U.S. patent application number 15/237737 was filed with the patent office on 2016-12-08 for image-guided therapy of a tissue.
This patent application is currently assigned to MONTERIS MEDICAL CORPORATION. The applicant listed for this patent is MONTERIS MEDICAL CORPORATION. Invention is credited to Eric ANDREWS, Mark GRANT, Brooke REN, Richard TYC.
Application Number | 20160354163 15/237737 |
Document ID | / |
Family ID | 54140931 |
Filed Date | 2016-12-08 |
United States Patent
Application |
20160354163 |
Kind Code |
A1 |
ANDREWS; Eric ; et
al. |
December 8, 2016 |
IMAGE-GUIDED THERAPY OF A TISSUE
Abstract
Image-guided therapy of a tissue can utilize magnetic resonance
imaging (MRI) or another medical imaging device to guide an
instrument within the tissue. A workstation can actuate movement of
the instrument, and can actuate energy emission and/or cooling of
the instrument to effect treatment to the tissue. The workstation
and/or an user of the workstation can be located outside a vicinity
of an MRI device or other medical imaging device, and drive means
for positioning the instrument can be located within the vicinity
of the MRI device or the other medical imaging device. The
instrument can be an MRI compatible laser or high-intensity focused
ultrasound probe that provides thermal therapy to, e.g., a tissue
in a brain of a patient.
Inventors: |
ANDREWS; Eric; (St. Anthony,
MN) ; GRANT; Mark; (Winnipeg, CA) ; REN;
Brooke; (Maple Grove, MN) ; TYC; Richard;
(Winnipeg, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MONTERIS MEDICAL CORPORATION |
Plymouth |
MN |
US |
|
|
Assignee: |
MONTERIS MEDICAL
CORPORATION
Plymouth
MN
|
Family ID: |
54140931 |
Appl. No.: |
15/237737 |
Filed: |
August 16, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14661212 |
Mar 18, 2015 |
|
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15237737 |
|
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61955124 |
Mar 18, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 90/37 20160201;
A61B 90/50 20160201; A61N 2007/0047 20130101; A61B 5/0035 20130101;
A61B 18/22 20130101; A61B 2018/0293 20130101; A61B 5/702 20130101;
A61B 34/20 20160201; A61B 5/742 20130101; A61B 5/748 20130101; A61F
5/3707 20130101; A61B 2034/2051 20160201; A61B 6/0492 20130101;
A61B 2018/1869 20130101; A61B 5/015 20130101; A61B 2018/00011
20130101; A61B 5/4839 20130101; A61B 2090/374 20160201; A61N
2005/1055 20130101; A61B 17/3403 20130101; A61B 6/0421 20130101;
A61N 5/062 20130101; A61F 5/37 20130101; A61N 5/1048 20130101; A61B
90/11 20160201; A61B 34/10 20160201; A61B 5/0042 20130101; A61B
5/055 20130101; A61N 2007/025 20130101; A61B 18/1492 20130101; A61B
2018/00446 20130101; A61B 2090/3954 20160201; A61B 17/00234
20130101; A61B 2018/00791 20130101; A61N 7/022 20130101; A61N
2005/1051 20130101; A61B 2034/107 20160201; A61B 18/04 20130101;
A61B 90/14 20160201; A61B 2018/00321 20130101; A61B 5/01 20130101;
A61B 17/1703 20130101; A61B 18/1477 20130101; A61B 2576/026
20130101; A61B 2034/2065 20160201; A61N 7/02 20130101; A61N
2007/003 20130101; A61N 2005/1097 20130101; A61B 6/04 20130101;
A61B 5/0555 20130101; A61B 17/1739 20130101; A61B 2018/20361
20170501; A61B 2090/103 20160201; A61B 6/032 20130101 |
International
Class: |
A61B 34/20 20060101
A61B034/20; A61N 7/02 20060101 A61N007/02; A61B 5/055 20060101
A61B005/055; A61B 6/03 20060101 A61B006/03; A61B 90/14 20060101
A61B090/14; A61B 5/01 20060101 A61B005/01; A61B 18/14 20060101
A61B018/14; A61N 5/06 20060101 A61N005/06; A61B 5/00 20060101
A61B005/00; A61B 90/11 20060101 A61B090/11; A61B 18/22 20060101
A61B018/22 |
Claims
1. A system for setting a trajectory of a neurosurgical instrument
introduction apparatus, comprising: a low profile skull anchor
device configured to attach to an area of a skull of a patient; a
removable guide stem configured to detachably connect to the low
profile skull anchor device, wherein the removable guide stem
comprises an opening that, when the removable guide stem is
connected to the low profile skull anchor device, is positioned
above an entry formed in the skull of the patient, and the
removable guide stem is configured to adjust a trajectory
corresponding to the opening of the removable guide stem in at
least one of a pivot alignment and a rotation alignment; a
processor; and a memory having instructions stored thereon, wherein
the instructions, when executed by the processor, cause the
processor to, after the low profile skull anchor device with
removable guide stem has been connected to the skull of the
patient: obtain image data of at least one of the removable guide
stem and a test tool inserted into the opening of the removable
guide stem, align the image data with pre-treatment image data, and
confirm, based upon the alignment, an initial trajectory in
relation to a region of interest within the skull of the
patient.
2. The system of claim 1, wherein confirming the initial trajectory
comprises identifying locations of at least three fiducial markers
arranged upon a surface region of the neurosurgical instrument
introduction apparatus.
3. The system of claim 2, wherein a first fiducial marker of the at
least three fiducial markers differs from the remaining fiducial
marker of the at least three fiducial markers in one or more of
length, width, and shape.
4. The system of claim 1, wherein the instructions, when executed
by the processor, further cause the processor to, prior to
confirming the initial trajectory, actuate a guidance device to
adjust the trajectory of the opening of the removable guide stem in
at least one of a rotational and a pivot direction.
5. The system of claim 1, wherein the instructions, when executed
by the processor, further cause the processor to, prior to
confirming the initial trajectory, activate a self-test function
that confirms positioning accuracy, wherein the self-test function
includes adjusting, via actuations of the guidance device, the
trajectory of the opening of the removable guide stem in a
plurality of rotational and/or pivotal directions; and confirming a
respective trajectory corresponding to each of the plurality of
rotational and/or pivotal directions.
6. The system of claim 1, wherein the instructions, when executed
by the processor, further cause the processor to cause presentation
of instructions upon a graphical user interface to an operator,
wherein the instructions instruct the operator to insert a
neurosurgical instrument into the opening of the removable guide
stem, wherein the neurosurgical instrument is introduced at the
surface of the skull of the patient in accordance with the initial
trajectory.
Description
RELATED APPLICATIONS
[0001] The present application is a divisional of U.S. patent
application Ser. No. 14/661,212 filed Mar. 18, 2015, which is
related to and claims the benefit of U.S. Provisional Patent
Application 61/955,124 entitled "Image-Guided Therapy of a Tissue"
and filed Mar. 18, 2014. The present disclosure is also related to
U.S. Provisional Patent Application 61/955,121 entitled
"Image-Guided Therapy of a Tissue" and filed Mar. 18, 2014. The
contents of each of the above listed applications are hereby
incorporated by reference in their entireties.
BACKGROUND
[0002] Cancerous brain tumors can be "primary" tumors, meaning that
the tumors originate in the brain. Primary tumors include brain
tissue with mutated DNA that grows (sometimes aggressively) and
displaces or replaces healthy brain tissue. Gliomas are one type of
primary tumor that indicate cancer of the glial cells of the brain.
While primary tumors can appear as single masses, they can often be
quite large, irregularly-shaped, multi-lobed and/or infiltrated
into surrounding brain tissue.
[0003] Primary tumors may not be diagnosed until the patient
experiences symptoms, including those such as headaches, altered
behavior, and sensory impairment. However, by the time the symptoms
develop, the tumor may already be large and aggressive.
[0004] One treatment for cancerous brain tumors is surgery. Surgery
involves a craniotomy (i.e., removal of a portion of the skull),
dissection, and total or partial tumor resection. The objectives of
surgery may include removing or lessening of the number of active
malignant cells within the brain, or reducing a patient's pain or
functional impairment due to the effect of the tumor on adjacent
brain structures. Not only can surgery be invasive and accompanied
by risks, for some tumors, surgery is often only partially
effective. In other tumors, surgery may not be feasible. Surgery
may risk impairment to the patient, may not be well-tolerated by
the patient, and/or may involve significant costs, recovery time,
and recovery efforts.
[0005] Another treatment for cancerous brain tumors is stereotactic
radiosurgery (SRS). SRS is a treatment method by which multiple
intersecting beams of radiation are directed at the tumor such
that, at the point of intersection of the beams, a lethal dose of
radiation is delivered, while tissue in the path of any single beam
remains unharmed. However, confirmation that the tumor has been
killed is often not possible for several months post-treatment.
Furthermore, in situations where high doses of radiation may be
required to kill a tumor, such as in the case of multiple or
recurring tumors, it is common for the patient to reach a toxic
threshold for radiation dose, prior to killing all of the tumors.
Reaching this toxic threshold renders further radiation is
inadvisable.
SUMMARY
[0006] In one aspect, the present disclosure relates to an
apparatus including a low profile skull anchor device configured to
attach to an area of a skull of a patient, the low profile skull
anchor device including a central opening for access to an entry
formed in the skull of the patient, where the low profile skull
anchor device, upon attachment to the area of the skull, protrudes
from the area of the skull at a height no greater than forty
millimeters. The apparatus may further include a removable guide
stem configured to detachably connect to the low profile skull
anchor device, the removable guide stem including a cylindrical
opening, where upon connection of the removable guide stem to the
low profile skull anchor device, the cylindrical opening is
positioned substantially above the entry formed in the skull of the
patient, and the removable guide stem is configured to adjust a
trajectory of the cylindrical opening in at least one of a tilt
direction and a rotation direction.
[0007] In some implementations, the low profile skull anchor device
includes at least three fastener positions for attaching the low
profile skull anchor device to bone anchors set in the skull of the
patient using screws. The low profile skull anchor device may
include at least three skull pins for maintaining a gap between the
low profile skull anchor device and a surface of the skull of the
patient, thereby avoiding skin compression. The central opening of
the low profile skull anchor device may be at least sixty
millimeters in diameter.
[0008] In some implementations, the low profile skull anchor device
includes at least two fastener openings for connecting the
removable guide stem to the low profile skull anchor device. The
removable guide stem may include a ball joint for adjusting the
trajectory of the cylindrical opening in both the tilt direction
and the rotation direction. The removable guide stem may include a
tilt adjustment mechanism for adjusting the trajectory of the
cylindrical opening in a tilt direction and a separate rotation
adjustment mechanism for adjusting the trajectory of the
cylindrical opening in a rotation direction. At least one of the
removable guide stem and the low profile skull anchor device may
include a number of guide lines for aid in setting the trajectory
of the cylindrical opening.
[0009] In some implementations, the apparatus includes a guide
sheath, where the guide sheath is configured for insertion within
the cylindrical opening of the removable guide stem, and the guide
sheath includes at least one hollow lumen extending between a
proximal end of the guide sheath and a distal end of the guide
sheath, where the at least one hollow lumen is configured for
introduction of a neurosurgical instrument. The removable guide
stem may include a lock mechanism for locking the guide sheath to
the removable guide stem at a selected linear depth of insertion
within the cylindrical opening of a number of linear depths of
insertion available for selection. The distal end of the guide
sheath may include two or more openings for deployment of the
neurosurgical instrument.
[0010] In one aspect, the present disclosure relates to a head
fixation system including an upper ring portion including a nose
indent for positioning the nose of a patient when a head of the
patient is encircled by the head fixation system, and a lower ring
portion including a number of support posts, where the number of
support posts are configured to support the head of the patient
laid upon the lower ring portion, and the lower ring portion is
configured to lock to the upper ring portion after positioning the
head of the patient upon the number of support posts.
