U.S. patent application number 12/306900 was filed with the patent office on 2009-08-06 for method of identification of an element in two or more images.
Invention is credited to Jesper Carl, Morten Sorensen.
Application Number | 20090196470 12/306900 |
Document ID | / |
Family ID | 35169353 |
Filed Date | 2009-08-06 |
United States Patent
Application |
20090196470 |
Kind Code |
A1 |
Carl; Jesper ; et
al. |
August 6, 2009 |
METHOD OF IDENTIFICATION OF AN ELEMENT IN TWO OR MORE IMAGES
Abstract
The present invention relates to a method and an apparatus for
identification of an element in two or more images. The method
comprises the steps of, identifying, in an image an integral
three-dimensional element visible in the image, and identifying in
a first image the three-dimensional element, identifying in a
second image the three-dimensional element. Subsequently, collating
is performed based on the first image and the second image and
based on a determination of the position of the three-dimensional
element in the first image and the position of the
three-dimensional element in the second image. Thereby, a position
and/or an extension in three dimensions of a bodily matter of
interest within the human body or the animal body may be
established.
Inventors: |
Carl; Jesper; (Nibe, DK)
; Sorensen; Morten; (Copenhagen, DK) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
35169353 |
Appl. No.: |
12/306900 |
Filed: |
June 29, 2007 |
PCT Filed: |
June 29, 2007 |
PCT NO: |
PCT/DK2007/050081 |
371 Date: |
March 16, 2009 |
Current U.S.
Class: |
382/128 |
Current CPC
Class: |
A61B 2017/00867
20130101; A61B 2090/374 20160201; A61B 2090/3983 20160201; G06T
7/33 20170101; A61B 90/36 20160201; A61N 5/1049 20130101; A61B
90/39 20160201; A61N 2005/1058 20130101; G06T 2207/10072 20130101;
A61N 2005/1055 20130101; G06T 2207/30096 20130101; A61N 2005/1061
20130101; A61N 5/1067 20130101 |
Class at
Publication: |
382/128 |
International
Class: |
G06K 9/00 20060101
G06K009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 30, 2006 |
DK |
PCT/DK2006/000387 |
Claims
1-47. (canceled)
48. A method for identification of an element in two or more
images, the method comprising the steps of, identifying, in an
image, a single integral three-dimensional element visible in the
image, said single integral three-dimensional element being in
position in a human body or an animal body in relation to a bodily
matter of interest within the human body or the animal body, the
method comprising the steps of: identifying in a first image the
single integral three-dimensional element, visible in the first
image, identifying in a second image the same single integral
three-dimensional element, visible in the second image, collating
the first image and the second image based on a determination of
the position of the one and same single integral three-dimensional
element in the first image and the position of the one and same
single integral three-dimensional element in the second image.
49. A method according to claim 48, said method comprising the
further step of, establishing a position and/or establishing an
extension and/or establishing a shape of the at least one single
integral three-dimensional element in reference to the bodily
matter of interest within the human body or the animal body, the
establishing being based on collating the first image and the
second image.
50. A method according to claim 48, where identifying the position
of the at least one single integral three-dimensional element is
used also for determining at least one of the following physical
characteristics in relation to the at least one single integral
three-dimensional element: A shape of the element and/or an
extension of the element.
51. A method according to claim 48, wherein the two or more images,
being derived by different types of imaging equipments, are
collated based on determination of at least one of the following
characteristics of the single integral three-dimensional element,
in each of the images: the position or the extension or the shape
of the element.
52. A method according to claim 48, wherein the two or more images,
being derived under different set-up conditions when deriving the
images, are collated based on determination of at least one of the
following characteristics of the single integral three-dimensional
element, in each of the images: the position or the extension or
the shape of the element.
53. A method according to claim 52, wherein the two or more images
are derived with a time interval between the deriving of the images
and are collated based on determination of at least one of the
following characteristics of the single integral three-dimensional
element, in each of the images: the position or the extension or
the shape of the element.
54. A method according to claim 48, wherein the two or more images
are being collated automatically, based on an automatic
identification of the single integral three-dimensional element in
the different images.
55. A method according to claim 53, wherein more images are derived
with a time interval between the deriving of the images and are
being collated automatically and continuously, based on an
automatic identification of at least one of the following
characteristics of the single integral three-dimensional element,
in each of the images: the position or the extension or the shape
of the element.
56. A method according to claim 48, said method comprising the
further step of, setting up treatment specifications according to
the information in the two or more collated images.
57. A method according to claim 48, said method comprising the
further step of, comparing at least one of the following
characteristics of the bodily matter of interest: the position or
the extension or the shape of the matter, in reference to at least
one of the following characteristics of the single integral
three-dimensional element, in each image: the position or the
extension or the shape of the element.
58. A method according to claim 48, said method comprising the
further step of, using at least one of the following
characteristics of the single integral three-dimensional element:
the position or the extension or the shape of the element, relative
to a reference in the first image as a reference-position,
comparing at least one of the characteristics of the single
integral three-dimensional element: the position or the extension
or the shape of the element, relative to the same reference in the
second image, with the reference-position in the first image
59. A method according to claim 58, said method comprising the
further step of, guiding a treatment equipment according to the
comparison of at least one of the characteristics of the single
integral three-dimensional element relative to the reference in the
second image with at least one of the characteristics of the single
integral three-dimensional element relative to the
reference-position of the same reference in the first image.
60. A method according to claim 59, wherein the treatment equipment
to be guided is an external beam radio therapy equipment.
61. A method according to claim 57, wherein the same single
integral three-dimensional element is used for setting Up treatment
specifications, based on collated pre-treatment images, and for
comparing at least one of the characteristics of the single
integral three-dimensional element, relative to a reference in one
or more just-before-treatment-images or in one or more
during-treatment-images, with the reference-position in the
pre-treatment images, and possibly the step of guiding a treatment
equipment, where the same single integral three-dimensional element
possibly is used without re-insertion or re-positioning of the
single integral three-dimensional element.
62. A method according to claim 48, wherein the imaging equipment
is medical imaging equipment such as Magnetic Resonance scan
(MR-scan), Nuclear Magnetic Resonance scan (NMR-scan), Magnetic
Resonance Image scan (MRI-scan), Computerized Tomography scan
(CT-scan), Cone Beam CT-scan, Positron Emission Tomography (PET),
Single Positron Emission Computed Tomography (SPECT), Single
Positron Emission Tomography (SPET), Image-Guided-Radiation-Therapy
(IGRT), Ultrasound-scan, or X-ray, high-energy photons equipment or
high/mega voltage equipment.
63. A method according to claim 48, wherein the single integral
three-dimensional element (7) is intended for being placed and
fixed inside a natural body cavity of the human body or the animal
body.
64. A method according to claim 63, wherein the at least one single
integral three-dimensional element is a tubular endoluminal
prosthesis.
65. A method according to claims 63, wherein the at least one
single integral three-dimensional element (7) is a helical coil of
at least one wire.
66. A method according to claim 48, wherein at least a part of the
at least one single integral three-dimensional element (7) has a
shape allowing passage of a liquid, gas or solid inside the cavity
in which the element is in position.
67. A method according to claim 66, wherein the at least one single
integral three-dimensional element is a tubular endoluminal
prosthesis.
68. A method according to claims 66, wherein the at least one
single integral three-dimensional element (7) is a helical coil of
at least one wire.
69. A method according to claim 48, wherein said cavity has at
least one surrounding wall, and wherein the at least one single
integral three-dimensional element (7) has a collapsible design
enabling a collapsed design before the element (7) is positioned in
the cavity, and enabling an expanded design when the element (7) is
in position in the cavity.
70. A method according to claim 48, wherein the at least one single
integral three-dimensional element (7) is in position in the body
preliminary to deriving the first image and the second image, said
positioning of the element having been performed through a natural
opening of the body (1) without substantially penetrating any
tissue of the body (1).
71. A system for carrying out the method according to claim 48,
comprising image deriving equipment for identifying a single
integral three-dimensional element (7) in the first image and in
the second image, image processing equipment for identifying the
position of the single integral three-dimensional element (7) in
the first image and in the second image, image processing equipment
for collating the first image and the second image, said collating
being based on a determination of at least the position of the one
and same single integral three-dimensional element in the first
image and of at least the position of the one and same single
integral three-dimensional element in the second image.
72. A system according to claim 71, wherein the imaging equipment
is medical imaging equipment such as Magnetic Resonance scan
(MR-scan), Nuclear Magnetic Resonance scan (NMR-scan), Magnetic
Resonance Image scan (MRI-scan), Computerized Tomography scan
(CT-scan), Cone Beam CT-scan, Positron Emission Tomography (PET),
Single Positron Emission Computed Tomography (SPECT), Single
Positron Emission Tomography (SPET), Image-Guided-Radiation-Therapy
(IGRT), Ultrasound-scan, or X-ray, high-energy photons equipment or
high/mega voltage equipment.
73. A system according to claim 71, wherein the at least one single
integral three-dimensional element (7) has a design enabling at
least one of the following operations: insertion and retraction of
the element (7) with specifically adapted endoscopic equipment.
Description
FIELD OF INVENTION
[0001] The present invention generally relates to a method for
identifying an element common in two or more images and
subsequently collating the two or more images based on the common
element. The present invention specifically relates to a method for
identifying an element being positioned in a human body or an
animal body in relation to bodily matter such as a tissue or an
organ or other bodily matter.
[0002] The invention may also relate to establishing a bodily
parameter such as temperature, blood flow, nerve impulses or other
bodily parameters of interest within the human body or the animal
body. The bodily parameter is established based on identifying the
element in relation to the bodily matter of interest.
BACKGROUND
[0003] A problem associated with the prior art medical imaging
techniques concerns the accurate selection and comparison of views
of identical areas in images that have been obtained by imaging
equipment at different times or by images obtained essentially at
the same time using different image modalities, e.g., CT, MRI,
SPECT, and PET, or by images obtained essentially at the same time
using different set-up conditions. This problem has two
aspects.
[0004] First, in order to relate the information in an image of the
anatomy to the anatomy itself, it is necessary to establish a
one-to-one mapping between points in the image and points on the
anatomy. This is referred to as registering image space to physical
space.
[0005] The second aspect concerns the registration of one image
space to another image space. The goal of registering two
arbitrarily oriented images is to align the coordinate systems of
the two images such that any given point in the scanned anatomy is
assigned identical addresses in both images. The calculation of the
rigid body transformation necessary to align images requires
knowledge of the movement and rotation of the anatomy in the
images.
[0006] Calculation of the rigid body transformation of the anatomy
for planar alignment of the coordinate systems of two-dimensional
images requires knowledge of the coordinates of either at least two
single points or a line in the images. Calculation of the rigid
body transformation of the anatomy for three-dimensional alignment
of the coordinate systems of three-dimensional images or multi
angle two-dimensional images requires knowledge of the coordinates
of either at least three single points, two lines in the images or
a three-dimensional object in the images.
[0007] Single identifiable points marking identical locations in
the images are called "fiducial points" or "fiducials," and the
fiducials used are the geometric centres of markers, which are
called "fiducial markers". These fiducials are used to correlate
image space to physical space and to correlate one image space to
another image space. The fiducial markers provide a constant frame
of reference visible in a given imaging mode to make registration
possible.
[0008] One problem extant in the field lies in the provision of
fiducials capable of use with several imaging modalities. MRI and
X-ray CT images are digital images, in which the images are formed
point by point. These points are called picture elements, or
pixels, and are associated with an intensity of light emitted from
a cathode ray tube, or are used to form an image on film. The array
of lighted pixels enables the observer to view an image.
[0009] The manner in which the intensity of any given pixel is
altered or modulated varies with the imaging modality employed. In
X-ray CT, such modulation is a function primarily of the number of
electrons per unit volume being scanned. In MR imaging, the
parameters primarily influencing this modulation are the proton
spin density and longitudinal and transverse relaxation times T1
and T2, which are also known as the spin-lattice and spin-spin
relaxation times, respectively.
[0010] By using and combining different imaging modalities, one can
benefit from the characteristics of the different modalities,
facilitating some in-body objects being clearer and easier to
identify in one image modality than in another and vice versa.
