U.S. patent application number 13/426445 was filed with the patent office on 2012-07-12 for fiduciary markers and method of use thereof.
This patent application is currently assigned to BEST MEDICAL INTERNATIONAL, INC. Invention is credited to RASHMI AMIN, KRISHNAN SUTHANTHIRAN.
Application Number | 20120179027 13/426445 |
Document ID | / |
Family ID | 46455794 |
Filed Date | 2012-07-12 |
United States Patent
Application |
20120179027 |
Kind Code |
A1 |
SUTHANTHIRAN; KRISHNAN ; et
al. |
July 12, 2012 |
FIDUCIARY MARKERS AND METHOD OF USE THEREOF
Abstract
The invention provides devices and methods used to locate target
areas within a patient for repeat therapeutic treatments. In the
invention, fiduciary markers made of metal or metal alloys are
placed within a patient near or at a target site as reference
coordinates for particular body locations on the patient. Repeat
treatments may then be given to the patient over a period of time
based on the coordinates given by the fiduciary markers. The
fiduciary markers are specially shaped or put into strand to
improve marker attachment and prevent marker migration.
Inventors: |
SUTHANTHIRAN; KRISHNAN;
(LORTON, VA) ; AMIN; RASHMI; (SPRINGFIELD,
VA) |
Assignee: |
BEST MEDICAL INTERNATIONAL,
INC
Springfield
VA
|
Family ID: |
46455794 |
Appl. No.: |
13/426445 |
Filed: |
March 21, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11423906 |
Jun 13, 2006 |
8170647 |
|
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13426445 |
|
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Current U.S.
Class: |
600/414 ;
600/424 |
Current CPC
Class: |
A61B 90/39 20160201;
A61B 5/064 20130101; A61N 5/1049 20130101 |
Class at
Publication: |
600/414 ;
600/424 |
International
Class: |
A61B 6/00 20060101
A61B006/00; A61B 6/03 20060101 A61B006/03; A61B 5/055 20060101
A61B005/055; A61B 8/00 20060101 A61B008/00 |
Claims
1. A marker for locating regions of interest in a subject
comprising of at least one radio-opaque seed, a. wherein said
radio-opaque seed remains readily detectable in vivo using common
imaging modalities; and b. said marker being sized and shaped for
firm implantation into tissue or organ of said subject; c. said
radio-opaque seed has a length ranging from 0.1 mm to 5 cm; d. said
radio-opaque seed is made of a biocompatible metal or alloy of
metals; e. said radio-opaque seed have a proximal end and a distal
end; and f. a plurality of fingers is affixed to said distal end of
the radio-opaque seed.
2. A marker of claim 1, wherein said radio-opaque seed is made of a
metal or metal alloy comprising as least one metal or metal alloy
selected from the group consisting of stainless steel, gold,
titanium, platinum, tantalum, copper, and tungsten.
3. A marker of claim 1, wherein said radio-opaque seed is made of
titanium.
4. A marker of claim 1, wherein said radio-opaque seed can be of
any shape.
5. A marker of claim 1, wherein a. said distal end of the
radio-opaque seed is shaped as a cone; b. said proximal end of the
radio-opaque seed is shaped as a ball; and c. said proximal end and
distal end is connected by a substantial cylindrical portion.
6. A marker of claim 5, wherein the fingers a. remain closed before
said seed is implanted into the subject; and b. open up when said
seed is implanted into a desired tissue within the subject.
7. A marker of claim 1, wherein at least one said radio-opaque seed
is enclosed in absorbable material forming substantially a
strand.
8. A marker of claim 7, wherein in the absorbable material is made
of a polymer selected from a group consisting of a. a Polydextran;
b. a Polyvinylpyrrolidone; c. a
Poly(bis(p-carboxyphenoxy)-propane); or d. a Biopolymer.
9. A marker of claim 7, wherein at least two said radio-opaque seed
is separated by at least one absorbable spacer.
10. A marker of claim 9, wherein said absorbable spacer is made of
a polymer selected from a group consisting of a. a Polydextran; b.
a Polyvinylpyrrolidone; c. a Poly(bis(p-carboxyphenoxy)-propane);
or d. a Biopolymer.