[0011] In some implementations, the support posts are adjustably
connected to the lower ring portion via a number of slots, where
the head fixation system includes more slots than support posts.
Each support post of the number of support posts may include at
least one connection point for connecting a fastener. The at least
one connection point may be configured for connection of a skull
pin. Each support post of the number of support posts may include
at least three connection points for connecting a fastener, where a
positioning of a fastener upon a first support post of the number
of support posts is user selectable. Upon positioning the head of
the patient between the lower ring portion and the upper ring
portion and locking the lower ring portion to the upper ring
portion, a user may tighten the fasteners to fix a position of the
head of the patient.
[0012] In some implementations, the head fixation system includes
one or more additional upper ring portions, where the upper ring
portion is selected based upon a size of the head of the patient.
The lower ring portion may be curved to provide at least forty
degrees of angular head adjustment upon placing the head fixation
system within a fixation ring channel of a patient table.
[0013] In one aspect, the present disclosure relates to a probe for
use in effecting intracranial high intensity focused ultrasound
(HIFU) treatment, including at least one ultrasonic transducer, an
acoustic coupling medium contacting the at least one ultrasonic
transducer, and a rigid external shaft for interstitial positioning
of the at least one ultrasonic transducer, where the rigid shaft is
up to 3.5 millimeters in diameter, and the at least one ultrasonic
transducer is mounted within the rigid external shaft. The probe
may be configured to drive ultrasonic energy at least three
centimeters into tissue for effecting thermal treatment of the
tissue.
[0014] In some implementations, the at least one ultrasonic
transducer is mounted in a side-firing position within the rigid
external shaft. The at least one ultrasonic transducer may include
a linear array of three or more ultrasonic transducers. The at
least one ultrasonic transducer may be a planar transducer. The
thermal treatment may include one of coagulation and
cavitation.
[0015] The foregoing general description of the illustrative
implementations and the following detailed description thereof are
merely example aspects of the teachings of this disclosure, and are
not restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an illustration of an exemplary layout of an MRI
Control Room, an MRI Scan Room, and an MRI Equipment Room;
[0017] FIG. 2 is an illustration of a perspective view of a patient
inserted into an MRI, with a head fixation and stabilization system
installed;
[0018] FIG. 3 illustrates a probe driver;
[0019] FIGS. 4A and 4B are flow charts illustrating an exemplary
procedure for treating a patient;
[0020] FIGS. 5A through 5E illustrate a low profile skull anchoring
device and example guide stems;
[0021] FIGS. 5F and 5G illustrate a guide stem and sheath
configured to interconnect with the low profile skull anchoring
device;
[0022] FIGS. 5H and 5I illustrate example internal configurations
of a guide sheath;
[0023] FIGS. 6A and 6B illustrate a head fixation system;
[0024] FIG. 6C illustrates a locking mechanism;
[0025] FIGS. 6D and 6E illustrate a mounting location on an MRI
platform for the head fixation system of FIGS. 6A and 6B;
[0026] FIG. 7 is an illustration of an MRI coil holder;
[0027] FIG. 8 is an illustration of a pre-shaped probe deployed
from a rigid sheath;
[0028] FIGS. 9A through 9C illustrate a high intensity focused
ultrasound probe;
[0029] FIGS. 10A and 10B illustrate a method for MR thermal
monitoring using offset thermal imaging planes; and
[0030] FIG. 11 illustrates exemplary hardware of a workstation.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
[0031] In the drawings, like reference numerals designate identical
or corresponding parts throughout the several views.
[0032] As used herein, the words "a," "an" and the like generally
carry a meaning of "one or more," unless stated otherwise. The term
"plurality", as used herein, is defined as two or more than two.
The term "another", as used herein, is defined as at least a second
or more. The terms "including" and/or "having", as used herein, are
defined as comprising (i.e., open language). The term "program" or
"computer program" or similar terms, as used herein, is defined as
a sequence of instructions designed for execution on a computer
system. A "program", or "computer program", may include a
subroutine, a program module, a script, a function, a procedure, an
object method, an object implementation, in an executable
application, an applet, a servlet, a source code, an object code, a
shared library/dynamic load library and/or other sequence of
instructions designed for execution on a computer system.
[0033] Reference throughout this document to "one embodiment",
"certain embodiments", "an embodiment", "an implementation", "an
example" or similar terms means that a particular feature,
structure, or characteristic described in connection with the
example is included in at least one example of the present
disclosure. Thus, the appearances of such phrases or in various
places throughout this specification are not necessarily all
referring to the same example. Furthermore, the particular
features, structures, or characteristics may be combined in any
suitable manner in one or more examples without limitation.
[0034] The term "or" as used herein is to be interpreted as an
inclusive or meaning any one or any combination. Therefore, "A, B
or C" means "any of the following: A; B; C; A and B; A and C; B and
C; A, B and C". An exception to this definition will occur only
when a combination of elements, functions, steps or acts are in
some way inherently mutually exclusive.
[0035] Further, in individual drawings figures, some
components/features shown are drawn to scale to exemplify a
particular implementation. For some drawings, components/features
are drawn to scale across separate drawing figures. However, for
other drawings, components/features are shown magnified with
respect to one or more other drawings. Measurements and ranges
described herein relate to example embodiments and identify a value
or values within a range of 1%, 2%, 3%, 4%, 5%, or, preferably,
1.5% of the specified value(s) in various implementations.
[0036] The system or method may include one or more processors and
circuits that embody aspects of various functions by executing
corresponding code, instructions and/or software stored on tangible
memories or other storage products. A display may include various
flat-panel displays, including liquid crystal displays.
[0037] The treatment of tumors by heat is referred to as
hyperthermia or thermal therapy. Above approximately 57.degree. C.,
heat energy needs only to be applied for a short period of time
since living tissue is almost immediately and irreparably damaged
and killed, for example through a process called coagulation,
necrosis, or ablation. Malignant tumors, because of their high
vascularization and altered DNA, are more susceptible to
heat-induced damage than healthy tissue. In other procedures, heat
energy is applied to produce reversible cell damage. Temporary
damage to cellular structures may cause the cells to be more
conducive to certain therapies including, in some examples,
radiation therapy and chemotherapy. Different types of energy
sources, for example, laser, microwave, radiofrequency, electric,
and ultrasound sources may be selected for heat treatment based on
factors including: the type of tissue that is being treated, the
region of the body in which the tissue to be treated is located,
whether cellular death or reversible cellular damage is desired,
the nature of energy application parameters for each source, and
variability of the energy application parameters. Depending on
these factors, the energy source may be extracorporeal (i.e.,
outside the body), extrastitial (i.e., outside the tumor), or
interstitial (i.e., inside the tumor).
[0038] In interstitial thermal therapy (ITT), a tumor is heated and
destroyed from within the tumor itself, energy may be applied
directly to the tumor instead of requiring an indirect route
through surrounding healthy tissue. In ITT, energy deposition can
be extended throughout the entire tumor. The energy can be applied
to heat tissue in the treatment area to a temperature within a
range of about 45.degree. to 60.degree. C.
[0039] An exemplary ITT process begins by inserting an ultrasound
applicator including one or more transducers into the tumor. The
ultrasonic energy from the applicator may therefore extend into the
tissue surrounding the end or tip including the one or more
transducers to effect heating within the tumor. In some
implementations, the transducer(s) is/are aligned with an edge of
the applicator and the applicator is rotatable so as to rotate the
ultrasonic energy beam around the axis of the applicator to effect
heating of different parts of the tumor at positions around the
applicator. In other implementations or for other applications, the
transducer(s) are presented on a tip of the applicator or otherwise
surrounding an inserted portion of the applicator. Depending upon
the distribution of transducers, the applicator may be moved
longitudinally and/or rotated to effect heating of the tumor over a
full volume of the targeted region.
[0040] In yet other implementations, the ultrasonic applicator is
controlled and manipulated by a surgeon with little or no guidance
apart from the surgeon's memory of the anatomy of the patient and
the location of the tumor. In still other implementations, images
may be used during the ITT process to provide guidance for
treatment. For example, locations of tumors and other lesions to be
excised can be determined using a magnetic resonance imaging (MRI)
system or computer tomography (CT) imaging system. During the ITT
process, for example, MRI imaging can be used in real time to
control or aid in guidance accuracy in an automated or
semi-automated fashion.
[0041] In some implementations, thermography (e.g., MR
thermography, ultrasonic thermography, etc.) provides
contemporaneous temperature feedback regarding one or both of the
targeted region and the surrounding tissue during the ITT process.
The temperature information, for example, can be used to monitor
necrosis of tumor tissue while ensuring that surrounding (healthy)
tissue suffers minimal to no damage. The temperature feedback, in
some implementations, is used to perform either or both of:
automating engagement of the ultrasonic energy and cooling
functionality of the ultrasonic applicator. In this manner, it is
possible to control a temperature distribution or thermal dose in
and around the tumor.
[0042] Effecting treatment to a tissue, in some implementations,
includes an automated drive mechanism with a holder to hold a
treatment device (e.g., medical probe, ultrasonic applicator, laser
fiber, etc.). In some implementations, the drive mechanism is
motorless and consists of thermal imaging compatible components.
The drive mechanism, for example, can be configured without an
electric motor. The drive mechanism, in some examples, is included
in an MRI or MRI head coil. The drive mechanism can be coupled to
one or more wires or umbilicals such that a translation of the one
or more wires or umbilicals affects one or more of a longitudinal
displacement of the holder and a rotation of the holder. A
controller, in some implementations, processes position control
signals for setting and/or monitoring a position of the holder
(e.g., via an input interface to the wires or umbilicals), and
issues subsequent position control signals to manipulate
positioning of the holder (e.g., via an output interface to the
wires or umbilicals).
[0043] The system or method, in some implementations, includes a
guide mechanism that is attachable to a surface of a patient. The
guide mechanism, for example, can include a base structure
configured to remain stationary relative to the patient when the
guide mechanism is attached to the surface of the patient in a
locked state. The guide mechanism can further include a tilt
portion that is coupled to the base structure and provides an
adjustable tilt between a trajectory of the drive mechanism and the
base structure. The guide mechanism can further include a rotation
portion that provides an adjustable rotation of the tilt portion
relative to the base structure.
[0044] The controller, in some implementations, is configured to
process a sequence of the position control signals to direct the
guide mechanism to move the holder during treatment. For example,
the controller can be programmed to move the holder to a first
position for effecting the treatment to the tissue at a first
portion of the tissue that coincides with the first position and
then move the holder to a second position for effecting the
treatment to the tissue at a second portion of the tissue that
coincides with the second position.
[0045] During treatment, in some implementations, a workstation
transmits the position control signals to the controller and
displays feedback images (e.g., MRI images and/or thermometry
images) of the tissue to a user of the workstation. The
workstation, for example, can continuously display the thermometry
images of the tissue during the treatment to the tissue at the
first and second portions of the tissue, and while the holder moves
between the first and second positions.
[0046] In some implementations, an imaging system receives images
of the tissue and the treatment device and analyzes the images to
monitor control of positioning and/or therapeutic energy delivery
within the tissue. For example, the imaging system may process, in
real time, the images of the tissue and the treatment device, as
well as the thermometry images of the tissue to forecast errors or
interruptions in the treatment to the tissue. Responsive to the
analysis, the imaging system may display, via the workstation, an
appropriate warning. Position control signals may be updated and
transmitted by the workstation to the controller based on one or
more of the images, as the images are received by the workstation
in real time.
[0047] In some implementations, treatment is delivered via an
energy emission probe, such as an ultrasonic applicator or laser
probe. The energy emission probe, in some examples, may include one
or more emitters, such as a radiofrequency emitter, HIFU emitter, a
microwave emitter, a cryogenic cooling device, and a photodynamic
therapy light emitter. The energy emission probe may include
multiple emitters, where the emitters are longitudinally spaced
with respect to a longitudinal axis of the energy emission
probe.
