for example) and length of the
active catheter. The actuator kinematics describes the relationship
between the actuation coordinates and the joint coordinates. The
task, joint, and bending actuation coordinates for the robotic
catheter are illustrated in FIG. 39. By describing the kinematics
in this way we can separate out the kinematics associated with the
catheter structure, namely the basic kinematics, from those
associated with the actuation methodology.
[0176] The development of the catheter's kinematics model is
derived using a few essential assumptions. Included are assumptions
that the catheter structure is approximated as a simple beam in
bending from a mechanics perspective, and that control elements,
such as thin tension wires, remain at a fixed distance from the
neutral axis and thus impart a uniform moment along the length of
the catheter.
[0177] In addition to the above assumptions, the geometry and
variables shown in FIG. 40 are used in the derivation of the
forward and inverse kinematics. The basic forward kinematics
relates catheter task coordinates to joint coordinates, as
expressed in further detail in U.S. application Ser. No.
11/637,951. The actuator forward kinematics, relating the joint
coordinates to the actuator coordinates are also expressed in
application Ser. No. 11/637,951
[0178] As illustrated in FIG. 38, the catheter's end-point position
can be predicted given the joint or actuation coordinates by using
the forward kinematics equations described above. Calculation of
the catheter's actuated inputs as a function of end-point position,
referred to as the inverse kinematics, can be performed
numerically, using a nonlinear equation solver such as
Newton-Raphson. A more desirable approach, and the one used in this
illustrative embodiment, is to develop a closed-form solution which
can be used to calculate the required actuated inputs directly from
the desired end-point positions.
[0179] As with the forward kinematics, we separate the inverse
kinematics into the basic inverse kinematics, which relates joint
coordinates to the task coordinates, and the actuation inverse
kinematics, which relates the actuation coordinates to the joint
coordinates. The basic inverse kinematics, relating the joint
coordinates to the catheter task coordinates is expressed in
application Ser. No. 11/637,951. The actuator inverse kinematics,
relating the actuator coordinates to the joint coordinates is also
expressed in application Ser. No. 11/637,951.
[0180] Referring back to FIG. 32, pitch, yaw, and extension
commands are passed from the inverse kinematics block 3206 to a
position control block 3204 along with measured localization data.
FIG. 37 provides a more detailed view of the position control block
3204. After measured XYZ position data comes in from the
localization system, it goes through an inverse kinematics block
3702 to calculate the pitch, yaw, and extension the instrument
needs to have in order to travel to where it needs to be. Comparing
3704 these values with filtered desired pitch, yaw, and extension
data from the master input device, integral compensation is then
conducted with limits on pitch and yaw to integrate away the error.
In this embodiment, the extension variable does not have the same
limits 3706, as do pitch and yaw 3708. As will be apparent to those
skilled, in the art, having an integrator in a negative feedback
loop forces the error to zero. Desired pitch, yaw, and extension
commands are next passed through a catheter workspace limitation
block 3208, which may be a function of the experimentally
determined physical limits of the instrument beyond which
componentry may fail, deform undesirably, or perform unpredictably
or undesirably. This workspace limitation essentially defines a
volume similar to a cardioid-shaped volume about the distal end of
the instrument. Desired pitch, yaw, and extension commands, limited
by the workspace limitation block, are then passed to a catheter
roll correction block 3210.
[0181] This functional block is depicted in further detail in FIG.
34, and essentially comprises a rotation matrix for transforming
the pitch, yaw, and extension commands about the longitudinal, or
"roll", axis of the instrument--to calibrate the control system for
rotational deflection at the distal tip of the catheter that may
change the control element steering dynamics. For example, if a
catheter has no rotational deflection, pulling on a control element
located directly up at twelve o'clock should urge the distal tip of
the instrument upward. If, however, the distal tip of the catheter
has been rotationally deflected by, say, ninety degrees clockwise,
to get an upward response from the catheter, it may be necessary to
tension the control element that was originally positioned at a
nine o'clock position. The catheter roll correction schema depicted
in FIG. 34 provides a means for using a rotation matrix to make
such a transformation, subject to a roll correction angle, such as
the ninety degrees in the above example, which is input, passed
through a low pass filter, turned to radians, and put through
rotation matrix calculations.
