KR101799655B1 - Apparatus and method for detecting gamma-ray - Google Patents

Abstract

A gamma ray detection apparatus is disclosed. The gamma ray detecting apparatus measures a distribution of a gamma ray generated by a nuclear reaction between a particle beam and a therapeutic target, and includes a first multi-slit focusing unit having a plurality of first slit holes opened front and rear with a first partition wall therebetween; A second multi-slit focusing unit positioned above the first multi-slit focusing unit and including a plurality of second slit holes spaced apart from each other by a second partition; Detecting a gamma ray passing through the first slit holes and detecting the gamma ray; And a second scintillation detecting unit for detecting the gamma ray that has passed through the second slit holes, wherein the first slit holes and the second slit holes may be staggered from each other.

Description

[0001] APPARATUS AND METHOD FOR DETECTING GAMMA-RAY [0002]

The present invention relates to an apparatus and a method for detecting a gamma ray, and more particularly, to a gamma ray detecting apparatus and method for measuring a distribution of a gamma ray generated due to a nuclear reaction of a treated region of a patient and an irradiated particle beam .

Recently, in the medical field, radiation therapy has been generalized for therapeutic purposes such as the removal of tumors such as cancer.

In contrast, medical therapy using proton beams is widely used in medical treatments such as cancer therapy because it is capable of delivering high doses to tumor sites such as cancer and delivering small doses to normal cells. Therefore, when the patient is treated using the proton beam as described above, it is necessary to know precisely the point at which the proton dose falls.

Accordingly, in recent years, it has been suggested that the measurement point of the dose drop point can be measured by detecting the gamma ray emitted from the nuclear reaction in the patient's body so as to accurately measure the plunging point of the proton dose irradiated to the affected part of the patient.

Korean Patent No. 10-0783506 discloses a method for detecting a gamma ray immediately using a measuring device composed of a focusing device composed of a single slit and a detector.

However, since the single channel detection system uses a scanning method for measuring the gamma ray distribution, it is impossible to determine the particle beam non-detection in real time. Therefore, it is necessary to develop a system composed of multi-channel detectors for clinical application. For this purpose, a multi-slit camera including a multifocal focusing device and a multichannel flash detector has recently been proposed.

However, the multi-slit camera focusing system developed so far consists of a bulkhead and a square parallel hole for selectively measuring high-energy instantaneous gamma rays incident vertically in the beam traveling direction, Which is a serious limitation in precisely determining the undulations of the beam.

In addition, the conventional multi-slit camera has a problem that the detection area is small and the instantaneous gamma ray distribution to be measured is measured together with the distribution of background radiation unnecessary for measurement, so that the accuracy of beam non-crystallization deteriorates.

The present invention provides a gamma ray detecting apparatus and method capable of resolving physical measurement limitations between a slit hole and a partition of a multitrack focusing apparatus.

Further, the present invention provides a gamma ray detecting apparatus and method capable of securing a wide detection field.

The present invention also provides a gamma ray detecting apparatus and method capable of eliminating the influence of background radiation.

The gamma ray detecting apparatus according to the present invention measures the distribution of gamma rays generated by a nuclear reaction between a particle beam and a therapeutic target and measures the distribution of gamma rays generated by the first multi- part; A second multi-slit focusing unit positioned above the first multi-slit focusing unit and including a plurality of second slit holes spaced apart from each other by a second partition; Detecting a gamma ray passing through the first slit holes and detecting the gamma ray; And a second scintillation detecting unit for detecting the gamma ray that has passed through the second slit holes, wherein the first slit holes and the second slit holes may be staggered from each other.

The first slit holes may be arranged in the same straight line with the second partition walls in the vertical direction, and the second slit holes may be arranged in the same straight line in the vertical direction with the first partition walls.

In addition, the first slit holes may have the same width as the second partition walls, and the second slit holes may have the same width as the first partition walls.

The second multibranched slit focusing unit may be inclined with respect to the first multistage slit focusing unit such that a direction of the second slit holes and a direction of the first slit holes form a predetermined angle.

The apparatus may further include an angle adjusting unit for adjusting an angle of inclination of the second multibranched focusing unit with respect to the first multibranched focusing unit.

In addition, each of the first slit holes and the second slit holes has an incidence opening through which the gamma rays are incident and an exit opening through which the gamma rays exit, and the incidence opening may have a larger area than the emission opening.

In addition, each of the first slit holes and the second slit holes may gradually become narrower from the entrance to the exit.

