JP3790481B2 - Radiation therapy equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to radiation therapy equipment for tracking the irradiation field of the therapeutic radiation in accordance with the movement of the treated portion.
[0002]
[Prior art]
In the field of surgical treatment, there is radiation therapy that treats a lesion by irradiating the lesion with necrosis. Since radiation can be irradiated through the human body, this radiation treatment is effective for deep lesions that are difficult to open. At this time, it is necessary to irradiate radiation from multiple directions in order to irradiate the lesion formed in the deep part of the human body with a sufficient radiation dose for necrosis.
[0003]
A radiotherapy apparatus for performing radiotherapy is an isocentric or a head equipped with a therapeutic radiation source with respect to a treatment target site in order to irradiate the treatment target site that is a lesion from multiple directions. Some are configured to move and hold in a non-isocentric manner.
[0004]
An isocentric radiotherapy apparatus is constructed so that when the head is moved and therapeutic radiation is irradiated from multiple directions toward the treatment target site, the irradiated therapeutic radiation intersects at one point (isocenter). It has been. This isocentric radiotherapy apparatus has a small number of movable axes, a simple structure, and easy positioning of the irradiation field. Accordingly, irradiation accuracy is required, and the treatment target region is fixed and suitable for treatment of a region where radiation can be irradiated, for example, a brain tumor.
[0005]
In addition, the non-isocentric radiotherapy device can freely set the intersection of the therapeutic radiation to be irradiated within a certain range when irradiating the therapeutic radiation from multiple directions toward the target site by moving the head. can do. As this non-isocentric type radiotherapy device, radiation is generated in a robot arm equipped with a radiation generator on the head or a head portion having a swinging function (with two rotating shafts on the portion supporting the head). A gantry that operates with an isocentric (pseudo-isocentric) mounting device is generally known.
[0006]
The site to be treated is often irregular. Compared to the isocentric radiation therapy device that needs to move the treatment target site to the isocenter when irradiating therapeutic radiation from a different angle to the treatment target site, the non-isocentric radiation therapy device is Radiation can be irradiated without moving the treatment target region. Since the patient is rarely moved according to the irradiation position, the burden on the patient is reduced.
[0007]
In radiation therapy, collimators with different apertures are prepared to reduce the radiation dose to a healthy site and to make the volume density (radiation dose) of the radiation irradiated to an irregular treatment site uniform. ing. A suitable collimator is selected and used each time according to the size and shape of the site to be treated.
[0008]
Moreover, when performing radiotherapy, the position and shape of the site to be treated are determined in advance, and a radiation irradiation plan is made. Based on this irradiation plan, there is a radiotherapy apparatus provided with a variable exit collimator that changes the radiation exit. This radiotherapy apparatus does not require the operator to replace the collimator, and can change the shape of the radiation outlet by remote control.
[0009]
Positioning of the irradiation field with respect to the treatment target site is confirmed each time before radiation irradiation by an X-ray transmission diagnostic apparatus provided in synchronization with the radiation therapy apparatus. If the site to be treated is a site that is difficult to identify by imaging with an X-ray transmission diagnostic device, use a landmark such as a body tissue such as a bone or a gold plate embedded in the vicinity of the site to be treated. Based on the above, the site to be treated is confirmed.
[0010]
[Problems to be solved by the invention]
When radiation passes through the human body, it affects the cells in the transmitted part. Therefore, radiation must be irradiated to the site to be treated while avoiding organs that are susceptible to radiation from entering the irradiation route. In the case where the treatment target part moves between the time when it is confirmed by the X-ray transmission diagnostic apparatus and the time when the radiation is irradiated, it is necessary to predict the movement destination and irradiate the radiation.
[0011]
The circulatory system, digestive system, and their surroundings move due to heartbeat, respiratory movement, peristaltic movement of the digestive system, and the like. For respiratory motion, there is a method of optically tracking the movement of a marker attached to the chest and irradiating radiation at a set position. However, the actual movement of the organ is complicated and varies depending on the physical condition. Therefore, it is difficult to match the planned radiation field to the treatment target region that moves irregularly. Further, if the irradiation field is set narrow in order to prevent the radiation dose exceeding the allowable dose from being applied to a healthy part, there will be a part where the planned dose cannot be sufficiently irradiated.
