U.S. patent application number 11/481244 was filed with the patent office on 2008-01-03 for endoscopic/percutaneous electronic radiation applicator and delivery system.
Invention is credited to Darius Francescatti, Paul A. Lovoi.
Application Number | 20080004478 11/481244 |
Document ID | / |
Family ID | 39688974 |
Filed Date | 2008-01-03 |
United States Patent
Application |
20080004478 |
Kind Code |
A1 |
Francescatti; Darius ; et
al. |
January 3, 2008 |
Endoscopic/percutaneous electronic radiation applicator and
delivery system
Abstract
Treatment of lesions in any luminal or organ system of mammalian
anatomy is performed using an electronic source of ionizing
radiation and aided by an endoscopic or percutaneous approach.
Inventors: |
Francescatti; Darius;
(Barrington, IL) ; Lovoi; Paul A.; (Saratoga,
CA) |
Correspondence
Address: |
THOMAS M. FREIBURGER
P.O. BOX 1026
TIBURON
CA
94920
US
|
Family ID: |
39688974 |
Appl. No.: |
11/481244 |
Filed: |
July 3, 2006 |
Current U.S.
Class: |
600/3 |
Current CPC
Class: |
A61N 5/1002 20130101;
A61N 5/1014 20130101; A61B 1/005 20130101; A61B 1/12 20130101; A61B
1/015 20130101; A61N 5/1001 20130101 |
Class at
Publication: |
600/3 |
International
Class: |
A61N 5/00 20060101
A61N005/00 |
Claims
1. A system for delivering brachytherapy radiation internally to a
patient, comprising: an endoscope capable of insertion into a
patient to position a distal end of the endoscope in a cavity or
space within the patient's body adjacent to a lesion, tumor or
other anomaly to be treated by irradiation, the endoscope having
provision for an operator to visualize placement of the distal end
of the endoscope, the endoscope having a channel for receiving a
catheter to extend through the endoscope and essentially beyond the
distal end of the endoscope, a catheter having at its distal end an
electronic x-ray source which is controllable as to voltage and
thus x-ray penetration depth, the catheter being of a size to fit
through the channel of the endoscope, and a controller in
communication with the x-ray source, whereby the endoscope can be
inserted into the patient such that its distal end is within the
patient's body adjacent to a lesion, tumor or other anomaly, and
the catheter can be extended through the endoscope such that the
x-ray source extends beyond the end of the endoscope in position to
irradiate the anomaly, and radiation from the x-ray source can be
controlled on/or and as to depth of penetration by the operator or
the controller until substantially a desired dose of radiation has
been delivered to the anomaly.
2. The system of claim 1, further including a momentary switch in a
convenient position for use by the operator, the switch being
connected to the controller or the x-ray source to switch power on
to the x-ray source when desired.
3. The system of claim 1, wherein the endoscope includes a light
source at its distal end for illuminating a path for insertion of
the endoscope and for illuminating a patient's tissue to be
irradiated.
4. The system of claim 1, wherein the endoscope further includes a
suction channel, and including suctioning out liquid adjacent to
the anomaly prior to irradiating.
5. The system of claim 1, wherein the catheter further includes a
suction channel, and including suctioning out liquid adjacent to
the anomaly prior to irradiating.
6. The system of claim 2, further including flushing the site of
the anomaly through the endoscope prior to suctioning.
7. The system of claim 1, wherein the catheter and x-ray tube are
connected to a power supply and a processor, the processor having
an input device and including the operator's entry of data relating
to the desired irradiation of the patient's anomaly, with the
processor calculating a treatment plan including voltage settings
and time duration of irradiation, such that when the electronic
x-ray tube is switched on the voltage and duration of irradiation
are controlled by the power supply and the processor.
8. The system of claim 1, wherein the electronic x-ray source in
the catheter is capable of emitting radiation in different selected
rotational positions, whereby the emitted field of radiation from
the x-ray tube can be rotated as a patient is treated.
9. The system of claim 1, wherein said provision on the endoscope
for an operator to visualize placement includes a camera at the
distal end of the endoscope, and a monitor within view of an
operator, the monitor being connected to the camera to provide a
live image of the patient's tissue and the anomaly as the patient
is treated.