[0182] In one embodiment, the roll correction angle is determined
through experimental. experience with a particular instrument and
path of navigation. In another embodiment, the roll correction
angle may be determined experimentally in-situ using the accurate
orientation data available from the preferred localization systems.
In other words, with such an embodiment, a command to, for example,
bend straight up can be executed, and a localization system can be
utilized to determine at which angle the defection actually
went--to simply determine the in-situ roll correction angle.
[0183] Referring briefly back to FIG. 32, roll corrected pitch and
yaw commands, as well as unaffected extension commands, are output
from the catheter roll correction block 3210 and may optionally be
passed to a conventional velocity limitation block 3212. Referring
to FIG. 35, pitch and yaw commands are converted from radians to
degrees, and automatically controlled roll may enter the controls
picture to complete the current desired position 3502 from the last
servo cycle. Velocity is calculated by comparing the desired
position from the previous servo cycle, as calculated with a
conventional memory block calculation 3506, with that of the
incoming commanded cycle. A conventional saturation block 3504
keeps the calculated velocity within specified values, and the
velocity-limited command 3506 is converted back to radians and
passed to a tension control block 3514.
[0184] Tension within control elements may be managed depending
upon the particular instrument embodiment, as described above in
reference to the various instrument embodiments and tension control
mechanisms. As an example, FIG. 36 depicts a pre-tensioning block
3602 with which a given control element tension is ramped to a
present value. An adjustment is then added to the original
pre-tensioning based upon a preferably experimentally-tuned matrix
pertinent to variables, such as the failure limits of the
instrument construct and the incoming velocity-limited pitch, yaw,
extension, and roll commands. This adjusted. value is then added
3604 to the original signal for output, via gear ratio adjustment,
to calculate desired motor rotation commands for the various motors
involved with the instrument movement. In this embodiment,
extension, roll, and sheath instrument actuation 3606 have no
pre-tensioning algorithms associated with their control, The output
is then complete from the master following mode functionality, and
this output is passed to the primary servo loop 2702.
[0185] Referring back to FIG. 27, incoming desired motor rotation
commands from either the master following mode 2710, auto home mode
2708, or idle mode 2704 in the depicted embodiment are fed into a
motor servo block 2706, which is depicted in greater detail in
FIGS. 28-31.
[0186] Referring to FIG. 28, incoming measured motor rotation data
from digital encoders and incoming desired motor rotation commands
are filtered using conventional quantization noise filtration at
frequencies selected for each of the incoming data streams to
reduce noise while not adding undue delays which may affect the
stability of the control system. As shown in FIGS. 30-31,
conventional quantization filtration is utilized on the measured
motor rotation signals at about 200 hertz in this embodiment, and
on the desired motor rotation command at about 15 hertz. The
difference 2804 between the quantization filtered values forms the
position error which may be passed through a lead filter, the
functional equivalent of a proportional derivative ("PD")+low pass
filter. In another embodiment, conventional PID, lead/lag, or state
space representation filter may be utilized. The lead filter of the
depicted embodiment is shown in further detail in FIG. 29.
[0187] In particular, the lead filter embodiment in FIG. 29
comprises a variety of constants selected to tune the system to
achieve desired performance. The depicted filter addresses the
needs of one embodiment of a 4-control element guide catheter
instrument with independent control of each of four control element
interface assemblies for +/-pitch and +/-yaw, and separate roll and
extension control. As demonstrated in the depicted embodiment,
insertion and roll have different inertia and dynamics as opposed
to pitch and yaw controls, and the constants selected to tune them
is different. The filter constants may be theoretically calculated
using conventional techniques and tuned by experimental techniques,
or wholly determined by experimental techniques, such as setting
the constants to give a sixty degree or more phase margin for
stability and speed of response, a conventional phase margin value
for medical control systems.
