U.S. patent application number 15/727266 was filed with the patent office on 2018-02-22 for system and method for robotic surgical intervention in a magnetic resonance imager.
The applicant listed for this patent is UNIVERSITY OF MASSACHUSETTS, WORCESTER POLYTECHNIC INSTITUTE. Invention is credited to Gregory A. Cole, Gregory S. Fischer, Julie G. Pilitsis.
Application Number | 20180049826 15/727266 |
Document ID | / |
Family ID | 43781104 |
Filed Date | 2018-02-22 |
United States Patent
Application |
20180049826 |
Kind Code |
A1 |
Fischer; Gregory S. ; et
al. |
February 22, 2018 |
SYSTEM AND METHOD FOR ROBOTIC SURGICAL INTERVENTION IN A MAGNETIC
RESONANCE IMAGER
Abstract
A system and method for image guided assisted medical procedures
using modular units, such that a controller, under the direction of
a computer and imaging device, can be utilized to drive and track
low cost, purpose specific manipulators. The system utilizes
modular actuators, self tracking, and linkages. The systems can be
optimized at a low cost for most effectively performing surgical
procedures, while reusing the more costly components of the system,
e.g. the control, driving, and tracking systems. The system and
method may utilize MRI real time guidance during the above
procedures.
Inventors: |
Fischer; Gregory S.;
(Jamaica Plain, MA) ; Cole; Gregory A.;
(Worcester, MA) ; Pilitsis; Julie G.; (Albany,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WORCESTER POLYTECHNIC INSTITUTE
UNIVERSITY OF MASSACHUSETTS |
Worcester
Boston |
MA
MA |
US
US |
|
|
Family ID: |
43781104 |
Appl. No.: |
15/727266 |
Filed: |
October 6, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12873152 |
Aug 31, 2010 |
9844414 |
|
|
15727266 |
|
|
|
|
61238405 |
Aug 31, 2009 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2090/374 20160201;
A61B 2034/301 20160201; A61B 34/30 20160201 |
International
Class: |
A61B 19/00 20060101
A61B019/00 |
Claims
1. A modular system for image guided assisted medical procedure,
the system comprising: a manipulator for a specific medical
procedure; a controller connected to said manipulator and directing
at least one motion thereof, said controller also capable of
directing at least one other manipulator; an imaging device
enabling visualization of a tissue at said specific medical
procedure; and a computer connected to said imaging device and said
controller, wherein the computer collects and processes images from
said imaging device and instructs said controller to direct said
manipulator.
2. The system of claim 1, wherein said medical procedure is a
surgical procedure.
3. The system of claim 2, wherein said surgical procedure is a deep
brain stimulation procedure.
4. The system of claim 2, wherein said surgical procedure is
performed in the presence of an MRI scanner.
5. The system of claim 4, wherein at least part of the surgical
procedure is performed within the MRI scanner.
6. The system of claim 5, wherein interactively updated MRI images
are used to guide the image guided assisted system.
7. A modular system for image guided robotic assisted medical
procedure, the system comprising: a manipulator for performing a
deep brain stimulation procedure; a controller connected to said
manipulator and directing at least one motion thereof, said
controller also capable of directing at least one other
manipulator; an imaging device enabling visualization of a tissue
at said deep brain stimulation procedure; and a computer connected
to said imaging device and said controller, wherein the computer
collects and processes images from said imaging device and
instructs said controller to direct said manipulator.
8. The system of claim 7, wherein the imaging device is an MRI
scanner.
9. The system of claim 8, wherein the manipulator is designed to
operate in the MRI environment.
10. The system of claim 9, wherein the manipulator is designed to
operate with a minimal degradation of MRI image quality.
11. A method for image guided robotic assisted medical procedure,
the method comprising: identifying an area of a body for a medical
procedure; defining at least one motion of an instrument, said at
least one motion being required for performing the medical
procedure; assembling a manipulator adapted for said medical
procedure, said assembling comprising identifying linkages for
performing said at least one motion, and selecting actuators and
sensors for connecting to said linkages for controlling movements
thereof; and connecting said manipulator to a controller capable of
directing said manipulator, said controller also capable of
directing at least one other manipulator.
12. The method of claim 11, wherein the medical procedure is deep
brain stimulation lead placement.
13. The method of claim 11, wherein the manipulator encompasses an
actuator module and an end effector.
14. The method of claim 11, wherein at least part of the
manipulator is application specific.
15. The method of claim 14, wherein at least part of the
manipulator is patient specific.
16. The method of claim 11, wherein the method is designed to
operate in an MRI scanner environment.
Description
CROSS-REFERENCE
[0001] This application is a continuation application of U.S.
non-provisional application Ser. No. 12/873,152, filed Aug. 31,
2010, entitled "SYSTEM AND METHOD FOR ROBOTIC SURGICAL INTERVENTION
IN A MAGNETIC RESONANCE IMAGER", naming Gregory S. Fischer, Gregory
A. Cole and Julie G. Pilitsis as the inventors, which claims
priority to and the benefit of U.S. provisional application No.
61/238,405, filed Aug. 31, 2009, the contents of both of which are
incorporated herein by reference.
FIELD OF INVENTION
[0002] The present teachings relate generally to the field of
guidance equipment and, more particularly, to equipment that is
used to aid in the accurate guidance of surgical tools and/or
sensors to locations in the human body.