[0048] In some implementations, the energy emission of the probe
can be controlled to generate a number of different energy output
patterns. The different patterns, for example, can include energy
delivered via two or more ultrasonic transducers and/or two or more
laser fibers. For example, a laser probe may include a first laser
fiber for outputting a symmetrical output pattern with respect to a
longitudinal axis of the first laser fiber and a second laser fiber
for outputting an asymmetrical output pattern with respect to a
longitudinal axis of the second laser fiber. In another example, an
ultrasonic applicator may include a first ultrasonic transducer for
outputting a first ultrasonic frequency and a second ultrasonic
transducer for outputting a second ultrasonic frequency.
[0049] The energy output pattern, in some implementations, includes
a pulsed output pattern. For example, a higher power density may be
achieved without causing tissue scorching or carbonization by
pulsing a high power laser treatment for x seconds with y seconds
break between so that tissue in the immediate vicinity of the
treatment area has an opportunity to dissipate. In a particular
example, the laser pattern may be active for two seconds and
inactive for one second.
[0050] In some implementations, the treatment pattern includes
effecting treatment while simultaneously moving the probe (e.g.,
linearly and/or rotationally). For example, an ultrasonic probe may
be rotated while an emission pattern is simultaneously adjusted to
effect treatment at a desired depth based upon a particular
geometry of a region of interest (ROI) including a targeted tissue
area. In one embodiment, the ROI includes multiple targeted tissue
areas, which are treated either concurrently, consecutively, or in
succession. In this manner, for example, while the ultrasonic
treatment beam is focused upon a radial portion of the tumor having
a depth of 1.5 centimeters, the power density of the HIFU probe may
be tuned for this first treatment depth. Upon rotation to a second
radial portion of the tumor may have a depth of 2 centimeters, the
power density of the HIFU probe may be increased accordingly to
tune for this second treatment depth of 2 centimeters.
[0051] An energy source generates energy for the probe. In some
implementations, the workstation transmits energy control signals
to the energy source. The workstation, for example, may be
configured to process a sequence of the energy control signals to
first effect a symmetrical treatment area with respect to the
tissue, via the probe, and subsequently effect an asymmetrical
treatment area with respect to the tissue, via the probe, after the
symmetrical treatment. In a particular example, the workstation may
be configured to process a sequence of position and laser control
signals to move the holder to a first position for effecting the
treatment to the tissue at a first portion of the tissue that
coincides with the first position, effect a symmetrical treatment
to the first portion of the tissue with the first laser fiber, move
the holder to a second position for effecting the treatment to the
tissue at a second portion of the tissue that coincides with the
second position, and effect an asymmetrical treatment to the second
portion of the tissue with the second laser fiber. During
treatment, the workstation may be configured to display thermometry
images of the tissue continuously and concurrently with processing
control signals specifying the position and energy associated with
the symmetrical and asymmetrical treatments.
[0052] In some implementations, the system or method includes a
guide sheath configured to accept two or more probes associated
with different energy modalities as the treatment device. The
modalities may include, for example, laser, radiofrequency, HIFU,
microwave, cryogenic, photodynamic therapy, chemical release and
drug release. The guide sheath may include one or more off-axis
lumens for positioning an emitting point of one or more of the
number of probes at an off-axis angle.
[0053] A system in accordance with this disclosure incorporates, in
an embodiment, MRI-compatible energy emission probes and/or other
treatment devices and accessories for controlled delivery of
thermal therapy to a number of locations and tumor sizes within a
brain. The system, however, is not limited to MRI-guided thermal
therapy, as other therapies such as computer tomography (CT) are
utilized in other embodiments. Further, this disclosure refers to
an MRI scanner as an exemplary medical imaging machine, which may
be referred to herein as an MRI.
[0054] I. Overview
[0055] Turning to FIG. 1, in certain embodiments, an environment
100 for intracranial therapy includes an interface platform 102
(herein an interface platform or interface console), a system
electronics rack 104 and components (herein rack), and a control
workstation 106 (herein workstation). The interface platform 102
may be used to manipulate and monitor therapy equipment related to
one or more energy sources, such as probe introduction equipment
including, in an embodiment, a probe driver, a probe, and/or a
probe holding and alignment device. The probe introduction
equipment, in some examples, can include the low profile anchoring
system described in FIGS. 5A-5G below or the stereotactic miniframe
described in U.S. patent application Ser. No. 13/838,310 to Tyc,
filed Mar. 14, 2013 and titled "Image-Guided Therapy of a Tissue,"
incorporated herein by reference in its entirety. In certain
embodiments, the workstation 106 is configured to control the
interface platform 102 for control of the energy emission therapy
equipment.
[0056] The interface platform 102 is secured to a patient table 108
of an MRI system 110. The MRI system 110 may include a head coil
and stabilization system (herein stabilization system), an
instrument adaptor, and an MRI trajectory wand. Exemplary MRI
systems that can be utilized together with the features discussed
herein include those manufactured by Siemens AG, Munich, Germany
(including the MAGNETOM AVANTO, TRIO, ESPREE, VERIO MRI Systems,
which are trademarks and/or trade names of Siemens AG). Further,
example MRI systems include those manufactured by General Electric
Company, Fairfield, Conn. (including the SIGNA, OPTIMA and
DISCOVERY MRI systems, which are trademarks and/or trade names of
General Electric Company).
[0057] In certain embodiments, all of the above components of the
interface platform 102 and the energy emission therapy equipment
are MRI compatible, which refers to a capability or limited
capability of a component to be used in an MRI environment. For
example, an MRI compatible component operates and does not
significantly interfere with the accuracy of temperature feedback
provided by the MRI system operating with exemplary flux densities
including: magnetic flux densities of 1.5 T or 3.0 T, where no
hazards are known for a specified environment (e.g., 1.5 T or 3.0
T). Compatibility can also be defined with respect to one or more
other magnetic flux densities, including at least 0.5 T, 0.75 T,
1.0 T, 2 T, and 5 T.
[0058] In certain embodiments, the system electronics rack 104
includes cables, penetration panels and hardware that effectuate
mechanical, electrical, and electronic operation of the energy
emission therapy equipment and the MRI system 110. The system
electronics rack 104 may further be used to power and route control
signals and/or communications for the control workstation 106.
[0059] The workstation 106 includes a display that displays a user
interface, e.g., a graphical user interface (GUI) and/or a command
line interface that enables a user to plan a treatment procedure
and interactively monitor the procedure, the interface platform
102, and the entire MRI system 110. In certain embodiments, the
user interface also provides the user, e.g., a medical
professional, the ability to directly control the energy emission
therapy equipment including an energy source associated therewith,
and therefore, enables directly control of the application of the
therapy to the patient.
[0060] Turning to FIG. 2, an exemplary position of a patient on the
patient table 108 of the MRI system 110 is illustrated. The
interface platform 102 is secured to the patient table 108 together
with a head coil 202 and stabilization system, which is a head
fixation device that immobilizes a patient's head. The
stabilization system includes a head fixation ring 204. A probe 206
and probe driver 208 are coupled to probe introduction equipment
210, and to the interface platform 102 via umbilicals. A cable, for
example, can be used to provide data, laser, fluid, etc.
connections between the probe 206, probe driver 208, and interface
platform 102 and the electronics rack 104 in the MRI equipment room
(as illustrated in FIG. 1).
[0061] The probe introduction equipment 210, in certain
embodiments, includes at least a portion that is detectable by the
MRI system (e.g., included in temperature data that is displayed by
an imaging portion of the MRI system) and is used for trajectory
determination, alignment, and guidance of the probe 206. An MRI
trajectory wand (e.g., an MRI detectable, fluid-filled tube) may be
placed into the probe introduction equipment 210, for example, to
confirm a trajectory, associated with an intended alignment, to a
targeted tissue region, via MRI. After confirmation, the probe 206
may be introduced into the probe introduction equipment 210 to
effect surgery or therapy.
[0062] The probe 206 may be composed of MRI compatible materials
that permit concurrent energy emission and thermal imaging, and can
be provided in multiple lengths, cross-sectional areas, and
dimensions. Types of probes that can be utilized with the
components and procedures discussed herein include RF, HIFU,
microwave, cryogenic, and chemical release probes; the chemical
release probes may include photodynamic therapy (PDT), and drug
releasing probes. Treatments in accordance with the descriptions
provided in this disclosure include treatments that ablate (i.e.,
"treat") a tissue to destroy, inhibit, and/or stop one or more or
all biological functions of the tissue, or otherwise cause cell
damage or cell death that is indicated by a structural change in
cells of the targeted tissue area. Ablation can be effected by
laser, RF, HIFU, microwave, cryogenic, PDT and drug or chemical
release. A corresponding probe and/or other instrument, such as a
needle, fiber or intravenous line can be utilized to deliver one or
more of these ablation agents intracorporeally or percutaneously
and proximate to, in the vicinity of, abutting, or adjacent to a
targeted tissue area so as to effect treatment. The probe 206 can
be a gas-cooled probe so as to control delivery of the energy to
the targeted tissue area. The length and diameter of the probe 206
is preselectable based on the targeted tissue area and/or the ROI.
The probe 206, in some particular examples, can be a laser delivery
probe that is used to deliver laser interstitial thermal therapy or
a HIFU applicator that is used to deliver HIFU interstitial thermal
therapy.
[0063] The probe driver 208 controls positioning, stabilization and
manipulation of the probe 206 within a specified degree of
precision or granularity. Turning to FIG. 3, the components of the
probe driver 208 generally include a commander 302, umbilicals 304,
a follower 306, and a position feedback plug 308 that receives
position feedback signals from, for example, potentiometers within
the follower 306. The probe 206 (illustrated in FIG. 2) can be
inserted into the follower 306, and the follower 306 can control a
rotational and longitudinal alignment and/or movement of the probe
206. The probe driver 208 can further include a rotary test tool
(not illustrated) that can be used during a self-test procedure to
simulate attaching a probe to the follower 306. An exemplary probe
driver that can be utilized in accordance with the various aspects
presented in this disclosure is described in U.S. Pat. No.
8,728,092 to Qureshi, entitled "Stereotactic Drive System" and
filed Aug. 13, 2009, the entirety of which is incorporated herein
by reference.
[0064] The probe driver 208 (illustrated in FIG. 2) is mounted to
the interface platform 102. The position feedback plug 308
(illustrated in FIG. 3) connects to the interface platform 102 in
order to communicate the position of the probe 206 to the user
and/or the workstation 106 (illustrated in FIG. 1). The probe
driver 208 is used to rotate or translate, e.g., by extending or
retracting the probe 206. The probe driver 208, in a particular
example, can provide, at a minimum, a translation of 20-80 mm,
30-70 mm, 40-60 mm or 40 mm, with a maximum translation of 60 mm,
80 mm, 100 mm, 120 mm or 60-150 mm. The probe driver 208, further
to the example, can also provide, at a minimum, a rotation of
300.degree.-340.degree., with a maximum rotation of 350.degree.,
359.degree., 360.degree., 540.degree., 720.degree. or angles
therebetween.
[0065] Returning to FIG. 1, in certain embodiments, the workstation
106 outputs signals to the MRI system 110 to initiate certain
imaging tasks. In other implementations, the workstation 106
outputs signals to an intermediary system or device that causes the
MRI system 110 to initiate the imaging tasks. In certain
embodiments, the workstation 106 additionally outputs signals to
the electronics rack 104. The electronics rack 104 includes various
actuators and controllers that control the thermal therapy devices,
such as, in some examples, a cooling fluid pressure and/or a flow
rate of the cooling fluid, and a power source that powers a thermal
therapy device. In one example of a thermal therapy device, the
power source is a laser source that outputs laser light via an
optical fiber. As illustrated in FIG. 1, the electronics rack 104
is located in an MRI Equipment Room and includes storage tanks to
hold the cooling fluid, one or more interfaces that receive the
signals from the control workstation 106 and/or a separate MRI
workstation, an energy emission source (e.g. laser), and an output
interface. One or more of the interfaces are connected with or
include physical wiring or cabling that receives the signals and
transmits other signals, as well as physical wiring or cabling that
transmit energy to corresponding components in the MRI Scan Room
through a portal that routes the signals and/or energy in a manner
that minimizes any interface with or by the MRI system 110. The
wiring or cabling are connected at or by the interface platform 102
to corresponding components to effect and actuate control of a
thermal therapy device and/or an associated thermal therapy
session. Controlling the thermal therapy device, for example, by a
user in the MRI control room prevents the introduction of noise to
the MRI system, which includes the MRI cabin. The remotely
controlled procedure enhances thermal therapy efficiency and
accuracy by preventing heating loss due to stopping and restarting
energy application.