11. A marker of claim 10, wherein said biopolymer is selected from
group consisting of gelatin, human serum albumin, and
cellulose.
12. A marker of claim 1, wherein at least one said radio-opaque
seed is wrapped in surgical suture.
13. A marker of claim 12, wherein at least two said radio-opaque
seeds are wrapped in surgical suture to form a strand.
14. A marker of claim 13, wherein at least two said radio-opaque
seed is separated by at least one absorbable spacer.
15. A marker of claim 14, wherein said absorbable spacer is made of
a polymer selected from a group consisting of a. a Polydextran; b.
a Polyvinylpyrrolidone; c. a Poly(bis(p-carboxyphenoxy)-propane);
or d. a Biopolymer.
16. A marker of claim 19, wherein said biopolymer is selected from
group consisting of gelatin, human serum albumin, and
cellulose.
17. A method of locating a region of interest in a subject for
treatment using a marker, comprising the following steps: a.
producing a marker comprising of at least one radio-opaque seed
wherein said seed remains readily detectable in vivo using common
imaging modalities; and sized and shaped for firm implantation into
tissue or organ of said subject; b. implanting one or more of said
marker into said tissue or organ close to or at said region of
interest c. opening a plurality of fingers on said radio-opaque
seed; d. fixing said radio-opaque seed into tissue; e. detecting
said marker in vivo using common imaging modalities; f. locating
said region of interest using said markers as reference points; and
g. delivering treatment to the region of interest.
18. A method of claim 17, wherein said common imaging modalities
includes: a. Stereotaxy; b. Ultrasound; c. CT; or d. MRI.
19. A method of claim 18, wherein said markers are implanted using
one of the following method: a. an implantation gun; b. a catheter;
and c. a syringe.
20. A method of claim 19, wherein said marker a. is implanted for a
period of time, b. is used in a series of treatments; and c. is
removed after said treatments.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of the following U.S.
patent application Ser. No. 11/423,906, and incorporates into
reference all the limitations. In addition, the present application
incorporates into reference provisional application, titled
FIDUCIARY MARKSERS AND METHOD OF USE THEREOF, application No.
60/760,388, filed on Jan. 20, 2006 by inventor Krishnan
Suthanthiran and Rashimi Amin (attorney docket number 2005-03P).
All of this application are incorporated herein by reference.
BACKGROUND
[0002] The accurate positioning of patients and tissue localization
are crucial steps before performing many types of medical
treatments. One category of medical treatments in which the proper
placement and verification of the position of patient or tissue is
of particular importance is in the field of radiation therapy.
[0003] Radiation therapy involves medical procedures that
selectively expose certain areas of a human body, such as cancerous
tumors, to high doses of radiation. The intent of the radiation
therapy is to irradiate the targeted biological tissue such that
the harmful tissue is destroyed. To minimize damage to surrounding
body tissue, many conventional treatment methods utilize "dose
fractionating" technique. According to "dose fractionating"
technique, radiation dosage is delivered in a planned series of
treatment sessions with each delivers only a portion of the total
planned dosage. Healthy body tissue typically has greater capacity
to recover from the damage, thus reducing the amount of permanent
damage to healthy tissue while maintaining enough radiation
exposure to destroy tumoral tissue.
[0004] The efficacy of "dose fractionating" procedure depends in
large part upon the ability to irradiate the exact same position on
a body over multiple radiation sessions. The goal is to place the
patient or body parts of the patient in a way that the target area
is in the same position relative to the radiation source in each
and every treatment session. Inaccuracies in positioning could
result in errors in radiation dosage and treatment locations,
leading to unpredictable disease relapse or damage to healthy
tissues. However, problem arises when doctors attempting to
recreate the same target area of a patient at every radiation
session.