BACKGROUND
[0003] While the field of image guided surgical robotic assistance
is still in its infancy, it is expanding rapidly. The benefit of
image guided robotically assisted surgery is fairly clear: the
combination of computer controlled precision movement and high
resolution soft tissue imaging allows the surgeon to accomplish the
procedural goals with minimized damage to surrounding tissue. There
are many organizations across the globe developing imaging
compatible systems of, though currently few are on the market. Most
research facilities are either attempting to rebuild general
purpose serial manipulators for imaging compatibility, or
developing single purpose units to perform a multitude of tasks on
a single area of the body.
[0004] Stereotactic neural intervention is a commonly practiced
surgical procedure today. There are many treatments and operations
that require the accurate targeting of, and intervention with, a
specific area of the brain which utilize stereotactic neural
intervention. One common use of this procedure is Deep Brain
Stimulation (DBS), which is often used for the treatment of
Parkinson's Disease.
[0005] Magnetic resonance imaging (MRI) compatible systems have
been developed, though they typically manually driven, bulky and/or
inconvenient to use. There are systems for specific procedures such
as DBS therapy, though those systems are inconvenient to use and/or
lack accuracy due to the lack of real time image guidance.
[0006] DBS is a technique for influencing brain function through
the use of implanted electrodes. Direct magnetic resonance (MR)
image guidance during DBS insertion would provide many benefits;
most significantly, interventional MRI can be used for planning,
real-time monitoring of tissue deformation, insertion, and
placement confirmation. The accuracy of standard stereotactic
insertion is limited by registration errors and brain movement
during surgery. With real-time acquisition of high-resolution MR
images during insertion, probe placement can be confirmed
intraoperatively. Direct MR guidance has not taken hold because it
is often confounded by a number of issues including: MR
compatibility of existing stereotactic surgery equipment and
patient access in the scanner bore. The high resolution images
required for neurosurgical planning and guidance require high-field
MR (1.5-3T); thus, any system must be capable of working within the
constraints of a closed, long-bore diagnostic magnet. Currently, no
technological solution exists to assist MRI guided neurosurgical
interventions in an accurate, simple, and economical manner.
[0007] Currently, a typical DBS placement procedure is comprised of
the following events: [0008] 1. Patient arrives at hospital for
pre-procedure MRI scan. [0009] 2. Surgeons analyze the patient's
images, and produces a surgical plan. [0010] 3. Patient returns to
the hospital where a stereotactic surgical frame is attached to the
skull in the operating room. [0011] 4. A computed tomography (CT)
scan is taken of the patient with the frame to register the
surgical plan to the frame. [0012] 5. The surgical frame is
manually aligned and used to guide a drill for drilling the burr
holes to gain access to the cranial cavity. [0013] 6. The surgical
frame is used to guide the placement of electrodes through the burr
hole. [0014] 7. Some form of placement confirmation is utilized
(often micro electrode recordings, fluoroscopy, or computed
tomography.) [0015] 8. Often the procedure is repeated for
bilateral insertion of a second electrode. [0016] 9. Patient is
sent to recovery.
[0017] This process has been used for several decades, though
tissue deformation can cause registration errors between the
preoperative images used to create the surgical plan, and the state
of the patients anatomy during the procedure. These errors can lead
to a host of negative side effects including: reduced effectiveness
of the DBS equipment, unwanted neurological changes (mood shift,
chronic gambling), brain injury, brain hemorrhage, etc.
[0018] This procedure has several other drawbacks, such as the
following: [0019] during the time between when the surgical plan is
generated and the procedure occurs, there is a possibility of soft
tissue shift within the patient, causing inaccurate placement of
electrodes; [0020] when the cerebrospinal fluid drains after the
first burr hole is drilled, there is another possibility of soft
tissues shift; [0021] for some applications of DBS, micro electrode
recordings cannot be used for placement confirmation due to a high
possibility of causing brain damage; [0022] shifts in soft tissue
increase the risk of a blood vessel being moved into the surgical
path, which could cause brain hemorrhage; and [0023] electrode
insertion itself will cause tissue deformation as it is being
inserted into the operative area.
[0024] Therefore, it would be beneficial to have a superior system
and method for performing a plurality of robotic surgical
interventions utilizing real-time MM imaging.
SUMMARY
[0025] The needs set forth herein as well as further and other
needs and advantages are addressed by the present embodiments,
which illustrate solutions and advantages described below.
[0026] The system of the present invention is based on embodiments
which use modular units, such that a controller can be utilized to
drive and track low cost, purpose specific manipulators. The system
utilizes modular actuators, self tracking, and linkages constructed
from, for example, but not limited to, hard image compatible
plastics that are not ferro magnetic, although under other
circumstances such as, where magnetics are not utilized, ferro
magnetic material may be used. Therefore, the system can be
optimized at a low cost for most effectively performing a plurality
of individual surgical procedures, while reusing the more costly
components of the system, e.g. the control, driving, and tracking
systems.
[0027] In one embodiment the system comprises a manipulator linkage
which targets DBS electrode placement and allows the procedure to
be performed based on interactively updated MRI images.
Alternatively, the system may be used to perform the procedure
based almost entirely on pre operative images in a manner similar
to the typical approach in the operating room. The system is a safe
and reliable electrode placement assistant that overcomes the
difficulties of working in a closed high-field MRI. The objective
of the system, but is not limited to, enables registering and
placing electrodes within the brain under image guidance with half
millimeter accuracy. The system reduces procedure time, cost, and
complications while improving effectiveness and availability.
[0028] The method of the present embodiment includes, but is not
limited to, MRI-compatible self-positioning stereotactic surgical
guidance that bridges the gap between high resolution imaging
modalities and interventional procedures that utilize them for
planning purposes.
