Radiation measuring instrument support device, radiation measuring device, and radiation measuring method

Abstract

To provide a radiation measuring technology to easily execute radiation measuring equipment installation work according to the position of an irradiation port in a particle beam therapy system in which the position of the irradiation port changes.SOLUTION: A radiation measuring equipment support device 30 includes: a circular column case 31 forming a circular columnar shape that houses a phantom 40 and radiation measuring equipment 41; a foundation 32 for supporting the circular column case 31 rotatably in a circumferential direction in a state that the cylindrical axis is directed in a horizontal direction, and fixing the circular column case 31 at an arbitrary rotation angle in the circumferential direction; and angle display parts 38 and 39 for displaying the rotation angle.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] Embodiments of the present invention relate to radiation measurement technology.

Background Art

[0002] In a particle beam therapy system having a rotating gantry, an irradiation port rotates around a patient, and particle beams (radiation) are irradiated from an arbitrary direction according to the treatment site of the patient. In such a particle beam therapy system, before the start of treatment, radiation measurement according to the position of the irradiation port is required to confirm the quality such as the energy of the particle beam, the beam size, the accuracy of the irradiation position, and the dose distribution.

[0003] Conventionally, a technique is known in which a phantom and a radiation measuring device are fixed to an irradiation port by an attachment to measure the particle beam (radiation) emitted from the irradiation port. However, the work of fixing the phantom and the radiation measuring device to the irradiation port is time-consuming.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide a radiation measurement technology that can easily perform the work of installing a radiation measuring device according to the position of an irradiation port in a particle beam therapy system in which the position of the irradiation port changes.

Means for Solving the Problems

[0006] An embodiment of the present invention provides a radiation measuring instrument support device comprising: a cylindrical case that houses a phantom and a radiation measuring instrument and is cylindrical in shape; a base that supports the cylindrical case so as to be rotatable in the circumferential direction with the cylindrical axis facing horizontally, and fixes the cylindrical case at any rotation angle in the circumferential direction; and an angle display unit that displays the rotation angle. [Effects of the Invention]

[0007] According to an embodiment of the present invention, a radiation measurement technology is provided that allows for the easy installation of a radiation measuring instrument in accordance with the position of the irradiation port in a particle beam therapy system in which the position of the irradiation port changes. [Brief explanation of the drawing]

[0008] [Figure 1] A side view showing the rotating gantry of a particle beam therapy system. [Figure 2] A front view showing the rotating gantry corresponding to the II-II section in Figure 1. [Figure 3] A front view showing the rotating gantry when it rotates and the position of the irradiation port changes. [Figure 4] A front view showing the radiation measuring instrument support device of the first embodiment. [Figure 5] A side view showing the radiation measuring instrument support device of the first embodiment. [Figure 6] A bottom view showing the radiation measuring instrument support device of the first embodiment. [Figure 7] A perspective view showing the frame unit. [Figure 8] A cross-sectional view showing the radiation detector support device when the rotation angle is 0 degrees. [Figure 9] A cross-sectional view showing the radiation detector support device when the rotation angle is 90 degrees. [Figure 10] A cross-sectional view showing a radiation detector support device when the rotation angle is 135 degrees. [Figure 11] A cross-sectional view showing a radiation detector support device when the rotation angle is 180 degrees. [Figure 12]Cross-sectional view showing the radiation measuring device support apparatus of the second embodiment. [Figure 13] Cross-sectional view showing the radiation measuring device support apparatus of the third embodiment. [Figure 14] Cross-sectional view showing the radiation measuring device support apparatus of the fourth embodiment. [Figure 15] Cross-sectional view showing the radiation measuring device support apparatus of the fifth embodiment. [Figure 16] Block diagram showing the radiation measuring device support apparatus of the fifth embodiment.

Embodiments for Carrying Out the Invention

[0009] (First Embodiment) Hereinafter, embodiments of a radiation measuring device support apparatus, a radiation measuring device, and a radiation measuring method will be described in detail with reference to the drawings. First, the first embodiment will be described using FIGS. 1 to 11.

[0010] Reference numeral 1 in FIG. 1 denotes a particle beam therapy system. This particle beam therapy system 1 includes a rotating gantry 5. The particle beam therapy system 1 irradiates a lesion tissue (cancer) of a patient 8 as a subject with a particle beam 7 (therapeutic radiation) such as carbon ions transported through a vacuum duct 6 to perform treatment.