[0005] The traditional approach to control patient positioning is
to place marks or tattoos at specific locations on the patient's
skin. Several laser or light sources from predetermined locations
project beams of light at the patient's body. To control the
patient positioning, a therapist moves the patient until the marks
are aligned with the lines from the lasers or light sources. A
significant drawback to this approach is that the accuracy and
consistency of the patient positioning is heavily dependent upon
the skill level of the therapist in manually positioning the
patient. In addition, with heavier patients, it is possible that
only the skin of the patient is moved into the proper position
without moving the body part to be irradiated into the appropriate
position. Moreover, this approach does not provide an efficient way
to record and reflect the positioning quality in the patient's
records. Shortcoming of this approach may be fully illustrated by
problems faced in external-beam radiotherapy (EBRT). EBRT is a
commonly used curative treatment for a variety of cancers including
prostate cancer. The efficacy and tolerance of EBRT depends on
accurate localization and the maximal exclusion of critical normal
structures, such as organs at risk, with conformal field
arrangements. However, the position of the target is typically
inferred only from skin markings, which serves as external
references points, which are used to align the patients on the
treatment machine. The accuracy of this alignment is monitored with
periodic portal imaging of the skeletal structures of the lower
pelvis. Although external reference points should be reproducibly
related to skeletal structures, portal imaging often reveals
displacement from the intended position, and this is often referred
to as setup variation. In prostate cancer EBRT, investigators
demonstrated that the error in field alignment might exceed 10 mm
along each of the mutually perpendicular axes of the coordinate
system. Vigneault E, Pouliot J, Laverdiere J, et al. Electronic
portal imaging device detection of radio-opaque markers for the
evaluation of prostate position during megavoltage irradiation. Int
J Radiat Oncol Biol Phys 1997; 37:205-212. Tinger A, Michalski J M,
Cheng A, et al. A critical evaluation of the planning target volume
for 3-D conformal radiotherapy of prostate cancer. Int J Radiat
Oncol Biol Phys 1998; 42:213-221. Stryker J A, Shafer J, Beatty R
E. Assessment of accuracy of daily set-ups in prostate radiotherapy
using electronic imaging. Br J Riol 1999; 72:579-583. Zelefsky M J,
Crean D, Mageras G S, et al. Quantification and predictors of
prostate position variability in 50 patients evaluated with
multiple CT scans during conformal radiotherapy. Radiother Oncol
1999; 50:225-234. The setup variation only partially accounts for
uncertainties in the position of the target relative to the
treatment beam. The position of the prostate is not fixed relative
to the skin marks or the skeletal anatomy of the pelvis. The state
of bladder and rectal filling may result in displacement of the
prostate. Roeske J C, Forman J D, Mesina C F, et al. Evaluation of
changes in the size and location of the prostate, seminal vesicles,
bladder, and rectum during a course of external beam radiation
therapy. Int J Radiat Oncol Biol Phys 1995; 37:205-212. Beard C J,
Kijewshi P, Bussiere M, et al. Analysis of prostate and seminal
vesicle motion: Implications for treatment planning. Int J Radiat
Oncol Biol Phys 1996; 34:451-458. This organ motion adds an
additional component of uncertainty, which may also exceed 10 mm,
in localizing the target for treatment delivery.
[0006] Another approach to control patient positioning is to
utilize an immobilization device to maneuver the patient into a
particular position. An immobilization device physically attaches
to the human body to keep the patient from moving once proper
positioning is achieved. A drawback of using an immobilization
device is that such devices do not exist for all body parts.
Immobilization devices are generally effective only for positioning
the head and neck of a patient. Moreover, in many known
immobilization devices, a patient can still move to a significant
degree within the confines of the immobilization device. In
addition, these devices can be extremely uncomfortable for the
patient. Furthermore, the immobilization has little or no control
over aforementioned organ movement.
[0007] To solve these problems, researchers have developed a
real-time electronic portal imaging device procedure to identify
gold markers located within the patient's body and correct daily
variations in target position during external beam radiotherapy for
prostate cancer. Gold intraprostatic markers are implanted around
the target of interest in the patients through CT-guided
transgluteal approach or a transscrectal ultrasound-guided perineal
approach and are used to localize internal reference points. The
researchers found that a direct match to the markers provides an
easy, time-efficient, and more reliable method than using portal
skeletal images and obviates the need to calculate the centroid. M.