[0029] Further embodiments are used to facilitate MRI guided
insertion of electrodes for deep brain stimulation under live
imaging. The embodiments comprise a central controller or
controller, and actuated manipulator or armature, and a user
workstation. The controller of the system contains a computing unit
that can process sensor information from the actuated armature as
well as generate driving signals to operate the armatures'
actuators. Additionally, the central control unit communicates with
a user workstation which combines position information from the
armature with scanner images in order to register the armatures
position within the imaging space, and allow the user to generate
position commands for the robotic manipulator.
[0030] The method for the design of all of these components has
generated a system which produces minimal degradation (that is,
almost no visually identifiably interference) on MRI image quality.
The modular system is designed to be able to use a wide variety of
procedure specific mechanism, with the same controller so that the
mechanism can have numerous, limited degrees of freedom and more of
the system is precision mechanically constrained. The workstation
may register the position of the robotic manipulator relative to
the scanner and the patient, at which point the operator may
develop or import a surgical plan to interact with the desired
intervention points. Once the plan is developed, the operator may
perform the procedure under live or real-time imaging guidance.
[0031] Thus, the embodiments provide for a modular system for image
guided robotic assisted medical procedures. The embodiments of the
system comprises a manipulator for a specific medical procedure, a
controller, an imaging device and a computer. The controller of the
system is connected to the manipulator. The controller directs at
least one motion of the manipulator. The controller is also capable
of directing at least one other manipulator. The imaging device of
the system enables visualization of a tissue at the specific
medical procedure. The computer of the system is connected to the
imaging device and the controller. The computer collects and
processes images from the imaging device and instructs the
controller to direct the manipulator. The system of the present
invention can also be used when the medical procedure is a surgical
procedure. The surgical procedure can be, but is not limited to, a
deep brain stimulation procedure.
[0032] The embodiments also provide for a method for image guided
robotic assisted medical procedures. The method comprises
identifying an area of a body for a medical procedure. The method
also comprises defining at least one motion of an instrument, this,
at least one motion, is required for performing the medical
procedure. The method further comprises assembling a manipulator
which can be used for the medical procedure. Assembling of the
manipulator comprises identifying linkages for performing the above
at least one motion, and selecting actuators and sensors for
connecting to the linkages. The actuators and sensors are used for
controlling movements of the linkages. The method even further
comprises connecting the manipulator to a controller which is
capable of directing the manipulator. The controller is also
capable of directing at least one other manipulator.
[0033] Other embodiments of the system and method are described in
detail below and are also part of the present teachings and can
include work with various other body parts such as, but not limited
to; prostates, lungs, breasts, hearts, limbs such as knees, hips
and the like.
[0034] For a better understanding of the present embodiments,
together with other and further aspects thereof, reference is made
to the accompanying drawings and detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIGS. 1A and 1B block diagrams illustrating a design of the
system architecture;
[0036] FIG. 2 is a flowchart illustrating a method of the
system;
[0037] FIG. 3 is a flowchart illustrating a method of using the
system;
[0038] FIG. 4 is a schematic diagram illustrating functional units
comprising the controller of the system and their
interconnects;
[0039] FIG. 5 is a schematic diagram of an embodiment of the system
of this invention;
[0040] FIG. 6 is a schematic diagram of the components and
connections of the controller;
[0041] FIGS. 7A and 7B illustrate the modular equipment rack design
of the Gausian cage for the controller without the feet shown;
[0042] FIG. 8 illustrates schematically the power converter of the
controller;
[0043] FIG. 9 is a schematic diagram of the actuator drivers of the
controller;
[0044] FIG. 10 is a schematic diagram of the power converter;
[0045] FIG. 11 is a schematic illustration depicting the kinetic
equivalency of the eight-degree of freedom embodiment of the
manipulator of the system;
[0046] FIG. 12A illustrates the three degrees of freedom 6, 7 and 8
of FIG. 11 provided by the yolk of the manipulator;
[0047] FIG. 1214 illustrates the three degrees of freedom provided
by a prismatic X-Y-Z-stage as the manipulator is used with a
skull;
[0048] FIG. 13 is a schematic depiction of an embodiment of the
manipulator with six degrees of freedom; and
[0049] FIG. 14 illustrates the basic system configuration of an
embodiment of the present invention.
DETAILED DESCRIPTION
[0050] The present teachings are described more fully hereinafter
with reference to the accompanying drawings, in which the present
embodiments are shown. The following description is presented for
illustrative purposes only and the present teachings should not be
limited to these embodiments. In addition, the publication
entitled, "MRI Compatibility Evaluation of a Piezoelectric Actuator
System for a Neural Interventional Robot," authored by Yi Wang'
Gregory A. Cole, Hao Su, Julie G. Pilitsis and Gregory Fischer,
presented at the 31St Annual International Conference of the IEEE
EMBS, Minneapolis, Minn., USA,
[0051] Sep. 2-6, 2009 is incorporated in its entirety by
reference.
[0052] Referring now to FIG. 1, shown is a block diagram depicting
an embodiment of the system architecture. The system 100 comprises
a workstation 102, a controller 104, a robotic device or
manipulator 106. Also shown is the clinical equipment or hospital
equipment 108 that may cooperate with the system. The user
workstation 102 serves as a planning and navigation workstation for
the user. Workstation 102 may be, but is not limited to, a laptop
computer located in an MRI scanner's console room. Alternatively,
it may be a separate computer, integrated into the medical imaging
equipment, or a part of a standalone system (not shown).
Workstation 102 is communicative coupled via data connections or
couplings 110 and 112 to the robot controller 104 which, in one
embodiment, is located inside the MRI scanner room and coupled via
fiber optic communications. Alternatively, coupling 110 and 112 may
be a shielded cable or wireless link. The workstation 102 sends
commands and registration to the robotic device or manipulator 106
via 110 and receives robot status and location via connection 112.