10. The system of claim 9, including a light source on the distal
end of the endoscope for illuminating the patient's tissue.
11. The system of claim 1, wherein said wherein said provision on
the endoscope for an operator to visualize placement includes a
coherent fiber optic bundle extending through the endoscope.
12. The system of claim 11, including a light source on the distal
end of the endoscope for illuminating the patient's tissue.
13. A system for delivering brachytherapy radiation internally to a
patient, comprising: an electronic x-ray source at the distal end
of the endoscope, the x-ray source being controllable as to voltage
and thus x-ray penetration depth, and a controller in communication
with the x-ray source.
14. The system of claim 13, further including a momentary switch in
a convenient position for use by the operator, the switch being
connected to the controller or the x-ray source to switch power on
to the x-ray source when desired.
15. The system of claim 13, wherein the endoscope includes a light
source at its distal end for illuminating a path for insertion of
the endoscope and for illuminating a patient's tissue to be
irradiated.
16. The system of claim 13, wherein the catheter and x-ray tube are
connected to a power supply and a processor, the processor having
an input device and for an operator's entry of data relating to the
desired irradiation of the patient's anomaly, with the processor
having means for calculating a treatment plan including voltage
settings and time duration of irradiation, such that when the
electronic x-ray tube is switched on the voltage and duration of
irradiation are controlled by the power supply and the
processor.
17. The system of claim 13, wherein the endoscope includes a
coherent fiber optic bundle for viewing tissue through the
endoscope.
18. The system of claim 13, wherein the endoscope includes a camera
at its distal end.
Description
BACKGROUND OF THE INVENTION
[0001] This invention is concerned with therapeutic irradiation of
lesions in organs or lumina of mammalian patients, especially
humans.
[0002] Therapeutic delivery of radiation therapy to many organs,
lumina, and systems within the body using radioactive isotopes is
well known. Presently, radiation therapy is directed to tissue
within an organ system of the body that permits the introduction of
the device to both target and treat; examples of routes that could
be used are the gastrointestinal tract and all its tributaries,
i.e. the common duct hepatic duct and the pancreatic duct, the
urinary tract and its tributaries, i.e. the urethra and ureter
providing access to the kidney and all distal organ systems of the
urinary tract, the vascular system including the lymphatic system,
which will provide access to any organ system in the body including
the integument, the neurological, the endocrine, the pulmonary, the
musculoskeletal and the hematopoietic systems. This list should not
be considered complete because of other points of access to all
areas of the body via a percutaneous or transvisceral route
specific portions of the alimentary, biliary, vascular,
neurological, gynecologic, and urinary systems. Traditionally,
therapeutic radiation is generated by large units operating outside
the patient and is a beam of radiation directed to specific
anatomy. If the beam is omni directional, shielding of non-diseased
areas adjacent to the anatomy to be treated is required. In order
to avoid damaging exposure to areas of the patient's skin and other
tissue leading to the target region, multiple beams of radiation
may be directionally administered so as to intersect at the lesion
or abnormality being treated. These beams may be applied
simultaneously or sequentially, such that the prescribed dose is
applied to the tumor, but lesser radiation is applied to normal
tissue. Irradiation using such intersecting, externally-applied
beams is sometimes known as intensity modulated radiation therapy,
or IMRT.
[0003] In some instances, radioisotopes are used within organs and
lumina within the body in an effort to more directly treat diseased
tissue. Because of the isotropic nature of the radiation emitted by
radioisotopes, however, present methods of internal treatment may
require the therapist to compromise in preparing treatment plans in
order to prevent damage to normal tissue adjacent to the target
lesions, but still effectively treat the lesion. The potential for
serious complications exists. Thus, treatment of the abnormalities
is often times compromised resulting in less than optimal therapy
to the tumor itself. In addition, use of radioisotopes has
attendant radiation safety concerns for therapeutic personnel. The
practical effect of these limitations and concerns is that both
externally and internally applied treatment modalities lack optimal
targeting specificity, and are less focused on the tumor than
desired. As a consequence, normal tissue is damaged.