Hereby improved identification of in-body objects and improved
diagnosis is facilitated.
[0011] In constructing a fiducial marker, one must be aware that an
agent that can be imaged under one imaging modality will not
necessarily be imageable under another modality. And yet, the
ability to image under both CT and MRI with a given marker would be
especially useful, in that one would then be able to register
images derived from different imaging modalities. For example, the
capability to register CT and MR images would allow the integration
of information concerning bony structure provided by a CT scan with
the soft tissue anatomical information provided by an MRI scan.
There remains a need for a fiducial marker that can be used to
establish a known coordinate system under several imaging
modalities, and which facilitates anatomical alignment of the
different images.
[0012] A further problem in the field arises from the competing
needs of accommodating patient comfort, which would tend to lead
clinicians toward the minimization of marker size, for a less
traumatic implantation process, with the desire of clinicians to
use markers that are as bright and thus as large in the images as
possible. Such brightness is desirable because it provides a strong
signal that can be distinguished from noise inherent in the imaging
process. The use of large-sized markers is also desirable so that
the image of the marker occupies as many full pixels as possible.
Increasing the number of full pixels occupied by the marker
increases the accuracy with which the position of the marker can be
determined, and the safety that the fiducial point can be clearly
identified and is not mixed up with other points in the images.
[0013] Furthermore, the general technique of using fiducial markers
requires the determination of the centroid of the marker; it is
easier to compute the centroid for a large, bright marker than for
a smaller, dimmer marker. On the other hand, the larger the marker
of the prior art is, the more difficult it is for the patient to
tolerate its presence for extended periods of time when the marker
is buried in the tissue. There remains a need for a marker which
can exploit the advantages presented by increased size that would
also be tolerated by the patient during the period of its use.
There is also a need for a small multi-modality marker that can be
implanted into a patient and remain there for more extended periods
of time, without harming the patient.
[0014] Furthermore there is a need for a single marker that can
provide information on the coordinates of at least three points
within the different images.
[0015] Such a more permanent fiducial marker would preferably be
detectable by a non-invasive technique so that its position in
physical space could be determined and its centroid computed even
as it remains hidden from visual inspection beneath the patient's
skin.
[0016] U.S. Pat. No. 6,333,971 describes an implantable fiducial
marker having a sealed cavity for the introduction of an imaging
agent that provides imaging capability in several modes, including
Computed Tomographic imaging (CT) and Magnetic Resonance Imaging
(MRI). The marker may be permanent, or it may be temporary and
readily detachable from its anchor site. Combinations or agents
imageable under CT scanning are combined with agents imageable
under MRI scanning. The choice of imaging agents allows for the
construction of a marker that is visible under both CT and MRI
imaging modalities. Furthermore, by using a marker that comprises a
solid outer portion and an aqueous inner portion, the marker can be
located through the use of a non-invasive transcutaneous detection
system, such as one employing ultrasound to detect the presence of
the solid-liquid interface between the aqueous core and the solid
outer portion. The use of solid metal is eschewed throughout. The
presence of metal may cause unwanted artefacts and image distortion
in the image, and may impede efforts to localize the marker.
[0017] Visicoil.TM., a product from Radiomed Corporation in the
USA, consists in linear fiducial markers that are naturally visible
by ultrasound, X-Ray, CT, MRI, and high-energy photons (portal
images), allowing the physicians to implant the markers under one
mode and later visualize them by another technique for treatment
planning. Visicoil.TM. markers can be more easily recognized than
the much larger point markers and with less confusion. Two or more
Visicoil.TM. markers is needed for providing three-dimensional
volume information. The Visicoil.TM. markers have to be implanted
into the tissue of interest by invasive surgery and the
Visicoil.TM. technique needs at least two markers for establishing
an exact determination of a location of the tissue of interest.
Thus, both the invasive surgery and the implantation of two or even
more markers increase the risk of trauma to the patient.
[0018] One example of applications benefiting from alignment of
different images is in relation to treatment of cancerous lesions
in the human body irradiation of the disordered tissue, such as a
tumor, is used in order to destroy the disordered tissue. The
disordered tissue may be placed in all parts of the body. When the
disordered tissue is positioned in some parts it may be difficult
to irradiate without crucially damaging other essential parts of
the body and in some cases the irradiation can cause irreversible
damage.
[0019] Thus, the irradiation of the disordered tissue is restricted
by the amount of irradiation, which healthy tissue may tolerate
without being crucially or irreversible damaged. This limitation of
the irradiation is further increased by the fact that it may be
difficult to precisely locate the disordered tissue and to
determinate the extension of the disordered tissue inside the
body.
[0020] Due to the fact that different diagnostic imaging
technologies result in different parts and organs of the patient's
body to be clearly identified, a combination of different imaging
technologies such as CT, MR, PET, SPECT, X-ray, High-voltage X-ray
is often used for localisation of the bodily matter of interest
(e.g. a cancerous tumor being the target for irradiation. The
different images might be merged in a fusion of two or more images
using data processing equipment. By combining the different imaging
technologies a more accurate identification and localisation of a
bodily matter of interest is possible, e.g. a cancerous tumour. In
order to make the identification and localisation of the bodily
matter of interest accurate, the images need to be aligned
accurately near the bodily matter of interest.
[0021] A combination of different images, generated by different
imaging technologies is for example used during the planning of
radiation therapy. During the planning of radio therapy, the
cancerous tumour is identified in diagnostic images, e.g. CT, MR,
PET, SPECT, X-ray. Hereafter position and form of the tumour is
localised and a profile of the irradiation to be given to the
patient is generated, based on the form and position of the
tumour.
[0022] Diagnostic images made with different imaging technologies
and different apparatuses are often obtained with a time interval
between the images, and with the patient repositioned on a
different couch for each image. This results in different set-up
conditions for each image. The different set-up conditions result
in a difference between the actual positions of the bodily matter
of interest inside the body of the patient in the different images,
compared to visual objects in the images (bone structures, outer
surface of the patient's body etc.), placed a distance from the
bodily matter of interest. The difference between the positions of
the bodily matter of interest in the different images can occur
either by internal organ motion inside the patient's body and/or by
inaccurate positioning of the patient under the image generating
equipment.
[0023] Today, fusion between different diagnostic images is often
aligned by using anatomic markers, which are visual in the
different diagnostic images (bone structure, outer surface of the
patient's body etc.). Those anatomic markers are often positioned a
distance from the bodily matter of interest. Due to the fact that
the bodily matter of interest will often have made a relative
motion, compared to the anatomic markers positioned a distance away
from the bodily matter of interest, an alignment of the different
images based on the anatomical markers will result in inaccurate
alignment of the images near the bodily matter of interest.
[0024] Alternatively fusion between the different diagnostic images
can be aligned according to implanted fiducial markers or implanted
line markers. Other factors which can lead to inaccurate alignment
of the images are differences in the set-up conditions for the
imaging equipment or the patient (e.g. the images are not obtained
in exactly the same angle, and/or the image quality is not
identical in the individual images (the image quality does often
depend on the focal point).
[0025] A combination of different images can also be used for
setting up treatment apparatuses, for example an irradiation
equipment for external beam radio therapy of a cancerous tumor. The
irradiation target is localised in at least one reference image
during a planning session, prior to the treatment session. When
starting a treatment session the treatment apparatus can be set up
based on fusion between the reference image and an image obtained
just before treatment or during treatment.
[0026] U.S. Pat. No. 5,853,366 describes a system to be used for
radio therapy of a tumor. The location of the tumor is performed by
inserting at least three markers in relevant positions around the
periphery of the tumor. These markers are made from stainless steel
capable of being detected in a conventional X-ray image of the body
in order to position the irradiation source in relation to the
tumor before irradiation of the tumor. Each marker is depicted as
one point in an X-ray image. These markers are inserted directly
into the tissue surrounding the tumor and the markers are barbed or
V-shaped in order to securely fasten the markers into the tissue
thereby inhibit movement of the markers. Subsequently to
positioning of the markers and irradiation of the tumor, the barbed
markers have to be removed by invasive surgery.
[0027] WO 99/27839 discloses a system for positioning and
repositioning of a portion of a patient's body with respect to a
treatment or imaging machine including multiple cameras to view the
body and the machine. Index markers placed externally on the
patient's body, either light-emitting, passive, geometric shapes,
or natural landmarks, are identified and located by the cameras in
3D space. Anatomical targets determined from image scanning can be
located relative to reference positions associated with the
treatment or diagnostic machine. Several forms of camera, index
markers, methods and systems accommodate different clinical uses.
X-ray imaging of the patient further refines anatomical target
positioning relative to the treatment or diagnostic imaging
reference point. Movements of the patient based on comparative
analysis of imaging determined anatomical targets relative to
reference points on treatment or diagnostic apparatus are
controlled by the system and process.
[0028] WO 02/19908 discloses a method and an apparatus for
compensating for breathing and other motions of the patient during
treatment, the method comprising: generating images of the target
region prior to the treatment; periodically generating positional
data about the internal target region based on markers implanted in
the patient's body; continuously generating positional data about
external motion of the patient's body using one or more external
sensors; and generating a correspondence between the position of
the internal target region and the external sensors so that the
treatment is directed towards the position of the target region of
the patient based on the positional data of the external sensors.
The target region's position is subsequently matched to the
position of the target region in the preoperative images.
[0029] WO 02/100485 discloses a system and method for accurately
locating and tracking the position of a target, such as a tumor or
the like, within a body. In one embodiment, the system includes one
or more excitable beacons positioned in or near the target, an
external excitation source that remotely excites the beacons to
produce an identifiable signal, and a plurality of sensors spaced
apart in a known geometry relative to each other. A computer is
coupled to the sensors and configured to use the beacon signals to
identify a target isocenter within the target. The computer
compares the position of the target isocenter with the location of
the treatment isocenter. The computer also controls movement of the
patient and a patient support device so the target isocenter is
coincident with the treatment isocenter before and during radiation
therapy.
[0030] Markers as described above are used to define the extent of
a disordered tissue area, and/or to guide the treatment equipment,
but still the whole area may be difficult to view in the image. For
this reason and other reasons when planning irradiation of
disordered tissue, the medical practitioner or the attending
physician plans the irradiation by applying an irradiation margin
in order to be sure that all of the disordered tissue area is
irradiated. This margin results in some of the healthy tissue being
deliberately irradiated and therefore the aforementioned crucial
damages may occur. Also, only fiducial markers are disclosed. A
fiducial marker itself provides no possibility of identifying any
rotation of the marker. Fiducial markers provide no possibility of
localizing the disordered tissue without having at least two, and
as disclosed, preferably three fiducial markers employed.
[0031] Further reasons for applying the irradiation margin is the
inaccuracy in positioning the patient below the irradiation
equipment, the inaccuracy of the resolution of the derived image of
the disordered tissue and the fact that the internal organs may
move over time. Such movement of the internal organs may be caused
by respiration and/or by day-to-day movements. The use of implanted
markers for guiding the treatment as described above can, to some
extend, improve the accuracy of the positioning of the patient.
[0032] U.S. Pat. No. 6,307,914 discloses a moving body pursuit
irradiating device comprising a linac for controlling the
irradiation of a medical treatment beam to a tumor, and a tumor
marker buried in the vicinity of the tumor, a first X-ray
fluoroscope for picking up an image of said tumor marker from a
first direction, and a second X-ray fluoroscope for picking up the
image of said tumor marker from a second direction at the same time
as said first X-ray fluoroscope, first and second recognition
processing sections which execute template matching at a real time
level at a predetermined frame rate by a shading normalization
mutual correlation method for applying a template image of the
tumor marker registered in advance to image information digitized
by said first and second image input sections, and calculate first
and second two-dimensional coordinates of said tumor marker, a
central arithmetic processing section for calculating
three-dimensional coordinates of said tumor marker from the first
and second two-dimensional coordinates calculated by said first and
second recognition processing sections; and an irradiating control
section for controlling the irradiation of the medical treatment
beam of said linac by said calculated three-dimensional coordinates
of the tumor marker.
[0033] Implanted markers of prior art that is positioned in the
body of the patient are buried in tissue and therefore require
invasive surgery to be inserted in the body as well as further
subsequent invasive surgery to be retracted from the body.