[0011] The radiation therapy technique using the particle beam therapy system 1 is also referred to as a heavy particle beam cancer therapy technique. This technique enables the carbon ions to precisely target the cancer lesion (affected part) and damage the cancer lesion while minimizing the damage to normal cells. Note that the particle beam 7 is defined as a radiation heavier than an electron and includes a proton beam, a heavy particle beam, and the like. Among these, the heavy particle beam is defined as a particle heavier than a helium atom.

[0012] In cancer treatment using heavy particle beams, compared with conventional cancer treatments using X-rays, gamma rays, and proton beams, it has a higher ability to kill cancer lesions, has a low radiation dose on the surface of the patient's body, and has the characteristic that the radiation dose peaks in the cancer lesion. Therefore, the number of irradiations and side effects can be reduced, and the treatment period can be made shorter.

[0013] The particle beam therapy system 1 includes a beam generator (not shown), a circular accelerator (not shown), and a beam transport line (not shown).

[0014] The beam generator has an ion source for carbon ions, which are charged particles, and generates a particle beam 7 with these carbon ions. The circular accelerator forms a ring shape in plan view and accelerates the particle beam 7 generated by the beam generator. The beam transport line transports the particle beam 7 accelerated by the circular accelerator to the rotating gantry 5. A patient 8 to be irradiated with the particle beam 7 is placed on the rotating gantry 5.

[0015] In this particle beam therapy system 1, first, the particle beam 7 of carbon ions generated by the beam generator is incident from the beam generator into the circular accelerator. This particle beam 7 is accelerated to about 70% of the speed of light while orbiting the circular accelerator about one million times. Then, this particle beam 7 is guided to the rotating gantry 5 via the beam transport line.

[0016] The beam generator, the circular accelerator, and the beam transport line include a vacuum duct 6 (beam pipe) whose interior is evacuated. The particle beam 7 travels inside this vacuum duct 6. The vacuum ducts 6 of the beam generator, the circular accelerator, and the beam transport line are integrated to form a transport path for guiding the particle beam 7 to the rotating gantry 5. That is, the vacuum duct 6 is a sealed continuous space having a sufficient degree of vacuum to allow the particle beam 7 to pass through.

[0017] As shown in the cross-sectional view of FIG. 1, the rotating gantry 5 is a device having a cylindrical shape. This rotating gantry 5 is provided such that the axis (horizontal axis 9) of the cylinder faces the horizontal direction. The rotating gantry 5 is rotatable about this horizontal axis 9.

[0018] The rotating gantry 5 is supported by the building structure 10 of the treatment facility where the particle beam therapy system 1 is installed. For example, end rings 11 are fixed to the front and rear of the main body 19 of the rotating gantry 5. Below these end rings 11, a rotary drive unit 12 is provided, which supports the end rings 11 in a rotatable state and is equipped with a drive motor. This rotary drive unit 12 is supported by the building structure 10. The driving force of the rotary drive unit 12 is supplied to the rotating gantry 5 via the end rings 11, causing the rotating gantry 5 to rotate around the horizontal axis 9.

[0019] The rotating gantry 5 is equipped with a vacuum duct 6 extending from the beam transport line. The vacuum duct 6 is first guided inward from the rear side of the rotating gantry 5 along its horizontal axis 9. Then, the vacuum duct 6 extends outward from the outer surface of the rotating gantry 5, and then extends again inward from the rotating gantry 5. The tip of this vacuum duct 6 extends to a position close to the patient 8.

[0020] Although not specifically shown in the diagram, a predetermined rotation mechanism is provided in the vacuum duct 6 along the horizontal axis 9 of the rotating gantry 5. The portion of the vacuum duct 6 outside of this rotation mechanism is stationary, while the portion inside of this mechanism rotates in conjunction with the rotation of the rotating gantry 5.

[0021] Furthermore, the rotating gantry 5 is equipped with an irradiation port 13 for directing the particle beam 7 towards the patient 8, and a transport unit 14 for transporting the particle beam 7 to the irradiation port 13. In other words, the irradiation port 13 and the transport unit 14 are supported by the rotating gantry 5.