[0066] In certain embodiments, the system is indicated for use to
ablate, necrotize, carbonize, and/or coagulate the targeted tissue
area (e.g., an area of soft tissue) through interstitial
irradiation or thermal therapy, in accordance with neurosurgical
principles, with a HIFU thermal therapy device. The HIFU thermal
therapy device or probe includes ultrasonic transducers for
directing ultrasonic energy at the targeted tissue area, causing
the tissue to heat. The ultrasonic beam of the HIFU probe can be
geometrically focused (e.g., using a curved ultrasonic transducer
or lens) or electronically focused (e.g., through adjustment of
relative phases of the individual elements within an array of
ultrasonic transducers). In an ultrasonic transducer array, the
focused beam can be directed at particular locations, allowing
treatment of multiple locations of an ROI without mechanical
manipulation of the probe. The depth of treatment can be controlled
by adjusting the power and/or frequency of the one or more
transducers of the HIFU probe.
[0067] In certain embodiments, either additionally or alternatively
to HIFU thermal therapy, a laser-based thermal therapy is utilized
in the MRI system. Laser probes of a variety of outputs can be
utilized, including, in some examples, laser probes emitting laser
light having wavelengths of 0.1 nm to 1 mm, and laser probes
emitting laser light in one or more of the ultraviolet, visible,
near-infrared, mid-infrared, and far-infrared spectrums. Types of
lasers used with respect the laser probe include, for example, gas
lasers, chemical lasers, dye lasers, metal-vapor lasers,
solid-state lasers, semiconductor lasers, and free electron lasers.
In a particular example, one or more wavelengths of the laser light
emitted by the laser probe are within the visible spectrum, and one
or more wavelengths of the laser probe are within the near-infrared
spectrum.
[0068] In certain embodiments, the environment 100 can be utilized
for planning and monitoring thermal therapies effected via
MRI-imaging, and can provide MRI-based trajectory planning for the
stereotactic placement of an MRI compatible (conditional) probe.
The environment 100, in certain embodiments provides real-time
thermographic analysis of selected MRI images and thus, temperature
feedback information and/or thermal dose profiles for the targeted
tissue area. For example, thermographic analysis of the MRI images
can provide real-time verification of cellular damage in a targeted
tissue area that corresponds to necrosis, carbonization, ablation,
and/or coagulation. In another example, thermographic analysis can
be used to monitor tissue surrounding a periphery of an ROI to
ensure minimal if any damage to healthy tissues. Components of the
environment 100 may assist in guiding, planning, adjusting,
performing and confirming a thermal therapy session and
trajectories associated therewith.
[0069] A procedure includes, generally, identifying an ROI and/or
associated targeted tissue areas in a patient that should be
treated, planning one or more trajectories for treating the tissue,
preparing the patient and components for the treatment, and
performing the treatment. Aspects of the various parts of the
treatment are described throughout this disclosure, and an
exemplary sequence of treatment steps is illustrated in FIGS. 4A
and 4B.
[0070] Turning to FIG. 4A, a process flow diagram illustrates an
exemplary method 400 for pre-planning a treatment of a patient. In
pre-planning the thermal therapy session, in certain embodiments,
pre-treatment Digital Imaging and Communications in Medicine
(DICOM) image data is loaded and co-registered, for example, via
the workstation 106 (illustrated in FIG. 1). Using the DICOM image
data, one or more ROIs and/or targeted tissue areas and one or more
initial trajectories can be determined and set (402).
[0071] In preparation for treatment, in certain embodiments, a head
coil and fixation system is attached to the patient (404), for
example by positioning the head coil and stabilization system on
the surgical table. The patient can be immobilized using a head
fixation ring. To ensure stable imaging, for example, the patient's
head can be secured with the head fixation ring and remain fixed
for the entire imaging portion of the flow chart in FIG. 4A. An
example head fixation system is described below in relation to
FIGS. 6A through 6E.
[0072] Prior to applying thermal energy to an ROI, a probe entry
location into the skull is identified. In certain embodiments, a
burr hole is drilled in the skull (406). The burr hole may be
drilled prior to attachment of probe introduction equipment (e.g.,
a miniframe, anchoring device, guide stem, instrument sheath,
etc.). A twist-drill hole, in certain embodiments, can be created
following a trajectory alignment of the probe introduction
equipment. The twist-drill hole can have a size of 1-5 mm, 2 mm, 3
mm, 4 mm or 4.5 mm.
[0073] The probe introduction equipment, such as a stereotactic
miniframe or low profile anchoring device, in certain embodiments,
is attached to the patient's head (408). Probe aligning equipment,
such as the miniframe or guide stem, can then be aligned along the
intended trajectory, for example using image-guided navigation.
After attaching the probe introduction equipment, the head coil can
be attached. An exemplary head coil system is described below in
relation to FIG. 7. Depending on a process flow that is specific to
a surgical center, the interface platform may be attached prior to
or after MRI trajectory confirmation. The order of steps in a
site-specific process may be determined based on members of MRI or
surgical support team and may be determined during on-site training
with respect to the MRI system. The interface platform (IP) is
attached to the head end of the head coil and stabilization system.
Then, the IP power and motor plugs are connected.
[0074] In certain embodiments, the patient is positioned in the MRI
cabin, and MRI imaging is performed to confirm a trajectory (410)
associated with a thermal therapy device and/or probe introduction
equipment. For example, an MRI trajectory wand may be inserted into
the probe introduction equipment for use in confirming its
trajectory. The trajectory of the probe introduction equipment, for
example, can be evaluated using MRI imaging prior to inserting a
probe into the brain. Volumetric imaging or volumetric
visualization may be captured to include the entire head and full
extent of the probe introduction equipment. Along with trajectory
confirmation, in some examples, beam fiducial marker detection may
also be performed. For example, the captured images may also
display a position of a beam fiducial marker located in a portion
of the probe introduction equipment. This marker can be detected
and identified by the MRI imaging system and method to store an
orientation of the physical direction of the probe. The captured
images, in implementations where pre-treatment image data is not
available, can be used for planning a thermal therapy session.
[0075] In certain embodiments, a probe actuation and guidance
device (e.g., a follower) and a test tool are attached to the probe
introduction equipment, to provide positional feedback for a
self-test function (412). The self-test function, for example, may
be used to confirm that inputs to the probe actuation and guidance
device, (e.g., from the workstation), accurately and/or precisely
drive the probe. Upon completing the self-test function, the rotary
test tool may be removed. Upon completing the procedure described
in relation to FIG. 4A, the procedure equipment may be introduced
and the procedure initiated.
[0076] Turning to FIG. 4B, a process flow diagram illustrates an
exemplary method 420 for a treatment procedure. In certain
embodiments, a probe is attached and inserted into the probe
introduction equipment and/or the patient's skull (e.g., secured
for manipulation via the probe actuation and guidance device)
(422). Exemplary implementations of neurosurgical probes are
discussed in below under the section entitled "Probes." It is noted
that different types of probes can be used in conjunction different
types of thermal therapy, for example, when an ROI is not in the
brain. An MRI scan can then be conducted to ensure probe alignment
is correct and confirm movement and delivery of the probe along the
intended trajectory. In one example, the acquired image data can be
displayed, along with pre-planning image data by the workstation
106. Using a graphical user interface (GUI), a user can adjust the
probe displayed by the GUI by interacting with, for example, the
GUI to match the probe artifact on the acquired image to ensure
that the alignment and arrangement of the probe as physically
placed in the probe introduction equipment and inserted into the
patient coincides with the rendered probe at the workstation. The
probe's trajectory, for example, can be adjusted to a desired
position for delivering thermal energy, via interaction with the
GUI. Further, the probe's rotational position can also be adjusted
to a desired direction or angle for thermal delivery, via
interaction with the GUI. Once the probe rendering presented by the
GUI matches the probe artifact on the display, the user may confirm
the trajectory via the GUI.
[0077] In certain embodiments, one or more scan planes are selected
for cuing a thermal monitoring sequence via the MRI system's
sequence protocol list (424). In another embodiment, a 3D volume is
selected and in yet another embodiment, a linear contour is
selected. Parameters associated with scan plane, in some examples,
can be entered by a user via a workstation connected with the MRI
system or directly into the thermal monitoring sequences protocol's
geometry parameters of the MRI.
[0078] In certain embodiments, temperature feedback information
and/or thermal dose profiles are initialized and monitored (426).
For example, under a noise masking heading of the workstation
interface, at least three reference points (e.g., six, twelve,
twenty, etc.) can be selected by the user at the periphery of the
ROI. The ROI, for example, may include an overlaid, orange noise
mask in one or more image monitoring view panes to illustrate the
intended thermal delivery area. The noise masking may be used to
improve accuracy of temperature monitoring during tissue
treatment.
[0079] In certain embodiments, energy delivery via the probe is
actuated to begin the thermal therapy session (428). For example,
once "Ready" indicator or the like is displayed under a laser
status heading of the GUI at the workstation, the user may depress
a foot pedal operatively connected to the workstation to deliver
thermal energy to the ROI or a targeted tissue area within the ROI.
Thermal energy can then be either continuously or intermittently
delivered while monitoring thermal dose profiles, which can be
presented as contours that are overlaid onto one or more (e.g.,
three) thermal monitoring view panes rendered by the GUI of the
work station. Thermal delivery may be halted as desired or as
necessary by releasing the foot pedal. The view panes, for example,
may display an energy dose profile or thermal dose profile supplied
by the probe, with respect to a specified time period and/or a
specified targeted tissue area or ROI; the thermal dose or energy
dose profile can be displayed as a succession of temperature
gradients. The thermal dose profiles and/or the temperature
gradients permit the determination of an extent of cellular damage
in the targeted tissue area and/or other effects upon the targeted
tissue area occurring as a result of the thermal therapy.
[0080] Once a thermal dose for a particular alignment and
positioning of the probe is completed, if further probe alignments
are desired within the treatment plan (430), a rotational and/or
linear alignment of the probe may be adjusted (432) by translating
or rotating the probe. For example, an energy output of the probe
may be terminated and then the probe may be subjected to linear
translation and/or rotational movement, which can be controlled,
for example, by a probe driver (a particular implementation of
which is illustrated in FIG. 3). After adjusting the probe
alignment, in certain embodiments, the process returns to step 422
to verify a current placement of the probe. In certain embodiments,
a second thermal treatment procedure is not initiated (e.g., when
repeating step 428) until one or more targeted tissue areas within
the ROI returns to a baseline body temperature. The thermal dose
associated with the one or more targeted tissue areas in the ROI,
as described in relation to steps 422 through 432, may continue at
various probe rotational and/or linear alignments until the entire
ROI has been treated.
[0081] Upon determining that the thermal therapy is complete (430),
should treatment with an additional probe be needed or desired
(434), the procedure can be repeated by attaching the new probe to
the probe introduction equipment and verifying probe placement
(422). If, instead, the second probe was initially included within
the probe introduction equipment (e.g., via a separate lumen in a
guide sheath in relation to the first probe), the user may initiate
positioning of the second probe, for example, via the GUI, and
verify placement of the second probe (422). A multi-probe
configuration is described in greater detail in relation to FIG.
5I.