[0034] Diagnostic images made with different imaging technologies
and with different medical imaging equipment can be derived with a
time interval between the images, and with the patient repositioned
on a different couch for each image. This results in different
set-up conditions for each image. The different set-up conditions
result in a difference between the actual position of the tissue of
interest inside the body of the patient in the different images,
compared to visually clear objects in the images, placed a distance
from the tissue of interest, such as bone structures, outer surface
of the patient's body etc. The difference between the positions of
the tissue of interest in the different images can occur either by
internal organ motion inside the patient's body and/or by
inaccurate positioning of the patient below the medical imaging
equipment.
[0035] A need exists however of an improved marker and a method for
collating different images obtained by different imaging equipment,
and/or obtained with a time interval between the images, and/or
obtained with different set-up conditions for the images, in order
to at least partly overcome the aforementioned disadvantages of the
prior art relating to localizing the tissue of interest. An
improved marker is a marker easy to detect and sufficiently precise
to detect in different imaging equipment. An improved marker may
alternatively or additionally be a marker easy to implement into
and/or easy to retract from the human or animal body.
SUMMARY OF THE INVENTION
[0036] An objective of the present invention is to provide a method
for overcoming the disadvantages and drawbacks of the known methods
and systems presented above.
[0037] These objectives and the advantages that will become evident
from the following description of the invention are obtained by the
following embodiments and aspects of the method according to the
present invention by providing a method for identification of an
element in two or more images, the method comprising the steps of,
[0038] identifying, in an image, at least one integral
three-dimensional element visible in the image, said at least one
integral three-dimensional element being in position in relation to
a bodily matter of interest within a human body or an animal body,
the method comprising the steps of: [0039] identifying in a first
image the three-dimensional element, visible in the first image,
[0040] identifying in a second image the three-dimensional element,
visible in the second image, [0041] collating the first image and
the second image based on a determination of the position of the
three-dimensional element in the first image and the position of
the three-dimensional element in the second image, and
[0042] A method according to the invention, employing an improved
marker, said marker possible being a single marker with at least
three identifiable points, results in knowledge not hitherto
obtainable about movement and/or rotation and/or change of shape
and/or change of extension of the tissue or the organ of interest,
preferably in three dimensions.
[0043] With the three-dimensional element being positioned and
fixed in relation to a bodily matter of interest a mutual
positional relationship between the three-dimensional element and
the bodily matter of interest can be established. The knowledge
about the position of the three-dimensional element in the image
gives an exact knowledge of where the bodily matter of interest is
positioned, because the bodily matter of interest and the
three-dimensional element have been found to have a substantially
fixed relationship and any possible movement of the bodily matter
of interest results in corresponding movement of the
three-dimensional element and vice versa. Images can be aligned
according to the three-dimensional element and hereby also bodily
matter of interest will be aligned in the images.
[0044] In the context of the present invention, bodily matter is to
be construed as any matter relating to the body, e.g. any of the
different body organs, body tissue including abnormal body tissue
such as a tumor or body substances such as ascites, bile, blood,
cerebrospinal fluid, lymph or urine, etc.
[0045] In the context of the present invention, tissue is defined
as cells grouped together in the body to form tissues, i.e. a
collection of similar cells that group together to perform a
specialized function. Four primary tissue types are defined in the
human body:
[0046] Epithelial tissue--The cells of epithelial tissue pack
tightly together and form continuous sheets that serve as linings
in different parts of the body. Epithelial tissue serves as
membranes lining organs and helping to keep the body's organs
separate, in place and protected. Some examples of epithelial
tissue are the outer layer of the skin, the inside of the mouth and
stomach, the intestines and the tissue surrounding the body's
organs, the respiratory epithelium and the endothelium of the
various blood vessels.
[0047] Connective tissue--Generally speaking, connective tissue
adds support and structure to the body. Most types of connective
tissue contain fibrous strands of the protein collagen that add
strength to connective tissue. Some examples of connective tissue
include the inner layers of skin, tendons, ligaments, cartilage,
bone and fat tissue. In addition to these forms of connective
tissue, bone is also considered a form of connective tissue.
[0048] Muscle tissue--Muscle tissue is a specialized tissue that
can contract. Muscle tissue contains the specialized proteins actin
and myosin that slide past one another and allow movement. Examples
of muscle tissue are contained in the muscles throughout the
body.
[0049] Nerve tissue--Nerve tissue contains two types of cells:
neurons and glial cells. Nerve tissue has the ability to generate
and conduct electrical signals in the body. These electrical
messages are managed by nerve tissue in the brain and transmitted
down the spinal cord to the body.
[0050] In the context of the present invention, organs are defined
as a structure containing at least two different types of tissue
functioning together for a common purpose. The different body
organs may be of interest imaging for the purpose of diagnosis
and/or therapy and/or surgery. There are ten major organ systems in
the human body:
[0051] Skeletal system: The skeletal system is providing support
for the body, to protect internal organs and to provide attachment
sites for the organs. Major skeletal system organs are bones
including the skull, cartilage, tendons and ligaments.
[0052] Muscular system: The muscular system providing movement.
Muscles work in pairs to move limbs and provide the organism with
mobility. Muscles also control the movement of materials through
some organs, such as the stomach and intestine, and the heart and
circulatory system. Major muscular system organs are skeletal
muscles and smooth muscles.
[0053] Circulatory system: The circulatory system is transporting
nutrients, gases (such as oxygen and CO.sub.2), hormones and wastes
through the body. Major circulatory system organs are the heart,
blood vessels and the blood.
[0054] Nervous system: The nervous system is transmitting
electrical signals through the body. The nervous system directs
behaviour and movement and, along with the endocrine system,
controls physiological processes such as digestion, circulation,
etc. Major nervous system organs are the brain, the spinal cord and
the peripheral nerves.
[0055] Respiratory system: The respiratory system is providing gas
exchange between the blood and the environment. Primarily, oxygen
is absorbed from the atmosphere into the body and carbon dioxide is
expelled from the body. Major respiratory system organs are the
nose, trachea and the lungs.
[0056] Digestive system: The digestive system is breaking down and
absorbing nutrients that are necessary for growth and maintenance.
Major digestive system organs are the mouth, esophagus, the
stomach, small and large intestines.
[0057] Excretory system: The excretory system is filtering out
cellular wastes, toxins and excess water or nutrients from the
circulatory system. Major excretory system organs are the kidneys,
ureters, the bladder and urethra.
[0058] Endocrine system: The endocrine system is transmitting
chemical messages through the body. In conjunction with the nervous
system, these chemical messages help control physiological
processes such as nutrient absorption, growth, etc. Many glands
exist in the body that secrete endocrine hormones. Among these, the
major endocrine system organs are the hypothalamus, pituitary,
thyroid, pancreas and adrenal glands.
[0059] Reproductive system: The reproductive system is producing
cells that allow reproduction. In the male, sperm are created to
inseminate egg cells produced in the female. Major female
reproductive system organs are the ovaries, oviducts, the uterus,
vagina and mammary glands. Major male reproductive system organs
are the prostate, the testes, seminal vesicles and the penis.
[0060] Immune system: The immune system is destroying and removing
invading microbes and viruses from the body. The lymphatic system
also removes fat and excess fluids from the blood. Major immune
system organs are lymph, lymph nodes and vessels, white blood
cells, T- and B-cells.
[0061] According to a possible method according to the invention,
the method further comprises a step of [0062] establishing a
position and/or establishing an extension of a bodily matter in the
human body or the animal body, the establishing being based on
collating the first image and the second image.
[0063] According to the present invention, each individual image
may be a two dimensional projection image or a three-dimensional
image, and wherein the image is derived and processed by medical
imaging equipment.
[0064] According to the invention the steps of identifying the
three-dimensional element and collating the images based on the
determination of the position of the three-dimensional element in
the images may be performed in more than two images.
[0065] According to the invention the steps of identifying the
three-dimensional element and collating the images based on the
determination of the position of the three-dimensional element in
the images may be performed in images obtained by different imaging
modalities.
[0066] According to the invention the steps of identifying the
three-dimensional element and collating the images based on the
determination of the position of the three-dimensional element in
the images may be performed in images obtained with different
set-up conditions (e.g. images obtained from different angles, or
images obtained with a deliberate or an undeliberate movement of
the patient and/or of the tissue of interest (and hereby a movement
of the three-dimensional element) between the images).
[0067] According to the invention the steps of identifying the
three-dimensional element and collating the images based on the
determination of the position of the three-dimensional element in
the images may be performed in images obtained with a time interval
between the images being obtained, potentially resulting in
different set-up conditions in the images, and/or movement of the
tissue of interest (and hereby a movement of the three-dimensional
element) within the human body or the animal body between the
images.
[0068] Given a possibility to align different images more exactly
than by the prior art methods, facilitates the possibility to track
a development over time, within images obtained at different times.
Tracking a development over time, within images obtained at
different times, facilitates tracking of movement and/or
growth/shrinking of body elements, in general called bodily matter,
for better diagnosis (e.g. tracking of the growth of a cancerous
tumor or tracking of the movement of a cancerous tumor according to
the patient's breathing cycle).
[0069] Examples of applications which might benefit from exact
alignment of different images are:
[0070] Collating images (obtained by different imaging technologies
and/or obtained in different planes/angles). Collating images
(obtained by different imaging technologies and/or obtained in
different planes/angles) by the method according to the invention,
and incorporating use of a three-dimensional element as a marker,
results in improved identification of bodily matter and the better
identification results in a better diagnosis.
[0071] Possible use applications in relation to collating images by
a method according to the invention may be the following
non-exhaustive list of applications: [0072] Reduction of
inaccuracies due to set-up differences between the images [0073]
Identification of unwanted in-body elements (e.g. position and size
of cancer tumors, position and size of encrustations or
stone-formations, position and size of foreign bodies or one or
more fetuses) [0074] Planning of treatment and/or identification of
treatment target (e.g. planning of irraditation treatment) [0075]
Identification and/or diagnosis of orthopaedic damages (bone
fractures, joint fractures or joint dislocations) [0076]
Identification of possible obstructions of bodily lumens (e.g.
urothelial obstructions due to encrustation or foreign bodies,
cardiovascular obstructions due to encrustation, etc.)
[0077] Further examples of applications which might benefit from
exact alignment of different images are:
[0078] Comparing images (obtained at different times. comparing a
present image with a reference image). Comparing images by the
method according to the invention, and incorporating use of a
three-dimensional element as a marker, results in tracking of
progress of movement and/or growth/shrinkage of a bodily matter of
interest.
[0079] Possible use applications in relation to comparing images by
a method according to the invention may be the following
non-exhaustive list of applications: [0080] Tracking of growth or
shrinkage of a cancerous tumor. [0081] Tracking of growth or
shrinkage of a cardiovascular lumen. [0082] Tracking movement of a
foreign body, a parasite or the like. [0083] Correction of
inaccuracies due to set-up differences between obtaining the
reference image and obtaining the present image. [0084] Correction
of inaccuracies due to internal body organ movements between
obtaining the reference image and obtaining the present image.
[0085] Tracking internal body organ movements.
[0086] The correction of inaccuracies due to set-up differences
and/or due to internal body organ movements, and/or the tracking of
internal body organ movements may be established for different
reasons, such as: [0087] Controlling external treatment equipment
according to linear movement and rotation of the treatment target
(e.g. guiding an irradiation equipment).
[0088] According to a possible method step according to the
invention, subsequent to establishing a position of a bodily matter
of interest and/or establishing an extension of a bodily matter in
the human body or the animal body, a bodily parameter is derived
based on establishing the position and/or the extension of the
bodily matter.
[0089] In the context of the present invention, bodily parameters
are to be construed as any parameter related to the body, e.g.
physiologic parameters such as temperature, bodily fluid parameters
such as flow of ascites, bile, blood, cerebrospinal fluid, lymph or
urine flow, bodily electrochemical parameters such as nerve
impulses, etc.
[0090] Combination of different images, generated by different
imaging technologies, and/or generated under different set-up
conditions may be used during the planning of therapy or surgery.
