U.S. patent application number 13/372447 was filed with the patent office on 2012-06-07 for applicator for use in a brachytherapy radiation treatment.
This patent application is currently assigned to Xoft, Inc.. Invention is credited to Paul A. Lovoi.
Application Number | 20120142992 13/372447 |
Document ID | / |
Family ID | 40089030 |
Filed Date | 2012-06-07 |
United States Patent
Application |
20120142992 |
Kind Code |
A1 |
Lovoi; Paul A. |
June 7, 2012 |
APPLICATOR FOR USE IN A BRACHYTHERAPY RADIATION TREATMENT
Abstract
In brachytherapy radiation treatment, particularly on the breast
following a tumor resection, adequate skin to balloon distance must
be maintained, to avoid damage to the skin. Often the distance is
too small in certain areas or at a single point. The disclosed
procedures and devices are effective to manipulate the
skin-to-balloon distance to increase that distance when necessary,
using vacuum, friction or other means to grip, move and "bunch" the
breast tissue from regions of larger balloon-skin distance to
regions with inadequate balloon-skin distance. The apparatus can
include a ring or ring shaped array that fits around the breast,
larger than the balloon, a circular vacuum device, or a cup which
is pushed over the breast to move tissue toward a thin tissue
region. In many cases only a few millimeters of added distance are
needed to meet minimum requirements so that the radiation procedure
can commence.
Inventors: |
Lovoi; Paul A.; (Saratoga,
CA) |
Assignee: |
Xoft, Inc.
Sunnyvale
CA
|
Family ID: |
40089030 |
Appl. No.: |
13/372447 |
Filed: |
February 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11810415 |
Jun 4, 2007 |
8114005 |
|
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13372447 |
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Current U.S.
Class: |
600/7 |
Current CPC
Class: |
A61N 5/1015 20130101;
A61N 2005/1094 20130101; A61B 2018/00291 20130101 |
Class at
Publication: |
600/7 |
International
Class: |
A61M 36/12 20060101
A61M036/12 |
Claims
1. An applicator for use in brachytherapy radiation treatment for
positioning overlying or adjacent to a resection cavity, the
applicator comprising: a support manifold having at least one port
for coupling to a vacuum source; an array of individual vacuum
tubes mounted from the support manifold and extending distally
therefrom; a compacting ring disposed about and in contact with the
array of tubes; the compacting ring constructed and arranged to be
controlled so as to bunch the skin and tissue overlying the
resection cavity with an attendant increase in the skin-to-cavity
tissue thickness.
2. The applicator of claim 1 including attaching the distal ends of
the tubes to the skin by applying vacuum, followed by compacting
the array by advancing the ring distally.
3. The applicator of claim 1 wherein the compacting ring comprises
a belt tightened so as to compact the array.
4. The applicator of claim 1 wherein the manifold forms a common
vacuum chamber to facilitate concurrent vacuum application.
5. The applicator of claim 1 wherein each tube has its own vacuum
source or can be individually valved to permit sequential
application of vacuum for attachment to the patient's skin.
6. An applicator for use in brachytherapy radiation treatment for
positioning overlying or adjacent to a resection cavity, the
applicator comprising: a proximal portion having a vacuum port
leading to a source of vacuum; a distal portion, defining with the
proximal portion, a maifold vacuum chamber therebetween; the distal
portion having undulations or corrugations extending from a distal
outer surface thereof and rising substantially into the manifold
vacuum chamber.
7. The applicator of claim 6 wherein the proximal portion has
radially extending undulations functioning as downward ridges.
8. The applicator of claim 7 wherein the proximal portion includes
a proximal outer wall, and the undulations extend downwardly in the
proximal outer wall into the manifold vacuum chamber.
9. The applicator of claim 8 wherein the proximal and distal
undulations nearly abut, but are not joined together.
10. The applicator of claim 8 wherein the undulations of the
proximal portion are disposed radially and the undulations of the
distal portion are disposed concentrically.
11. The applicator of claim 7 wherein the proximal and distal
undulations are formed os at least one of spacer strips, molded
solid ridges and convolutions.