[0022] Furthermore, the transport unit 14 is equipped with superconducting magnets 15 that generate a magnetic field that forms a path for transporting the particle beam 7. These superconducting magnets 15 are, for example, deflecting electromagnets that change the direction of travel of the particle beam 7 along the vacuum duct 6, or quadrupole electromagnets that control the focusing and divergence of the particle beam 7.

[0023] The irradiation port 13 is located at the tip of the vacuum duct 6 and irradiates the patient 8 with the particle beam 7 guided by the transport unit 14. This irradiation port 13 is fixed to the inner surface of the rotating gantry 5. The particle beam 7 is irradiated from the irradiation port 13 in a direction perpendicular to the horizontal axis 9.

[0024] A treatment space 16 for particle beam therapy is provided inside the rotating gantry 5. The patient 8 is placed on a treatment table 17 located in this treatment space 16. This treatment table 17 can be moved with the patient 8 on it. By moving the treatment table 17, the patient 8 can be moved to the irradiation position of the particle beam 7 and positioned accordingly. Therefore, the particle beam 7 can be irradiated to the appropriate area, such as the lesion tissue of the patient 8.

[0025] The patient 8 is positioned at the horizontal axis 9, and by rotating the rotating gantry 5, the irradiation port 13 can be rotated around the stationary patient 8. For example, the irradiation port 13 can be rotated 180 degrees clockwise (right) or counterclockwise (left) in a front view, around the patient 8 (horizontal axis 9) (Figures 2 to 3). Then, the particle beam 7 can be irradiated from any direction around the patient 8. In other words, the rotating gantry 5 is a device that can change the direction of irradiation of the particle beam 7 guided by the beam transport line to the patient 8. Therefore, the burden on the patient 8 can be reduced while irradiating the affected area with higher precision from the appropriate direction.

[0026] As particle beam 7 passes through patient 8's body, it loses kinetic energy and its speed decreases. At the same time, it encounters resistance that is approximately inversely proportional to the square of its speed, and once it reaches a certain speed, it comes to a sudden stop. This stopping point of particle beam 7 is called the Bragg peak, and high energy is delivered to the affected area. By aligning this Bragg peak with the location of the lesion tissue in patient 8, the particle beam therapy system 1 can destroy only the lesion tissue while minimizing damage to normal tissue.

[0027] As shown in Figure 1, a virtual point is set in the treatment space 16 where the particle beam 7 is most concentrated. This virtual point is called the isocenter 28. When performing treatment, the affected area of ​​the patient 8 is positioned at this isocenter 28. The isocenter 28 is located, for example, at the horizontal axis 9 of the rotating gantry 5. The position of the isocenter 28 does not change even when the rotating gantry 5 rotates.

[0028] The treatment space 16 located inside the rotating gantry 5 is formed to be integrated with the treatment room 18 located on the front side of the rotating gantry 5. The floor, ceiling, and walls of the treatment room 18 are made up of building-side structures 25 supported by the building's frame 10. The treatment table 17 is supported by these building-side structures 25. In other words, even if the rotating gantry 5 and irradiation port 13 are rotated, the position of the treatment table 17 does not change.

[0029] An inner wall portion 20 serving as a decorative panel is provided inside the rotating gantry 5. This inner wall portion 20 is disc-shaped, and its periphery is supported by a support rail 21 that extends around the entire inner circumference of the rotating gantry 5. This inner wall portion 20 is supported by the support rail 21 so as to be rotatable in the circumferential direction.

[0030] A reverse-rotating synchronous motor 23 is connected to the central part of the inner wall 20, opposite to the treatment space 16. This reverse-rotating synchronous motor 23 is fixed to the inner circumferential surface of the rotating gantry 5 via a support rod 24. When the rotating gantry 5 rotates, the reverse-rotating synchronous motor 23 is driven, and the resulting driving force causes the inner wall 20 to rotate in the opposite direction to the rotation of the rotating gantry 5.

[0031] For example, when the rotating gantry 5 rotates clockwise in a front view, the inner wall section 20 is rotated counterclockwise. At this time, the rotation speed of the rotating gantry 5 and the rotation speed of the inner wall section 20 are controlled to be the same. In other words, the inner wall section 20 appears to remain stationary even when the rotating gantry 5 is rotating.