During the planning of therapy or surgery, a bodily matter of
interest, such as an organ of interest, e.g. the prostate, or such
as a tissue of interest, e.g. a cancerous tumor, or such as a
substance of interest, e.g. urine, is identified in diagnostic
images. Hereafter position and shape of the bodily matter is
localised and the specifications of the therapy or surgery to be
given to the patient is generated, based on the shape and/or
position and or extension of the bodily matter.
[0091] Any inaccuracy of the identification of the bodily matter
during the planning of therapy or surgery will result in inaccuracy
during the treatment or surgery, resulting in a risk that the
therapy or surgery does not effect the intended bodily matter of
interest. Possibly, it may result in a traumatic effect of healthy
matter and/or it may result in part of the unhealthy matter not
being treated or not being properly handled during treatment.
[0092] By deriving at least a first image and a second image, and
by collating the images by determining the position of the
three-dimensional element, the three-dimensional element and hereby
the bodily matter of interest will be identically positioned in the
images. Thereby, the possible advantages of the first type of
medical imaging equipment and the possible other or additional
advantages of the second type of medical imaging equipment will be
obtained at the one and same time in respect of the mutual
positional relationship between the three-dimensional element and
the bodily matter of interest. Additionally or alternatively
inaccuracies in the alignment of the images resulting from
different set-up conditions, when obtaining the images, may be
compensated.
[0093] By using a three-dimensional element as marker being
positioned inside, or at least in close vicinity of the bodily
matter of interest, the images can be collated very accurately near
the marker, and hereby near the bodily matter of interest. Hereby
it is possible to collate the images accurately based on the
position, in the images, of the three-dimensional element, hereby
ensuring that the position and/or the shape and/or the extension of
the bodily matter of interest, being positioned in an accurate
position in relation to the three-dimensional element, is also
determined accurately in the images.
[0094] By using a three-dimensional element as marker being
positioned inside, or at least in close vicinity of the bodily
matter of interest, it is furthermore possible to compensate for
different image quality in the images. Often the image quality in
one image is depending on the focal point of the image. By
collating the images according to a three-dimensional element
located inside or near the tissue of interest, improved
compensation of different image quality in the images is
facilitated and/or improved compensation of different image quality
in different parts of each individual image is facilitated.
[0095] Given the more accurate determination of the position and/or
the shape and/or the extension of the bodily matter of interest in
the different images of the different medical imaging equipment, a
physicist and/or medical personnel will be able to identify and
localise the bodily matter of interest, such as a cancerous tumor,
very accurately.
[0096] Contrary hereto, when trying to compare images that are
derived by different medical imaging equipment, according to prior
art methods, the mutual positional relationship between a marker
and the bodily matter of interest is not possible to establish
accurately due to the fact of the marker, either not being present
in the human or animal body, or the marker not being positioned in
a position ensuring a constant mutual relationship between the
position of the marker and the position of the bodily matter of
interest.
[0097] By using a marker that is a three-dimensional element, such
as a tubular, endoluminal prosthesis with a well known
three-dimensional geometry, the collation of the different images
can be guided by an automatic detection of the three-dimensional
element in the different images, hereby making it possible to
automatically guide the collation of the position, in the different
images, of the three-dimensional element and thus of the bodily
matter of interest.
[0098] If the dimensions of the three-dimensional element are known
in advance, the dimensions of the three-dimensional element give an
exact knowledge of how the three-dimensional element is positioned
inside the body and perhaps is being rotated inside the body. By
knowing the dimensions of the three-dimensional element in advance
and by being able to detect the dimensions in an image, the exact
position of the three-dimensional element inside the body may be
calculated automatically. The knowledge about the position of the
three-dimensional element established in the image gives also an
exact knowledge of where the bodily matter of interest is
positioned, because the bodily matter of interest and the
three-dimensional element have a substantially fixed relationship
and any possible movement of the bodily matter of interest results
in corresponding movement of the three-dimensional element and vice
versa.
[0099] Hereby, alignment of the images and of the bodily matter of
interest depicted in the images may be performed accurately and
automatically based on the position of the element even though the
patient and/or the image equipment has been moved between the image
sessions or has moved just before setting up the patient and the
imaging equipment.
[0100] It is likewise possible during a treatment of the patient to
adjust a treatment equipment so that the element and thereby the
bodily matter of interest, such as a tumor, of the patient stays in
focus of the treatment equipment.
[0101] By being able to adjust the treatment equipment based on the
element, the treatment may be performed more precisely and the
adjustment of the treatment equipment may be done automatically by
a computer.
[0102] Additionally, the method according to the present invention
may further comprise the steps of: [0103] monitoring over time a
possible movement of the three-dimensional element in relation to
the images,
[0104] A monitoring over time of the movement of the
three-dimensional element and hereby of the bodily matter of
interest facilitates a constant alignment of images and/or a
calculation of a cyclic movement of the bodily matter of interest
(e.g. due to respiration) and/or a constant equalizing of a
treatment apparatus, whereby an improved treatment is possible.
Such a tracking can be calculated and controlled by a computer.
[0105] The steps of identifying, establishing, monitoring and
adjusting may be done automatically, and the monitoring step may be
executed at an appropriate frequency, such as once every 3 seconds
or less depending on the equipment available.
[0106] Monitoring of the movement of the three-dimensional element
may according to the present invention be performed by producing up
to 50 images per second, at least 2-50 images per second, at least
1 image per second, at least 12 images per minute or at least 2
images per minute depending on the medical imaging equipment, at
least 2-50 images per second, at least 1 image per second, at least
12 images per minute or at least 2 images per minute.
[0107] By sampling as frequently as described, the possible
movement of the three-dimensional element and thus of the bodily
matter of interest it is possible to track the movement almost in
real-time of the three-dimensional element and hereby of the bodily
matter of interest.
[0108] Hereby, the possible movements of the body and/or of the
element can be used to equalize continuous images by adjusting the
images in response to the possible movement of the
three-dimensional element. It is likewise possible during the
continuous imaging to adjust the imaging equipment so that the
three-dimensional element and thereby the bodily matter of interest
stays in focus of the image. Furthermore, the adjustment of the
images may be an adjustment of the position of the imaging
equipment, of the couch on which the patient is placed, of the
focal point of the images, and so forth.
[0109] Additionally, the possible movements of the body and/or of
the element can be used to adjust a treatment equipment, e.g. an
irradiation equipment, according to the tracking.
[0110] Movements to be tracked may be a forced movement, such as a
tilting or a partial rotation of the patient during irradiation.
The movement may also be a voluntary or involuntary movement by the
patient. The voluntary movement may be the patient moving on the
couch or walking around in the irradiation room and the involuntary
movement may be movements due to motoric diseases such as
Parkinson's Disease or Cerebral Palsy.
[0111] The three-dimensional element as a marker can be used for
collating two or more diagnostic images used for identification,
localisation and generation of a therapeutic or surgical scheme
generated during the planning of the therapeutic or surgical
specification scheme. Use of the same three-dimensional element for
both performing the therapy or surgery according to the
specification scheme and for collating images for planning of the
specification scheme is feasible without any need for reinsertion
or repositioning of the three-dimensional element.
[0112] The three-dimensional element as a marker can specifically
be used for collating two or more diagnostic images used for
identification, localisation and generation of an irradiation
profile generated during the planning of radio therapy. Use of the
same three-dimensional element for both guiding an external beam
radio therapy equipment and for collating images for planning of
the radiation therapy is feasible without any need for reinsertion
or repositioning of the three-dimensional element.
[0113] According to an aspect of the present invention the
three-dimensional element may be intended for positioning in an
existing natural cavity within the human or animal body, without
being buried in tissue. By positioning the three-dimensional
element in an existing natural body cavity, the risks related to
potential tissue damages and the patient's sensation of the element
may be eliminated or at least minimized compared to implantable
markers being implanted into the patient's tissue.
[0114] Additionally, according to an aspect of the present
invention insertion of the three-dimensional element may be
performed through a natural opening of the body without at all or
at least without substantially penetrating any tissue of the body.
This way of inserting a three-dimensional element as a marker does
not acquire invasive surgery, and thereby the risks related to such
surgery is eliminated or at least minimized compared to implantable
markers being inserted by invasion of skin surfaces and/or
tissue.
[0115] Furthermore, according to an aspect of the method of the
present invention a step may be employed of retracting the
three-dimensional element through a natural opening of the body
without at all or at least without substantially penetrating any
tissue of the body. By retracting the three-dimensional element
through the natural cavity or opening, the removal of the
three-dimensional element is performed without invasive surgery and
the risks related to such surgery is eliminated or at least
minimized compared to implantable markers being inserted by
invasion of skin surfaces and/or tissue.
[0116] The three-dimensional element, when inserted into a natural
cavity, is therefore not damaging the surrounding tissue because
the cavity is a natural opening of the body. The element is
therefore not penetrating any tissue in order to be fastened inside
the body. The three-dimensional element may be fastened by at least
partly abutting the inside of the cavity in order for the
three-dimensional element not to move inside the cavity.
[0117] The three-dimensional element may have different geometrical
properties depending on the actual intended position of the
three-dimensional element in the human or animal body. Additionally
or alternatively, the three-dimensional element may have different
physical properties depending on the actual intended use of the
three-dimensional element in the human or animal body, apart from
the use as a marker in different images. Possibilities of
geometrical and physical properties are mentioned in the
following.
[0118] Thus, the three-dimensional element may have a shape
allowing passage of a liquid, gas or solid inside the cavity in
which the three-dimensional element is positioned. Hereby the
natural flow of liquid, gas, or solid inside the cavity is
maintained, such as urine in the urethra and blood in the vein, or
such as intestinal gas in the intestines and breath in the trachea
or in the lungs, or such as solid faeces in the intestines, even
though a therapy or surgery may cause some swelling of the bodily
matter surrounding the cavity.
[0119] The three-dimensional element may be expandable towards the
cavity from inside the cavity, when released in the cavity, for
fixing the three-dimensional element in its position at a relative
position according to the bodily matter of interest. Likewise, the
natural flow of liquid, gas or solid is maintained inside the
cavity, such as urine in the urethra and blood in the vein, or such
as intestinal gas in the intestines and breath in the trachea or in
the lungs, or such as solid faeces in the intestines, even though
the therapy or surgery may cause some swelling of the bodily matter
surrounding the cavity.
[0120] Furthermore, by expanding the cavity into which the at least
one integral three-dimensional element is positioned, the
three-dimensional element is firmly positioned inside the cavity
without moving inside the cavity. Any other fastening means such as
a barbed shape of the three-dimensional element is dispensable, and
the element is easily removed without damaging the inside of the
cavity.
[0121] The three-dimensional element may have a tubular shape
allowing passage of a liquid, gas or solid inside the cavity in
which the three-dimensional element is positioned. A tubular shape
will maintain holding the cavity open also during the irradiation
and the possible resulting subsequent swelling.
[0122] The three-dimensional element may be a tubular endoluminal
prosthesis. The three-dimensional element may therefore already be
positioned inside the body for another purpose such as for
expanding a diminished urethra or ureter. The three-dimensional
element will maintain holding the cavity open, also during a
treatment session and the possible resulting subsequent swelling
caused by the irradiation. The three-dimensional element is capable
of staying in the cavity during a period of at least 30 days and is
therefore capable of keeping the cavity open to permeation of
liquids, gases or solids all during a treatment session even though
the treatment is divided into periods of hours, days or weeks.
[0123] In respect of the at least one integral three-dimensional
element being a substantially tubular endoluminal prosthesis, the
three-dimensional element reduces the need for any additional
catheters in order to hold the cavity in which the
three-dimensional element is inserted, open to permeation of
liquids, gases or solids.
[0124] The at least one integral three-dimensional element may in
yet another aspect of the present invention be a helical coil of at
least one wire. Hereby it is obtained that retraction of the
three-dimensional element is possible through the natural cavity or
opening through which it was inserted by pulling the wire.
[0125] The three-dimensional element may have a design enabling
insertion and/or retraction of the three-dimensional element with
conventional endoscopic equipment. The three-dimensional element
may have a collapsible design, enabling a collapsed design when
inserting the three-dimensional element in a cavity of the human or
animal body, and enabling an expanded design when the
three-dimensional element has been positioned in the cavity of the
human or animal body.