12. The applicator of claim 6 wherein each of the distal portions
have concentric undulations with a through port in each undulation,
these ports facilitating application of vacuum between the skin of
the patient and concentric vacuum chambers formed by the concentric
undulations.
13. The applicator of claim 6 wherein the distal portion has a belt
or draw string to assist in compacting the undulations of the
distal portion, bunching the tissue overlying the treatment
cavity.
14. The applicator of claim 6 further including a substantially
rigid element that lies proximally of the proximal portion.
15. The applicator of claim 14 wherein the rigid element is
constructed and arranged so as to create a secondary vacuum chamber
proximal of the proximal portion.
16. The applicator of claim 15 wherein the rigid element is
constructed and arranged to produce a desired contour at the skin
surface once the distal portion is secured to the skin and the
secondary chamber is evacuated.
17. The applicator of claim 14 wherein the distal portion has a
belt or draw string to assist in compacting the undulations of the
distal portion, bunching the tissue overlying the treatment
cavity.
18. The applicator of claim 14 wherein the distal portion has
concentric undulations each with a port and the rigid element also
has a port for drawing vacuum.
19. An applicator for use in brachytherapy radiation treatment for
positioning overlying or adjacent to a resection cavity, the
applicator comprising: a cup shaped structure defining an internal
chamber; a separate vacuum chamber disposed about a rim of the cup
shaped structure; the rim adapted to be placed against the
patient's skin while the the rim chamber is evacuated, securing the
cup to the skin; the internal chamber being evacuated, drawing the
skin into conformance with the internal chamber, causing the tissue
underlying the skin to bunch into the cup, increasing its thickness
and drawing the resection cavity toward the cup.
20. The applicator of claim 19 including a groove for a drawstring
or belt to facilitate compaction of tissue, and wherein the vacuum
chamber is annular in shape having a semi-circular cross-section.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/810,415, filed Jun. 4, 2007, entitled
METHOD FOR MODIFYING SKIN DISTANCE FROM A BRACHYTHERAPY BALLOON
APPLICATOR, the entire disclosure of which is herein incorporated
by reference.
BACKGROUND OF THE INVENTION
[0002] This invention concerns radiation therapy, especially
brachytherapy, for treating tissues which may have diffuse
proliferative disease.
[0003] In brachytherapy, the radiation source is generally placed
within a surgically created or naturally occurring cavity in the
body. In particular, this invention relates to delivery of
radiation therapy to glandular and adipose tissue as might be found
in the human breast, or to other similar tissue which can be easily
manipulated, often following surgical treatment of cancer.
[0004] Radiation therapy following tumor resection or partial
resection is generally administered over a period of time in
partial doses, or fractions, the sum of which comprises a total
prescribed dose. This fractional application takes advantage of
cell recovery differences between normal and cancerous tissue
whereby normal tissue tends to recover between fractions, while
cancerous tissue tends not to recover.
[0005] In brachytherapy, a prescribed dose is selected by the
therapist to be administered to a volume of tissue (the target
tissue) lying outside the treatment cavity into which the radiation
source will be placed. Generally the prescribed dose will include a
minimum dose to be delivered at a preferred depth outside the
treatment cavity (the prescription depth). Since, in accordance
with the laws of physics, radiation intensity falls off sharply
with increasing distance from the radiation source, it is desirable
to create and maintain a space between the source of radiation and
the first tissue surface to be treated (generally the cavity wall
since the source is placed within the cavity) in order to moderate
the absorbed dose at the cavity surface. This is often done by
placing a balloon or other applicator in the cavity with the
radiation source inside the applicator.
[0006] Although not always the case, generally the absorbed dose at
the prescription depth outside the cavity is to be uniform. In this
isotropic case, it is therefore important that the incident
radiation on the interior surface of the cavity be the same at all
points being treated. To accomplish this objective, it may be
necessary to sequentially position a single radiation source
through a series of positions (or utilize multiple sources
strategically placed) which, in the aggregate, produce a uniform
absorbed dose incident on the cavity surface being treated. When
this is achieved, the absorbed dose reaching into tissue will be
the same at all points being treated, and the minimum prescribed
dose can be delivered at the prescription depth as nearly as the
treatment plan will allow. Furthermore, by selecting the radiation
source intensity (radioisotope emissions or x-ray tube output) and
controlling treatment time and the distance from the source(s) to
the cavity interior surface, the incident radiation can be
sufficiently moderated to avoid substantial damage to normal
tissue.