The gamma ray detection method according to the present invention comprises the steps of: measuring a background radiation transmitted through the slit holes, the radiation being generated as a nuclear reaction between a particle beam and a treatment target, inserting a radiation blocking plate into each of the slit holes formed in the multiple slit focusing unit; Removing the radiation blocking plates from the slit holes and measuring a gamma ray passing through the slit holes; And removing the background radiation from the measured gamma radiation.

In addition, the radiation shielding plate may have a size and a shape corresponding to the slit holes.

According to the present invention, by arranging the two multislit focusing devices in a staggered arrangement, the measurement regions of gamma rays can be continuously arranged.

In addition, according to the present invention, it is possible to normalize the gamma ray measurement distribution detected by the two multislit focusing devices, thereby minimizing the variation of the distribution due to the detection efficiency difference according to the position of the detector array.

Further, according to the present invention, by providing the slit holes in a divergent shape, it is possible to secure a wide detection field and to have an improved measurement efficiency in the entire area of the treatment area of the patient.

In addition, according to the present invention, it is possible to maximize the measurement efficiency by adjusting the angles of the two multi-slit focusing devices to match the focus to the treatment area.

Further, according to the present invention, it is possible to obtain a precise gamma ray distribution by removing the influence of the background radiation generated in the surrounding environment or the setup apparatus of the patient, which is impossible.

1 is a view showing a gamma ray detecting apparatus according to an embodiment of the present invention.
2 is a front view showing the gamma ray detecting apparatus of FIG.
Fig. 3 is a diagram showing the arrangement relationship of the first and second multibranched slit focusing units of Fig. 1. Fig.
FIG. 4 is a graph illustrating a distribution obtained by combining gamma ray distributions measured in each of the first and second multitlit focusing units according to an embodiment of the present invention, and a distribution to which normalization is applied.
5 is a view illustrating a first multiple slit focusing part and a second multiple slit focusing part according to another embodiment of the present invention.
6 is a diagram illustrating a gamma ray detection method according to an embodiment of the present invention.
7 is a graph showing a gamma ray distribution graph according to the gamma ray detection method according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In this specification, when an element is referred to as being on another element, it may be directly formed on another element, or a third element may be interposed therebetween. Further, in the drawings, the thicknesses of the films and regions are exaggerated for an effective explanation of the technical content.

Also, while the terms first, second, third, etc. in the various embodiments of the present disclosure are used to describe various components, these components should not be limited by these terms. These terms have only been used to distinguish one component from another. Thus, what is referred to as a first component in any one embodiment may be referred to as a second component in another embodiment. Each embodiment described and exemplified herein also includes its complementary embodiment. Also, in this specification, 'and / or' are used to include at least one of the front and rear components.

The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It is also to be understood that the terms such as " comprises "or" having "are intended to specify the presence of stated features, integers, Should not be understood to exclude the presence or addition of one or more other elements, elements, or combinations thereof. Also, in this specification, the term "connection " is used to include both indirectly connecting and directly connecting a plurality of components.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a view showing a gamma ray detecting apparatus according to an embodiment of the present invention, and FIG. 2 is a front view showing a gamma ray detecting apparatus of FIG.

Referring to FIGS. 1 and 2, the gamma ray detecting apparatus 100 includes a gamma ray detecting apparatus 100 for detecting a gamma ray, which is generated by a nuclear reaction between a particle beam irradiated to a treatment target 10, Is measured. The gamma ray measured in the gamma ray detecting apparatus 100 includes a prompt gamma.

The gamma ray detection apparatus 100 includes a first multinomial slit focusing unit 110, a second multinomial slit focusing unit 120, an angle adjusting unit 130, a first flash detection unit 140, a second flash detection unit 150, .

The first multi-slit focusing section 110 is disposed with its front surface facing the treatment target 10. [ 1, the first multi-slit focusing unit 110 has a rectangular parallelepiped shape. However, the first multi-slit focusing unit 110 may have various shapes depending on the shape of the patient's treatment target 10, such as cancer cells. The first multi-slit focusing unit 110 may be made of a metal material. The first multi-slit focusing unit 110 may be made of tungsten. The first multi-slit focusing part 110 includes first slit holes 111 and first partition walls 112.