[0126] In case the three-dimensional element is inserted into a
bodily cavity, the cavity may have at least one surrounding wall,
and the at least one integral three-dimensional element may,
according to the invention, have a collapsible design when
inserting the three-dimensional element, and said three-dimensional
element may have a design being expandable towards the surrounding
wall of the cavity, when being released in the cavity. The
collapsible design reduces the impact on the inside wall of the
natural cavity through which the insertion takes place. When being
in the collapsed state, the element may have a substantially linear
extension, and when being in the expanded state, the element will
change from the possibly linear extension to the three-dimensional
extension.
[0127] An apparatus may be provided in conjunction with the
invention, said apparatus being capable of carrying out the method
according to any of the aforementioned methods, said apparatus
comprising means for identifying the three-dimensional element,
means for establishing a preliminary position of the
three-dimensional element and/or a therapeutic or surgical
equipment, means for monitoring a possible movement of the element
and/or means for adjusting the therapeutic or surgical equipment or
the human body or the animal body in response to the movement.
[0128] The means for identifying the three-dimensional element may,
in one aspect, be a computer program for image-detection and means
for establishing a preliminary position of the three-dimensional
element may also be a computer program for image-detection.
[0129] The therapeutic or surgical equipment may be any
conventional equipment for therapeutic or surgical treatment of
bodily matter, such as irradiation equipment for treating a tumor.
Means for monitoring a possible movement of the element may be a
computer transmitting signals to the means for adjusting the
therapeutic or surgical equipment such as an irradiation equipment
or to the means for adjusting the human body or the animal body in
response to the movement.
[0130] The three-dimensional element may be made of a biologically
compatible material, such as polymers, biological material or
metal, such as stainless steel, titanium, platinum, palladium,
nickel-titanium and other alloys or combinations of any of these
materials. By applying a three-dimensional element of such a
biologically compatible material the three-dimensional element does
not cause infection when being in the cavity of the human or animal
body.
[0131] The three-dimensional element may be made of a shape memory
alloy having a transition temperature with a one-way-memory effect
at a temperature above body temperature. By applying a shape memory
alloy the three-dimensional element is capable of expanding within
the cavity.
[0132] In another aspect of the present invention the at least one
integral three-dimensional element may be made of a shape memory
alloy having a transition temperature above body temperature,
preferably between 37.degree. C. and 50.degree. C. By using shape
memory alloy having a transition temperature between 37.degree. C.
and 50.degree. C., the surroundings inside the body is not scalded,
which otherwise may give rise to an infection or to damaged bodily
matter.
[0133] Body temperature is construed as the temperature of the body
of the human or of the animal during the application of the method
according to the invention. In most applications of the method, the
body temperature of a human will be around 37.degree. C.
[0134] The body temperature may however differentiate depending on
whether it is a human body or an animal body. Some animals have
lower normal body temperature than humans, and some animals have
higher normal body temperature than humans.
[0135] Also, the body temperature may differentiate depending on
the physical state of the human or the animal. The temperature may
be higher due to fewer if the human or the animal is suffering from
illness causing fewer, and the body temperature may be lower due to
perhaps unstable blood flow, if the human or animal is newborn or
is elderly, or if the human or the animal is suffering from illness
causing an unstable blood flow.
[0136] By applying a shape memory alloy the three-dimensional
element is capable of expanding within the cavity when heated to
the transition temperature. Provided the transition temperature is
about the normal body temperature of the human or animal body, the
expanding is performed when the body has warmed up the element and
this expansion of the three-dimensional element is performed
without additional applying of heat. In the case of a transition
temperature in range above the body temperature the expanding is
obtainable by heating the three-dimensional element e.g. by
flushing of sterile water or the like fluids, having a temperature
above the transition temperature.
[0137] Alternatively or additionally, the three-dimensional element
may be made of a material being plastically deformable by hand at a
temperature below body temperature, preferably at a temperature
below 37.degree. C., more preferred at a temperature below
20.degree. C. and above 5.degree. C. By using a material being
plastically deformable by hand the three-dimensional element may be
easily retracted by the manual force of a physician, and the
three-dimensional element may easily be deformed to a smaller size
during the retraction of the three-dimensional element.
[0138] Even in the alternative, the three-dimensional element may
be made of a shape memory alloy being super elastic at body
temperature.
[0139] The medical imaging equipment according to the aspect of the
invention may be any one of the following imaging equipment:
Magnetic Resonance scan (MR-scan), Nuclear Magnetic Resonance scan
(NMR-scan), Magnetic Resonance Image scan (MRI-scan), Computerized
Tomography scan (CT-scan), Cone Beam CT-scan, Positron Emission
Tomography (PET), Single Positron Emission Computed Tomography
(SPECT), Single Positron Emission Tomography (SPET),
Image-Guided-Radiation-Therapy (IGRT, Ultrasound-scan, or X-ray,
high-energy photons equipment or high voltage equipment.
[0140] The image may, according to the invention, be derived and
processed by utilizing energy of an irradiation source for
treatment. Thereby use of other equipment is no longer necessary
and a substantial amount of cost and space in the irradiation room
is saved.
[0141] In an additional aspect of the invention, the image may be
derived and processed by utilizing energy of the treatment
irradiation beam. Thus, use of other equipment is no longer
necessary and a substantial amount of cost and space in the
irradiation room is saved.
[0142] Medical marker elements may be delivered to a target bodily
matter such as a body organ or a body tissue via a marker element
delivery system. The marker element delivery system may be an
elongated device that is brought through to body vessels or other
body cavities or in proximity to target organs or tissue. Once the
marker element is in position, the marker element delivery system
is retracted, while the marker element stays in place. The marker
element delivery system may be specially designed depending
different parameters such as the shape of the marker element and/or
the body organ and/or the body tissue or the body cavity, into
which the marker is to positioned and/or on a possible body opening
through which the marker element delivery system is to be inserted
and retracted. Use of such marker element delivery system allows
medical personnel to perform marker positioning in a fast and
non-invasive manner.
[0143] Possible applications where collating of two or more
diagnostic images with a three-dimensional marker could be
advantageous are the following non-exhaustive applications: [0144]
Planning of external radio therapy treatment, i.e. by a beam
apparatus or other medical applications where there is an effect of
some bodily matter such as tissue and/or a body part being easier
to detect in one type of images than in another type of image.
[0145] Planning of internal radio therapy treatment including
brachytherapy or other medical applications where there is an
effect of some bodily matter such as tissue and/or body parts being
easier to detect in one type of images than in another type of
image. [0146] Follow-up on anatomic changes on a patient's anatomy,
e.g. growth or shrinking of a certain bodily matter such as a
tissue of interest, e.g. a cancer tumor or other foreign body, or
such as a bodily organ of interest, e.g. the liver or other more or
less vital body organs, or such as bodily parameters e.g. nerve
impulses from certain parts of the brain. [0147] Follow-up during
treatment, surgery or diagnosis of e.g. internal movement of
certain bodily matter such as a tissue of interest, e.g. a cancer
tumor or other foreign body, or such as a bodily organ of interest,
e.g. the liver or other more or less vital body organ, or such as a
bodily parameter of interest, e.g. nerve impulses to and form
certain part of the brain. [0148] Investigation of respiratory
movement and/or rhythm, e.g. for the use of possible gating of a
treatment session. [0149] Guidance of external treatment equipment,
e.g. an irradiation equipment, by tracking of internal body organ
movements and/or correction of inaccuracies due to set-up
differences, when obtaining the images.
[0150] The method according to the invention may be used in
conjunction with a method for guiding a treatment equipment located
outside a human body or outside an animal body. In the following an
external beam radio therapy equipment is used as an example. The
method could, however, be used for other types of treatment
equipments. Said method of guiding comprising the steps of: [0151]
identifying, in an image, at least one integral three-dimensional
element visible in the image, said at least one integral
three-dimensional element being in position in a cavity of the
human body or the animal body, [0152] establishing, in the image, a
preliminary position of the at least one integral three-dimensional
element visible in the image in relation to a reference, [0153]
establishing a preliminary position of the irradiation equipment in
relation to the reference, [0154] adjusting the irradiation
equipment in relation to the reference in response to the position
of the at least one integral three-dimensional element in relation
to the reference.
[0155] During the step of identifying, in an image, at least one
integral three-dimensional element visible in the image, the at
least one integral three-dimensional element is in position. Prior
to identifying, in an image, at least one integral
three-dimensional element visible in the image, an additional step
may be inserting the at least one integral three-dimensional
element into a cavity of the human body or the animal body.
[0156] By identifying the position of the at least one integral
three-dimensional element in relation to the position of the
disordered tissue, the position of the disordered tissue may then
be established based on establishing the position of the
three-dimensional element. This is advantageous due to the fact
that the disordered tissue is not identifiable in all kinds of
images, in which the three-dimensional element is identifiable. By
being able to establish the position of the three-dimensional
element in a two dimensional image, the exact position of the
disordered tissue may be established due to the fact that the
element and the disordered tissue moves simultaneously in relation
to the human or animal body.
[0157] The dimensions of the three-dimensional element are known in
advance and based on the two-dimensional image of the
three-dimensional element the dimensions give an exact knowledge of
how the three-dimensional element is positioned inside the body and
perhaps is being rotated inside the body. By knowing the dimensions
of the three-dimensional element in advance and by being able to
detect the dimensions in an image, the exact position of the
three-dimensional element inside the body may be calculated. The
knowledge about the position of the three-dimensional element
established in the image gives an exact knowledge of where the
disordered tissue is positioned, because the disordered tissue and
the three-dimensional element have been found to have a
substantially fixed relationship and any possible movement of the
disordered tissue results in corresponding movement of the
three-dimensional element and vice versa.
[0158] Hereby, positioning of the disordered tissue may be
performed accurately based on the position of the element even
though the patient has been moved between the examination room and
the irradiation room or has moved just before setting up the
patient and the treatment equipment for irradiation. It is likewise
possible during the irradiation of the patient to adjust the
equipment so that the element and thereby the disordered tissue,
such as a tumor, of the patient stays in focus of the irradiation
equipment.
[0159] By being able to adjust the irradiation equipment based on
the element, the irradiation may be performed more precisely and
the adjusting of the irradiation equipment may be done
automatically by a computer.
[0160] Additionally, by being able to irradiate more precisely, it
is possible to subject the patient to a higher total dose of
irradiation without damaging tissue surrounding the disordered
tissue and as a result it is possible to subject the patient to
irradiation more times with the same refractory doses in order to
more effectively eliminate the disordered tissue, or to subject the
patient to irradiation fewer times with higher refractory doses in
to more effectively eliminate the disordered tissue, without
damaging healthy tissue.
[0161] Additionally, the method according to the present invention
may further be used in conjunction with a method for adjusting an
irradiation equipment located outside a human body or outside an
animal body, said method comprising the steps of: [0162] monitoring
a possible movement of the three-dimensional element in relation to
the irradiation equipment, [0163] adjusting the irradiation
equipment in response to the possible movement of the
three-dimensional element.
[0164] Hereby, the aforementioned inaccuracies are increasingly
diminished in that the possible movements of the body and/or of the
element is equalized by adjusting the irradiation equipment in
response to the possible movement of the at least one integral
three-dimensional element. It is likewise possible during the
irradiation to adjust the equipment so that the three-dimensional
element and thereby the disordered tissue, such as a tumor, of the
patient stays in focus of the irradiation equipment. Furthermore,
the adjustment of the irradiation equipment may be an adjustment of
the position of the irradiation equipment, of the couch on which
the patient is placed, of the power of the irradiation source, of
the focal point of the beam, of the intensity of the irradiation
beam, of movement of plates or a shield changing the shape of the
irradiation beam, and so forth.
[0165] Additionally, the adjusting of the irradiation equipment may
furthermore be a deflection or a focusing of the irradiation beam
in relation to any movements during irradiation. Such movement may
be a forced movement, such as a tilting or a partial rotation of
the patient during irradiation. The movement may also be a
voluntary or involuntary movement by the patient. The voluntary
movement may be the patient moving on the couch or walking around
in the irradiation room and the involuntary movement may be
movements due to motoric diseases such as Parkinson's Disease or
Cerebral Palsy.