[0188] In an embodiment where a tuned master following mode is
paired with a tuned primary servo loop, an instrument and
instrument driver, such as those described above, may be "driven"
accurately in three-dimensions with a remotely located Master input
device. Other preferred embodiments incorporate related
functionalities, such as haptic feedback to the operator, active
tensioning with a split carriage instrument driver, navigation
utilizing direct visualization and/or tissue models acquired
in-situ and tissue contact sensing, and enhanced navigation
logic.
[0189] Referring to FIG. 39, in one embodiment, the master input
device may be a haptic master input device, such as those available
from SensAble Technologies, Inc., under the trade name
Phantoms.RTM. Haptic Devices, and the hardware and software
required for operating such a device may at least partially reside
on the master computer. The master XYZ positions measured from the
master joint rotations and forward kinematics are generally passed
to the master computer via a parallel port or similar link and may
subsequently be passed to a control and instrument driver computer.
With such an embodiment, an internal servo loop for a Phantoms.RTM.
Haptic Device generally runs at a much higher frequency in the
range of 1,000 Hz, or greater, to accurately create forces and
torques at the joints of the master.
[0190] Referring to FIG. 42, a sample flowchart of a series of
operations leading from a position vector applied at the master
input device to a haptic signal applied back at the operator is
depicted. A vector 4202 associated with a master input device move
by an operator may be transformed into an instrument coordinate
system, and in particular to a catheter instrument tip coordinate
system, using a simple matrix transformation 4204. The transformed
vector 4206 may then be scaled 4208 per the preferences of the
operator, to produce a scaled-transformed vector 4210. The
scaled-transformed vector may be sent to both the control and
instrument driver computer 4212 preferably via a serial wired
connection, and to the master computer for a catheter workspace
check 4214 and any associated vector modification 4216. This is
followed by a feedback constant multiplication 4218 chosen. to
produce preferred levels of feedback, such as force, in order to
produce a desired force vector 4220, and an inverse transform 4222
back to a force vector 4224 in the master input device coordinate
system for associated haptic signaling to the operator in that
coordinate system.
[0191] A conventional Jacobin may be utilized to convert a desired
force vector 4220 to torques desirably applied at the various
motors comprising the master input device, to give the operator a
desired signal pattern at the master input device. Given this
embodiment of a suitable signal and execution pathway, feedback to
the operator in the form of haptics, or touch sensations, may be
utilized in various ways to provide added safety and
instinctiveness to the navigation features of the system, as
discussed in further detail below.
[0192] FIG. 43 is a system block diagram including haptics
capability. As shown in summary form in FIG. 43, encoder positions
on the master input device, changing in response to motion at the
master input device, are measured 4302, sent through forward
kinematics calculations 4304 pertinent to the master input device
to get XYZ spatial positions of the device in the master input
device coordinate system 4306, then transformed 4308 to switch into
the catheter coordinate system and (perhaps) transform for
visualization orientation and preferred controls orientation, to
facilitate "instinctive driving".
[0193] The transformed desired instrument position 4310 may then be
sent down one or more controls pathways to, for example, provide
haptic feedback 4312 regarding workspace boundaries or navigation
issues, and provide a catheter instrument position control loop
4314 with requisite catheter desired position values, as
transformed utilizing catheter inverse 4316 kinematics
relationships for the particular instrument into yaw, pitch, and
extension, or insertion, terms 4318 pertinent to operating the
particular catheter instrument with open or closed loop
control.
[0194] As further reference, referring to FIG. 44, a systemic view
configured to produce an overlaid image is depicted. A known
fluoroscopy system 4402 outputs an electronic image in formats such
as those known as "S-video" or "analog high-resolution video". In
image output interface 4404 of a fluoroscopy system 4402 may be
connected to an input interface of a computer 4410 based image
acquisition device, such as those known as "frame grabber" 4412
image acquisition cards, to facilitate intake of the video signal
from the fluoroscopy system 4402 into the frame grabber 4412, which
may be configured to produce bitmap ("BMP") digital image data,
generally comprising a series of Cartesian pixel coordinates and
associated grayscale or color values which together may be depicted
as an image. The bitmap data may then be processed utilizing
computer graphics rendering algorithms, such as those available in
conventional OpenGL, graphics libraries 4414. In summary,
conventional OpenGL functionality enables a programmer or operator
to define object positions, textures, sizes, lights, and cameras to
produce three-dimensional renderings on a two-dimensional display.