The first slit hole 111 is provided as a through hole provided from the front side to the rear side of the first multislit focusing unit 110. The first slit hole 111 provides a path through which gamma rays pass to the first flash detection part 140 side. A plurality of first slit holes 111 are formed and are arranged to be spaced apart from each other in the width direction of the first multiple slit converging unit 110. Hereinafter, the passing direction of the first slit hole 111 is referred to as a first direction X, the direction of arrangement of the first slit holes 111 is referred to as a second direction Y, and the first and second directions X, Y) is referred to as a third direction (Z).

The first partition walls 112 are provided between the first slit holes 111 and define adjacent first slit holes 111, respectively.

The first slit holes 111 and the first bank 112 may have the same width in the second direction Y. [ The first slit holes 111 and the first partition walls 112 may each have a width of at least 2 mm or more. According to the embodiment, the first slit holes 111 and the first partition walls 112 may each have a width of 2 mm.

And the second multibranched slit focusing part 120 is located at the upper part of the first multibrit focusing part 110 in the third direction Z. [ The second multibranched slit focusing part 120 may have a shape, size, and material corresponding to the first multibranched focusing part 110. The second multitlit focusing part 120 may have a shape corresponding to that of the first multit slit focusing part 110, do.

The second slit hole 121 is provided as a through hole provided from the front surface to the rear surface of the second multibranched focusing unit 120. The second slit hole 121 provides a passage through which gamma rays pass to the second flash detection part 150 side. A plurality of the second slit holes 121 are formed and are arranged apart from each other in the second direction (Y).

The second barrier ribs 122 are provided between the second slit holes 121 and define adjacent second slit holes 121, respectively.

The second slit holes 121 and the first slit holes 111 may have the same width in the second direction Y. [ The second barrier ribs 122 may have the same width in the second direction Y with the first barrier ribs 112.

According to the embodiment, the second slit holes 121 and the second partition walls 122 may each have a width of 2 mm.

Fig. 3 is a diagram showing the arrangement relationship of the first and second multibranched slit focusing units of Fig. 1. Fig.

Referring to FIG. 3, the second multitrack slit focusing unit 120 is disposed such that the second slit holes 121 are staggered with the first slit holes 111. The second slit holes 121 are arranged in the same straight line with the first partition walls 112 in the third direction Z and the first slit holes 111 are arranged in the third direction Z in the second partition 122 Are arranged on the same straight line.

When a gamma ray is detected by a single multislit focusing unit, a physical limit is imposed on the measurement due to the region where the gamma ray can not pass, that is, the partition. In order to solve this problem, the present invention solves the physical measurement limit by providing two multi-slit focusing parts 110 and 120 and staggering the first and second slit holes 111 and 121 with each other. It is possible to measure a continuous gamma ray distribution by measuring a gamma ray distribution in units of 2 mm in each of the first and second multiple slit focusing units 110 and 120 and combining the measured gamma ray distributions. The combination of the gamma ray distribution will be described in detail in FIG.

The angle adjusting unit 130 adjusts the angle of inclination of the second multibranched focusing unit 120 with respect to the first multibranched focusing unit 110. According to the embodiment, the front surface of the first multi-slit focusing unit 110 and the front surface of the bottom surface of the second multi-slit focusing unit 120 are pin-coupled, and the angle adjusting unit 130 is coupled to the second multi- 120 to adjust the inclination angle of the second multibranched focusing unit 120 with respect to the first multibranched focusing unit 110. [ By adjusting the inclination angle, the direction in which the first slit holes 111 are oriented and the direction in which the second slit holes 121 are oriented forms a predetermined angle. The angle adjuster 130 adjusts the angle of the first slit hole 111 and the second slit hole 121 such that the direction of the first slit holes 111 and the direction of the second slit holes 121 face the center C of the treatment target 10, ) Can be adjusted. The gamma ray distribution can be effectively measured by adjusting the focal points of the first and second multibranched slit focusing units 110 and 120 to match the center C of the treatment target 10. [

The first flash detection part 140 is located behind the first multislit focusing part 110 in the first direction X and measures a gamma ray distribution through the first slit holes 111. The first flash detection part 140 is provided in a number corresponding to the first slit holes 111 and is located behind the first slit holes 111, respectively. The first flash detection part 140 includes a first scintillator 141 and a first photodiode 142. The first scintillation part 141 is provided as a plate having a predetermined thickness and is excited by gamma ray particles to emit visible light. The first scintillation part 141 may have a width corresponding to the first slit hole 111. The first photodiode 142 converts light generated in the first scintillation unit 141 into an electrical signal.