[0166] The advantages of being able to adjust the irradiation
equipment during irradiation reside in the possibility of
irradiating the body from different angles. Thereby, the
disadvantage of irradiating possibly healthy tissue surrounding the
disordered tissue is minimized. Furthermore, the adjustment may be
performed so that irradiation of certain critical healthy tissue is
avoided. The adjustment of the irradiation equipment may also be a
limitation of the total dose of irradiation from a certain angle in
order to avoid exceeding the irradiation limit of healthy tissue
being irradiated from that certain angle.
[0167] The steps of identifying, establishing, monitoring and
adjusting may be done automatically, and the monitoring step may be
executed at an appropriate frequency, such as once every 3 seconds
or less depending on the equipment available.
[0168] According to the present invention in general, and not only
related to guiding of irradiation equipment, different aspects and
advantages are disclosed in the following:
[0169] In one aspect, a reference may be a previous image of the
three-dimensional element having been inserted into the cavity of
the body. Such a previous image may conveniently be the image in
which the bodily matter of interest, such as a tumor, was detected
and the position and/or shape of the bodily matter of interest were
established during a pre-examination of the patient.
[0170] In another aspect, the previous image of the at least one
integral three-dimensional element may also be the last image
derived of the three-dimensional element or the image derived for
setting up the patient before therapy or surgery.
[0171] Additionally, according to an aspect of the present
invention insertion of the three-dimensional element may be
performed through a natural opening of the body without at all or
at least without substantially penetrating any tissue of the body.
This way of inserting a three-dimensional element as a marker does
not acquire invasive surgery, and thereby the risks related to such
surgery is eliminated or at least minimized.
[0172] Furthermore, according to an aspect of the method of the
present invention a step may be employed of retracting the
three-dimensional element through a natural opening of the body
without at all or at least without substantially penetrating any
tissue of the body. By retracting the three-dimensional element
through the natural cavity or opening, the removal of the
three-dimensional element is performed without invasive surgery and
the risks of contamination related to such surgery is eliminated or
at least minimized.
[0173] The three-dimensional element, when inserted into a natural
cavity, is therefore not damaging the surrounding tissue because
the cavity is a natural opening of the body. The element is
therefore not penetrating any tissue in order to be fastened inside
the body. The three-dimensional element is fastened by at least
partly abutting the inside of the cavity in order for the
three-dimensional element not to move inside the cavity.
[0174] Advantageously, when the invention is used in conjunction
with a method for adjusting a therapeutic or surgical equipment
such as an irradiation equipment located outside a human body or
outside an animal body, monitoring and adjusting of the therapeutic
or surgical equipment such as the irradiation equipment may be
performed during therapeutic or surgical treatment such as
irradiation of the bodily matter, e.g. a disordered tissue such as
the tumor.
[0175] In another aspect of the present invention the at least one
integral three-dimensional element may be a substantially tubular
endoluminal prosthesis.
[0176] Additionally, possible monitoring of the movement of the at
least one integral three-dimensional element may according to the
present invention be performed by producing up to 50 images per
second, at least 2-50 images per second, at least 1 image per
second, at least 12 images per minute or at least 2 images per
minute depending on the medical imaging equipment, at least 2-50
images per second, at least 1 image per second, at least 12 images
per minute or at least 2 images per minute.
[0177] By sampling as frequently as described, the possible
movement of the three-dimensional element and thus of the
disordered tissue may be equalized almost instantly and the method
is performed almost continuously, whereby the aforementioned damage
of healthy tissue can be substantially decreased.
[0178] According to the present invention, each individual image
may be a two dimensional projection image or a three-dimensional
image, and wherein the image is derived and processed by medical
imaging equipment.
[0179] Furthermore, when the invention is used in conjunction with
a method for adjusting an irradiation equipment located outside a
human body or outside an animal body, the patient is not
unnecessarily irradiated. When the dose of irradiation is
calculated, the irradiation of the patient, in order to produce
images to establish the extension of the disordered tissue, such as
a tumor, is included. The dose is calculated so that the
surrounding healthy tissue is not un-recoverably damaged. The
irradiation of the patient is thereby used in order to treat the
patient in the correct area and not just for producing examination
images.
[0180] By using the same equipment as for irradiation of a
disordered tissue, time is saved for changing equipment back and
forth when an image has to be derived.
[0181] When the invention is used in conjunction with a method for
adjusting an irradiation equipment located outside a human body or
outside an animal body, the image may be derived and processed by
utilizing electric energy from an energy source for producing
electric power for the irradiation source.
[0182] The at least one integral three-dimensional element may have
a design enabling insertion and/or retraction of the
three-dimensional element with conventional endoscopic equipment.
By being able to use conventional endoscopic equipment during
insertion and/or retraction of the three-dimensional element, costs
of additional equipment is saved and the time in changing between
utilizations of different equipment during the insertion or
retraction of the three-dimensional element is decreased.
[0183] In case the three-dimensional element is inserted into a
bodily cavity, the cavity may have at least one surrounding wall,
and the at least one integral three-dimensional element may,
according to the invention, have a collapsible design when
inserting the three-dimensional element, and said three-dimensional
element may have a design being expandable towards the surrounding
wall of the cavity, when being released in the cavity. The
collapsible design reduces the impact on the inside wall of the
natural cavity through which the insertion takes place. When being
in the collapsed state, the element may have a substantially linear
extension, and when being in the expanded state, the element will
change from the possibly linear extension to the three-dimensional
extension.
[0184] An apparatus may be provided in conjunction with the
invention, said apparatus being capable of carrying out the method
according to any of the aforementioned methods, said apparatus
comprising means for identifying the three-dimensional element,
means for establishing a preliminary position of the
three-dimensional element and a therapeutic or surgical equipment,
means for monitoring a possible movement of the element and means
for adjusting the therapeutic or surgical equipment or the human
body or the animal body in response to the movement.
[0185] The means for identifying the three-dimensional element may,
in one aspect, be a computer program for image-detection and means
for establishing a preliminary position of the three-dimensional
element may also be a computer program for image-detection.
[0186] The therapeutic or surgical equipment may be any
conventional equipment for therapeutic or surgical treatment of
bodily matter, such as irradiation equipment for treating a tumor.
Means for monitoring a possible movement of the element may be a
computer transmitting signals to the means for adjusting the
therapeutic or surgical equipment such as an irradiation equipment
or the human body or the animal body in response to the
movement.
[0187] Medical marker elements may delivered to a target bodily
matter such as a body organ or a body tissue via a marker element
delivery system. The marker element delivery system may be an
elongated device that is brought through to body vessels or other
body cavities or in proximity to target organs or tissue. Once the
marker element is in position, the marker element delivery system
is retracted, while the marker element stays in place. The marker
element delivery system may be specially designed depending
different parameters such as the shape of the marker element and/or
the body organ and/or the body tissue or the body cavity, into
which the marker is to positioned and/or on a possible body opening
through which the marker element delivery system is to be inserted
and retracted. Use of such marker element delivery system allows
medical personnel to perform marker positioning in a fast and
non-invasive manner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0188] In the following, the present invention will be described
with reference to the accompanying drawings, in which:
[0189] FIG. 1 shows a prior art marker being inserted by surgery
through the tissue of a human body,
[0190] FIG. 2 shows three prior art markers which have been
inserted into the tissue surrounding a tumor,
[0191] FIG. 3 shows a human body lying on a couch below a
therapeutic or surgical equipment, in the embodiment shown an
irradiation equipment,
[0192] FIG. 4 shows a three-dimensional element having been
inserted into the natural cavity a urethra of a male,
[0193] FIG. 5 shows an X-ray image of a three-dimensional element
as shown in FIG. 4,
[0194] FIG. 6 shows an X-ray image of another three-dimensional
element,
[0195] FIG. 7 shows a three-dimensional element having been
inserted into the natural cavity a urethra of a male,
[0196] FIG. 8 shows an example of a three-dimensional element,
[0197] FIGS. 9, 10 and 11 show other examples of a
three-dimensional element,
[0198] FIGS. 12 and 13 show an example of three-dimensional element
in an image derived from a mega voltage equipment, and
[0199] FIG. 14 shows an amalgamation of images having the
three-dimensional element in the center and derived by CT-scan.
[0200] The drawings are schematically and shown for the purpose of
illustration.
[0201] FIG. 1 shows the insertion of prior art markers m through
the skin by use of invasive surgery, the insertion being done in
order to locate the disordered tissue d, such as a tumor, in an
image derived for positioning the irradiation of the tumor d. When
inserted as shown in FIG. 2, the three or more markers m are
positioned in relation to the irradiation equipment, and the
irradiation source is turned on for a period of time. Subsequently
to the time period of irradiation, the irradiation is interrupted.
The irradiation of the tumor d may be continued when a period of at
least a few days has lapsed so that the surrounding healthy tissue
may withstand a new irradiation. During the time period of
irradiation, the irradiation equipment is at no time adjusted in
order to compensate for any movement of the tumor during this
irradiation.
[0202] The prior art markers in shown FIGS. 1 and 2 may move
considerably within the body between two irradiation periods in
which case more markers may have to be inserted.
DESCRIPTION OF THE PRESENT INVENTION
[0203] Given a possibility to collate, align and compare different
images more exactly than by the prior art methods, facilitates the
possibility to combine different images, being derived by different
imaging equipments, possibly being derived by different imaging
modalities, and to track a development over time, within images
obtained at different times. Combination of images being derived by
different imaging equipments, possibly being derived by different
imaging modalities, facilitates improved identification of a bodily
matter of interest, e.g. identification of a cancerous tissue to be
irradiated with an external beam radio therapy equipment. Tracking
a development over time, within images obtained at different times,
facilitates tracking of movement and/or growth/shrinking of bodily
matter for better diagnosis, e.g. tracking of the growth of a
cancerous tumor or tracking of the movement of a cancerous tumor
according to the patient's breathing cycle.
[0204] In the following description of the invention,
identification of a cancerous tumor, planning of the specifications
of the irradiation treatment to be delivered to the cancerous
tumor, and, tracking a movement of the cancerous tumor will be used
as one of several examples, where the present invention may be
employed.
[0205] Possible other use applications in relation to collating
images by the method according to the invention may be the
following non-exhaustive list of applications: [0206] Reduction of
inaccuracies due to set-up differences between the images. In one
example such as therapy by irradiation, inaccuracies may result in
difficulties in only radiating the target tissue or in difficulties
in controlling the intensity of irradiation. In an example of
diagnosis, inaccuracies may result in difficulties in performing a
medically safe diagnosis or in performing a sufficiently fast
diagnosis. In an example of surgery, inaccuracies may result in
difficulties in performing complicated surgery or in performing
surgery within a narrow space. [0207] Identification of unwanted
in-body elements, e.g. position and size of cancer tumors, position
and size of encrustations or stone-formations, position and size of
foreign bodies. [0208] Planning of treatment and/or identification
of treatment target, e.g. planning of irradiation treatment, or
identification of treatment target during diagnosis, or planning of
surgery process during a surgery based on perhaps different images
from different angles. [0209] Identification and/or diagnosis of
orthopaedic damages (bone fractures, joint fractures or joint
dislocations), e.g. identification of small bone fractures within
the body, or diagnosis of correct treatment of fractures or
dislocations of physically complicated joints. [0210]
Identification of possible obstructions of bodily lumens, e.g.
urothelial obstructions due to encrustation or foreign bodies,
cardiovascular obstructions due to encrustation, etc.
[0211] Possible use applications in relation to comparing images by
a method according to the invention may be the following
non-exhaustive list of applications: [0212] Tracking of growth or
shrinkage of a bodily matter such as tracking non-wanted growth of
cancerous tumor or tracking of intended shrinkage of a cancerous
tumor during irradiation therapy, or tracking of non-wanted further
shrinkage of cirrhosis of the liver, or tracking of intended growth
of internal body organs such as a treated cirrhosis of the liver.