[0012]
Therefore, in order to accurately irradiate the treatment target site with the planned dose, it is necessary to irradiate the radiation at the moment when the irradiation field coincides with the treatment target region. Therefore, the radiation treatment takes a long time.
[0013]
In addition, the digestive system that performs peristaltic movement, the site where the patient's physical condition is likely to change from moment to moment, such as the bladder, and the site to be treated around the site change during the treatment and the shape thereof also changes.
[0014]
In the case of an isocentric radiotherapy apparatus, it is conceivable to cause the treatment target site to follow the radiation field by moving the bed on which the patient is placed. However, moving the patient is not preferable because the position of the organ is further changed. In the case of a non-isocentric radiotherapy apparatus, it is conceivable to make the head follow the movement of the treatment target site. However, when the radiation generating device mounted on the head unit is made to follow a relatively fast movement such as a heartbeat or a respiratory motion, the radiation therapy device may vibrate due to the inertia of the radiation generating device. Due to this vibration, the radiation field is shifted, so that the radiation irradiation accuracy is deteriorated. Therefore, it is not possible to efficiently perform radiation therapy on a portion that may move during treatment.
[0016]
An object of the present invention is to provide treatment to the target site is to provide a radiation therapy equipment for irradiation field can irradiation accurately accurately therapeutic radiation to the target site to be treated by tracking of the therapeutic radiation.
[0017]
[Means for Solving the Problems]
In order to solve the above problems, radiation therapy equipment of the present invention, was as follows means.
[0018]
In order to solve the above-described problems, a radiotherapy apparatus according to the present invention has a plurality of radiation sources arranged so that emitted examination radiations intersect with each other at an examination target portion, and these radiation sources have a one-to-one correspondence. And a plurality of detectors for detecting inspection radiation transmitted through the inspection target portion, and an image forming apparatus that forms a three-dimensional image of the inspection target portion based on information detected by the detector And an analysis device for obtaining a three-dimensional position and a three-dimensional shape of a treatment target portion to be tracked that moves within the range of the inspection target portion based on the three-dimensional image formed by the image forming device, and an inspection target portion A radiation generator for irradiating therapeutic radiation and a large number of slides that move in a direction orthogonal to the emission direction, and these slides are bundled in a direction orthogonal to the above direction to form two slide groups, Sly 3 of the exit variable collimator that changes the irradiation field of the radiation emitted from the radiation generator arranged so that the abutting surface of the group is aligned with the direction along the body axis, and 3 of the treatment target site obtained by the analysis device based on the dimensions the position and three-dimensional shape, e Bei and a control device for controlling the sliding of said exit variable collimator, the control device according to the deformation of the target site to be treated, said exit variable collimator The radiation field of therapeutic radiation is tracked with respect to the treatment target site by changing the shape of the exit port of.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
A radiotherapy apparatus 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. A radiotherapy apparatus 1 shown in FIG. 1 includes a moving body tracking apparatus 2, a radiation generation apparatus 3, an emission port variable collimator 4, and a control apparatus 5. The moving body tracking device 2 includes two radiation sources 6, two detectors 7, an image forming device 8, and an analysis device 9.
[0021]
The radiation source 6 emits inspection X-rays as radiation. The radiation source 6 is arranged so that the emitted X-rays intersect each other at the examination target part, for example, the examination target part M of the patient P. The detector 7 is paired with the radiation source 6 and is arranged so as to detect X-rays transmitted through the inspection target part M. The detector 7 detects X-rays that have passed through the inspection target part M at predetermined time intervals.
[0022]
The image forming apparatus 8 constitutes a three-dimensional image of the inspection target part M based on the information of the X-rays detected by the two detectors 7. Further, the information of the detector 7 is updated every predetermined time interval, and the three-dimensional image is updated. The analysis device 9 is based on the three-dimensional image formed by the image forming device 8 and the tracking target portion designated within the range of the examination target portion M, for example, the three-dimensional position and 3 of the treatment target portion T to be subjected to radiation therapy. Find the dimensional shape. Further, the analysis device 9 identifies a shape similar to the previous treatment target region T as the designated treatment target region T from the three-dimensional image updated after a predetermined time interval. That is, the analysis device 9 can track the radiation irradiation control part T that is deformed and moved with time from the three-dimensional image, and can obtain the three-dimensional position and three-dimensional shape thereof.