[0007] In many instances, the treatment cavity may be near the skin
such that the treatment plan, if isotropic, may include points at
the prescription depth which lie outside the skin surface. If
prescription depth at those points lies far enough outside the
skin, too high a dose could be received at the skin, and the
therapist may be forced to locally shield emitted radiation from
within the treatment cavity (see copending application Ser. No.
11/471,277 incorporated by reference herein in its entirety), or to
resort to anisotropic radiation sources. Such capabilities may not
be readily available or practical. In such cases, and there are
many, the patient may therefore be denied the advantages of
brachytherapy.
[0008] One currently accepted standard in radiation therapy is
that, for a one centimeter prescription depth of tissue, and for
the applicator diameter range of intent, assuming the tissue at the
prescription depth receives the desired dose (1.times.), the tissue
nearest the source should not receive more than 2.5.times. to
3.times. the prescription dose. Standards also usually require that
the skin not receive a dose of more than 1.5.times. the
prescription dose. With a one centimeter prescription depth, this
usually requires the skin be at least 6-8 mm out from the surface
of a balloon applicator engaged against the tissue in a cavity. A
distance of less than about 6-8 mm may result in doses higher than
1.5.times. the prescription dose which are known to often result in
undesirable cosmesis. This problem commonly arises in breast
brachytherapy and is a counter-indication for brachytherapy. In
order to make brachytherapy available to more patients having
resection cavities in close proximity to skin surfaces or to other
radiation sensitive structures, the apparatus and/or methods of
this invention may be employed.
SUMMARY OF THE INVENTION
[0009] This invention employs external temporary fastenings to skin
which are then manipulated in order to bunch the tissue volume
overlying the treatment cavity into a smaller area. Because the
tissue underlying the skin tends to follow lateral skin
displacement, this effectively thickens the tissue layer and thus
the separation between the cavity and skin surface. A simple
example of such a device and method is a purse-string suture, the
application of which, on tightening, draws the purse-string
diameter inward. In this manner, a 5 mm separation can be
transformed into a 7 mm separation, thus making isotropic
brachytherapy an acceptable mode of radiation therapy. One
embodiment of this invention comprises an array of individual
vacuum tubes or cups, for example, which can be drawn into closer
proximity after attaching their distal ends to the skin by applying
vacuum, and then by compacting their arrangement. Such an array of
tubes might be joined to a common manifold to facilitate concurrent
vacuum application. Alternatively, each tube or cup can have its
own vacuum source or be individually valved to permit sequential
application of vacuum, and therefore attachment to the patient's
skin.
[0010] Once joined to the skin with each tube or cup in proper
starting position (before compaction), the tubes or cups can be
compacted or drawn together, for example by tightening a belt, or
alternatively where the tubes are splayed distally, by sliding a
ring in the distal direction such that the tube distal ends and the
skin to which they are secured are drawn together. The ring itself
can be one whose diameter can be drawn smaller, with the suction
ends or cups extending through the ring. A common tie-wrap would
comprise a typical such ring.
[0011] A specific preferred embodiment comprises a hollow, sealed
resilient structure. The distal surface of the structure is
undulating in a manner to form concentric rings which when pressed
into contact with the skin surface and evacuated, create a series
of concentric vacuum chambers. The proximal crest of the
undulations in the distal surface of each distal chamber has vents
leading into the hollow interior of the structure such that all
chambers are evacuated when vacuum is applied to the interior of
the structure, and the device is thereby secured to the skin by the
vacuum. The proximal surface of the structure has (at least
partially) a series of radially-arranged undulations or ridges
which abut the concentric chambers such that when vacuum is applied
to the interior of the structure through a valved port leading to a
vacuum source, the concentric undulations abut the ridges or radial
undulations such that the structure cannot collapse and block the
vacuum connection between the interior of the structure and the
concentric chambers. The totality of the structure has sufficient
resilience that it adjusts (or can be adjusted) into vacuum-tight
contact with the skin contour of interest, whether concave, convex
or of another complex configuration.