In one embodiment, the controller 104 receives alternating current
(AC) power from the scanner room via a grounded cable 118.
Alternatively, direct current (DC) power may be directly supplied
or a battery may be used to provide power. The physical manipulator
106 can be the robotic device that interacts with the patient. It
typically is MRI compatible and sits inside an MRI scanner bore
while performing an intervention. Manipulator 106 is coupled to
controller 104 via information connectors or signals 114 and 116.
Connector 114 provides the robot controller 104 with information
from the robot's sensors, including the position of the controller
or manipulator 104. Connector 114 may be an electrical connection
containing one or more channels from, for example, an optical
encoder utilizing a differential signal output. Alternatively, it
may provide a digital or analog digital from other encoder or
potentiometer. Position sensing may alternatively be performed
using fiber optics that communicate along connection 114.
Connection 114 may also include pressure, force, torque, or other
sensory information. Connection 116 provides control signals to the
manipulator's actuators. In one embodiment, connection 116 is a
shielded electrical cable that provides a drive signal to
piezoelectric motors. Alternatively, connection 116 may transmit
pneumatic or hydraulic power to the manipulator 106. Manipulator
106 performs the surgical intervention. In one embodiment,
manipulator 106 is an actuated frame for assisting deep brain
stimulation lead placement inside an MRI seamier. In one
embodiment, the manipulator 106 is composed of two separable
components, a motor module and an application-specific or
patient-specific mechanism.
[0053] Hospital equipment 108 can include the medical imaging
equipment. In one embodiment, equipment 108 includes an MRI
scanner. The MRI scanner transmits images via communication
coupling 120 to the workstation 102. The workstation 102 can
operate software which tracks a patient anatomy and generates the
user interface overlaying the position of the manipulator 106. This
workstation 102 is designed to contain all of the software utilized
to interface with the user and manages a large portion of the high
power processing such as three dimensional image creation and
analysis. The software facilitates interactions with the MRI
scanner located in the equipment 108 and the controller 104 of the
system 100. The workstation 102 may communicate with an image
server located in hospital equipment 108 associated with the MRI so
that images generated by the scanner may be utilized by the
navigation software. The images may be transferred via a Digital
Imaging and Communications in Medicine (DICOM) server, direct
connection, real-time streaming, or other means. In one embodiment,
the workstation 102 can also send commands to the MRI scanner to
control scan parameters including, but not limited to, scan plane
location, scan plane orientation, field of view, image update rate
and resolution. The workstation 102 may first register the position
of the robotic device or manipulator 106 relative to the patient or
imaging system, at which point the operator may develop a surgical
plan to interact with the desired intervention points. Once the
plan is developed, the operator may perform the procedure under
live imaging or real-time guidance so that during the procedure the
operator will be able to confirm that the intervention axis is
oriented optimally for insertion. Additionally, the operator will
be able to confirm the placement of surgical instruments at desired
locations.
[0054] In one embodiment, the manipulator 106 is mechanically
coupled to a platform placed upon the bed of the MRI scanner,
wherein the platform also includes imaging coils and head fixation.
In a further embodiment, the controller 104 also controls the
orientation of the MRI imaging coil to align an opening with the
planned robot trajectory. The imaging coil may be controlled by the
robot controller or controller 104 or by other means such that it
may be reconfigured to optimize patient access while maintaining
image quality. Further, the manipulator 106 and the platform may
also incorporate active or passive tracking fiducials or coils to
localize the robot in the MRI scanner. In alternate embodiment, the
manipulator 106 is coupled to a head frame and/or operating room
table and the controller 104 is also located in the operating
room.
[0055] This system 100 of the present invention is, essentially, a
high precision, closed loop system that can be used to compile MRI
image slices into three dimensional images, overlay a three
dimensional image of a manipulator that can be operated within the
scanner bore, select a course of motion for an intervention, and
execute the intervention under live image guidance. While this has
benefits in the medical world, there are also benefits to other
industries where the precision internal images of the MRI can be
utilized. Some of the industries used with the system can be
instrumental and are, for example, art restoration, plant splicing,
and veterinary work. Additionally, while this system is MRI
compatible, it is also compatible with most other imaging
modalities currently utilized. As such, under other imaging
modalities that do not require magnetic compatibility, this system
could be utilized, for example, by law enforcement, or manipulation
of internal structures of devices.
[0056] The system 100 described herein has modular architecture.
The system 100 can be integrated into an MRI surgical suite.
Individual surgeons or hospitals can use a variety of manipulators
106 or end effectors for the manipulator 106 for the specific
procedures that they perform. Alternatively, custom
patient-specific modules for the manipulators 106 may be used with
the system. A single controller 104 is capable of operating the
variety of manipulators 106. This distributes the cost of both
equipment and maintenance of the devices in a manner where
"everyone just pays for what they use." By distributing the payment
structure, different institutions and individuals may be
responsible for their own segments of equipment.
[0057] In another embodiment, although not limited thereto, the
system comprises an MRI-compatible self-positioning surgical guide
utilizing a similar procedure planning to stereotactic
intervention. This system bridges the gap between high resolution
imaging modalities and interventional procedures that utilize them
for planning purposes. The system may utilize live MRI guidance
during these procedures. Alternate embodiments of the system may be
used for applications other than deep brain stimulation such as
with other body parts such as prostrates, lungs, hearts, knees and
the like. Other neurosurgical procedures may be performed with the
present invention including lead placement, thermal and cryogenic
ablation, injections, evacuation, and surgical interventions. The
invention is not restricted to only the specifically mentioned
clinical applications. Further embodiments may be used to access
other organ systems including for MRI image-guided prostate
brachytherapy, biopsy and ablation.