[0023]
The radiation generating apparatus 3 is arranged so that it can irradiate the therapeutic X-ray toward the examination target part M without interfering with the radiation source 6 and the detector 7.
[0024]
The emission port variable collimator 4 includes two slide groups 10a and 10b. Each of the slide groups 10a and 10b includes a large number of slides 11a and 11b that move in a direction S perpendicular to the radiation direction A of the therapeutic X-ray. The slides 11a and 11b are bundled in the direction W perpendicular to the radiation direction A of the therapeutic X-rays and the direction S in which the slides 11a and 11b move to form slide groups 10a and 10b. Each of the slide groups 10a and 10b is disposed with the end portions 11c and 11d abutted against each other in the moving direction S of the slides 11a and 11b. The slides 11a and 11b include a metal having a large specific gravity, such as tungsten, and have a sufficient thickness in the radiation direction A for therapeutic X-rays to absorb the therapeutic X-rays.
[0025]
The control device 5 controls the slides 11a and 11b, and forms an emission port 12 through which the therapeutic X-ray passes between the slide groups 10a and 10b. The exit port 12 has a radiation X-ray irradiation field 13 emitted from the radiation generator 3 based on the three-dimensional position and the three-dimensional shape of the treatment target site T obtained by the analysis device 9. It is provided so as to overlap the projected area from the radiation generator 3 of T. The therapeutic X-rays are irradiated to the treatment target site T of the patient P through the emission port 12.
[0026]
The radiotherapy apparatus 1 configured as described above irradiates examination X-rays from a radiation source so as to cross each other at the detection target portion M. The irradiated X-rays pass through the inspection target part M and are detected by the detection unit 7 at predetermined time intervals. The detected X-ray is formed into a three-dimensional image by the image forming apparatus. A treatment target region T to be irradiated with therapeutic X-rays is designated from the constructed three-dimensional image. When the treatment target region T is selected, the slides 11a and 11b of the emission port variable collimator 4 are controlled to change the shape of the emission port 12 according to the projected area on the treatment target region T.
[0027]
As shown in FIG. 2, when the treatment target site T is deformed and moved from Ta to Tb, the shape of the emission port 12 is changed by detecting the treatment target site T at a sufficiently short time interval with respect to the deformation and movement. It is changed continuously from 12a to 12b. Thereby, the irradiation field 13 of the therapeutic X-ray emitted from the radiation generator 3 is continuously tracked in accordance with the shape and position of the treatment target site T that changes from Ta to Tb.
[0028]
The radiotherapy apparatus 1 of the present embodiment tracks the movement and deformation of the treatment target site T by changing the emission port 12 of the emission port variable collimator 4. Since the portions that move to track the treatment target site T are the slides 11a and 11b, the moment of inertia is small, and the tracking responsiveness to the deformation and movement of the treatment target site T is good. Therefore, even when the treatment target site T moves during cardiac X-ray irradiation due to heartbeat, movement of the diaphragm due to breathing, peristaltic movement of the digestive organ, etc., the therapeutic X-ray irradiation field is continuously applied to the treatment target site T. Tracking, and therapeutic X-rays can be irradiated.
[0029]
Moreover, the exit variable collimator 4 can increase the tracking distance of the treatment target site T by increasing the slides 11a and 11b of the slide groups 10a and 10b. When the treatment target site T moves due to heartbeat, breathing motion, peristaltic motion, etc., it moves more greatly along the body axis direction of the patient P. Therefore, by arranging the abutting surfaces of the slide groups 10a and 10b of the emission port variable collimator 4 in the direction along the body axis B, the treatment target site T can be tracked over a wider range.
[0030]
Since the moving body tracking device 2 tracks the treatment target region T based on the three-dimensional position and the three-dimensional shape obtained from the three-dimensional image, the moving object tracking device 2 can accurately track the deformation and movement of the treatment target region T.
[0031]
Moreover, by continuously changing the shape and position of the exit port 12 of the exit port variable collimator 4 in accordance with the change of the three-dimensional position 置及 beauty three-dimensional shape of the target site to be treated T to be tracked by the moving body tracking device 2 Thus, the irradiation field 13 of the radiation generator 3 can be accurately tracked to the treatment target site T without mechanically moving the radiation generator 3.