[0012] When positioned on the skin overlying the treatment cavity,
evacuating the interior of the structure will additionally tend to
draw the structure to a smaller overall diameter, thus forcing the
concentric chambers closer together and concentrating the tissue
over the cavity, bunching the skin and underlying tissue. This
reduction in the diameter of the applicator device can be manually
urged toward a desired configuration, or a drawstring or belt can
be applied to the outside diameter of the applicator to effect such
change.
[0013] In order to enhance a vacuum-tight seal with the skin, the
distal outer surface of the device may be coated with a medical
grade adhesive (for example, an adhesive as disclosed in U.S. Pat.
No. 5,387,450) or an adherent hydrogel or similar material to seal
small vacuum leaks or sealing imperfections between the device and
the skin. Alternatively, the skin can be wetted with a
semi-adherent gel or viscous coating.
[0014] In another embodiment of the device described, the device
can be secured to a more rigid proximal element shaped so as to
produce a desired contour in the skin contacting surface. After
securing the resilient, distal portion of the device to the skin, a
secondary vacuum chamber formed under the proximal element is
actuated, for example by application of vacuum independently of the
skin fastenings, to draw the resilient member and skin toward the
desired contour. An example of this embodiment of the invention is
a cup shaped vacuum device, with a generally annular vacuum chamber
formed against the skin at its rim, and with more extreme curvature
internally than the natural contour of the breast. The cup is
engaged around a critical region where balloon-to-skin distance is
adequate. The edge of the cup first seals against the breast tissue
at the cup rim, and when a vacuum is drawn on the interior of the
device independently of the rim device, the breast is forced toward
conformance with the device, making the distance from the skin to
the balloon applicator larger in the critical region. In such an
example, the vacuum may be applied independently of the internal
volume of the cup as described above, or it may be applied
concurrently. If concurrent, a dual vacuum chamber device may well
be unnecessary.
[0015] In a simpler form of cup-shaped device only one vacuum
chamber is involved, which is the interior of the cup. The applied
vacuum seals the rim of the cup against the skin, and then draws
the skin radially inwardly to bunch the tissue at a critical
region.
[0016] Although the "footprints" of these embodiments are described
as more or less circular, one of ordinary skill would be competent
to adapt the principles disclosed to other shapes and therapeutic
situations. The pattern of engagement of the skin (e.g., the
breast) need not be a circuit but can contraction or bunching a
force exerted from one direction, or from several directions, but
not necessarily from all around the region of inadequate tissue
depth. Also, engaging the device to cause the attendant tissue
bunching, care must be taken to assure new cases of
less-than-minimum tissue thickness have not been created. This can
be assured by reimaging or by other remeasurement of the
tissue.
[0017] The invention is not limited to use of vacuum cups or
channels applied against the skin. For example, adhesive pads could
be used, without the need for any vacuum chambers, such that an
array of contact points are adhered to the skin, then the skin is
manipulated to move and "bunch" tissue to increase the depth of
tissue between the skin and the underlying cavity at a particular
region. Such movement can be effected by a drawstring or belt, or
by any appropriate form of mechanical device to move the temporary
fastening points or adhesive contact points into a different
pattern or configuration as desired. Generally, the movement is
toward a smaller footprint of the array of contact points in order
to accomplish the objective.
[0018] The invention generally encompasses manipulation of tissue
by manipulation of the skin overlying or adjacent to the tissue. In
particular, the invention is directed to tissue manipulation during
brachytherapy in a human breast from which a lesion has been
resected, resulting in an underlying cavity. The form of
manipulation must be reliable and consistent and able to manipulate
the tissue depth over a critical region in a reliable manner,
without causing cavitation (separation) between the balloon of an
applicator and the breast tissue at the surface of the resection
cavity. The device is preferably removed from the skin between
radiotherapy fractions.