[0082] If the second probe is being deployed to treat the same ROI
or the same targeted tissue area at the same linear and rotational
alignment(s) associated with the first probe, in certain
embodiments, step 424 involving selection of scan planes for the
cuing the thermal monitoring sequence may be skipped. If, instead,
a second probe is deployed at a different linear position or a
different trajectory, step 422 may be performed to confirm the
trajectory and alignment of the second probe.
[0083] When the thermal therapy is complete (434), in certain
embodiments, the patient is removed from the MRI bore and the
probe, probe actuation and guidance device, and probe introduction
equipment are detached from the patient. The bore hole may be
closed, for example, at this time.
[0084] II. Low Profile Probe Introduction Equipment
[0085] A. Low Profile Skull Anchoring Device
[0086] In certain embodiments, when preparing for an intracranial
neurosurgical procedure, a patient 502 is fitted with a low profile
skull anchoring device 504, as illustrated in an exemplary mounting
illustration 500 of FIG. 5A. The low profile skull anchoring device
504 may be releasably attached to the head of the patient 502, for
example, using three or more bone anchors mounted to the skull of
the patient 502. Turning to FIG. 5B, the low profile skull
anchoring device 504 includes three bone screws 508 for connecting
to bone anchors within the skull of the patient 502, as well as
pins 510 for further securing the low profile skull anchoring
device 504 to the head of the patient 502 and for ensuring that the
low profile skull anchoring device 504 mounts above the surface of
the head of the patient 502. In this way, there will be minimal or
no compression of the patient's scalp, and frameless, on-trajectory
access is provide, as discussed in further detail below. In one
embodiment, the low profile skull anchoring device 504 has an oval
or an oblong shape.
[0087] In one embodiment, the screws 508 and pins 510 are composed
of, for example, titanium. It should be noted that the screws 508
and the pins 510 are not necessarily limited to three pins; the
number of screws 508 and pins 510 is the number which is necessary
to provide sufficient rigidity. The screws 508 and pins 510 may be
evenly spaced around the circumference of the low profile skull
anchoring device 504 (e.g., positioned approximately every 120
degrees). In another embodiment, the screws 508 and pins 510 are
positioned at unequal distances apart, for example, based on an
irregular skull curvature. In yet another embodiment, the screws
508 and the pins 510 are movable with respect to the low profile
skull anchoring device 504. In still another embodiment, the screws
508 are replaced with a sufficiently rigid adhesive or a staple,
each of which provide sufficient rigidity to allow for the drilling
of a burr hole in the skull.
[0088] Due to the low height of the low profile skull anchoring
device 504, the medical team is provided with greater access for
lateral trajectories of biopsy, probes, and other apparatus to be
inserted intracranially into the patient 502 via the low profile
skull anchoring device 504. This may be especially useful when
working within the confines of an MRI bore, for example during
MRI-guided thermal therapy treatments. As such, the low profile
skull anchoring device 504 may be composed of MRI compatible
materials and, optionally, include MRI visible markers for aligning
a desired trajectory or defining a particular direction relative to
the low profile skull anchoring device 504. In another example, the
low profile skull anchoring device 504 may allow easier access to
back-of-the-head entry trajectories, such as trajectories used in
performing epilepsy treatments. A mounting height of the low
profile skull anchoring device 504, for example, may be thirty
millimeters or less from the surface of the skull of the patient
502.
[0089] In some implementations, the low profile skull anchoring
device 504 includes one or more fiducial markers for reference
within an MRI scan. For example, the low profile skull anchoring
device 504 may include at least three fiducial markers used, in an
MRI scan, to identify a position and orientation of the low profile
skull anchoring device 504 as attached to the surface of the skull
of the patient 502. In a particular example, three fiducial
markers, at least one of which having a unique length, width,
and/or shape in comparison to the others, may be positioned upon
the low profile skull anchoring device 504 to allow for visual
display and confirmation of a position and orientation of the low
profile skull anchoring device 504 as attached to the skull of the
patient 502. The fiducial marker(s) may be held in place via any
suitable connector including, but not limited to, an adhesive or
the like.
[0090] B. Removable Guide Stem
[0091] Turning to FIG. 5A, the low profile skull anchoring device
504 includes a removable guide stem 506. The removable guide stem
506, in some examples, may lock to the low profile skull anchoring
device 504 using a screw mechanism, keyed locking mechanism, or
other connector configured to firmly connect the removable guide
stem 502 to the low profile skull anchoring device 504 with
relative ease of removal.
[0092] Turning to FIG. 5B, the exemplary the low profile skull
anchoring device 504 includes three connection points 512 for
securing the removable guide stem 506 to the low profile skull
anchoring device 504. The removable guide stem 506, for example,
may include a series of guide stem connectors 514 (e.g., screws or
locking pins) which mate with the connection points 512 of the low
profile skull anchoring device 504, as shown in FIGS. 5A and 5C. In
one embodiment, the alignment of the guide stem connectors 514 and
the connection points 512 differs based on a skull curvature of the
patient.
[0093] A central cylindrical portion of the removable guide stem
506 is configured to receive various adapters and/or instruments
such as, in some examples, drill bits, biopsy needles, and
treatment probes. The central cylindrical portion of the removable
guide stem 506, in certain embodiments, is rotatably adjustable,
allowing an orientation of central cylindrical portion of the
removable guide stem 506 to be manipulated to align the probe in
accordance with a desired trajectory. Upon alignment, in certain
embodiments, a locking mechanism 516 may be actuated to lock the
central cylindrical portion of removable guide stem 506 into place
at the set alignment.
[0094] Turning to FIG. 5C, the removable guide stem 506 may
include, for example, a ball joint 518 for establishing an
adjustable trajectory for passing instruments to the skull of the
patient 502 via the central cylindrical portion of removable guide
stem 506. In certain embodiments, the central portion has another
geometric or polygonal shape that corresponds to a cross-section of
the probe. In certain embodiments, interior portions of the central
cylindrical portion of the removable guide stem 506 are deformable
so as to cover an outer surface of the probe. In still other
embodiments, the interior portions of the central cylindrical guide
stem are comprised of shape memory alloys that have a transition
temperature that exceeds a maximum temperature associated with a
specified thermal therapy.
[0095] The ball joint 518 can achieve a number of trajectories that
is based on the granularity with which the ball joint 518 is
manipulated. Upon setting the trajectory of the central cylindrical
portion of removable guide stem 506, for example, the ball joint
518 may be clamped into position using the locking mechanism 516.
In one embodiment, the locking mechanism 516 is a cam lock. In
another embodiment, the locking mechanism 516 is a ring clamp. In
still another embodiment, the locking mechanism 516 has a screw
engagement.
[0096] Turning to FIGS. 5D and 5E, illustrative examples of a
removable guide stem 520 including both a tilt adjustment 522 and a
rotation adjustment 524 are shown. The separate tilt adjustment 522
and rotation adjustment 524, for example, may be used to more
precisely adjust a trajectory of the central cylindrical portion of
removable guide stem 520. Upon adjusting the tilt adjustment 522,
for example, a tilt lock mechanism 526 (e.g., screw, pin and slot,
etc.) may be activated to hold the central cylindrical portion of
removable guide stem 520 at the tilt position. In another example,
upon adjusting the rotation of the central cylindrical portion of
removable guide stem 520, for example by turning the rotation
adjustment 524, a rotation lock mechanism 528 (e.g., screw, pin and
slot, etc.) may be activated to hold the removable guide stem 520
at the selected rotation. In an embodiment, either or both of the
tilt lock mechanism 526 and the rotation lock mechanism 528 are
actuated by a motor. In another embodiment, the motor is wirelessly
controlled via a remotely located controller. The removable guide
stem 520 is removable during a thermal therapy session, prior to
completion of the treatment, and independent of removing the low
profile skull anchoring device 504.
[0097] In certain embodiments, guide lines such as a set of guide
lines 530 are marked on the removable guide stem 520 (or the
removable guide stem 506 illustrated in FIG. 5A) to provide a user
with an indication of the selected trajectory. For example, an
angle of tilt in relation to the low profile skull anchor 504 may
be selected via the guide lines 530 (e.g., within a one, two, or
five degree angle of adjustment). The guide lines 530, in certain
embodiments, are MR indicators, such that an MR image captured of
the removable guide stem 520 will allow a software package to
register an initial trajectory in relation to the head of the
patient (e.g., patient 502 of FIG. 5A).
[0098] In certain embodiments, in addition to a tilt and rotation
adjustment, either the first removable guide stem 506 or the second
removable guide stem 520 may be modified to include an x,y degree
of freedom adjustment mechanism (not illustrated). In this manner,
a position of the central cylindrical portion of guide stem 506 in
relation to a burr hole opening beneath the low profile skull
anchor 504 may be adjusted by the user, thus providing
on-trajectory access. Rather than the central cylindrical portion
of guide stem 506 or 520 being centered within the low profile
skull anchor 504, for example, an x,y adjustment mechanism may
allow an offset of the central cylindrical portion of removable
guide stem 506 or 520. In a particular example, should the burr
hole fail to be centered between bone anchors planted within the
skull of the patient 502, the central cylindrical portion of guide
stem 506 or 520 may be adjusted by up to at least ten to twenty
millimeters to be centered above the burr hole using an x,y
adjustment mechanism.
[0099] In some implementations, the removable guide stem 506 or 520
includes at least one fiducial marker for identifying, via an MRI
scan, at least an angle of trajectory of the removable guide stem
506 or 520. If the removable guide stem 506 or 520 additionally
includes an adjustment mechanism, fiducial marker(s) may be used to
identify the x,y offset of the removable guide stem 506 or 520
relative to the low profile anchoring device 504.
[0100] Turning to FIG. 5B, upon removal of the removable guide stem
506 or 520, the skull entry location becomes accessible, for
example to allow for formation of a burr hole or to otherwise
prepare the skull entry location. After preparation of the
entrance, the removable guide stem 506 or 520 may be locked to the
low profile skull anchor 504. For example, as illustrated in FIG.
5D, the removable guide stem 520 may be locked to the low profile
skull anchor device 504 by attaching screws at three connection
locations 532. At any point in a procedure, should access to the
entrance be desired, the guide stem 520 may be removed. Removal of
the guide stem 520, for example, allows a medical professional
quick access to react to bleeding or to adjust the burr hole
opening for trajectory correction.
[0101] When performing a medical procedure via the low profile
skull anchoring device 504, in certain embodiments, the low profile
skull anchoring device 504 may first be aligned with screw anchors
mounted upon the patient's skull and then screwed to the head of
the patient 502, as illustrated in FIG. 5A. The skull entry
location may be prepared for treatment during the thermal therapy
while the removable guide stem 506 or 520 has been separated from
the low profile skull anchoring device 504. Following preparation
of the skull entry location, the removable guide stem 506 or 520
may be replaced and its trajectory aligned.
[0102] To align the removable guide stem 506, 520 with a desired
treatment trajectory, in certain embodiments, the removable guide
stem 506, 520 is manipulated via an image guided system (e.g.,
MRI-imaging system) or manipulated via a trajectory planning module
of an MRI-imaging method. The manipulations of the removable guide
stem 506, 520, for example, may be performed by a probe actuation
and guidance device. In a particular example, as described in
relation to the method 400 of FIG. 4A, a test tool may be inserted
into the removable guide stem 506, 520, and the test tool may be
aligned with pre-treatment image data to determine an initial
trajectory. In other implementations, a user manually adjusts the
trajectory of the removable guide stem 506, 520. Alignment of the
trajectory of the removable guide stem 506, 520, in certain
embodiments, is aided by one or more guide lines or fiducial
markers upon the surface of the low profile skull anchoring device
504 and/or upon the surface of the removable guide stem 506, 520,
such as the guide lines 530 illustrated in FIG. 5D.
[0103] Upon positioning the trajectory of the removable guide stem
506, 520, in certain embodiments, the trajectory is locked via a
locking mechanism, such as the locking mechanism 516 of FIG. 5C or
the locking mechanisms 526 and 528 of FIG. 5D.