[0032]
Since the radiation therapy apparatus 1 is provided with the radiation source 6 that emits the examination X-rays and the radiation generator 3 that emits the therapy X-rays separately, the treatment target region T that moves within the range of the examination target portion M is provided. Can be observed during radiation therapy. Therefore, the irradiation field of the therapeutic X-ray can be tracked accurately and continuously with respect to the continuous change of the treatment target site T.
[0033]
If it is difficult to identify the treatment target region T by detecting the X-rays emitted from the radiation source 6 with the detector 7, a target landmark such as a gold plate is embedded in the vicinity of the treatment target region T. Track the landmark's 3D position. Alternatively, a plurality of landmarks may be arranged in the vicinity of the treatment target site, and the position and shape of the treatment target site may be predicted based on the position and the distance between the landmarks.
[0034]
【The invention's effect】
Radiation therapy equipment of the present invention has the following effects.
[0035]
A plurality of radiation sources arranged so that the emitted inspection radiation intersects with each other in the inspection target portion, and inspection radiation that is arranged in a one-to-one pair with these radiation sources and passes through the inspection target portion Based on information detected by the detector, an image forming apparatus that forms a three-dimensional image of the inspection target portion, and a three-dimensional image formed by the image forming apparatus An analysis device for obtaining a three-dimensional position and a three-dimensional shape of a treatment target part to be tracked that moves within the range of the target part, a radiation generator for irradiating therapeutic radiation to the examination target part, and a direction orthogonal to the emission direction Radiation generation with two slide groups formed by bundling these slides in a direction perpendicular to the above direction, with the abutment surfaces of the slide groups aligned along the body axis The above-mentioned slide of the exit variable collimator is controlled based on the output variable collimator that changes the irradiation field of the radiation emitted from the device, and the three-dimensional position and the three-dimensional shape of the treatment target portion obtained by the analysis device The control device tracks the irradiation field of the therapeutic radiation with respect to the treatment target region by changing the shape of the emission port of the variable emission port collimator according to the deformation of the treatment target region. According to the radiotherapy apparatus of the present invention, the three-dimensional position and the three-dimensional shape of the tracking target part are obtained from the three-dimensional image of the examination target part, and the shape of the emission port of the variable emission port collimator is adjusted accordingly. Since the irradiation field of the therapeutic radiation is tracked according to the treatment target region, the therapeutic radiation can be accurately irradiated to the treatment target region.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a moving body tracking device of a radiation therapy apparatus according to an embodiment of the present invention.
2 is a perspective view schematically showing a positional relationship between an emission port of the emission port variable collimator of the radiotherapy apparatus of FIG. 1 and a radiation irradiation target portion;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Radiation therapy apparatus 2 ... Moving body tracking apparatus 3 ... Radiation generator 4 ... Output port variable collimator 5 ... Control apparatus 6 ... Radiation source 7 ... Detector 8 ... Image forming apparatus 9 ... Analysis apparatus 12 ... Output port 13 ... Irradiation Field M ... Inspection target part T ... Treatment target region (tracking target region)

Claims (1)

A plurality of radiation sources arranged so that the emitted inspection radiation intersects with each other in the inspection target part; and
A plurality of detectors which are arranged in a one-to-one pair with these radiation sources and detect inspection radiation transmitted through the inspection target part;
Based on the information detected by the detector, an image forming apparatus that constitutes a three-dimensional image of the inspection target part;
An analysis device for obtaining a three-dimensional position and a three-dimensional shape of a treatment target portion to be tracked that moves within the range of the examination target portion based on the three-dimensional image formed by the image forming device;
A radiation generator for irradiating therapeutic radiation to the examination target; and
A plurality of slides moving in a direction orthogonal to the emission direction are provided, and these slides are bundled in a direction orthogonal to the above direction to form two slide groups, and the butting surfaces of the slide groups are directions along the body axis An exit variable collimator that changes an irradiation field of radiation emitted from the radiation generator arranged in accordance with
Based on the three-dimensional position and three-dimensional shape of the target site to be treated obtained by the analyzer, and a control device for controlling the sliding of said exit variable collimator, the control device of the target site to be treated A radiation therapy apparatus for tracking a treatment radiation irradiation field with respect to the treatment target region by changing an emission port shape of the emission port variable collimator according to deformation .

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