[0019] It is therefore among the objects of the invention to
facilitate brachytherapy treatment from within a resection cavity
in situations where such treatment, at least conventional forms of
such treatment, might be ruled out or limited due to inadequate
distance from some areas of the patient's skin to the radiation
source. This is accomplished by movement of tissue, and is
particularly pertinent to breast brachytherapy, at and beneath the
skin to "bunch" or thicken the depth of tissue in critical regions
so that adequate distance is created and maintained between the
radiation source and the skin at all points around the resection
cavity. These and other objects, advantages and features of the
invention will be apparent from the following description of a
preferred embodiment, considered along with the accompanying
drawings.
DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1A is a side view of a multi-tube device of the
invention with a vacuum manifold and a compacting ring shown
positioned over a near-skin treatment cavity.
[0021] FIG. 1B shows the device of FIG. 1A applied to skin over a
treatment cavity with the compacting ring advanced and the tubes
compacted. The tissue is bunched and thickened over the treatment
cavity
[0022] FIG. 1C shows manifold, vacuum port and tube detail of the
device of FIGS. 1A and B in section.
[0023] FIG. 2 is a section view in plan of the device from the line
2-2 as shown in FIG. 1A.
[0024] FIG. 3A is a side view of a preferred device in section
showing radial and concentric undulations, and an outer, compacting
belt.
[0025] FIG. 3B is a side view of a preferred device in section
showing the device of FIG. 3A after compaction of the concentric
undulations and tightening of the belt.
[0026] FIG. 3C is a top plan view showing radial undulations in the
proximal surface of the device of FIG. 3A.
[0027] FIG. 3D is a bottom plan view of the device shown in FIG.
3B, showing the compacted concentric undulations in the distal
surface and showing vacuum ports.
[0028] FIG. 3E is a partial sectional elevation view showing a
ridge formed in the proximal wall of the device.
[0029] FIG. 3F is a partial sectional elevation, as seen along the
line 3F in FIG. 3C, showing an undulation in the proximal wall of
the device, an alternative to FIG. 3E.
[0030] FIG. 4 is a section view of a dual chamber cup-shaped
embodiment of the invention.
[0031] FIG. 5A is a section view of another dual chamber embodiment
of the invention shown placed on the skin of the patient, overlying
a resection cavity in the underlying tissue.
[0032] FIG. 5B is a section view of the device of FIG. 5A after
fastening onto the skin by vacuum, showing a thickening of the
tissue between the device and the resection cavity.
[0033] FIG. 5C is a section view of the device of FIGS. 5A and 5B
after evacuation of a second chamber of the device, cupping the
device and further thickening the tissue between the device and the
resection cavity.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0034] An device embodiment 1 shown in FIG. 1A is positioned above
a near-skin treatment cavity C of a patient. The device 1 comprises
a central manifold 2 positioned proximally with respect to a series
of tubes 4 separated or splayed apart from one another at their
distal ends for suction contact with the skin 12 of the patient.
The ends are positioned so as to be able to be compacted more
closely together subsequently, bunching the skin to which they are
attached. The array of ends of the tubes 4 define a diameter (or
other, non-circular shape) larger than the underlying treatment
cavity C resulting from the tumor resection. The manifold 2 has a
port 6 which is valved and leads to a source of vacuum such as a
pump or wall suction as might be present in a medical facility
treatment room (neither pump nor wall suction is shown). The
manifold is preferably of a relatively rigid material such as an
engineering plastic like polycarbonate or polyethylene
terephthalate (PET). The tubes 4 are preferably more resilient than
the manifold 2 so as to be more easily positioned against the skin,
and some or all may be at least partially formed in convolutions 8
as in shown in FIG. 1C to provide axial compliance to accommodate
non-planar skin contours. If desired, the vacuum on the tubes may
be individually controlled by conventional valving (not shown)
rather than collectively through a manifold. Suitable tube
materials include ionomer or silicone rubber. Positioned around and
in contact with the array of the tubes 4 is a compacting ring 10.
The ring 10 may be of a structural plastic (e.g., polycarbonate or
Nylon), metal (e.g., stainless steel), or elastomer, (e.g.,
silicone rubber) which may be advanced distally after vacuum is
applied in order to compact the tubes 4. FIG. 1B shows the
compacting ring 10 having been advanced and bunching of the skin 12
and tissue overlying the treatment cavity C with an attendant
increase in the skin-to-cavity tissue thickness.