The process of building a scene, describing objects, lights, and
camera position, and using OpenGL, functionality to turn such a
configuration into a two-dimensional image for display is known in
computer graphics as rendering. The description of objects may be
handled by forming a mesh of triangles, which conventional graphics
cards are configured to interpret and output displayable
two-dimensional images for a conventional display or computer
monitor, as would be apparent to one skilled in the art. Thus the
OpenGL software 4414 may be configured to send rendering data to
the graphics card 4416, which may then be output a conventional
display 4420.
[0195] A triangular mesh generated with OpenGL software may be used
to form a cartoon-like rendering of an elongate instrument moving
in space according to movements from, for example, a master
following mode operational state, may be directed to a computer
graphics card, along with frame grabber and OpenGL processed
fluoroscopic video data. Thus a moving cartoon-like image of an
elongate instrument would be displayable. To project updated
fluoroscopic image data onto a flat-appearing surface in the same
display, a plane object, conventionally rendered by defining two
triangles, may be created, and the updated fluoroscopic image data
may he texture mapped onto the plane. Thus the cartoon-like image
of the elongate instrument may be overlaid with the plane object
upon which the updated fluoroscopic image data is texture mapped.
Camera and light source positioning may be pre-selected, or
selectable by the operator through the mouse or other input device,
for example, to enable the operator to select desired image
perspectives for his two-dimensional computer display. The
perspectives, which may be defined as origin position and vector
position of the camera, may be selected to match with standard
views coming from a fluoroscopy system, such as anterior/posterior
and lateral views of a patient lying on an operating table. When
the elongate instrument is visible in the fluoroscopy images, the
fluoroscopy plane object and cartoon instrument object may be
registered with each other by ensuring that the instrument depicted
in the fluoroscopy plane lines up with the cartoon version of the
instrument. in one embodiment, several perspectives are viewed
while the cartoon object is moved using an input device such as a
mouse, until the cartoon instrument object is registered with the
fluoroscopic plane image of the instrument. Because both the
position of the cartoon object and fluoroscopic image object may be
updated in real time, an operator, or the system automatically
through image processing of the overlaid image, may interpret
significant depicted mismatch between the position of the
instrument cartoon and the instrument fluoroscopic image as contact
with a structure that is inhibiting the normal predicted motion of
the instrument, error or malfunction in the instrument, or error or
malfunction in the predictive controls software underlying the
depicted position of the instrument cartoon.
[0196] Referring back to FIG. 44, other video signals (not shown)
may be directed to the image grabber 4412, besides that of a
fluoroscopy system 4402, simultaneously. For example, images from
an intracardiac echo ultrasound ("ICE") system, intravascular
ultrasound ("IVUS"), or other system may be overlaid onto the same
displayed image simultaneously. Further, additional objects besides
a plane for texture mapping fluoroscopy or an elongate instrument
cartoon object may be processed using OpenGL or other rendering
software to add additional objects to the final display.
[0197] Referring to FIGS. 45A-B and 46, an elongate instrument is a
robotic guide catheter, and fluoroscopy and ICE are utilized to
visualize the cardiac and other surrounding tissues, and instrument
objects. Referring to FIG. 45A, a fluoroscopy image has been
texture mapped upon a plane configured to occupy nearly the entire
display area in the background. Visible in the fluoroscopy image as
a dark elongate shadow is the actual position, from fluoroscopy, of
the guide catheter instrument relative to the surrounding tissues.