[0104] After the removable guide stem 502 has been locked into its
initial trajectory, in certain embodiments, instruments may be
guided into the skull via the removable guide stem 506 or 520. For
example, biopsy tools, a thermal treatment probe, medicament
delivery probe, or other neurosurgical device may be delivered to a
ROI of the brain of the patient via the removable guide stem 506 or
520.
[0105] C. Guide Sheath
[0106] Turning to FIGS. 5F and 5G, in certain embodiments, rather
than inserting instruments directly into the removable guide stem
506 or 520, a guide sheath 540 is inserted into the removable guide
stem (e.g., removable guide stem 506). The guide sheath 540 may
include, for example, one or more distal openings and one or more
proximal openings to introduce at least one neurosurgical
instrument to the ROI in the patient's brain.
[0107] In certain embodiments, instead of using the guide sheath
540 configured for receipt of neurosurgical devices, a hollow
trocar may be introduced via the removable guide stem 506 or 520 to
prepare an initial entry into a region of the brain. For example,
when entering a particularly fibrous area, rather than pushing in
directly with a neurosurgical instrument and risking damage to the
neurosurgical instrument, a trocar or stylette, for example with a
bullet shaped nose and sharp distal opening, may be used to cut a
path for the neurosurgical instrument. In other implementations, a
stylette or trocar may be introduced to the ROI via the guide
sheath 540. In one embodiment, the guide sheath 540 has a shape of
a 3D almond. In another embodiment, a ball joint portion of the
guide sheath 540 rotates around a track. In yet another embodiment,
the probe holder is attached at a non-zero angle to the
longitudinal access of at least a portion of the probe.
[0108] In certain embodiments, the guide sheath 540 locks to the
removable guide stem 506. The guide sheath 540, for example, may be
configured to lock to the removable guide stem 506 at a variable
linear height depending upon a distance between the skull opening
and a ROI. In this manner, the guide sheath 540 may be deployed in
proximity to, in the vicinity of, or adjacent to an ROI without
abutting or entering the ROI. As such, upon removal of one or more
neurosurgical instruments via the guide sheath 540, cells from the
ROI will not be able to contaminate other regions of the patient's
brain.
[0109] Turning back to FIG. 5C, in certain embodiments, a guide
stem locking mechanism 519 may be used to clamp the guide sheath
540 at a particular linear depth. The guide sheath 540, in a
particular example, may have spaced indentations or other
connection points for interfacing with the guide stem locking
mechanism 519 (e.g., set screw or spring-loaded plunger). The
indentations (or, alternatively, ratcheting teeth) may be
positioned at precise measurements (e.g., 1 mm apart) to aid in
linear position adjustment. In other examples, the guide sheath 540
and guide stem locking mechanism 519 may be configured to provide
positive feedback to a medical professional during adjustment. For
example, a linear actuator system such as a rack and pinion may be
used to provide precise linear position adjustment (e.g., one
"click" per millimeter). Upon adjustment, to lock the guide sheath
540 at the selected linear position, in certain embodiments a cam
lock mechanism may be used to engage teeth or depressions within
the guide sheath 540. For example, a cam lock mechanism such as the
locking mechanism 516 illustrated in FIG. 5C may be used to lock
the guide sheath 540 at a selected linear depth.
[0110] Turning back to FIG. 5D, the removable guide stem 520
similarly includes a guide stem locking mechanism 534. In other
implementations, the guide sheath 540 may directly connect to the
low profile skull anchoring device 504 or to another receiving port
connected to the low profile skull anchoring device 504 (not
illustrated).
[0111] The guide sheath 540, upon interlocking with the guide stem
506, 520 and/or the low profile skull anchoring device 504 and
receiving one or more neurosurgical tools, may create an air-tight
seal during a neurosurgical operation. For example, the proximal
and/or distal end of the guide sheath 540 may include a receiving
port adaptable to the surgical instrument being introduced. In
certain embodiments, various guide sheaths can be used
interchangeably with the guide stem 506, 520, such that a guide
sheath corresponding to the surgical instrument diameter may be
selected. In other implementations, one or more guide sleeves (not
illustrated) may be secured inside the guide sheath 540, each of
the one or more guide sleeves having a different distal end
diameter. A divided (e.g., bifurcated) guide sleeve, in certain
embodiments, may be used to introduce two or more instruments
simultaneously or concurrently, each with a particular instrument
diameter.
[0112] In certain embodiments, the guide sheath 540 is
intracranially delivered using an introducer and guide wire. An
image guidance system, such as the MRI imaging system, may be used
instead of or in addition to the introducer and guide wire during
placement of the guide sheath 540. The guide sheath 540 may be
composed of MRI compatible materials.
[0113] The materials of the guide sheath 540, in certain
embodiments, are selected to provide rigid or inflexible support
during introduction of one or more neurosurgical tools within the
guide sheath 540. For example, the guide sheath 540 may be composed
of one or more of Kevlar, carbon fiber, ceramic, polymer-based
materials, or other MRI-compatible materials. The geometry of the
guide sheath 540, in certain embodiments, further enhances the
strength and rigidity of the guide sheath 540.
[0114] In certain embodiments, the guide sheath 540 (or guide
sleeve, as described above) includes two or more lumens for
introduction of various neurosurgical instruments. By introducing
two or more neurosurgical instruments via the guide sheath 540, a
series of treatments may be performed without interruption of the
meninges layer between treatments. For example, FIG. 5I illustrates
two neurosurgical instruments 552 and 554 that are simultaneously
inserted into a guide sheath 550 and can be used to carry out
treatment of a tissue consecutively, concurrently, or
simultaneously.
[0115] Neurosurgical instruments deployed via the guide sheath 540
may exit a same distal opening or different distal openings. In
certain embodiments, the guide sheath 540 may include at least one
off-axis distal opening. For example, as illustrated in FIG. 5H,
exemplary guide sheath 550 includes a contact surface 556 having a
predefined angle. Upon encountering the contact surface 556, the
trajectory of a surgical instrument 552 presented through the guide
sheath 550 may be deflected to exit the proximal end via an
off-axis delivery hole 558, as illustrated in FIG. 5I. The angles
shown in FIGS. 5H and 5I can be considered as drawn to scale in one
implementation. However, the alignment of the contact surface 556
and the delivery hole 558 can be varied by adjusting their
respective axial angles. By adjusting these angles, a number of
possible positions of the surgical instrument 554 are provided.
Further, multiple off-axis delivery holes and multiple contact
surfaces can be provided, which are displaced from each other in a
direction of the longitudinal axis of the guide sheath.
[0116] Upon introducing a neurosurgical instrument such as a probe,
in certain embodiments, the guide sheath 510 enables coupling
between the probe and a probe actuation and guidance device. For
example, commands for linear and/or rotational control of the probe
may be issued to the probe via an interface within the guide sheath
540.
[0117] III. Probes
[0118] A number of different probes can be utilized in accordance
with the various aspects presented in this disclosure. Example
probes are described in: U.S. Pat. No. 8,256,430 to Torchia,
entitled "Hyperthermia Treatment and Probe Therefor" and filed Dec.
17, 2007; U.S. Pat. No. 7,691,100 to Torchia, entitled
"Hyperthermia Treatment and Probe Therefor" and filed Aug. 25,
2006; U.S. Pat. No. 7,344,529 to Torchia, entitled "Hyperthermia
Treatment and Probe Therefor" and filed Nov. 5, 2003; U.S. Pat. No.
7,167,741 to Torchia, entitled "Hyperthermia Treatment and Probe
Therefor" and filed Dec. 14, 2001; PCT/CA01/00905, entitled "MRI
Guided Hyperthermia Surgery" and filed Jun. 15, 2001, published as
WO 2001/095821; and U.S. patent application Ser. No. 13/838,310,
entitled "Image-Guided Therapy of a Tissue" and filed Mar. 15,
2013. These documents are incorporated herein by reference in their
entireties.
[0119] A number of probe lengths are provided in any of the probe
examples described herein based on a degree of longitudinal travel
allowed by a follower and a depth of the tissue to be treated. An
appropriate probe length can be determined by the interface
platform and/or the workstation during a planning stage, or
determined during a trajectory planning stage.
[0120] Exemplary probe lengths can be indicated on the probes with
reference to a probe shaft color, in which white can indicate
"extra short" having a ruler reading of 113 mm, yellow can indicate
"short" having a ruler reading of 134 mm, green can indicate
"medium" having a ruler reading of 155 mm, blue can indicate "long"
having a ruler reading of 176 mm, and dark gray can indicate "extra
long" having a ruler reading of 197 mm. Different model numberings
can also be utilized on the probes to indicate different
lengths.
[0121] An energy output pattern of a probe, such as a laser probe
or HIFU probe, in certain embodiments, includes a pulsed output
pattern. For example, a higher power density may be achieved
without causing tissue scorching by pulsing a high power laser
treatment for x seconds with y seconds break between (e.g.,
allowing for tissue in the immediate vicinity to cool down). In a
particular example, the energy output pattern of a probe may
include a ten Watt output for two seconds followed by a one second
period of inactivity. In certain embodiments, a particular energy
output pattern may be developed based upon the type of probe (e.g.,
laser, HIFU, etc.), an emission style of the probe tip (e.g.,
side-firing, diffuse tip, etc.), and/or the depth of the ROI or the
targeted tissue area (e.g., based in part on the shape of a tumor
region, etc.).
[0122] In certain embodiments, a treatment pattern includes
effecting treatment while concurrently or simultaneously moving the
probe (e.g., linearly and/or rotationally). For example, a HIFU
probe may be automatically rotated (e.g., using a commander and
follower as described in FIG. 3, etc.) while an emission pattern is
simultaneously or concurrently adjusted to effect treatment to a
desired depth based upon a particular geometry of the ROI. In this
manner, for example, while the ultrasonic probe's beam is focused
on a radial portion of the tumor having a depth of 1.5 centimeters,
the power density of the HIFU probe may be tuned for the first
treatment depth. Upon rotation, a second radial portion of the
tumor may have a depth of 2 centimeters, and the power density of
the HIFU probe may be increased accordingly to tune for the
treatment depth of 2 centimeters.
[0123] A. Side-Fire HIFU Probe
[0124] Turning to FIG. 9A, a view 900 of an exemplary treatment
scenario involving a HIFU probe 902 deployed to treat an ROI 906 is
illustrated. HIFU technology advantageously provides directional
control and greater depth penetration as compared with laser-based
thermal therapy. For example, in comparison to laser therapy,
ultrasonic therapy may achieve at least three to four times greater
depth penetration. For example, estimated depths of thermal
treatment using HIFU technology include three to five centimeters
or greater than six centimeters. By completing treatment via an
initial trajectory, the treatment may be performed faster and less
invasively than it may have been performed using a laser probe. As
such, a HIFU probe may be used to treat a larger ROI without the
need to adjust a probe trajectory or introduce the probe into
multiple locations within the brain. Although treatment may be
provided at a greater depth, it also may be provided using a narrow
focal beam, containing a width of the treated tissue. Furthermore,
although HIFU-based thermal therapy can advantageously achieve a
greater penetration depth than laser-based thermal therapy, the
ultrasonic treatment has greater uniformity over temperature
gradients than laser-based thermal therapy, which heats a portion
of the targeted tissue area close to the probe much more rapidly
than portions of the targeted tissue area further away from the
probe. In selecting thermal therapy via a HIFU probe, scorching or
carbonization of the targeted tissue area close to the probe may be
avoided and/or the HIFU probe may be operated independently of
external cooling to protect immediately surrounding tissue.
[0125] In performing thermal therapy using a HIFU probe,
constructive and destructive interference can be utilized by
selecting a number of different longitudinal spaced emission points
to fine tune a position and depth of energy applied to a targeted
tissue area and/or an ROI. As such, the depth of energy, as such,
may be tuned to conform with a non-uniform, irregular, and/or
non-polygonal shape of the ROI which, for example, corresponds to a
tumor. Preparing trajectories, determining linear translational
adjustments and/or rotational movements, and/or energy output
patterns may be selected and/or optimized to prevent heating of the
skull and/or bouncing energy off of the surfaces of the skull. HIFU
treatment, in some examples, can be used for opening a blood-brain
barrier, coagulation of tissue, or cavitation of tissue.