[0035] FIG. 1C shows a partial section of the device 1 of FIGS. 1A
and 1B, including a part of the manifold 2 near the vacuum port 6,
and a method of joining the tubes 4 to the manifold 2. The method
includes the manifold 2 having protruding nipples 16 to accommodate
joining to the tubes 4. In FIG. 1C, an exemplary tube 4 is shown
with the optional convolutions 8 mentioned above. With the proximal
ends of the tubes sized to slip over the nipples 16, conventional
bonding can be used to assemble the tubes to the manifold. Other
conventional techniques known to those of skill in the art may also
be used.
[0036] FIG. 2 shows the device 1 of FIG. 1a in section view as seen
at 2-2, through the manifold 2. The array of tubes 4 are shown in a
circular configuration and splayed, and the interior 5 of the
nipples 16 are shown. Other tube layout configurations are optional
with only minor design adjustments obvious to those of skill in the
art.
[0037] FIG. 3A shows a preferred embodiment of the invention in
section view taken along the line 3A-3A in FIG. 3C. The device 20
has an upper (proximal) portion 22 and a lower (distal) portion 24.
The proximal portion 22 has a valved vacuum port 26 leading to a
vacuum pump or wall suction (valve not shown). The proximal portion
22 has radially extending undulations 28, functioning as downward
ridges, as shown in FIGS. 3A and 3C. FIG. 3F shows one of the
undulations in section. The undulations extend downwardly in the
proximal outer wall 30 of the device 20, extending only along the
lines 28 down into a manifold vacuum chamber 32. FIG. 3E shows
simple ridges 29 for this purpose. The distal portion 24 of the
device 20 has concentric undulations or corrugations 36 extending
from the distal outer (or lower) surface of the device 20 and
rising substantially into the manifold vacuum chamber 32 as shown,
toward the radial undulations 28. The proximal and distal
undulations nearly abut, but are not joined together. The radial
undulations can comprise any form of spacer strips on the inner
side of the upper wall 22. They can be in the form of molded solid
ridges, or they can formed convolutions in the material of the
upper portion 22 as shown. When vacuum is applied, the concentric
undulations 36 bear against the radial ridges or undulations 28,
holding the manifold vacuum chamber 32 open, as shown in FIG. 3B.
At the proximal or inner crest of the concentric undulations 36 are
ports 38 (the cutting plane for the sectional view of the ports is
rotated 45' from the position shown in FIG. 3A) which communicate
with the manifold vacuum chamber 32 of the device. These ports
facilitate application of vacuum between the skin 5 of the patient
and concentric vacuum chambers 42 formed by the concentric
undulations 36.
[0038] FIG. 3B shows the device 20 of FIG. 3A, but after
application of vacuum and attachment to the skin 12 (not shown). As
may be seen, the diameter of the device 20 in contact with the skin
is substantially reduced. If spontaneous reduction in diameter of
device 20 fails to occur upon application of vacuum, and if manual
assistance is inadequate or only temporarily creates the desired
diameter reduction, a groove 43 and a belt 44 or any form of
drawstring may be provided as shown in FIG. 3A at the outer
periphery of the device 20 to assist in compacting the concentric
undulations 36 of the rubbery distal portion, bunching the tissue
overlying the treatment cavity C. Loops (as on pants for a belt,
not shown) or other features may be needed to help locate the belt
around the device periphery and to facilitate such compacting
manipulation. As shown in FIG. 3A, a structure or configuration may
be needed in the proximal portion 22 of the device to allow the
distal portion 24 to easily reduce in diameter and bunch the tissue
to which it is attached. In FIGS. 3A and 3B, such a structure is an
outer toroidal ring 45 which deforms from a circular cross section
in FIG. 3A to a more elliptical cross section in FIG. 3B, providing
substantial independent radial mobility to the distal portion
24.
[0039] Although the concentric undulations 36 form separate
concentric vacuum chambers 42 in the device as described above,
other configurations can also be used. Furthermore, rather than
collectively evacuated, concentric vacuum chambers 42 may be
sequentially evacuated by providing conventional valving as known
to those skilled in the art. As an example of an alternate
configuration, a hexagonal matrix of separate cup-like chambers may
be arrayed on the distal applicator surface, each cup in
communication with a common or individual vacuum source, and each
joined to its neighbors by a thin membrane to retain the vacuum,
the membrane being adapted to crumple as the matrix is compacted
after application to the skin by vacuum. Other configurations are
also possible.