Overlaid in front of the fluoroscopy plane is a cartoon rendering
(white in color in FIGS. 45A-B) of the predicted, or "commanded",
guide catheter instrument position. Further overlaid in front of
the fluoroscopy plane is a small cartoon object representing the
position of the ICE transducer, as well as another plane object
adjacent the ICE transducer cartoon object onto which the ICE image
data is texture mapped by a technique similar to that with which
the fluoroscopic images are texture mapped upon the background
plane object. Further, mouse objects, software menu objects, and
many other objects may be overlaid. FIG. 45A shows a similar view
with the instrument in a different position. For illustrative
purposes, FIGS. 45A-B depict misalignment of the instrument
position from the fluoroscopy object, as compared with the
instrument position from the cartoon object. As described above,
the various objects may be registered to each other by manually
aligning cartoon objects with captured image objects in multiple
views until the various objects are aligned as desired, image
processing of markers and shapes of various objects may be utilized
to automate portions of such a registration process.
[0198] Referring to FIG. 46, a schematic is depicted to illustrate
how various objects, originating from actual medical images
processed by frame grabber, originating from commanded instrument
position control outputs, or originating from computer operating
system visual objects, such as mouse, menu, or control panel
objects, may be overlaid into the same display.
[0199] Further, a pre-acquired image of pertinent tissue, such as a
three-dimensional image of a heart, may be overlaid and registered
to updated images from real-time medical imaging modalities as
well. For example, in one embodiment, a beating heart may be
preoperatively imaged using gated computed tomography (CT). The
result of CT imaging may be a stack of CT data slices. Utilizing
either manual or automated thresholding techniques, along with
interpolation, smoothing, and/or other conventional image
processing techniques available in software packages such as that
sold under the tradename Amira.RTM. product available from Mercury
Computer Systems of Chelmsford, Mass., a triangular mesh may be
constructed to represent a three-dimensional cartoon-like object of
the heart, saved, for example, as an object (".obj") file, and
added to the rendering as a heart object. The heart object may then
be registered as discussed above to other depicted images, such as
fluoroscopy images, utilizing known tissue landmarks in multiple
views, and contrast agent techniques to particularly see show
certain tissue landmarks, such as the outline of an aorta,
ventricle, or left atrium. The cartoon heart object may be moved
around, by mouse, for example, until it is appropriately registered
in various views, such as anterior/posterior and lateral, with the
other overlaid objects.
[0200] Referring to FIG. 47, a distributed system architecture
embodiment is depicted. A master control computer running a
real-time operating system, such as QNX, is connected to each of
the other computers in the system by a 1 gigabit Ethernet
"Real-time Network", and also by a 100 megabit Ethernet "System
Network", using a conventional high-speed switch. This enables
localized custom computing for various devices to be pushed locally
near the device, without the need for large cabling or a central
computing machine. In one embodiment, the master control computer
may be powered by an Intel.RTM. Xeon.RTM. processor available from
Intel Corporation of Santa Clara, Calif., the visualization
computer powered by a personal computer (PC) with a high-end
microprocessor based on the Intel architecture running Windows XP
and having multiple video cards and frame grabbers, the instrument
driver and master input device CPUs being PC or "EPIC" standard
boards with two Ethernet connections for the two networks. An
additional master input device, touchscreen, and console may be
configured into an addition operator workstation in a different
location relative to the patient. The system is very
expandable--new devices may be plugged into the switch and placed
onto either of the networks.
[0201] Referring to FIG. 47, two high resolution frame grabber
boards 4702 acquire images from two fluoro devices (or one in the
case of single plane fluoro), Which a nominal resolution frame
grabber board 4702 acquires images from an intracardiac echo
system. Such image data may be utilized for overlaying, etc., as
described in reference to FIGS. 44-46, and displayed on a display,
such as the #2 display, using a video card 4704 of the
visualization computer, as depicted. Heart monitor data, from a
system such as the Prucka CardioLab EP System distributed by GE
Healthcare of Waukesha, Wis., may be directly channeled from video
out ports on the heart monitor device to one of the displays. Such
data may also be acquired by a frame grabber. Similarly,
electrophysiological mapping and treatment data and images from
systems available from distributors such as Endocardial Solutions,
Biosense Webster, Inc., etc., may be directed as video to a
monitor, or data to a data acquisition board, data bus, or frame
grabber. Preferably the master control computer has some interface
connectivity with the electrophysiology system as well to enable
single master input device driving of such device, etc.