The second flash detection part 150 is located behind the second multislit focusing part 120 and measures the gamma ray distribution through the second slit holes 121. The second flash detection part 150 is provided in a number corresponding to the second slit holes 121 and is located behind the second slit holes 121, respectively. The second scintillation detecting unit 150 includes a second scintillator 151 and a second photodiode 152. The second scintillation portion 151 is provided as a plate having a constant thickness, and is excited by gamma ray particles to emit visible light. The second scintillation part 151 may have a width corresponding to the second slit hole 121. The second photodiode 152 converts light generated from the second light source 151 into an electrical signal.

FIG. 4 is a graph illustrating a distribution obtained by combining gamma ray distributions measured in each of the first and second multitlit focusing units according to an embodiment of the present invention, and a distribution to which normalization is applied.

Referring to FIG. 4, when the gamma ray distribution is measured in the first and second multi-slit focusing units 110 and 120 and the gamma ray distribution is directly combined, a distribution as shown in the graph (a) is obtained. The reason why the phenomenon as shown in the graph (a) occurs is that the gamma rays generated by the irradiation of the irradiated particle beam with the treatment target 10 reach the first and second scintillator detection units 140 and 150, (10). Since the gamma ray has little reaction in the air but has a reaction with the therapeutic target 10, the longer the distance from the therapeutic target 10 becomes, the larger the number of gamma rays reacting with the therapeutic target 10 becomes, And the number of gamma rays reaching the second flash detection part (140, 150) is reduced. 2, the distance d1 at which the gamma rays reaching the first flash detection unit 140 exits the treatment target 10 is a distance from the second flash detection unit 140 150 is shorter than the distance from which the therapeutic target 10 exits. Therefore, the number of the gamma rays reaching the first flash detection part 140 is larger than the number of the gamma rays reaching the second flash detection part 150. For this reason, the number of gamma rays arriving at the first and second scintillator detectors 140 and 150 varies, and the gamma-ray distribution may fluctuate as shown in the graph (a), which may affect the particle beam non-crystallization .

In order to solve this problem, the graph (b) can be obtained by normalizing the gamma ray distribution measured by the first and second multibranched slit converters 110 and 120. In the normalization process, the sum of the gamma rays measured by the first and second scintillator detectors 140 and 150 is used. The number of gamma rays reaching the first flash detection part 140 is larger than the number of the gamma rays reaching the second flash detection part 150 for the above reason. For example, assuming that a total of 10,000 gamma ray distributions are measured by the first flash detector 140 and a total of 8,000 gamma ray distributions are measured by the second flash detector 150, the gamma rays measured by the first flash detector 140, The distribution was divided by 10000, the gamma ray distribution measured by the second flash detector 150 was divided by 8000, and the gamma ray distributions were combined. As a result, the graph (b) can be obtained, and it can be confirmed that the variation is smaller than the gamma-ray distribution of the graph (a).

5 is a view illustrating a first multiple slit focusing part and a second multiple slit focusing part according to another embodiment of the present invention.

Referring to FIG. 5, the first slit hole 111 formed in the first multiple slit converging unit 110 and the second slit hole 121 formed in the second multiple slit converging unit 120 have a divergent shape. Specifically, the first slit hole 111 and the second slit hole 121 have a larger width than the discharge port (b) through which the incidence port (a) into which the gamma ray is incident exits the gamma ray. The width of the first slit hole 111 and the second slit hole 121 may gradually decrease from the incident opening a to the discharge opening b.

The slit holes 111 and 121 having the above-described shapes can measure a wider area than the conventional slit holes 111a and 121a. The maximum area in which the slit holes 111 and 121 having the above-described shape can be measured extends to the second area B while the maximum area in which the square-shaped slit holes 111a and 121a can be measured is the first area A, . The shapes of the slit holes 111 and 121 have the effect of widening the measurable area of the gamma rays while keeping the size of the multislit focusing parts 110 and 120 the same as the conventional ones.

6 is a diagram illustrating a gamma ray detection method according to an embodiment of the present invention.

Referring to FIG. 6, the gamma ray detecting apparatus 100 further includes a radiation shield plate 160. The radiation shielding plate 160 may be provided as a plate of a size and shape corresponding to the slit holes 111. [ The radiation shield plate 160 may be made of a metal material. The radiation shield plate 160 may be made of tungsten. The radiation blocking plate 160 is inserted into each of the slit holes 111, and blocks the gamma rays from passing through the slit holes 111.