[0040] FIG. 3C shows a plan view from the proximal (or upper) side
of the applicator 20 as seen in FIG. 3A, and shows the arrangement
of the radial undulations 28. As mentioned above, other
arrangements, e.g. simple radial ridges on the inner (lower) side
of the wall 30, as shown in the partial section of FIG. 3E, are
possible so long as they serve to hold the manifold vacuum chamber
32 (not shown in FIG. 3C) open when the manifold is evacuated.
[0041] FIG. 3D is a plan view of the device 20 of FIG. 3B from the
distal side (sometimes referred to as the bottom side). The
concentric vacuum chambers 42 and the vacuum ports 38 (shown in
proper rotation in contrast to what is shown in FIG. 3A) are shown,
communicating between the manifold vacuum chamber 32 and the
concentric vacuum chambers 42.
[0042] In this embodiment the proximal portion 22 and the distal
portion 24 may be one monolithic structure formed by rotomolding or
blowmolding, or alternatively they may be pressure formed or molded
in separate halves and joined by conventional techniques such as
bonding or welding as is known to those of skill in the art.
Suitable materials include silicone rubber, ionomer, ethylene
propylene rubber, or similar materials. The distal portion 24 can
be, as illustrated, an elastomeric structure, with the proximal
wall 30 being metal or hard plastic, with appropriate bonding or
sealing. The elastomeric portion includes at least the distal
portion of the outer toroidal ring 45, and can include that entire
toroidal ring.
[0043] This preferred embodiment is described as though the
skin-contacting distal surface is planar before and after
attachment to the skin for convenience in describing the device.
The embodiment in fact need not be planar. The device can be
fashioned so as to produce a skin-contacting surface (formed by the
concentric undulations 36) which is contoured before and/or after
attachment to the skin. One convenient method is to control the
spacing between the abutting concentric and radial undulations
within the vacuum chamber 32. For example, if the space between
abutting undulations is minimal at the periphery of the device, and
spaced apart toward the center as would result if the more-rigid
proximal portion 22 is cupped, the distal portion 24 and skin
contacting surface of the device will mimic the cupped shape of the
proximal portion 22 when vacuum is applied. Furthermore, if
sequential application of vacuum is used, outer concentric chamber
42 first, next compacting, and finally applying vacuum to inner
chambers 42, an enhanced bunching will result.
[0044] Enhanced bunching can also result from sequential
application of vacuum is a dual chamber device. For example, as
shown in FIG. 4, a cup shaped device 50 with a separate vacuum
chamber 52 in its rim can be provided. Such a device can be
semi-resilient or rigid in its construction. Suitable material is
silicone rubber or polycarbonate, for example. In use, the rim 54
of the cup is placed against the patient's skin 12 and the rim
chamber 52 evacuated, securing the cup to the skin. Next, the
internal chamber 56 of the cup is evacuated, drawing the skin into
conformance with the chamber 56, causing the tissue underlying the
skin to bunch into the cup, increasing its thickness and drawing
the resection cavity C toward the cup. Optionally, the cup shaped
device 50 can be more resilient, and a groove 58 for a drawstring
(not shown) can be provided to facilitate compaction of tissue
under the device.
[0045] In an alternate method of use, the cup shaped device 50
could be positioned on the skin 12 and the central vacuum chamber
56 can be evacuated directly without first evacuating the rim
chamber 52. Such use would facilitate tissue adjacent the device 50
to slide under the rim to more easily fill the chamber 56. This
would be similar to use of a simple cup-shaped device (not shown)
without a separate rim chamber for vacuum.
[0046] As shown in FIG. 5A, another dual-chambered embodiment 60
comprises a fully resilient element 62 shaped similarly to that of
the device FIGS. 3A-D. In addition, a substantially rigid element
64 lies proximally of resilient element 62 and is secured thereto,
for example by bonding or another conventional method. The rigid
element 64 is shaped so as to create a secondary vacuum chamber 66
proximal of the resilient element 62, and to produce a desired
contour at the skin surface once the resilient element 62 is
secured to the skin 12 and the secondary chamber 66 is evacuated.