G. Herman, T. M. Pisansky, J. J. Kruse, et al., Technical aspects
of daily online positioning of the prostate for three-dimensional
conformal radiotherapy using an electronic portal-imaging device,
Int. J. of Radiation Oncology Biol. Phys., 57:4, pp 1131-1140
(2003). J. M. Schallenkamp, M. G. Herman, J. Kruse, T. M. Pisansky,
Prostate position relative to pelvic bony anatomy based on
intraprostatic gold markers and electronic portal images, Int. J.
of Radiation Oncology Biol. Phys., accepted for publication Feb.
17, 2005. However, because the markers used in these experiments
are designed for other purposes and are mostly cylindrical in shape
with smooth surfaces, the same study also revealed that the
fiduciary markers might change positions over time.
[0008] Thus, there is a need for better designed markers and method
that improve attachment markers to the target sites within a
patient and thus minimizes marker migration after implant.
SUMMARY
[0009] The invention provides devices and methods for locating a
target tissue within a patient and for positioning a patient for
medical treatment procedures, such as three-dimensional conformal
radiotherapy. According to an aspect of the invention, markers are
placed within a patient, as reference coordinates for particular
body locations on the patient. The markers may be shaped to provide
firm attachment to the body, which allows easy and accurate patient
positioning and tissue locating for a sequential treatments. An
embodiment of a device having features of this invention may be
dumbbell shaped marker with a spherical end and a conic end. The
conic end of the fiduciary marker may have a series of grooves cut
into it creating a rougher surface to enhance marker attachment.
Another embodiment of a device having features of the invention is
cylindrical marker with flexible fingers on one of its end. The
closed fingers may open up once placed with the patient. Yet
another embodiment of a device having features of the invention is
markers enclosed in absorbable strand or wrapped in sutures to form
longer fiduciary marker stands of desired lengths. In addition, the
marker body shape may have one or more distinct features, which may
be visualized in different marker orientations.
DESCRIPTION OF THE FIGURES
[0010] The accompanying drawings, which are incorporated in and
form a part of the specification, illustrate embodiments of the
present invention and, together with the description, serve to
explain the principles of the invention. Because the figures are
provided for the sole purpose of illustration, they are not drawn
to proportions.
[0011] FIG. 1A is a perspective view of a device embodying features
of the invention.
[0012] FIG. 1B is a cross-sectional view of one embodiment of
cone-end of the device along 3-3 of FIG. 1A.
[0013] FIG. 2A is another perspective view of a device embodying
features of the invention.
[0014] FIG. 2B is another aspect of the device shown in FIG.
2A.
[0015] FIG. 3 is a cross-sectional view of a device embodying
features of the invention along.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The drawings are shown for purposes of illustration. The
invention is embodied in a fiduciary marker or a fiduciary marker
strand. In the preferred embodiments of the present invention, the
marker is used in the human body. However, it will be recognized
that further embodiments of the invention may be used in animals or
other applications where positioning a body or body parts are
required. The invention is also not limited to radiotherapy. The
present invention provides devices and methods used to locate
target tissue in a patient for sequential treatments.
[0017] Referring to FIG. 1A, a fiduciary marker in accordance with
an embodiment of the present invention includes a dumbbell shaped
radio-opaque seed 8 with a spherical end 1 and a cone end 2
connected by a cylindrical middle section 5. The cone shaped end of
the marker (radio-opaque seed) may allow easier and deeper
insertion into the tissue adjacent or on a target site. Once placed
within a patient, the shape of the conic end may impede detachment
of the marker (radio-opaque seed) from the body tissue and prevent
marker migration within the body. The shape of the marker
(radio-opaque seed) may also indicate the direction of the marker,
which can be used to further marking the tissue or organ. A series
of grooves 4 may be cut into the surface of the cone shaped end of
a marker (radio-opaque seed) 2. FIG. 1B shows a cross-sectional
view of the fiduciary marker (radio-opaque seed) of FIG. 1A. These
grooves 4 may increase surface roughness of the end and increase
frictions between the surfaces 3 of the fiduciary marker and the
tissue 9 within which the marker is embedded. This feature allows
the marker (radio-opaque seed) 2 to take even a stronger hold of
the tissue.