[0058] The system 100 allows the use of in situ MRI guidance during
a neural intervention procedure with the added benefit of computer
controlled motion for the positioning of a tool guide. In one
embodiment, although not limited thereto, the system 100 operates
within the scanner bore of a closed-bore, high-field, diagnostic
MRI scanner. This device may actively drive the position of the
tool guide while leaving an acceptable volume of workspace for
performance of the operation by the surgeon. In order to accomplish
this, the system 100 may utilize similar planning methods to a
manual stereotactic surgical procedure. For instance, although not
limited thereto, system 100 may utilize a mechanically constrained
remote center of motion (RCM) style linkage, where the RCM point is
placed within the cranial volume at the target location. In such a
way, the primary insertion axis of the device targets the RCM point
no matter where the insertion guide is moved. This allows the
operator to set a desired intervention point and insert tools from
an arbitrary burr hole location on the skull to reach the same
target point. Alternatively, the RCM point may be placed in the
more traditional manner at the skull entry point and allow access
to a range of target locations through the same burr hole.
[0059] The system 100 may also incorporate power transmission,
although not limited thereto, that permits the use of modular end
effecters to expand the functionality of the system 100 with two
additional degrees of freedom (DOF) See FIG. 11. In one embodiment,
the system uses an armature that mounts to either side of the
patient's skull and is contained within a small volume in order to
leave as much room as possible within the scanner bore for the
surgeon to move. The system may also be integrated with the tray
that the patient rests on during the procedure, although not
limited thereto. The system may also be integrated with the MR
imaging coil, although not limited thereto.
[0060] The method of configuring the system 100 of the present
invention is illustrated in FIG. 2. The configuration is defined by
the medical procedure described in block 202 to be performed by the
system 100. The specific procedure and/or patient configuration are
used to determine the requirements as described in 204. The
requirements are used to select or develop manipulator 106 or end
effector as described in 206. The manipulator 106 or end effector
106 is coupled to the robotic system and controller 104.
[0061] A method used in system 100 can be as follows: [0062] 1)
identify the area of the body to be manipulated [0063] 2) identify
motions required to perform procedure [0064] 3) analyze motions and
forces [0065] 4) design manipulator to meet requirements [0066] 5)
select and apply actuators [0067] 6) select and apply sensors and
fiducial markers [0068] 7) analyze and insert kinematics of
manipulator in software system [0069] 8) once the manipulator is
constructed and the kinematics are inserted to the control
software, the new manipulator can be utilized.
[0070] The method of utilizing the system 100 of the present
invention is illustrated in FIG. 3, in a flow diagram re-procedural
imaging 302 is acquired prior to the intervention. Imaging 302 may
include, but is not limited to, anatomical MRI, functional MRI,
spectroscopic imaging and computed tomography or the like. These
images may be acquired days or weeks before the procedure, or may
be performed the day or immediately prior to the intervention.
Pre-procedural images 302 are used in medical procedure planning
304. The target or targets are identified 306. This step may be
manual, semi-automated, or fully automated. In one embodiment,
statistical atlases may be used to assist in locating the target
location. A planned trajectory is also identified in 306. This
trajectory may be manually generated or it may be generated in an
automated or semi-automated fashion. In one embodiment, blood
vessels and other critical structures are automatically located and
a safe trajectory is planned. Once the procedure is defined, a
patient is placed within the bore of a diagnostic scanner. In an
embodiment, the patient is placed inside an MRI scanner along with
the robotic device or manipulator 106. A series of images are taken
of the patient anatomy that the procedure needs to be performed on
and used to register the patient with eth pre-procedural plan. This
step may also be repeated iteratively or continuously during the
procedure. The images are assembled in the workstation 102 of FIG.
1 into a three-dimensional display where the physician can view and
modify the medical plan.
[0071] The robotic manipulator 106 is localized within the scanner
and registered to the patient in 308. Localization may be performed
by imaging fiducials, active tracking coils, an external tracking
system or other means. The motion plan for the robot is generated
based on the relative pose of the robot to the patient and the
planned trajectory or target 306. The manipulator 106 is commanded
to move and align the surgical tool as described in 312. The
surgical tool may be a needle, electrode, marker, drill, drill
guide, cannula, ablation probe, laser, or other similar device.
Real time or interactive medical images of the manipulator 106 and
the patient may be performed during motion 312 to guide alignment.
Position sensing on board the manipulator 106 or external to it may
be used to guide for alignment. Upon completion of motion or at a
stopping point in an iterative insertion, confirmation images are
acquired 314. If the tool is not yet at the target location, the
plan is updated in 310 and the process is repeated or iterated. In
one embodiment, continuous MRI images are used for closed loop
control of an electrode, cannula or other instrument. Once placed,
the interventional procedure, or a current step within, is
performed in 318. Placement is confirmed in 320 and the process may
be iterated to ensure appropriate position as defined in 324. In
one embodiment, confirmation 320 is performed via micro electrode
recordings. In an alternate embodiment, high resolution MRI imaging
is utilized. In another embodiment, fluoroscopy or computed
tomography imaging confirms appropriate placement. In procedures
with multiple stages, the process may be repeated as shown in 322.