[0213] Tracking of growth or shrinkage of a cardiovascular lumen
such as tracking of non-wanted stenosis shrinkage of blood vessels
or tracking of intended growth of a stenosis of a blood vessel
during therapy, or tracking of non-wanted further shrinkage of
urethra, or tracking of intended growth of ventricles of the heart
or volume of the lungs. [0214] Tracking movement of a foreign body,
a parasite or the like such as tracking of non-wanted biliary
calculus or tracking or tracking of intestinal parasites like
worms. [0215] Correction of inaccuracies due to set-up differences
between obtaining the reference image and obtaining the present
image such as inaccuracies occurring between different times of
treatment, where an outside element such as a patient bed is used
as reference or such as inaccuracies occurring between on reference
image of a first imaging equipment and another reference image of a
second imaging equipment. [0216] Correction of inaccuracies due to
internal body organ movements between obtaining the reference image
and obtaining the present image such as internal body organs moving
during inhalation and exhalation or such as internal body organs
having moved between one point of time imaging the body organ and a
later point of time imaging the body organ.
[0217] In the following description of the invention,
identification of a cancerous tumor, planning of the specifications
of the irradiation treatment to be delivered to the cancerous
tumor, and, tracking a movement of the cancerous tumor will be used
as one of several examples, where the present invention may be
employed. In the following, planning of irradiation treatment will
be used as one example among all the examples mentioned above and
among further examples of application, which the skilled person may
envisage as applications of the method according to the
invention.
[0218] In the following, a tumor 6 will be used as an example of
disordered tissue. However, other types of disordered tissue, other
than tumors, may also be treated during guiding of the irradiation
equipment when employing an equipment guidance method as described.
Also, other bodily matters of interest than disordered tissue may
be subject to treatment by therapy or surgery during operation of
therapeutic or surgical equipment when employing an equipment
operating method, such as the irradiation guiding as described.
[0219] As mentioned, in the following, the invention will be
described with reference to a cancerous tumor as example of bodily
matter of interest. However, as previously mentioned, in the
context of the present invention, bodily matter is to be construed
as any matter relating to the body, e.g. body organs such as the
prostate, body tissue such as a tumor or body substances such as
urine, etc. Also, the invention is not limited to bodily matter,
but may also be applied in relation to bodily parameters. As
previously mentioned, in the context of the present invention,
bodily parameters are to be construed as any parameter related to
the body, e.g. physiologic parameters such temperature, bodily
fluid parameters such as urine flow, bodily electrochemical
parameters such as nerve impulses, etc.
[0220] Furthermore, as mentioned, in the following, the invention
will be described with reference to irradiation and irradiation
equipment as example of a method and an equipment of treatment.
However, as previously mentioned, in the context of the present
invention, treatment may also be other types of therapeutic
treatment or may be surgical treatment, such as therapeutic
treatment by brachy therapy, treatment of blood vessels or other
vessels for the flow of bodily gas, liquid or solids etc. Possible
types of surgical treatment may be insertion of irradiating agents
for use in brachy therapy, insertions of surgical equipment for
biopsy, insertion of surgical equipment for fertilisation
treatment, guiding of surgical equipment during a surgery in any
parts of the body etc.
[0221] Accordingly, the specific example of a cancerous tumor as a
bodily matter of interest, and the specific example of irradiation
as a method of treatment by therapy or surgery, and the specific
example of irradiation equipment as an equipment for treatment by
therapy or surgery is not to be construed as limiting the scope of
protection according to the claims.
[0222] When a patient 1 has been given the diagnosis of having
cancer, the cancer is often positioned inside the body of the
patient in the form of disordered bodily matter, namely disordered
tissue 6, such as a tumor 6, as shown in FIG. 3. The disordered
tissue may result in a disordered organ such as the prostate. If
the patient is intended for having treatment by irradiation
therapy, a step of planning the specifications of the irradiation
to be delivered is often performed. The planning of the
specifications of the irradiation to be given is often based on
images depicting the bodily matter within and around the cancerous
tumor.
[0223] One important part of planning the specifications of the
irradiation to be given is to define the form of the target for the
irradiation to be delivered. The target of the irradiation profile
to be delivered will often contain both the tissue being identified
as the cancerous tumor, and a margin surrounding the tissue being
identified as the cancerous tumor, applied to compensate for any
inaccuracies in the identification of the cancerous tumor in the
planning images, and to compensate for any inaccuracies in the
actual delivery of the irradiation treatment, e.g. any inaccuracies
involved in positioning an irradiation equipment and a patient
exactly as planned before starting a treatment session.
[0224] Any limitation of the inaccuracies in the identification of
the cancerous tumor and any limitation of the inaccuracies involved
in exact positioning of the irradiation equipment and/or of the
patient facilitates a possibility to decrease the margin for
compensation of these inaccuracies, and hereby such limitations of
the inaccuracies may facilitate improved treatment with the
potential of less side effects for the patient.
[0225] The image 4 for planning of the specifications of the
irradiation to be given is investigated, and the tumor 6 is located
in the image 4 before the actual treatment of the patient 1. A
series of images 4 may be derived in order to establish the
extension of the tumor 6. In one aspect of the present invention,
the position of the three-dimensional element 7 is determined by
producing a series of images 4 using as an example MR-scanning
techniques or X-ray CT-scanning techniques. When establishing the
extent of the tumor and if no element is already positioned in the
body of the patient 1, a three-dimensional element 7, being
suitable as a marker of the tumor 6, is inserted into the patient 1
before obtaining the images. In other situations, when establishing
the extent of the tumor, an element, being suitable as a marker of
the tumor 6, is already positioned in the body of the patient 1.
The three-dimensional element is inserted or is in position within
a certain distance from the tumor 6 to be treated or inside the
volume to be treated. When irradiating a tumor 6 inside the
prostate, the three-dimensional element 7 is often positioned
inside the prostatic urethra and is therefore in immediate vicinity
of the area 6 to be treated as shown in FIGS. 4, 5, 6, 7, 12, 13
and 14.
[0226] When having the three-dimensional element inserted in the
patient, in a position within the cancerous tumor, or in a position
near the cancerous tumor, and the three-dimensional element is
known to be located and fixed in a position within the patient's
body which moves in a mutual relationship with the cancer tumor,
the three-dimensional element can be used for collating multiple
diagnostic images intended for identifying the treatment target,
and for planning the specifications of the irradiation.
[0227] Some imaging types are known to provide different
information of different types of bodily matter. Therefore some
tissue material (e.g. the cancerous tissue) may be easier to detect
in a MR-image, but other crucial information about the surrounding
bodily matter may be easier to detect in an X-ray CT-image, and
vice versa. Therefore an improved plan of the specifications for
the irradiation may be generated based on a fusion of images from
different imaging types, e.g. by collating MR-images and X-ray
CT-images.
[0228] A known problem resulting from the prior art methods is
however, that an exact alignment of the different types of images
is often very difficult to generate, since the set-up conditions of
the imaging equipments and/or the patient is not exactly identical
when obtaining the different images. Furthermore it may be
difficult to clearly detect identical points, lines, areas or
volumes in all the different images, due to the different quality
and characteristics of the different imaging types.
[0229] With the three-dimensional element inserted in the patient
prior to obtaining the images, the three-dimensional element, with
its characteristics of being clearly detectable in all types of
images, can be used as a marker for alignment of the coordinate
systems of the individual images, so that the different images are
accurately aligned according to the three-dimensional element,
possibly in three dimensions. Since the three-dimensional element
is known to be positioned and fixed in a position within the
patient's body in a mutual relationship with the bodily matter of
interest, an alignment of the three-dimensional element in the
images will also result in an alignment of the bodily matter of
interest in the images.
[0230] The collation of the images based on the three-dimensional
element will be accurate even though the images are obtained under
different set-up conditions of the imaging equipments and/or of the
patient, and even though the images might be obtained with a time
interval between the obtaining of the images, and even though the
images may have different picture quality.
[0231] The collation of the images used for planning the
specifications of the irradiation may be performed automatically,
guided by a computer, based on the known geometry of the
three-dimensional element.
[0232] In one aspect of the present invention, the pre-treatment
planning images may be stored as a reference for the later
irradiation session. In the pre-treatment planning images the
position of the three-dimensional element 7 is identified, and the
position of the three-dimensional element relative to the cancerous
tumor is stored for later referencing during the actual irradiation
session. A reference position within the pre-treatment images could
be set for example as a point in the middle of the
three-dimensional element 7.
[0233] When starting the actual irradiation treatment session the
irradiation equipment and/or the patient may be guided to its
intended position, according to the plan of the specifications for
the irradiation, by obtaining a new image of any imaging type, and
based on a collation of this image and the pre-treatment planning
images, based on the position of the three-dimensional element.
When collating this just-before-treatment-image and the
pre-treatment planning images the information about the difference
between the position and the difference between the rotation of the
three-dimensional in the just-before-treatment-image and the
pre-treatment planning images gives the information needed to
compensate for inaccuracies in the set-up of the irradiation
equipment and/or the patient's position.
[0234] By deriving additional images during the actual irradiation
session a similar guiding of the irradiation equipment and/or the
patient's position may be performed during the actual irradiation
session, based on the collation of the images according to the
position of the three-dimensional element in each individual image.
Hereby it becomes possible to compensate for any movements of the
irradiation equipment or the patient or internal organ movements
within the patient's body, etc. that may occur during the actual
irradiation process. If the frequency of obtaining the additional
images is high, and a rapid automatic collation of the images is
performed, an almost continuous guiding of the treatment is
possible. This facilitates for example guidance of the irradiation
according to a movement of the cancerous tumor, due to internal
organ movements resulting from respiratory movement of the
lung.
[0235] The following description describes in more details a
possible method for guiding an external beam radio therapy
equipment according to the present invention.
[0236] The position of the three-dimensional element 7 may be
determined by producing a series of images 4. The images 4 are
entered into the computer. The computer calculates and saves the
mutual relationship between the three-dimensional element 7 and the
tumor. The mutual relationship has been derived by establishing a
distance between the tumor 6 and the three-dimensional element 7,
which distance is fixed during any kinds of movements of tissue
inside the body in relation to for example the bone structure or
movements of the body 1 as a whole. By the wording a fixed distance
is meant that the tumor 6 and the three-dimensional element 7 have
substantially no relative movement in relation to one another.
[0237] Establishing a preliminary position of the three-dimensional
element 7 in the image 4 in relation to a reference may, according
to the invention, be performed by identifying a known geometrical
shape, such as the pitch distance between the windings of a coil
shaped element 7, the bending in a structural transition of the
three-dimensional element 7, a circumference or contour of the
three-dimensional element 7, etc.
[0238] Subsequently, a preliminary position of the irradiation
equipment 2 is automatically established by a computer.
Establishing a preliminary position of the irradiation equipment 2
in relation to the reference may be performed by measuring the
distance from the position, where radiation is emitted from the
irradiation equipment and to starting point/set-up point in the
image 4, including identifying a level in which the plane of the
image 4 is positioned. Establishing of a preliminary position of
the irradiation equipment in relation to the reference may also be
performed by identifying where a certain bone structure in the body
is positioned in relation to the irradiation head or it may be
performed by establishing the mutual relationship between the couch
and the position where the radiation is emitted form the
irradiation equipment.
[0239] During the period of time in which the irradiation equipment
2 is activated in order to irradiate the tumor 6, any possible
displacement of the element 7 is monitored. Provided a possible
movement is being detected the irradiation equipment 2 is adjusted
in response to the movement of the element so that the irradiation
of the tumor 6 is executed as precisely as possible.
[0240] In this regard, the irradiation equipment 2 comprises, among
other features, the couch where the patient may lie or sit, the
irradiation source, the irradiation beam, and plates or shield
defining the shape of the beam.
[0241] Adjusting the irradiation equipment 2 may therefore be an
adjustment of the position of the irradiation equipment 2, an
adjustment of the position of the couch 5 in relation to the
equipment 2, an adjustment of the power of the irradiation source,
an adjustment of the focal point of the beam 3, an adjustment of
the intensity of the beam 3, an adjustment of movement of the
plates or the shield in order of changing the shape of the beam 3
and so forth. The adjusting of the irradiation equipment 2 may
furthermore be a deflection of the irradiation beam 3 in relation
to a body to be irradiated.
[0242] The adjustment of the irradiation equipment 2 may also be to
turn down the power of the irradiation source, when the element 7
is monitored to be outside a certain area, and to turn on the power
again, when the element 7 is within the certain area again. It may
furthermore be possible to adjust the irradiation power during the
irradiation period, in order to subject some areas of the tumor 6,
to higher dose of irradiation than other areas, e.g. subjecting the
irradiation margin area to smaller dose of irradiation than the
tumor 6 itself, or subjecting some very critical areas in the human
or animal body to smaller dose of irradiation than the tumor 6
itself.