[0018] FIG. 2A illustrates another embodiment of a fiduciary marker
having features of the invention. The fiduciary marker 8 may be a
uniform cylinder with a proximal end 7 and a distal end 12. Cross
section 5 of the fiduciary marker 8 may be of any shape, such as
round, square, rectangular or pentagon. The distal end 12 of the
fiduciary marker 8 may have one or more fingers or forks 6. The
fingers or forks 6 may be held together before implantation, for
example by a needle or a catheter and may open up after placement
within the targeted tissue of a patient. The opened forks 6 of the
fiduciary marker 8, as shown in FIG. 2B may be extended into tissue
surrounding or at a target site, and prevent marker migration over
time. The end of the fingers or forks may be sharpened to allow
easy insertion.
[0019] FIG. 3 shows yet another embodiment of the fiduciary makers
having features of the invention. In this embodiment, radio-opaque
markers or strands are used to mark soft tissue for therapeutic
procedures. As shown in FIG. 3, a marker strand 8 may comprise of
one or more radio-opaque seeds 10 separated by several absorbable
spacers 11 and enclosed by an absorbable strand 12. In the
alternative, fiduciary markers may be coated with absorbable
materials and formed into a strand. The increased length of the
fiduciary marker strand may greatly reduce markers migration after
implantation, relative to the target site or to each other.
Therefore, a fiduciary marker strand may provide more efficient and
reliable internal reference points for future treatments. The total
length of the stand may be around 1-30 centimeters depending on the
tissue characteristics. The absorbable strands, spacers or coating
may be such that it will degrade in vivo over time. Such coatings
may be selected from polymers such as polydextrans,
polyvinylpyrrolidone, poly(bis(p-carboxyphenoxy)-propane), lactide,
and copolymers derived thereof, and biopolymers such as gelatin,
human serum, albumin, cellulose, etc. CP medical, Inc of Portland,
Oreg., is a manufacturer of a type of FDA 501(K) approved
absorbable strands.
[0020] In yet another embodiment, the fiduciary markers are
embedded or wrapped in sutures. Recently clinical data at Wake
Forest University have shown that patients who were treated with
radioactive seeds embedded in suture have significantly improved
dosimetric coverage of the prostate gland than those who were
implanted with loose seeds. William Robert Lee, et al.,
Radiotherapy and Oncology 2002, 65:123-127. Baird, et al., also
observed that placing two markers separated by absorbable spacers
or sutures prior to prostate brachytherapy may help reduce marker
migration and improve dosimetric result. Baird M C, Holt R W, Selby
T L, Improvement of trasperineal implant dosimetry by
intraoperative cystoscopic confin of prostate anatomy. J Urol 2000;
164:406-410.
[0021] In all embodiments, the fiduciary markers may be made of
stainless steel, gold, titanium, platinum, tantalum, copper,
tungsten or other biocompatible metals or an alloy of metals. The
length of a radio-opaque seed may range from 0.1 mm to 5 cm. The
technology of making metal markers or seeds is well known in the
art. One manufacturer having particular expertise in such
manufacturing is BEST Medical International, Inc., in Springfield
Va., which has been manufacturing and distributing medical devices
and radioisotopes since 1977.
A method having features of the invention comprises the step of
producing a fiduciary marker or a fiduciary marker strand having
features of the invention. The fiduciary markers or strands may be
then delivered by any method known to one of ordinary skill in the
art. For example, the marker or marker strand may be implanted or
inserted via use of an implantation gun, catheter, syringe or the
like. It is preferable that the delivery of the fiduciary marker or
marker strand include visual confirmation of its placement by
common imaging modalities such as stereotaxy, ultrasound, CT or
MRI. The specific placement pattern and quantity of fiduciary
marker or marker stands may be selected depending on the anatomical
and physiological properties of the area being treated, as known to
one of ordinary skill in the art. The target sites on a patient may
be then treated over a period of time based on coordinates given by
the fiduciary markers. The method may further include a step where
after several sessions of treatments, fiduciary markers are removed
from the patient surgically with the assistance of stereotaxy,
ultrasound, CT or MRI.
* * * * *