This may be the result of multiple stages. In one embodiment, the
manipulator guide alignment of a surgical drill to generate a burr
hole in the skull and then later aligns a guide cannula and an
electrode. The robot manipulator 106 may move in and out of
position between stages to allow improved patient access. Further,
the procedure may be repeated for multiple targets. When complete,
the manipulator 106 retracts or is removed 326. Additional
validation may be performed to ensure a successful procedure 328
and the procedure is completed 330. For procedural planning,
guidance and validation, the MRI imaging may include one or more
of: traditional diagnostic imaging, rapid imaging, 3D imaging of
arbitrary pose, volumetric imaging, functional imaging,
spectroscopic imaging, blood flow sensing, diffusion imaging or
other approach. Further, multi-modality imaging may be incorporated
to couple MRI imaging with ultrasound or other medical imaging
means.
[0072] The configuration of one embodiment of system 100 of the
present invention is illustrated in the block diagram of FIG. 4.
Navigation software 402 is located on workstation 102. The
navigation software 402 is used to guide the intervention and may
also be used for preoperative and intraoperative planning as
described previously. In one embodiment, the navigation software
402 is based on the modular, open source 3D Slicer software.
Alternatively, navigation software 402 may be a commercially
developed platform. Navigation software 402 is communicative
coupled to an MRI medical imaging system or interface computer or
interface 404. The communication interface may be an established
protocol such as DICOM or OpenIGTLink. Alternate protocols or
connections may be utilized. The navigation software 402 may send
control signals to the imaging system interface 404 to control scan
plane location, orientation or other parameters. In one embodiment,
the imaging continuously streams images to the navigation software
402 that visualizes them on workstation 102 of FIG. 1. Imaging
system interface 404 controls the MRI scanner or other imaging
system 408 and retrieves planar and volumetric image data from the
scanner. The robot controller 406 represents the controller 104 of
FIG. 1. The controller 104 is communicatively coupled to the
navigation software 402. In one embodiment, the coupling is a fiber
optic network connection. In an embodiment the navigation software
402 sends commands including, but not limited to, positions,
orientations, velocities, and/or forces to the controller 104. In
an embodiment, the robot controller 104 incorporates a control
computer that receive the data from the navigation software 402 and
performs the necessary computations. The computations may include
one or more of forward kinematics, inverse kinematics, trajectory
generation and registration. The robot controller 104 sends data to
navigation software 402 including, but not limited, to the
manipulator 106 position, orientation, workspace, and interaction
forces.
[0073] In an embodiment, the manipulator 106 is actuated by
piezoelectric motors 412 and joint positions are sensed by optical
encoders 414. The piezoelectric motors 412 are controlled by
piezoelectric motor drivers 410. In a further embodiment, the
piezoelectric motor drivers 410 are configured to minimize
interference with the MRI scanner 408 and may include filtering.
The motors 412 may be controlled to provide position control, speed
control, or force control. Force control of the piezoelectric
actuators may be accomplished by varying the drive waveform's
amplitude, frequency, phase or other parameters to modify the
friction between the driven element and the motion generating
elements of motors 412. In an additional embodiment of the present
invention the robotic manipulator 106 is teleoperated. In a further
embodiment, haptic feedback may be available. The robot controller
106 may communicate directly with the motor drivers 410, or there
may be an intermediate interface such as backplane with signal
aggregator. In an embodiment, the piezoelectric motor drivers 410
and robot controller 406 are contained in controller 104 which is
enclosed in an EMI shielded enclosure located in the MRI scanner
room. In an alternate embodiment, the functionality of the robot
controller 406 is integrated with the navigation software 402, and
the workstation 102 (see FIG. 1) communicates directly with the
motor divers 410 or corresponding interface. A modular system
architecture allows the location of the breaks between software and
hardware components to be adapted to a specific application.
[0074] A specific embodiment of system 100 of the present invention
is shown in FIG. 5. In FIG. 5, the user workstation 502 represents
workstation 102 and includes a computer and a communication
interface. In one embodiment, the communication interface is, but
not limited to, a fiber optic Ethernet media converter. A set of
coordinates for the end effector of the manipulator 506 (also 106)
are selected, and sent to the controller 504 (also 104). In one
embodiment, the controller 504 is enclosed in a Faraday cage
forming an electro-magnetic interference (EMI) shielded enclosure
and contains an AC-DC power rectifier, one or more low-noise,
linear or low frequency switching DC-DC power converters, a control
computer, actuator drivers with output filtering, sensor interfaces
and a communication interface. The in-room controller 504
represents controller 104 and uses the kinematic information about
the manipulator 506 (also 106) and the coordinate information to
generate a planned pose for the manipulator 506. The physical
manipulator 506 represents the manipulator 106, wherein it
incorporates a task-specific end effector. The end effector may be
in the form of a linkage mechanism. Further, the linkage mechanism
itself may be unactuated and coupled to an actuator module to
complete the manipulator 506 or 106. The manipulator 506 or 106 may
also include sensors and fiducial markers. The pose is then
achieved through manipulation of the individual actuators through
drive signals 512 in a closed loop fashion utilizing sensor
information 514 from the manipulator 506 itself. Once the
controller 504 interprets that the manipulator 506 has reached the
intended planned position, the workstation 502 utilizes a medical
imaging system to verify the position of the manipulator's end
effector. The medical imaging system may incorporate one or more of
an MRI scanner, patient table, imaging coils, DICOM or other
imaging server, power source and air supply as described in 508,
which represent the hospital equipment 108. The power source and
air supply 518 may be connected to the in-room robot controller
504. In one embodiment, the power source is, but may not limited
to, approximately 110 volt AC power and a ground cable that is
connected to the rectifier and DC-DC converted within controller
504.