FIG. 5B shows this embodiment with the resilient element 62 secured
to the skin 12 and having contracted under vacuum, bunching the
tissue over the resection cavity C. FIG. 5C shows the secondary
vacuum chamber 66 evacuated and drawing the underlying tissue into
configuration and further thickening the tissue between the device
60 and the resection cavity C. Optionally or as necessary, a
drawstring (not shown) may be employed in a peripheral groove 68 of
the resilient element to assist in tissue compaction under the
resilient element 62. In a single-chambered variation of the device
60, the proximal resilient wall 70 of the device may be perforated
(not shown), creating a single internal chamber.
[0047] Note also that a modified form of the device 60 can be
preformed with a curved (partial spherical) contour at the
skin-contacting distal end, i.e. with the undulating distal part 62
formed in a concave, curving or generally spherical shape, for
application to the breast in this contoured form. Then vacuum can
be applied to a single chamber.
[0048] In use, these devices are positioned over the treatment
cavity and urged into contact with the skin. When the therapist is
satisfied with placement, vacuum can be applied in a manner
described above, providing temporary attachment to the skin by the
suction force of the vacuum. If after attachment, the device's
"footprint" has not spontaneously reduced due to the action of the
vacuum on the device, it may be manually urged into a compacted
state, or it may be diametrally compacted by cinching a peripheral
belt or other appliance as described above in connection with the
description of FIGS. 3A and 3B.
[0049] As mentioned above, other techniques can be used for moving
the breast skin and underlying tissue so as to produce a deeper
skin-to-cavity or skin-to-applicator distance (skin-to-balloon
distance in the case of a balloon applicator used in the cavity).
Adhesives can be used on skin-manipulating ends, provided the
adhesive reliably grips the skin and is easily released (as by the
means disclosed in the referenced U.S. Pat. No. 5,387,450), or by
an appropriate solvent or simply by outward pulling force as
opposed to the shear forces involved in the skin manipulation. The
skin can be pushed along a selected pattern that does not amount to
a closed circuit, and this can be essentially from one or more
directions toward the region of inadequate tissue depth if desired.
Simple friction can be used, via contacting lines or points that
engage the skin, particularly the breast, so as to manipulate its
pliable tissues to increase depth at a critical region. Manual
methods of manipulation will also be appropriate in some
situations, to urge the tissue in a desired direction where its
position can then be maintained by any appropriate and reliable
means to overcome a deficiency in skin-to-cavity depth at a
particular location on the breast. Appropriate mechanical apparatus
can include a clamp-like device with two jaws, either straight or
concavely configured toward one another, and each with a
high-friction (e.g. rubbery) contacting surface so as to bring
tissue inward toward the critical region from opposed directions.
The salient feature of this invention is that in a brachytherapy
situation, when there is a region where the skin would be too close
to the radiation source under the skin, the tissue (particularly in
the case of a breast) is moved by some appropriate means, by
engagement with the skin in such a way as to "bunch" the tissue
under the skin adjacent to the treatment cavity at the critical
region to meet minimum distance requirements from skin to cavity
(actually, skin to inner radius of prescription dose region). This
can include some form of ring (including a ring-shaped array) with
adhesive or friction points or suction outlets to engage the
exterior surface of the skin, with some provision for effectively
reducing the diameter or size of the ring after skin
engagement.
[0050] Confirmation of improved separation between treatment cavity
and skin (thickness of tissue overlying the cavity) can be obtained
by conventional imaging techniques (for example, x-ray or
ultra-sound), if necessary with the help of a relatively
radio-opaque, cavity-filling balloon within the cavity. Such
reimaging will also assure no new thin regions have been
created.
[0051] The above described preferred embodiments are intended to
illustrate the principles of the invention, but not to limit its
scope. Other embodiments and variations to these preferred
embodiments will be apparent to those skilled in the art and may be
made without departing from the spirit and scope of the invention
as defined in the following claims.
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