[0202] Referring to FIG. 48, a depiction of the software and
hardware interaction is depicted. Essentially, the master state
machine functionality of the master control system real-time
operating system allows for very low latency control of processes
used to operate master input device algorithms and instrument
driver algorithms, such as those described in reference to the
control systems description above. Indeed, XPC may be utilized to
develop algorithm code, but preferably a universal modeling
language such as IBM Rational Rose from IBM Corporation of Armonk,
N.Y., or Rhapsody of I-Logix of Andover, Mass., is utilized to
build code and documentation using a graphical interface. With the
gigabit real-time network, in a matter of 200-300 microseconds, the
master input device or instrument driver algorithms are able to
communicate with FPGA driver code in the electronics and hardware
near the pertinent device to exchange new values, etc., and confirm
that all is well from a safety perspective. This leaves
approximately 700 microseconds for processing if a 1 millisecond
motor shutoff time is required if all is not well--and this is
easily achievable with the described architecture. The
visualization PC may be configured to cycle data from the master
control computer at a lower frequency, about 200 milliseconds. FIG.
49 illustrates the software interaction of one embodiment.
[0203] Although particular embodiments have been shown and
described, it should he understood that the above discussion is not
intended to limit the scope of these embodiments. While embodiments
and variations of the many aspects of the invention have been
disclosed and described herein, such disclosure is provided for
purposes of explanation and illustration only. Many combinations
and permutations of the disclosed embodiments are useful in
minimally invasive surgery, and the system is configured to be
flexible for use with other system components and in other
applications. Thus, various changes and modifications may be made
without departing from the scope of the claims.
[0204] For example, although embodiment are described with
reference to a telemanipulation system or robotic control system,
embodiments may also be manually controlled by a surgeon, e.g.,
near the proximal section of the sheath catheter Embodiments are
advantageously suited for minimally invasive procedures, they may
also be utilized in other, more invasive procedures that utilize
extension tools and may be used in surgical procedures other than
treatment of arrhythmias such as atrial fibrillation.
[0205] Further, although embodiments are described, with reference
to a fiber or fiber sensor coupled to or integral with a catheter,
embodiments may also involve a fiber or fiber sensor coupled to or
integral with a sheath, multiple catheters or other elongate
instruments, e.g., that extend through a sheath, a working
instrument, and other system components such as an a localization
sensor, an instrument driver, a patient's bed, a patient, and
combinations thereof. Further, such fibers may be positioned within
an elongate instrument or coupled to or integral with an outer
surface thereof.
[0206] Moreover, depending on the configuration of a system and
system components, a "controller" may be or include a unit coupled.
to a fiber, may be, or include, a computer or processor of a
robotic instrument system (e.g., in an electronics rack or at a
user workstation), or a combination thereof. Further, a unit that
sends and/or receives light may be a separate component or
integrated within a controller component of a robotic instrument
system. Thus, a "controller" may be a standalone or integrated
component or include multiple components that are operably coupled
together.
[0207] Further, it should be understood that embodiments of an
optical fiber sensor and apparatus, system and methods including or
involving the same may be used in various applications and be
configured in various different ways. For example, they may be
coupled to or integral with various system components intended for
insertion into a patent and that are intended for external use.
Optical fiber sensors may also include various numbers of FBGs,
which may be of the same or different wavelengths, and may be
arranged in different ways. Further, various optical systems can be
used with embodiments, and the exemplary components and read out
system are provided as one example of how embodiments may be
implemented.
[0208] Because one or more components of embodiments may be used in
minimally invasive surgical procedures, the distal portions of
these instruments may not be easily visible to the naked eye. As
such, embodiments of the invention may be utilized with various
imaging modalities such as magnetic resonance (MR), ultrasound,
computer tomography (CT), X-ray, fluoroscopy, etc. may be used to
visualize the surgical procedure and progress of these instruments.