[0075] Now referring to FIG. 6, the inner workings of one
embodiment of the robot controller 504/104 is described. The
continuous Faraday cage enclosure 602 houses the entirety of the
controller equipment. The patch panel 604 acts to allow the passage
of electrical and other forms of information and energy to be
passed in and out of the enclosure 602 without allowing the escape
of EMI. These connections include the optical data transfer
connection 624 which the control computer uses to communicate with
the workstation 502 (or 102), as well as the controller supply
lines 616 and the actuator and sensor signals 626. The next piece
of equipment is the controller computer 606 which is generally a
common, off the shelf computer capable of running the software
required to perform the operation described in FIG. 3. This is
generally implemented as a common, off the shelf computer with the
power supply removed so its electrical power can be supplied by the
custom power converter 612. This device is connected via digital
data connection to the signal aggregator 608, which can include,
but is not limited to Transmission Control Protocol/Internet
Protocol (TCP/IP), Universal Serial Bus (USB), Open Image Guided
Therapy Link (OpenIGTLink), or others. The signal aggregator 608 is
a device that manages the passage of information from the control
computer 606 to the actuator drivers 610, and back through physical
or data connections 620 and 628. Additionally, the signal
aggregator 608 combines the driving signal and sensor information
lines from the actuator drivers 610 to the multiconductor connector
in the patch panel 604 via the multiconductor electrical data
connection 626. Additionally, the media converter 614 communicates
with the control computer via electrical data connection 618, and
converts the media to an optical data stream that is passed out of
the patch panel 604 through optical connection 624. Finally, all
electrical devices within the enclosure get their power from the
power converter 612, which is built later to supply all the
required DC voltages, and connected to all supported equipment via
the DC voltage rail connections 622.
[0076] Continuing to FIGS. 7A and 7B, which is a diagram of the
continuous Faraday cage enclosure, surrounding the controller
equipment, the basic structure of this device is provided by the
conductive paneling 710 which can be made of many materials such
as, for example, but is not limited to, sheet aluminum, steel, or a
non conductive material with a conductive coating. Cut into this
sheeting is vent ports 704 which allow the exchange of air for the
purposes of cooling, which have EMI shielding vents mounted to
them. Additionally cut into the structural sheeting 710 is the port
for the supply connection patch panel 708 (also 604) where the
different electrical and non-electrical supplies are passed into
the controller in a manner that shields EMI from escaping. These
supplies can include, but are not limited to, AC wall current,
compressed air, and DC voltage supplies. Additionally, cut into the
structural sheeting 710 is the port for the manipulator connector
patch panel 706 where the multi-element cables used to transfer
driving signals and sensor information back and forth between the
manipulator and the controller box. These elements can include, but
are not limited to hydraulic, pneumatic, and electrical transfer
lines. Finally, the cage FIG. 7A is completed with a lid 702
designed to be opened and closed more frequently than the patch
panels and thus contains an EMI shielding gasket.
[0077] Referring now to FIG. 8, a general view of the internal
operation of an actuator driver is shown, beginning with the
command input 802 from the piezoelectric actuators which is fed
into the signal processor 804. The command input can be comprised
of a variety of forms of analog and digital data which may include,
but is not limited to velocity, position, and force commands. The
input 802 may be passed to the signal processor 804 via synchronous
or asynchronous serial communication, Ethernet, USB, fiber optics,
or other means. Driving signals are then produced and amplified in
the signal generation segment 808, which can be comprised of but is
not limited to, a series of operational amplifiers connected to the
output of a digital to analog converter that receives the digital
information from the signal processing unit or signal processor
804. The output of the signal generation segment 808 is then passed
into the filtering stage 810 which is used to block bandwidths of
electrical signals which may be in frequency ranges that cause
unfavorable image distortion. The output of the filtering stage 810
is then sent to the piezoelectric actuators 802 via the
multi-element shielded cable coming from the faraday cage 602 patch
panel 604. The cables may terminate in a shielded breakout board on
or near the manipulator 106 or connect directly to the
actuators.
[0078] Now referring to FIG. 9, the detailed internal function of
one embodiment of the piezoelectric actuator driver 610. Initially
command information 802 is passed from the signal aggregator 912
via the serial data connection 926 to the microcontroller 902. The
microcontroller 902 in this embodiment has the function of handling
communications with the aggregator 912, and control of the signal
generator and sensing information. The microcontroller 902
communicates with the FPGA 904 via position data connection 914, as
well as the volatile memory 906 via data connection (wavetables)
922. Data connection 922 where the data is in the form of waveform
tables that are produced in analog form to drive piezoelectric
actuators 804. The field programmable gate array (FPGA) 904, where
the FPGA 904 is used to pull waveform information from the volatile
memory 906 and use it to execute commands received over position
data connection 914. Where FPGA 904 is also used to receive sensor
information over position sensor signals 928 to be used for
purposes including, but not limited to, execution of said commands
received from microcontroller 902. Where the parallel data stream
916 produced by the FPGA 904 is then interpreted into analog
actuator drawing signals 920, by first converting them into a low
voltage analog waveform Connector 918 by the digital to analog
converter (DAC) and preamplifier 908. The preamplifier 908, which
can be comprised of, but is not limited to, high speed parallel
digital to analog converters which can convert the digital waveform
information stored in volatile memory 906. Once the low voltage
analog driver signal. 918 is produced, it is then amplified and
filtered by the output stage 910 which is capable of multiplying
the voltage and supplying a high amount of current. Components in
this stage are over-specced in order to prevent noise.
[0079] Referring now to FIG. 10, the power converter 612 as shown
in FIG. 6 is supplied by the patch panel 604 via the AC input 1002.