[0126] The HIFU probe 902 includes one or more side-firing
transducers 904 for effecting treatment to the ROI 906. The
ultrasonic transducer(s) 904 may be flat or rounded. The HIFU
probe, in some examples, can include a shaft composed of plastic,
brass, titanium, ceramic, polymer-based materials, or other
MRI-compatible materials in which one or more ultrasonic
transducer(s) 904 have been mounted. The ultrasonic transducer(s)
904 may be mounted upon an interior surface of the shaft of the
HIFU probe 902. The ultrasonic transducer(s) 904 may include a
linear array of individually controllable transducers, such that a
frequency or power output of each transducer 904 may be
individually tuned to control a treatment beam of the HIFU probe
902. For example, as illustrated in FIG. 9C, the tip of the probe
902 can include a linear array of three transducers 904. The
longitudinally spaced apart transducers 904 can be spaced equally
apart. However, in other implementations, the spacing between the
transducers 904 can be unequal.
[0127] In certain embodiments, the HIFU probe 902 includes a
cooling mechanism for cooling the ultrasonic transducers 904. For
example, a cooling fluid or gas may be delivered to the tip of the
HIFU probe 902 to control a temperature of the ultrasonic
transducer(s) 904. Additionally, the ultrasonic transducer(s) 904
may be surrounded by an acoustic medium, such as an acoustic
coupling fluid (e.g., water) to enable ultrasonic frequency tuning
of the ultrasonic transducer(s) 904.
[0128] As illustrated in FIG. 9A, the HIFU probe 902 is embedded
within an ROI 906 spanning multiple MR thermal monitoring planes
908. During treatment, thermal effects within each MR thermal
monitoring plane 908 may be monitored in order to monitor thermal
coagulation of the ROI 906. Information derived from the thermal
monitoring, for example, may be fed back into control algorithms of
the HIFU probe 902, for example, to adjust a power intensity and/or
frequency of the HIFU probe to tune a depth of treatment of the
ultrasonic beam or to adjust a rotational and/or linear positioning
of the HIFU probe 902 upon determining that ablation is achieved at
a current rotational and linear position.
[0129] To increase the monitoring region, additional MR thermal
monitoring planes 908 may be monitored (e.g., between four and
eight planes, up to twelve planes, etc.). Alternatively, in certain
embodiments, the three thermal monitoring planes 908 may be spread
out over the y-axis such that a first gap exists between plane 908a
and plane 908b and a second gap exists between plane 908b and plane
908c. The thermal monitoring algorithm, in this circumstance, can
interpolate data between the MR thermal monitoring planes 908.
[0130] In other implementations, rather than obtaining parallel
images of MR thermal monitoring planes, at least three thermal
monitoring planes, each at a distinct imaging angle bisecting an
axis defined by a neurosurgical instrument such as a thermal
ablation probe, may be interpolated to obtain thermal data
regarding a three-dimensional region.
[0131] Turning to FIG. 10A, an aspect illustration 1000
demonstrates three MR thermal monitoring planes 1002 for monitoring
ablation of an ROI 1004 by a probe 1006. The angles between the
thermal monitoring planes, in some examples, may be based upon an
anatomy of the region of the skull of the patient or a shape of the
ROI. The angles, in some examples, may differ by at least ten
degrees.
[0132] Turning to FIG. 10B, an end view 1010 of the probe 1006
provides an illustrative example of MR thermal monitoring planes
1002 that are each offset by sixty degrees. In comparison to using
parallel MR thermal monitoring planes, the thermal monitoring
planes 1002 provide a more realistic three-dimensional space. Thus,
volumetric visualization is provided. In certain embodiments,
volumetric visualization that independent of ablation is provided.
Temperature gradients and/or thermal dose profiles between the
thermal monitoring planes 1002 can be interpolated. Similar to
increasing a number of parallel MR thermal monitoring planes, in
other implementations, four or more thermal monitoring planes may
be captured and combined, for example, to increase thermal
monitoring accuracy.
[0133] As a result of the side-firing capability of the HIFU probe
902, a number of rotationally different portions of the ROI can be
treated with the ultrasonic energy by rotating the HIFU probe 902.
For example, as illustrated in an x-axis sectional view 910, the
HIFU probe 902 may be rotated is illustrated in an arrow 912 to
effect treatment throughout the ROI 906. Additionally, the HIFU
probe 902 can be longitudinally translated, for example
automatically by a follower of a probe driver, to change a
longitudinal position at which ultrasonic energy is applied within
the ROI 906.
[0134] Rotation, power intensity, duty cycle, longitudinal
positioning, and cooling, in certain embodiments, are controlled by
the electronics rack 104 and the workstation 106, such as the
electronics rack 104 and workstation 106 described in relation to
FIG. 1. A sequence, such as an algorithm or software encoding, can
be executed to cause a probe tip or a number of probe tips to
execute a particular energy output pattern effect a predefined
thermal therapy to a targeted tissue area. The energy output
pattern can be based on rotational and/or longitudinal movements of
the probe.
[0135] B. Pre-Shaped Probe
[0136] Turning to FIG. 8, in certain embodiments, a probe delivery
apparatus 800 includes a pre-shaped probe 802 (e.g., laser probe)
that accesses an ROI 806 along a curved path. The pre-shaped probe
802 can be provided proximate to the ROI 806 through a rigid sheath
804 or guide cannula. Although the rigid sheath 804 is straight,
the pre-shaped probe 802 is flexible such that it exits the rigid
sheath 804 in a predetermined arc. The curvature of the pre-shaped
probe 802, for example, can be configured to deploy towards a known
radial position, for example in a quarter arc of a circle. In
exiting the rigid sheath 804, the pre-shaped probe 802 follows a
clean arc along a path into the ROI 806. In this manner, the
pre-shaped probe 802 avoids tearing tissue, for example due to
pushing a distal end of the probe against the targeted tissue area
and/or an ROI.
[0137] In certain embodiments, the pre-shaped probe 802 includes a
wire and/or polymer encasement for a laser fiber. The materials of
the pre-shaped probe 802, for example, may prevent the laser probe
(and optical fiber corresponding thereto) from straightening, which
is its natural inclination. The pre-shaped probe 802, in certain
embodiments, is composed of MRI-compatible materials to enable use
in MRI-guided neurosurgery. In one example, the pre-shaped probe
may include a polymer tubing with a pre-curved band to the probe
tip, surrounding a laser fiber. In certain embodiments, a tip
region of the pre-shaped probe 802 includes at least one fiducial
marker to aid in validating an angle of deployment from the rigid
sheath 804.
[0138] During thermal therapy, the pre-shaped probe 802, in certain
embodiments, may be deployed into the ROI 806 at a first location,
then withdrawn into the rigid sheath 804, rotated, and deployed
into the ROI 806 at a different radial location. A range outline
808 demonstrates a rotational range of the pre-shaped probe 802 at
a current linear position. Rotational adjustment of the pre-shaped
probe 802 may be repeated a number of times, for example to effect
treatment spanning substantially a full rotational range 808.
Additionally, upon withdrawal, the rigid sheath 804 may be made
linearly adjusted (e.g., manually or automatically using a probe
driver) and the pre-shaped probe 802 deployed in a different linear
region at the same or a different rotational projection.
[0139] In some examples, a length of the rigid sheath 804 can be
approximately twelve to fifteen centimeters, and a diameter of the
rigid sheath 804 can be approximately three-tenths of a centimeter
to one centimeter. A diameter of the pre-shaped probe 802 can be
one-tenth of a millimeter to three millimeters. A curved extension
of the pre-shaped probe, for example, may be about one to two
centimeters. The pre-shaped probe 802 can include one or more
energy delivery elements. For example, the pre-shaped probe may
include a diffuse laser emission tip. In certain embodiments, the
pre-shaped probe 802 includes a cooling element. Examples of energy
element and cooling element configurations of laser probes are
illustrated, for example, in U.S. patent application Ser. No.
13/838,310 to Tyc, filed Mar. 14, 2013 and titled "Image-Guided
Therapy of a Tissue," incorporated herein by reference in its
entirety.
[0140] In certain embodiments, additional neurosurgical instruments
may be provided to the ROI 806 via the rigid sheath 804 along with
the pre-shaped probe 802. For example, the pre-shaped probe 802 may
be positioned within the rigid sheath 804 along with other probes
to be used consecutively, contemporaneously, simultaneously or
concurrently with the pre-shaped probe 802.
[0141] IV. Head Coil and Stabilization
[0142] Prior to positioning in an MRI bore, a head fixation ring is
attached to the patient's head to ensure a fixed position during
the thermal therapy. A standard fixation ring can be problematic,
both in fitting various sizes of patients and in the difficulty of
positioning the patient within the ring. For example, patients with
spinal deformation or unusually large heads (e.g., due to steroid
treatments) may be difficult to position within the standard
fixation ring, which is pre-formed.
[0143] Turning to FIG. 6A, rather than using a standard size
fixation ring for fixating a patient's head, a head fixation system
600 includes an upper ring portion 602 and a lower ring portion
604. A patient's head may be laid upon the lower ring portion 604,
and the upper ring portion 602 may be lowered and connected to the
lower ring portion 604 such that the patient's nose is aligned with
an indent 606 of the upper ring portion 602.
[0144] In certain embodiments, the upper ring portion 602 connects
with the lower ring portion 604 in an adjustable fashion, providing
for a secure and close fit for a variety of head sizes. In other
embodiments, various sizes of upper ring portions 602 may be
provided, such that, rather than connecting to form a circular
ring, each upper ring portion extends to form an ovoid shape of the
head fixation system 600 to a different length.
[0145] As illustrated in FIG. 6A, the lower ring portion 604
includes a number of support posts 608 for aiding in fixation of
the head. The support posts 608, in certain embodiments, are
selectively positioned in a number of support post mounting slots
610 arranged radially along both the upper ring portion 602 and the
lower ring portion 604. As illustrated, there are six support post
mounting slots 610 arranged on the upper ring 602 and seven support
post mounting slots 610 arranged on the lower ring 604. In other
implementations (not illustrated), the support posts 608 are
mounted in fixed positions upon one or both of the upper ring
portion 602 and the lower ring portion 604. The number of support
post mounting slots 610 may vary. Additionally, in another
embodiment, the support posts 608 may selectively mount by two or
more pegs or posts connected to each support post 608 rather than
by a single connection point (e.g., support post mounting slot
610).
[0146] The support posts 608 can be used to introduce a number of
fasteners, such as a set of skull pins 612a and 612b, for affixing
the ring portions 602, 604 to the head of the patient. As
illustrated, each support post 608 includes a series of four pin
mounts for mounting a skull pin 612. In another example, each
support post 608 may include a number of offset pin mounts (not
illustrated), such that the pin mounts will not necessarily be
centered upon the support post. In this manner, the medical
professional may adjust both radial pinning locations via the
support post mounting slots 610 and linear pinning locations via
the pin mounts of each support post 608 to adaptably secure a
patient within the head fixation system 600. In other
implementations, rather than using pins, a passive fixation system
can provide conforming abutments, such as formable pads, for
closely securing the head of the patient within the head fixation
system 600 without the use of pins 612. The conforming abutments,
in one embodiment, are fixedly mounted to each support post 608. In
other embodiments, the conforming abutments may be releasably
connected in a manner similar to the fixation pins 612.
[0147] A patient's head can be positioned into the lower ring
portion 604 and onto skull pins 612. The lower ring portion 604,
for example, may be mounted within a channel 622 of a ring mount
624 of a platform 620, as illustrated in FIGS. 6D and 6E. The upper
ring portion 602 may then be lowered into place, connecting with
the lower ring portion 604 (e.g., at mating points 616 and 618).