It may also be desirable to know the precise location of any given
catheter instrument and/or tool device at any given moment to avoid
undesirable contacts or movements. Thus, embodiments may be
utilized with localization techniques that are presently available
may be applied to any of the apparatuses and methods disclosed
above, Further, a plurality of sensors, including those for sensing
patient vitals, temperature, pressure, fluid flow, force, etc., may
be combined with the various embodiments of flexible catheters and
distal orientation platforms.
[0209] Various system components including catheter components may
be made with materials and techniques similar to those described in
detail in U.S. patent application Ser. No. 11/176,598, incorporated
by reference herein in its entirety. Further, various materials may
be used to fabricate and manufacture sheath catheter segment,
rotatable apparatus and orientation platform devices. For example,
it is contemplated that in addition to that disclosed above,
materials including, but not limited to, stainless steel, copper,
aluminum, nickel-titanium alloy (Nitinol), Flexinol.RTM. (available
from Toki of Japan), titanium, platinum, iridium, tungsten,
nickel-chromium, silver, gold, and combinations thereof, may be
used to manufacture components such as control elements, control
cables, segments, gears, plates, hall units, wires, springs,
electrodes, thermocouples, etc. Similarly, non-metallic materials
including, but not limited to, polypropylene, polyurethane
(Pebax.RTM.), nylon, polyethylene, polycarbonate, Delrin.RTM.,
polyester, Kevlar.RTM., carbon, ceramic, silicone, Kapton.RTM.
polyimide, Teflon.RTM. coating, polytetrafluoroethylene (PTFE),
plastic (non-porous or porous), latex, polymer, etc. may be used to
make the various parts of a catheter, orientation platform, tool,
etc.
[0210] Additionally, certain system components are described as
having lumens that are configured for carrying or passage of
control elements, control cables, wires, and other catheter
instruments. Such lumens may also be used to deliver fluids such as
saline, water, carbon dioxide, nitrogen, helium, for example, in a
gaseous or liquid state, to the distal tip. Further, some
embodiments may be implemented with an open loop or closed loop
cooling system wherein a fluid is passed through one or more lumens
in the sidewall of the catheter instrument to cool the catheter or
a tool at the distal tip.
[0211] Further, embodiments may be utilized with various working
instruments including end effectors including, for example, a
Kittner dissector, a multi-fire coil tacker, a clip applier, a
cautery probe, a shovel cautery instrument, serrated graspers,
tethered graspers, helical retraction probe, scalpel, basket
capture device, irrigation tool, needle holders, fixation device,
transducer, and various other graspers. A number of other catheter
type instruments may also be utilized together with certain
embodiments including, but not limited to, a mapping catheter, an
ablation catheter, an ultrasound catheter, a laser fiber, an
illumination fiber, a wire, transmission line, antenna, a dilator,
an electrode, a microwave catheter, a cryo-ablation catheter, a
balloon catheter, a stent delivery catheter, a fluid/drug delivery
tube, a suction tube, an optical fiber, an image capture device, an
endoscope, a Foley catheter, Swan-Ganz catheter, fiberscope, etc.
Thus, it is contemplated that one or more catheter instruments may
be inserted through one or more lumens of a flexible catheter
instrument, flexible sheath instrument, or any catheter instrument
to reach a surgical site at the distal tip. Similarly, it is
contemplated that one or more catheter instruments may be passed
through. an orientation platform to a region of interest.
[0212] While multiple embodiments and variations of the many
aspects of the present disclosure have been disclosed and described
herein, such disclosure is provided for purposes of illustration
only. Many combinations and permutations of the disclosed system
are useful in minimally invasive medical intervention and
diagnosis, and the system is configured to be flexible. The
foregoing illustrated and described embodiments of the present
disclosure are susceptible to various modifications and alternative
forms, and it should be understood that the present disclosure
generally, as well as the specific embodiments described herein,
are not limited to the particular forms or methods disclosed, but
also cover all modifications, equivalents and alternatives.
Further, the various features and aspects of the illustrated
embodiments may be incorporated into other embodiments, even if no
so described herein, as will be apparent to those skilled in the
art.
* * * * *