[0004] In view of the shortcomings of the methods described above,
there is a need for apparatus and methodology for delivery of a
controllable, more finely focused radiation therapy. It is
therefore an object of this invention to enable the therapist the
ability to accurately direct the radiation therapy at the lesion
according to an optimal plan, either by manual control of the
radiation source, aided by direct visualization of the target area
during the treatment process, or by using automated control
methods. It is a further object of this invention that radiation
risk to both the therapist and the patient be minimized during the
treatment process.
SUMMARY OF THE INVENTION
[0005] Small electronic x-ray radiation sources are known (for
example those disclosed in U.S. Pat. No. 6,319,188, the
specification of which is incorporated herein in its entirety by
reference) and along with their methods of use, comprise a part of
this invention. Using an electronic radiation source, penetration
depth can be controlled and the therapeutic radiation field can be
limited or shaped. With control of the radiation beam as described
below and, with this invention, direct visualization or imaging
assures that the target lesion is treated while essentially
avoiding injury to normal tissue or structure adjacent to the
lesion. If desired, the control of radiation exposure to normal
tissue within or adjacent to the operative site can be provided by
methods other than by visualization, for example by endoscopically
positioned radiation shielding. See, for example, copending
application Ser. No. 11/471,277, the disclosure of which is
incorporated herein by reference. Unlike the typical isotope
radiation used therapeutically, electronically generated, low
intensity x-ray radiation is effectively attenuated by positioning
even modest shielding material over the areas to be protected.
[0006] Both rigid and flexible catheter, laparoscopic, and
endoscopic apparatus and methods of use exist which comprise fiber
optic or other methods to illuminate the operative field and
coherent fiber optic bundle or camera means wherein the therapist
is able to view his field, either by looking through a lens or by
observing his field on a monitor driven by inputs from within the
patient. Since such catheters and endoscopes often comprise fiber
optic bundles, it is a simple matter using conventional methods to
assign optic channels for visual light markers directed at the
point of incidence of the x-rays onto tissue. For example, this
marker might comprise an "X" at the point of incidence. With such
markers, the surgeon can visually aim his beam at the target
tissues for which treatment is prescribed.
[0007] Many such endoscopes or laparoscopes additionally include
operating channels through which instruments can pass into the
operative field. Through such an endoscope operating channel, an
instrument can be both accurately aimed and manipulated or actuated
under direct or monitored visualization by manipulating the
endoscope. Such an instrument might comprise a wand or catheter
with an electronic radiation source at or near its distal
extremity, and which may easily pass through the working channel or
an auxiliary entry port. If desired, such a radiation source can
have a narrowly directed beam. The shaft of the instrument can also
comprise lumina for flushing and suctioning the operative site. As
an alternative to flushing and suction functionality in the
endoscope, the catheter itself may be fashioned with lumina to
provide such functionality.
[0008] Some visualization means currently used in
minimally-invasive surgery comprise a semiconductor chip camera
(CCD or CMOS device) which is very small, and which can communicate
outside the patient's body for visualization of the field by either
wire or wireless means. Such a camera, along with illumination and
other optional features including those mentioned above, can all be
incorporated into a radiation source catheter, thus integrating the
functions of the endoscope and the radio-therapy catheter into one
device. Such integration can result in a smaller device than a
conventional endoscope adequate to accommodate a source catheter
and its associated systems.
[0009] Armed with one of the devices as described above, a
minimally-invasive radiation therapist can gain access to any
lesion which is within an organ system of the body that permits the
introduction of the device to both target and treat the lesion or
other abnormality. Examples of access routes that can be used
comprise the gastrointestinal tract and all its tributaries, i.e.
the common duct, hepatic duct and the pancreatic duct, the urinary
tract and its tributaries, i.e. the urethra and ureter providing
access to the kidney and all distal organ systems of the urinary
tract, the vascular system including the lymphatic system, which
will provide access to any organ system in the body including the
integument, the neurological, the endocrine, the pulmonary, the
musculoskeletal and the hematopoietic systems. In addition, known
methods of percutaneous or transvisceral access can be utilized,
either through natural anatomic entrances into body, or by
percutaneous access using known methods. A planned dose of
therapeutic radiation can therefore be delivered accurately to any
abnormality amenable to radiation as a form of curative or
palliative treatment. Since the radiation field is controllable,
and since risk of inadvertent radiation exposure to the patient and
therapeutic personnel can be easily minimized, safe and controlled
targeting of tissue under direct vision is possible with minimal
protective measures.