The AC input 1002 is carried by the wall current connector 1008
which is of the form of a cable rated to handle the electrical load
required to operate the rest of the electrical equipment. This AC
current is passed into the bridge rectifier 1004 where the voltage
is divided before rectification to approximate the highest DC
voltage required by the system. There is then a large capacitive
filter pre and post rectification or full phase recited voltage
1010 in the rectifier 1004 to prevent rejection of noise back
through the supply line and passing of noise to the converters.
Once the input line is fully rectified and filtered 1006, it is
then passed through the programmable buck converters 1006.
Programmable converters are utilized so that the switching
frequency can be controlled to prevent image degradation. Finally
the DC voltage rails or supplies 1012 are passed out of the custom
power converter 612 of signals via connection
[0080] Referring now to FIG. 11 and FIGS. 12A and 12B, the
kinematics of one embodiment of the manipulator 106 as per its
design for use assisting with DBS electrode implantation. The
first, second and third degree of freedom (DOE) are all contained
within what is commonly called a prismatic XYZ stage labeled as the
three DOF Translation Base 1102. The next two degrees of freedom
are expressed as a two DOF remote center of motion style linkage
1104, where the RCM linkage can be described as, but is not limited
to, mimicking the motion of a stereotactic neural insertion frame.
The next two degrees of freedom are expressed as an optional yoke
1106 and increases 6 degrees of freedom to 8 degrees of freedom
that can be used to achieve insertion angles other than those along
the RCM axis. This allows the manipulator 106 to achieve greater
degrees of dexterity. The final axis which is, but is not limited
to, a passive insertion axis 1108, where the surgeon may manually
insert an electrode. FIG. 11B and 11C show pictorially how the
manipulator allows for 8 degrees of freedom and can be used with a
skull in a DBS electrode implementation. The design is not
restricted to six or eight DOF, alternate embodiments may encompass
other numbers of degrees of freedom. Alternate specific
applications will result in alternate mechanism designs.
[0081] Referring now to FIG. 12A and 12B, the manipulator 106
described earlier in a specific embodiment of said manipulator 106
adapted for DBS electrode insertion. The manipulator 106 can be
constructed of rigid plastic links 1208 pin jointed 1202 via non
conductive rods with plastic sleeve bearings 1205 as shown in FIG.
13 and may be used at all pin joint locations. The RCM point 1204
is clearly shown, and is targeted through all positions of the
manipulator sweep 1207-1211 allowing a single target point 1204 to
be reached from multiple insertion angles 1207, 1209, 1211 shown in
FIG. 13 represents three manipulator configurations overlaid to
demonstrate the mechanically constrained rotation center concept
generated by motions 1104. This mimics the motion of a standard
stereotactic insertion frame. The rotation center may be placed at
or near the target or it may be placed at or near the skull entry
point. Additional dexterity afforded by the extra degrees of
freedom of yolk 1106 enables repositioning of the rotation center
though software control. The 3 DOF translation base can be used to
change the position of the remote center of motion point. An
enlarged view of FIG. 11B is shown and FIG. 13 to show the extra
DOF 6 and 7.
[0082] The configuration of a specific embodiment of system 100 of
the present invention is shown in FIG. 14. Patient 1402 is placed
inside MRI scanner 1404 located in MRI scanner room 1400 and rests
upon scanner bed 1406. Patient's head 1408 rests upon an integrated
head rest platform 1412. Head fixation 1414 maintains head position
relative to the platform 1412. MRI imaging coil 1418 is coupled to
platform 1412. In one embodiment imaging coil 1418 is a standard
head coil, surface coils, or other readily available imaging coil.
Alternatively, imaging coil 1418 may be specific for this system.
In one embodiment, the imaging coil 1418 is actuated and
reconfigurable. Robot base 1420 is fixed to platform 1412.
Manipulator 1422 (also 106) sits upon platform 1412. In one
embodiment, robot base 1420 is a prismatic motion stage for
positioning and the manipulator 106 and provides 3 degrees of
freedom for manipulator 106. The manipulator 106 may be
application-specific or patient-specific. In one embodiment, the
manipulator 1422 may be in itself un. actuated base and coupled to
an actuation module 1420 as described earlier. The robotic device
comprising base 1420 and line manipulator 1422, and also
representing 106, is coupled to the controller 1430 via line 1432.
In one embodiment, line 1432 is a shielded multiconductor cable
transmitting motor power from the controller to piezoelectric
motors in the robotic device or manipulator 1422 or 106 (not shown)
and receiving encoder signals from the robotic device to the
controller. In one embodiment, one or more breakout boards are
coupled to platform 1412 or robot base 1420 to distribute control
and sensor signals. In an alternate embodiment, pneumatic or
hydraulic power may be transmitted via line 1432. Alternatively,
line 1432 may include fiber optic communications. In one
embodiment, controller 1430, which also represents 104, is also
coupled to imaging coil 1418 via cable 1434 for control of the
imaging coil configuration. Controller 1430 receives power via
cable 1438 from the MRI scanner room. Power may include AC
electricity and a ground connection. Connection 1438 may also
include pressurized fluid such as air or nitrogen. Controller 1430
is communicatively couple to workstation 1450 or 102 via cable or
other coupling 1440. Cable 1440 may be a fiber optic communication
cable that passes through waveguide 1444 in the wall 1446 of the
MRI scanner room 1400. Workstation 1450 represents user workstation
102 and may be located in the MRI console or control room 1452 as
described earlier.
[0083] Although the invention has been decided with various
embodiments, it should be realized that this invention is also
capable of further and other embodiments within the spirit and
scope of the appended claims.
* * * * *