The mating points 616 and 618, in certain embodiments, include
spaced indentations or openings for interfacing with a locking
mechanism such as a set screw or spring-loaded plunger. In other
implementations, the head fixation system 600 may have spaced
ratcheting teeth on one of the ring portions 602, 604 for
interfacing with a ball plunger or toggle release mounted on the
other ring portion 602, 604. In further implementations, a linear
actuator system such as a rack and pinion may be used to provide
position adjustment (e.g., one "click" per linear setting),
lockable, for example, using a cam lock.
[0148] Positions of the support posts 608 and/or skull pins of the
upper ring portion 602 may be adjusted. When a desired positioning
has been achieved, the upper ring portion 602 may be locked to the
lower ring portion 604, as illustrated in FIG. 6B.
[0149] Turning to FIG. 6C, in a particular example, a locking
mechanism 614 demonstrates that the upper ring portion 602 may lock
to the lower ring portion 604 using keyed shapes secured with a
fastener, such as a thumb screw. After locking the upper ring
portion 602 to the lower ring portion 604, the skull pins can be
tightened to achieve appropriate fixation. At this point, in
certain embodiments, the patient can be wheeled upon the platform
620 to an MRI room, where users can utilize the handles 626 to move
the fixated patient from, e.g., a wheeled operating table to an MRI
table. In other implementations, the platform is part of the MRI
table, for example as illustrated in FIG. 2. The fixation system
600 may be locked to the ring mount 624 via knobs 628.
[0150] In certain embodiments, upon positioning the head fixation
system 600 into the ring mount 624, an angle of the head of the
patient can be adjusted. For example, turning to FIG. 6D, the head
fixation system 600 (not illustrated) may be rotated within the
channel 622 (e.g., up to fifty degrees to either the left or the
right) prior to locking the head fixation system 600 into the ring
mount 624 via the knobs 628.
[0151] The head fixation system 600, in certain embodiments,
includes one or more fiducial markers used, for example, to
identify a position or type of head fixation ring. For example, if
the upper ring portion 602 is one of a set of various radiuses of
upper ring portions, one or more fiducial markers may identify the
particular upper ring portion 602 selected. In another example, one
or more fiducial markers can be used to identify an angle of
rotation of the head fixation system 600 from a central position
(e.g., nose indent 606 pointing upwards. The fiducial markers, in a
particular example, may be arranged radially upon an exterior of at
least one of the upper ring portion 602 and the lower ring portion
604) for aiding in registration of an MR image. Furthermore, the
fiducial markers may be used by a software tool to provide modeling
for the head fixation system 600 in relation to an instrument
introduction apparatus, neurosurgical instruments, and/or other
medical equipment used during the neurosurgical procedure. The
fiducial markers, for example, may provide the software with an
indication of angle of rotation of the head of the patient.
[0152] After attaching the head fixation system 600 to the patient,
a head coil can be fixed to the head fixation system 600 and/or a
head coil support 630. For example, turning to FIG. 2, a patient is
arranged on a patient table 108 in a bore of the MRI system 110.
The patient's head 210 is fixed to a head fixation ring 204 by
fixation pins. The head fixation ring 204 is received in a ring
mount of the patient table 108, for example the ring mount 624
illustrated in FIG. 6E. The patient table 108 extends, in a
direction away from the bore of the MRI system 110, providing a
head coil support.
[0153] Turning to FIG. 7, a head coil system 700 including a coil
holder 702 that accommodates various off-the-shelf MRI coils, such
as an MRI coil 704 is illustrated. The coil holder 702, for
example, can include adjustable attachment points for attaching the
MRI coil 704 to the coil holder 702. The adjustable attachment
points, for example, can include mated fastener openings 708, 710
between a cover 706 and the coil 704. The cover 706, for example,
may align over the MRI coil 704 such that fastener openings 708 in
the cover 706 align with fastener openings 710 within the coil 704
to hold the coil 704 in place against the coil holder 702. The MRI
coil 704 may be aligned with openings in the MRI coil 704
positioned to expose one or more fastener attachment points 712.
The user may then secure the MRI coil 704 to the coil holder 702 by
attaching fasteners through the fastener openings 708, 710 of the
cover 706 to fastener attachment points 712 upon the coil holder
702. Any number of fastener openings 708, 710 and fastener
attachment points 712 can be included the head coil system 700 to
accommodate a variety of off-the-shelf MRI coils, such that the
coil holder 702 and cover 706 provide a "universal" attachment
system for a number of styles and/or brands of off-the-shelf MRI
coils. In other implementations, rather than including fastener
openings 708, 710 in the cover 706 and fastener attachment points
712 upon the coil holder 702, the cover 706 may mateably engage
with the coil holder 702. For example, upon positioning the MRI
coil 704 within the coil holder 702, the cover 706 may be slid into
mating grooves and snapped into place, securing the MRI coil 704.
In another example, latches or clips formed into one of the coil
holder 702 and the cover 706 may mate to opposing connection points
on the other of the coil holder 702 and the cover 706. Rather than
the cover 706, in certain embodiments, two or more attachment bands
or sections may releasably attach to the coil holder 702 (e.g., in
a manner described above in relation to the cover 706), securing
the MRI coil 704 in place.
[0154] The head coil system 700, in certain embodiments, includes
openings that provide access for neurosurgical instruments, such as
an opening 714. A user can adjust the openings to align the
openings with a desired trajectory. Due to the open structure of
the head coil system 700, while a patient is positioned within the
head coil system 700, a surgical team has access to a wide variety
of trajectories for performing neurosurgical operations, such as a
trajectory at or near a side to forehead region of the patient's
head, a trajectory at a side of the patient's head, or a trajectory
at the top of the patient's head. The components of the head coil
system 700 are easily released to incorporate different MRI
coils.
[0155] After the user has achieved a desired alignment and
positioned the patient within the MRI bore with the head coil
system 700, the user can connect the head coil system 700 to a
cable to energize the MRI coil 704. Further, the user can drape the
patient and attach probe introduction equipment, such as a
miniframe or low profile skull anchor and guide. Due to a smooth
inner surface of the head coil system 700, surgical draping of the
patient is simplified.
[0156] The procedures and routines described herein can be embodied
as a system, method or computer program product, and can be
executed via one or more dedicated circuits or programmed
processors. Accordingly, the descriptions provided herein may take
the form of exclusively hardware, exclusively software executed on
hardware (including firmware, resident software, micro-code, etc.),
or through a combination of dedicated hardware components and
general processors that are configured by specific algorithms and
process codes. Hardware components are referred to as a "circuit,"
"module," "unit," "device," or "system." Executable code that is
executed by hardware is embodied on a tangible memory device, such
as a computer program product. Examples include CDs, DVDs, flash
drives, hard disk units, ROMs, RAMs and other memory devices.
[0157] FIG. 11 illustrates an exemplary processing system 1100, and
illustrates example hardware found in a controller or computing
system (such as a personal computer, i.e., a laptop or desktop
computer, which can embody a workstation according to this
disclosure) for implementing and/or executing the processes,
algorithms and/or methods described in this disclosure. The
processing system 1100 in accordance with this disclosure can be
implemented in one or more the components shown in FIG. 1. One or
more processing systems can be provided to collectively and/or
cooperatively implement the processes and algorithms discussed
herein.
[0158] As shown in FIG. 11, the processing system 1100 in
accordance with this disclosure can be implemented using a
microprocessor 1102 or its equivalent, such as a central processing
unit (CPU) and/or at least one application specific processor ASP
(not shown). The microprocessor 1102 is a circuit that utilizes a
computer readable storage medium 1104, such as a memory circuit
(e.g., ROM, EPROM, EEPROM, flash memory, static memory, DRAM,
SDRAM, and their equivalents), configured to control the
microprocessor 1102 to perform and/or control the processes and
systems of this disclosure. Other storage mediums can be controlled
via a controller, such as a disk controller 1106, which can
controls a hard disk drive or optical disk drive.
[0159] The microprocessor 1102 or aspects thereof, in alternate
implementations, can include or exclusively include a logic device
for augmenting or fully implementing this disclosure. Such a logic
device includes, but is not limited to, an application-specific
integrated circuit (ASIC), a field programmable gate array (FPGA),
a generic-array of logic (GAL), and their equivalents. The
microprocessor 1102 can be a separate device or a single processing
mechanism. Further, this disclosure can benefit from parallel
processing capabilities of a multi-cored CPU.
[0160] In another aspect, results of processing in accordance with
this disclosure can be displayed via a display controller 1108 to a
display device (e.g., monitor) 1110. The display controller 1108
preferably includes at least one graphic processing unit, which can
be provided by a number of graphics processing cores, for improved
computational efficiency. Additionally, an I/O (input/output)
interface 1112 is provided for inputting signals and/or data from
microphones, speakers, cameras, a mouse, a keyboard, a touch-based
display or pad interface, etc., which can be connected to the I/O
interface as a peripheral 1114. For example, a keyboard or a
pointing device for controlling parameters of the various processes
and algorithms of this disclosure can be connected to the I/O
interface 1112 to provide additional functionality and
configuration options, or control display characteristics. An audio
processor 1122 may be used to process signals obtained from I/O
devices such as a microphone, or to generate signals to I/O devices
such as a speaker. Moreover, the display device 1110 can be
provided with a touch-sensitive interface for providing a
command/instruction interface.
[0161] The above-noted components can be coupled to a network 1116,
such as the Internet or a local intranet, via a network interface
1118 for the transmission or reception of data, including
controllable parameters. A central BUS 1120 is provided to connect
the above hardware components together and provides at least one
path for digital communication there between.
[0162] The workstation shown in FIG. 1 can be implemented using one
or more processing systems in accordance with that shown in FIG.
11. For example, the workstation can provide control signals to
peripheral devices attached to the I/O interface 1112, such as
actuators 1124 to drive probe positioning and actuation equipment.
The workstation, in certain embodiments, can communicate with
additional computing systems, such as an imaging unit 1126 and/or
an MRI unit 1128, via the I/O interface 1112.
[0163] One or more processors can be utilized to implement any
functions and/or algorithms described herein, unless explicitly
stated otherwise. Also, the equipment rack and the interface
platform each include hardware similar to that shown in FIG. 11,
with appropriate changes to control specific hardware thereof.
[0164] Reference has been made to flowchart illustrations and block
diagrams of methods, systems and computer program products
according to implementations of this disclosure. Aspects thereof
are implemented by computer program instructions. These computer
program instructions may be provided to a processor of a general
purpose computer, special purpose computer, or other programmable
data processing apparatus to produce a machine, such that the
instructions, which execute via the processor of the computer or
other programmable data processing apparatus, create means for
implementing the functions/acts specified in the flowchart and/or
block diagram block or blocks.
[0165] These computer program instructions may also be stored in a
computer-readable medium that can direct a computer or other
programmable data processing apparatus to function in a particular
manner, such that the instructions stored in the computer-readable
medium produce an article of manufacture including instruction
means which implement the function/act specified in the flowchart
and/or block diagram block or blocks.
[0166] The computer program instructions may also be loaded onto a
computer or other programmable data processing apparatus to cause a
series of operational steps to be performed on the computer or
other programmable apparatus to produce a computer implemented
process such that the instructions which execute on the computer or
other programmable apparatus provide processes for implementing the
functions/acts specified in the flowchart and/or block diagram
block or blocks.
[0167] A number of implementations have been described.
Nevertheless, it will be understood that various modifications may
be made without departing from the spirit and scope of this
disclosure. For example, preferable results may be achieved if the
steps of the disclosed techniques were performed in a different
sequence, if components in the disclosed systems were combined in a
different manner, or if the components were replaced or
supplemented by other components. The functions, processes and
algorithms described herein may be performed in hardware or
software executed by hardware, including computer processors and/or
programmable circuits configured to execute program code and/or
computer instructions to execute the functions, processes and
algorithms described herein. Additionally, certain embodiments may
be performed on modules or hardware not identical to those
described. Accordingly, other implementations are within the scope
that may be claimed.
* * * * *