[0010] The invention is applicable with endoscopes, laparoscopes,
catheters and similar access devices, although the word endoscope
is primarily used in the following description. The word endoscope
is to be understood as including any such shaft device for
extending deeply into a patient's anatomy, percutaneously or
through a natural anatomical entrance, and with viewing or
placement-confirmation capability.
DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a system of the invention schematically in
relation to a patient.
[0012] FIG. 2 is a side view of a catheter with a miniature x-ray
source at it distal tip.
[0013] FIG. 3a is a side view of an integrated embodiment of the
invention comprising an x-ray source, imaging, targeting, flush and
suction functionality, steer-ability, and illumination in one
device.
[0014] FIG. 3b is a cross-sectional view through the shaft of the
embodiment of FIG. 3a.
[0015] FIG. 3c is a partially sectioned side view of the tip of the
embodiment of FIG. 3a.
[0016] FIG. 3d is a distal end view of the tip of the embodiment of
FIG. 3a.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0017] FIG. 1 shows a system 100 comprising an endoscope 101 with a
flexible shaft 102, and having at its distal tip, provision for
lighting the operative field 200 and the tumor 201. Light is
provided by light source 506. The endoscope 101 also comprises
imaging apparatus and transmission means to enable viewing of the
operative field 200 and the tumor 201 on a monitor 301 (tumor shown
as 201'). Note the target "X" 202' superimposed on tumor image
201', and source 502' on field image 200'. An image transmission
means 104 can be by a conductor or conductors, coherent fiber optic
bundle, or by wireless transmission to a processor 303, of which
the monitor 301 is a part. A camera can be located at the distal
end, as discussed below. A keyboard, tablet, voice activated or
other input device 302 completes processor system 300.
[0018] Within the endoscope 101 is a radiation source catheter 501,
having a miniature x-ray tube 502 at its distal tip and a hub 503
at its proximal end. The power supply 400 provides power to drive
the x-ray tube 502 through a power connection cable 401. The
radiation source 502 has a distally directed radiation beam 105,
such that radiation beam can be directed onto tumor 201 by
manipulating the distal tip of endoscope 101 within the operating
field. Alternatively, the beam can be directed elsewhere. At the
proximal end of the catheter 501 is the catheter hub 503. The hub
comprises a connection to the power cable 401 coming from the power
supply 400 to drive the x-ray tube, a connection to the on/off
switch 504, and an optional suction, flush or vent system 505
connection communicating with the distal tip of the catheter 501,
as described above.
[0019] The endoscope 100 generally has a flexible section which can
be steered as desired by the therapist. The endoscope has a hub 103
at its proximal end, the controls of which can be used to
manipulate the direction in which the distal tip is directed, and
hence the catheter tip and/or visualization apparatus. Such
controls are well understood by those of skill in the art, and are
therefore not detailed here. By hand manipulation of the endoscope,
the lesion can be illuminated and targeted, and by advancing or
withdrawing the catheter 501, the distance from the radiation
source 502 to the lesion 201 can be optimized for therapeutic
effect. Because visualization methods such as those described often
lack the means to provide depth perception, the catheter may be
advanced to touch a visualized surface within the operative field,
then withdrawn a calculated distance for free beam targeting at
optimal range. Graduated marks 106 can be provided on the catheter
shaft at or about the endoscope hub 103 to facilitate this
procedure.
[0020] The input device (keyboard, tablet or voice-actuated device)
302 is used to input prescription dose parameters for the x-ray
source 502 into the processor 303. The processor 303 computes input
voltage and current (and if required, laser light) parameters
corresponding to the prescription, and commands the power source
400 as necessary to produce the prescribed dose. During therapy, a
manual switch 504 emanating from the catheter hub 503 is used to
control whether the source 502 is powered and active. Preferably,
the switch 504 is normally open (switching radiation off when
untended) such that radiation is only emitted while the therapist
manually closes the switch. If desired, the source catheter 501 or
endoscope 101 may include a lumen or lumina connected to a circuit
505 connected to a suitable receptacle (not shown) to vent, flush
or suction the operative field.