[0243] Instead of turning on or turning down the power, the
irradiation beam may be deflected or the focal point of the
irradiation beam may be changed. By irradiating the whole area of
the tumor 6 it may be necessary to irradiate the tumor 6 by moving
the irradiation beam in a predefined movement pattern.
[0244] Monitoring a possible movement of the three-dimensional
element 7 in relation to the irradiation equipment 2 may be
performed in pre-selected intervals such as 10-20 times a second,
such as 1-2 per minute, etc. depending on the medical imaging
equipment and based on the expected frequency of movement of the
three-dimensional element 7.
[0245] When planning irradiation of the patient, an irradiation
margin is used in order to be certain that the tumor 6 is
irradiated sufficiently, even though the step of monitoring and of
adjusting provides for a decrease of the size of the irradiation
margin.
[0246] Before performing the actual irradiation, the
three-dimensional element 7 having been positioned in relation to
the tumor 6 is located when the patient is lying on the irradiation
couch or when the patient in any other way is located in the
irradiation room. The location of the three-dimensional element 7
may in one embodiment be established by deriving a high-voltage
image 4 using the irradiation equipment 2 itself. The patient or
the irradiation equipment 2 is positioned so that the
three-dimensional element 7 is positioned as previously planned,
and so that the reference is centered in the middle of the
three-dimensional element 7. Hereby a starting point is established
also called the preliminary position of the irradiation equipment 2
and of the element 7 in relation to the reference.
[0247] The reference may in this aspect be any previous image 4
derived identifying the tumor 6 in relation to the
three-dimensional element 7. The previous image 4 may also be the
last image 4 derived in order to monitor a possible movement of the
three-dimensional element 7, or the reference may be an image 4
derived during the pre-examination. By the previous image 4 is
meant an image 4 derived before the present image 4, in which
previous image 4 the position of the three-dimensional element 7
has been established.
[0248] In another aspect, the reference may be the couch on which
the patient is located during the irradiation or the reference may
be the irradiation equipment 2 itself. The reference may also be a
certain bone structure or another identifiable structure inside or
outside the human or animal body.
[0249] By automatically monitoring and detecting a possible
movement of the three-dimensional element 7, the method is capable
of adjusting the irradiation equipment 2 or the patient in relation
to each other every time the three-dimensional element 7 is moving
from the established preliminary position. It is hereby obtained to
compensate for frequent movement of the tumor caused for example by
respiration or small movements made by the patient, said movements
being made by force, being made voluntary by the patient or being
made involuntary by the patient. A considerable improvement of the
accuracy of the irradiation is accomplished and the irradiation of
healthy tissue is reduced.
[0250] FIG. 14 shows that merging different images 4 together based
on a center of the images being positioned within boundaries of the
three-dimensional element 7 gives a very accurate localization of
the tissue of interest, for example the prostate.
[0251] By sampling images 4 during the irradiation of the tumor the
monitoring of any possible movement of the three-dimensional
element 7 and thus of the tumor 6 may be equalized momentarily all
most the instance the movement appears. The sampling frequency may
vary from ten images per second or faster to one image per three
second depending on the equipment used for producing the images
4.
[0252] High voltage equipment such as the irradiation equipment 2
itself has a sampling frequency (or sampling rate) less than for
example MR-scanning equipment. However, when using the irradiation
equipment 2 itself the other equipment is dispensable.
[0253] Often, X-ray is used to establish the first image 4 for
localization of the tumor 6 in relation to the three-dimensional
element 7, but other equipment such as CT-scanning equipment and
MR-scanning equipment may be used likewise. The position of the
tumor 6 in relation to the three-dimensional element 7 is thus
determined prior to the patient entering the irradiation room.
[0254] In one aspect of the present invention the patient itself
inputs the first image 4 into the computer of the irradiation
equipment, said first image 4 being relied upon as the previous
image 4 and thereby as the reference in the computer of the
irradiation equipment 2. Subsequently, the computer controls the
irradiation equipment 2 for producing an image 4 for establishing
the position of the element 7 in relation to the irradiation
equipment 2. Then the computer adjusts the irradiation equipment 2
if necessary in relation to the position of the element 7 and the
irradiation of the human or animal body begins.
[0255] The three-dimensional element 7 may be all kinds of objects
provided in the body for a number of other reasons. Such objects
may be all kinds of endoluminal prosthesis often being tubular,
such as a element 7 placed in the urethra and other natural
cavities, such as the urological tract, the urethra, the biliary
tract, the airways, the intestine, or the blood vessels in the
human body.
[0256] If an element 7 is already present in the vicinity of the
tumor to be irradiated, the element 7 will secure the passage of
the liquid, gas or solid inside that natural cavity, as mentioned
above. It is well known that the tissue having been irradiated
becomes distended and thereby may cause a reduction of the volume
of the natural cavities. A three-dimensional element 7, such as a
tubular endoluminal prosthesis can help to counteract this
reduction of the volume of the cavity.
[0257] For the reason of avoiding a reduction of the volume of the
natural cavities one or more elements 7 may be provided which may
be used in guiding the irradiation equipment 2 in order to adjust
for the aforementioned momentary movements during the
irradiation.
[0258] Furthermore the three-dimensional element 7 may in another
aspect of the present invention have a shape enabling insertion and
retraction in a natural cavity. Additionally, when inserted into
the cavity a part of the element 7 may expand in order to provide a
force against the surrounding wall of the cavity so as to fasten
the element 7 in this position. In other embodiments of the present
invention the fastening of the element 7 in relation to the
surrounding walls of the cavities may be done by at least a part of
the element 7 being attached at least partly to tissue outside the
natural cavity or by the element 7 having an Y-shape, an I-shape or
the like shapes processing a locking mechanism blocking movements
in the longitudinal direction of the cavity, such as the ureter,
vein or the like cavity.
[0259] An example of such a three-dimensional element 7 according
to the present invention is a tubular stent used for insertion into
the urethra in the vicinity of the prostate as shown in FIGS. 4, 5,
7 and 8. When the stent has been positioned in the part of the male
urethra passing through the prostate and expansion of the end of
the element 7 closest to the external urethral sphincter has
occurred, the element 7 will remain in position and allow urinary
passage without obstructing the function of the sphincter.
[0260] The wire design of the element 7 is of particular advantage
when the element 7 is to be removed or retracted from a body cavity
because the element 7 of a shape memory alloy becomes soft when it
is cooled. The element 7 may be removed by grasping in any part of
the helically wound wire and subsequently pulling the coil out of
the cavity as a wire. Furthermore, the element 7 may have a
different design than a coiled wire and the element may be made of
other alloys so when cooled the element 7 becomes super elastic and
is retractable by folding up the element 7 before retraction.
[0261] A further advantage of using a three-dimensional element 7
with a kind of locking mechanism is that the element 7 will move
together with the tumor 6 during respiration or other partly
movements of the human or animal body or during total movement of
the same body as shown in FIG. 7. Due to the fact that the element
7 moves with substantially no relative movement in relation to the
tumor 6, the irradiation equipment 2 may be adjusted in relation to
the possible movement of the three-dimensional element 7 in order
to accurately irradiate the tumor 6. In an image 4 produced by the
irradiation equipment 2 the computer is not able to detect the
tumor 6 since it is not visible in such image 4. However, a
three-dimensional element 7 made of metal, such as stainless steel,
titanium, platinum, palladium, gold, nickel-titanium and other
alloys thereof is easier to detect in such an image 4. Therefore, a
possible momentary movement of the element 7 is also detectable and
the irradiation equipment 2 may be adjusted to equalize such a
momentary movement.
[0262] The element 7 may also be of other biologically compatible
materials, such as polymers and biological material being
detectable in some images.
[0263] The three-dimensional element 7 may have all kinds of shapes
detectable in image 4 derived and produced by all kinds of medical
imaging equipment, said shape resulting in a predefined
geometrically structure in said image 4. In order to monitor a
possible movement, the predefined geometrically structure is
identified in the image 4 and the adjusting of the irradiation
equipment 2 may either move the body or properly adjust the
position of other parameters of the irradiation equipment 2 in
response to this movement.
[0264] When using the aforementioned element 7 inserted in the
urethra in the vicinity of the prostate the predefined
geometrically structure may be the diameter of the helically wound
coil or the pitch distance between the windings of the coil. This
geometrically structure gives a number of detectable points and is
automatically detectable in the image 4 by image processing being
implemented on a computer.
[0265] Another predefined geometrically structure of the element 7
may be the angle v between the straight part of the element 7 shown
in FIG. 7 and the conical part or the predefined geometrically
structure may be transition point in which the straight part of the
element 7 and the conically part of the coil intersect. This
detection, like the aforementioned ways of detection, also provides
a three-dimensional positioning of the element 7.
[0266] Elements 7 and other kinds of endoluminal prosthesis are
often manufactured in various lengths and the aforementioned
predefined geometrically structure is independent of this variation
in the length of stents and other endoluminal prosthesis.
[0267] The three-dimensional element 7 may, as mentioned above,
possess all kinds of shapes giving a recognizable defined
geometrically structure in the aforementioned image 4. Examples of
such other shapes are shown in FIG. 8-11. Instead of a helically
wound kind of coil as shown in these figures the three-dimensional
element 7 may be a tube having a solid wall and/or an expandable
part or different kinds of locking mechanisms. The wall of the
tubular element 7 can be made from wire being wound in different
patterns, such as cross-patterns, knitting-patterns or the like.
The three-dimensional element 7 may, in another aspect of the
present invention, be an implant or the reference may be such
implant.
[0268] By the term mega-voltage equipment is meant all sorts of
electron accelerators operating over 150 kV, preferably above 1 MV,
and preferably below 50 MV. Such an electron accelerator may be the
irradiation equipment 2 used for treating the patient by
irradiating the tumor 6.
[0269] By medical imaging equipment is meant all kinds of equipment
usable for producing the image 4 of disordered tissue and the
three-dimensional element 7. Such equipment may be Magnetic
Resonance scan (MR-scan), Nuclear Magnetic Resonance scan
(NMR-scan), Magnetic Resonance Image scan (MRI-scan), Computerized
Tomography scan (CT-scan), Cone Beam CT-scan, Positron Emission
Tomography (PET), Single Positron Emission Computed Tomography
(SPECT), Single Positron Emission Tomography (SPET),
Image-Guided-Radiation-Therapy (IGRT), Ultrasound-scan, or X-ray,
high-energy photons equipment or high voltage equipment.
[0270] The term shape memory alloy is defined as a metal having
transformation from martensite to austenite at a certain
temperature range (Austenite Start to Austenite Finish (AS to AF)).
Within this temperature range (AS to AF) the expansion of the
three-dimensional element 7 starts and the expansion stops when all
the martensite is transformed into austenite. The element 7
"remembers" at this temperature range (AS to AF) its original
shape. At another temperature range (Martensite Start to Martensite
Finish (MS to MF)) the alloy reverses to martensite. Below this
other temperature (MF) the element 7 is easily deformable by hand
and the element 7 may therefore be easily deformable inside the
body cavity and retracted through the natural opening in which the
element 7 was inserted. Alternatively the element may be retracted
through another natural opening than the one through which it was
inserted. The shape memory alloy may also be called
temperature-activated alloy.
[0271] The term shape memory alloy may also be a metal having super
elastic properties at a certain temperature, such as about
37.degree. C., being the body temperature, and a plasticity at a
another temperature, such as below 0.degree. C. By the wording
super elastic properties is meant an alloy which can be elastically
deformed up to very high deformation rates compared to other metals
and which alloy does not necessarily have a temperature (AS) at
which the material is capable of remembering an original shape.
[0272] The shape memory alloy may be a nickel- titanium alloy, a
nickel-titanium-cobalt alloy, other transition and precious metal
alloys or thermoplastic heat settable material exhibiting shape
memory characteristics. Heating of the wire may be accomplished by
induction heating, immersion heating, application of RF energy, or
by flushing the area of the three-dimensional element 7 with a
fluid at the specified temperature.
* * * * *