Background radiation generated at various places such as a beam nozzle, a structure of a treatment room, and a focusing device in addition to a gamma ray generated by nuclear reaction of a particle in a patient and a particle in a patient can be detected by the flash detection units 140 and 150 connect. Detection of background radiation degrades the accuracy of particle beam non-crystallization. Therefore, there is a need for a method for improving the accuracy of beam non-crystallization by removing the influence of background radiation on the measured gamma ray distribution.

As shown in FIG. 6, the gamma ray detection method is a method of detecting a background radiation distribution generated by irradiating a particle beam to a water phantom 10 having a density similar to that of a human body before inserting the radiation shield plate 160 into each of the slit holes 111 Measure for a sufficient time. Then, the radiation shield plate 160 is removed from the slit holes 111, and the gamma ray distribution is measured during the treatment. Remove the background reflec- tion distribution from the measured gamma-ray distribution. The removal of the background radiation distribution can recalculate the background scatter line distribution taking into account the number of particle beams used in the actual treatment and remove the recalculated radiation distribution results from the actually measured gamma radiation distribution.

7 is a graph showing a gamma ray distribution graph according to the gamma ray detection method according to the present invention.

The graph shows the result of measurement of the instantaneous gamma ray distribution generated by irradiating a 150 MeV quantum beam to a water phantom having a density similar to that of a human body using the scintillation detection units 140 and 150.

Referring to FIG. 7, the first graph 21 is a graph showing a gamma ray distribution measured through the slit holes 111 in a state where the radiation shielding plate 160 is removed. . The second graph 22 is a graph showing the distribution of background radiation measured in a state where the radiation shield plate 160 is inserted into the slit holes 111. The third graph 23 is a final gamma ray distribution graph in which the background radiation distribution (second graph) is removed from the distribution in which the gamma rays and the background radiation are simultaneously measured (first graph). Since the third graph 23 shows only the gamma ray distribution closely related to the beam non-uniformity, it is possible to improve the accuracy in determining the non-uniformity of the beam.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. It will also be appreciated that many modifications and variations will be apparent to those skilled in the art without departing from the scope of the invention.

100: gamma ray detection device
110: first multi-slit focusing section
111: first slit hole
112: first partition
120: second multi-slit focusing section
121: second slit hole
122: second partition
130:
140: a first flash detection part
150: second flash detection part

Claims (9)

A gamma ray detection apparatus for measuring a distribution of a gamma ray generated by a nuclear reaction between a particle beam and a therapeutic target,
Wherein the first slit holes are formed in the first direction and the first slit holes are formed in the first direction and the first slit holes are provided respectively between the adjacent first slit holes and the first slit holes and the first partition walls are perpendicular to the first direction A first multi-slit focusing unit provided alternately and repeatedly in a second direction;
Second slit holes are formed in an upper portion of the first multi-slit converging portion in a third direction perpendicular to the first direction and the second direction, the second slit holes passing through the front side in the first direction are formed, A second multiple slit focusing part provided between the second slit holes, wherein the second slit holes and the second partition walls are repeatedly provided alternately along the second direction;
Detecting a gamma ray passing through the first slit holes and detecting the gamma ray; And
And a second scintillation detecting unit that detects the gamma rays that have passed through the second slit holes,
Wherein the first slit holes and the second partition walls have the same width in the second direction and are arranged in the same line in the third direction,
Wherein the second slit holes and the first partition walls have the same width in the second direction and are arranged on the same line in the third direction. delete delete The method according to claim 1,
And the second multibranched slit focusing section is disposed obliquely with respect to the first multibranched focusing section. 5. The method of claim 4,
And an angle adjusting unit for adjusting an angle of inclination of the second multibranched focusing unit with respect to the first multibranched focusing unit. The method according to claim 1,
Wherein each of the first slit holes and the second slit holes has an entrance through which the gamma rays are incident and a discharge port through which the gamma rays exit,
Wherein the incidence aperture has a larger area than the exit aperture. The method according to claim 6,
Wherein each of the first slit holes and the second slit holes is gradually narrowed in width from the entrance to the exit. A method for detecting a gamma ray generated by a nuclear reaction between a particle beam and a therapeutic target,
Inserting a radiation blocking plate into each of the slit holes formed in the multitrack focusing unit and measuring background radiation transmitted through the slit holes;
Removing the radiation blocking plates from the slit holes and measuring a gamma ray passing through the slit holes; And
And removing the background radiation from the measured gamma rays. 9. The method of claim 8,
Wherein the radiation shielding plate has a size and shape corresponding to the slit holes.

Images