[0021] If a greater degree of automation is desired, the apparatus
and system may further comprise optical recognition methodology as
described in co-pending patent application Ser. No. 60/742,118
filed Dec. 2, 2005, the specification of which is included by
reference herein in its entirety. The processor system may then
optionally comprise a timer and audible signaling device, for
example a buzzer, to indicate to the therapist when the prescribed
dose has been delivered. This is accomplished by cumulatively
tracking delivered dose intensity over time. By comparing the
real-time cumulative dose with a prescribed treatment plan and
prescription dose information entered into the processor,
verification of treatment to prescription can be accomplished and
radiation emission may then be terminated. This system eliminates
treatment beyond defined lesion boundaries as determined by the
therapist, and can further modulate dose intensity within the
treatment area.
[0022] FIG. 2 shows a catheter 501 incorporating a miniature
radiation source 502 at its distal tip. Miniature x-ray sources are
described in U.S. Pat. No. 6,319,188, but in general consist of a
flexible, high-voltage cable connected to a power source and
controller at its proximal end and to the small x-ray tube at its
distal end. The x-ray tube has a cathode (not shown) preferably at
its proximal end, which can be caused to emit electrons (for
example by heat) and a target anode (not shown) at its distal end.
The voltage between the cathode and anode causes acceleration of
the electrons emitted by the cathode past the anode, where they
next impinge on the target, resulting in bremsstrahlung, or in this
case, the creation of x-rays. The spectrum of energies produced is
related to the voltage applied between the cathode and anode and
the target material used. It is this variable voltage that can be
used to control the penetration depth into tissue of the emitted X
rays.
[0023] FIGS. 3a through 3d depict a single device with all
functionalities described above combined into one device
embodiment. Other functionality could be included or substituted.
Device 600 shown in FIG. 3a, which can be called an endoscope with
onboard x-ray source, comprises a shaft 601 having a central lumen
for a source catheter 615 having an x-ray source 605 at its distal
tip. The source 605 is positioned at or near the distal end of the
shaft 601. At the proximal end of the shaft 601 is a conventional
hub 602, comprising a central port 610 to accommodate the source
catheter 615 (FIG. 3c) and the necessary sub-systems 402 to support
operation of the source 605. These systems may include filament
current or laser energy to activate the cathode, accelerating
voltage, and fluid flow for cooling. A lower auxiliary port 508 is
provided for flushing and suction, and an upper port 507 for light
input for illumination and targeting. Just proximal of hub 602 is a
sort of swash plate 608 for manipulating the wires 609 (of which
there are at least two for planar manipulation or three for spatial
manipulation) for bending the flexible section or sections of the
shaft 601, i.e. bonding the endoscope. The wires act in a
coordinated, push-pull manner. These wires 609 pass through lumina
in the shaft 601 (see FIG. 3b) but are anchored at their distal
ends which are positioned at the distal extreme of the flexible
shaft portion 616 of the shaft 601 in FIG. 3c. FIG. 3b shows the
lumina 610 for the wires 609, as well as lumina 612 for flushing
and suction. These fluid lumina 612 terminate proximally in the
port 508 where they are connected conventionally to fluid source
and evacuation systems in the operating room. Lumina 612 terminate
at ports 603 (see FIGS. 3a, 3c) near the distal tip of shaft 601.
FIG. 3b also shows lumina 611 for fiber optic bundles for
illumination, and optionally for targeting. Proximally, these
lumina 611 terminate in port 507 where they are conventionally
connected to a light source or sources, such as is shown in FIG. 1
as light source 506. Distally, these fibers terminate at the end of
the shaft 601 and provide an illumination cone 606 (solid line cone
in FIG. 3d).
[0024] Targeting is accomplished by edge fibers 613 positioned at
the circumferential extremes of lumina 611. (See FIGS. 3b, 3d.)
These fibers 613 transmit colored light which preferably contrasts
with the operative field (for example, green light). Their distal
ends are beveled or otherwise shaped so as to provide a useful,
visible target 202, locating the direction of emitted x-rays for
the therapist. (Note the "X" shaped image 202' on the monitor
screen in FIG. 1). The target shape is arbitrary.
[0025] Adjacent to the source 605 at the distal tip of shaft 601
are two chip cameras 604 in diametrically opposed positions. With
this arrangement, stereoscopic visualization is provided through a
visualization cone 607 (phantom line cone in FIG. 3d).
Alternatively, one camera, or a coherent fiber bundle can be
substituted for these cameras 604. Such a coherent bundle could
pass through the shaft 601 through lumina 611.
[0026] Although the above describes a source-bearing catheter
positioned in a lumen of an endoscope or device, the construction
can be otherwise and more integral. With the x-ray source 605 at
the distal end of the device, the shaft 601 can be constructed in
various ways, so long as the source 605 is supported by adequate
dielectric and standoff spacing for high-voltage conductors leading
through the shaft. The dielectric material can be formed solidly
and fixedly in the center of the endoscope 600. The entire shaft
601 or endoscope 600 could be of dielectric material, with
conductors adequately spaced and not necessarily in the central
space described as a lumen with catheter 615 in FIGS. 3a-3d.
[0027] The miniature electronic x-ray source 502, 605 described in
connection with an endoscope has great advantages over treatment
with isotope radiation.
[0028] Radiation from radioisotopes is emitted in a known manner
with a decaying intensity measured by the isotope's half-life--the
time at which half the original intensity remains. Within practical
time constraints, these parameters for a given radioisotope are
fixed and they cannot be altered thus offering no possibilities for
control. Furthermore, radioisotopes emit radiation at a few
distinct energy bands, radiation from each band having its own
ability to penetrate tissue and deliver dose. For example, the
high-energy band of radiation emitted from .sup.192Ir, the most
common high dose-rate brachytherapy isotope, penetrates through
large thicknesses of shielding materials. In addition, isotopes are
always "on", so controlling the output with on/off switching is not
possible. Other common medically relevant radioisotopes also have
emission spectra containing high energy components that make
selective shielding within a body cavity impractical due to space
considerations. The radiation from these isotopes will penetrate
any practical thickness of shielding material. This high-energy
radiation easily penetrates well beyond the target site requiring
therapy, thus delivering radiation to healthy parts of the body and
risks injury.
[0029] In contrast, with electronically controlled radiation
sources, the shape of the anode and its structure, and any minimal
shielding utilized, determines the directionality of the x-rays
emitted. The emitted x-rays may be emitted isotropically, they may
be directed radially, axially, or a combination thereof. Anode
shaping is well known by those skilled in the art of x-ray
generation apparatus. Anode shape, target thickness and target
configuration can be used to change the radiation profile emitted
from the miniature x-ray source. For low energy miniature x-ray
sources, thin radiation shields can easily produce directional
radiation. For electronically produced x-rays, the acceleration
voltage determines the energy spectrum of the resulting x-rays. The
penetration of the x-rays in tissue is directly related to the
energy of the x-rays. The cumulative radiation dose directed at a
point of the lesion may be controlled by x-ray source beam current
or "on" time within the body of the patient.
[0030] In using the system of the preferred embodiment, the
therapist enters the desired prescription dose into the processor
system 300. The processor computes power parameters and transmits
those to the power supply 400. The therapist then positions the
endoscope 100 within the anatomical cavity in which the treatment
is to take place, and if necessary, performs flushing and/or
suctioning to prepare the treatment field. This can be done under
direct visualization. Next, and if needed, the therapist can verify
calibration of the radiation source using an ion chamber or similar
device. Then, the radiation catheter 501 is introduced and
positioned to treat the lesion, both by use of the endoscope
controls and by advancing the catheter 501 to achieve the proper
treatment range between the tip of the source and the lesion. When
ready to proceed with the treatment, the therapist closes the
switch 504, continually or intermittently as desired, until the
processor alarm sounds (or total time is determined by other means)
at which point the switch 504 is opened (released), concluding the
treatment. As previously described, some of these steps may be
wholly or partially automated.
[0031] Although this embodiment is discussed with particular
reference to endoscopic practice, similar methods can be utilized
with either laparoscopic or catheter methods without departing from
the scope of the invention. References to endoscope or endoscopic
in the claims is to be taken as referring to any of those
instruments and methods.
[0032] The above-described preferred embodiments are intended to
illustrate the invention, but not to limit its scope. Other
embodiments and variations to these preferred embodiments will be
apparent to those of skill in the art and may be made without
departing from the spirit and scope of the invention.
* * * * *