[0032] On the inner wall portion 20, track rails 22 are fixed to the side facing the treatment space 16. Additionally, track rails 22 are fixed to the building-side structure 25 on the side facing the treatment space 16. The positions of these track rails 22 do not change even when the rotating gantry 5 and irradiation port 13 are rotated. Multiple movable floors 26 are held between these track rails 22. Each movable floor 26 is a rectangular plate-shaped member. Each movable floor 26 is arranged along the inner circumferential surface of the rotating gantry 5, and both ends of each are held by the track rails 22.

[0033] As shown in Figures 2 and 3, the floor, walls, and ceiling of the treatment space 16 are formed by multiple movable floors 26. These movable floors 26 move together with the irradiation port 13 when the rotating gantry 5 and irradiation port 13 are rotated. Regardless of the position the irradiation port 13 is moved to, the movable floors 26 maintain the floor, walls, and ceiling of the treatment space 16.

[0034] The portion of the movable floor 26 that corresponds to the floor is positioned to be flush with the floor of the treatment room 18. When preparing for treatment, the patient 8 and the technician can walk on the floor surface formed by this movable floor 26. Since the movable floor 26 always forms the floor, walls, and ceiling of the treatment space 16, the inner surface of the rotating gantry 5 is concealed from view of the patient 8.

[0035] Next, the radiation measuring instrument support device 30 of the first embodiment will be described. In the particle beam therapy system 1, before the start of treatment, radiation measurements are taken according to the position of the irradiation port 13 in order to confirm the quality of the particle beam 7, such as its energy, beam size, irradiation position accuracy, and dose distribution. For example, the irradiation port 13 is rotated by a predetermined angle in either a clockwise (right) or counterclockwise (left) direction when viewed from the front, and radiation measurements are taken at each position. The radiation measuring instrument support device 30 is used to perform such radiation measurements.

[0036] The radiation detector support device 30 is installed on the top surface of the treatment table 17 or the stand 29. The radiation detector support device 30 is designed to be portable by approximately two workers. For example, the total weight of the radiation detector support device 30 is designed to be within 30 kg.

[0037] The radiation measuring device in the first embodiment consists of at least a radiation measuring device support device 30, a water equivalent phantom 40, and a radiation measuring device 41.

[0038] As shown in Figures 4 and 5, the radiation measuring instrument support device 30 of the first embodiment comprises a cylindrical case 31 and a base 32.

[0039] The cylindrical case 31 is cylindrical in shape. An incident window 33 is opened in a part of the cylindrical surface (front) of the cylindrical case 31, into which radiation (particle beam 7) is incident. In addition, a slit 34 is opened in a part of the cylindrical bottom surface (side) of the cylindrical case 31, for external confirmation of the position of the radiation measuring instrument 41 (Figure 9). Furthermore, multiple reference lines 35 are drawn on the surface of the cylindrical case 31. The cylindrical case 31 is supported on a base 32 with its cylindrical axis facing horizontally.

[0040] The base 32 supports the cylindrical case 31 so that it can rotate in the circumferential direction and fixes the cylindrical case 31 at any rotation angle in the circumferential direction. The upper part of the base 32 has a rounded portion 36 (Figure 9) into which the cylindrical case 31 fits from above and which is curved along a part of the circumference of the cylindrical case 31. In this way, the cylindrical case 31 can be supported in a rotatable state. The base 32 also has a U-shape when viewed from below, with a part of it cut out (Figure 6). The operator can manually rotate the cylindrical case 31 and fix it at any rotation angle.

[0041] The base 32 can be installed on the top surface of the treatment table 17 or the support frame 29 (Figures 2 to 3). Adjusters 37 are provided at each of the four corners of the bottom surface of the base 32. Note that it is sufficient to have at least three adjusters 37 on the bottom surface of the base 32. These adjusters 37 allow for fine adjustment of the height. In this way, the base 32 can be stably placed on the top surface of the treatment table 17 or the support frame 29.

[0042] The support frame 29 is installed on the floor portion of the movable floor 26 when the treatment table 17 is moved out of the treatment space 16. This support frame 29 allows the radiation measuring instrument support device 30 to be installed at any desired height.

[0043] Furthermore, the radiation measuring instrument support device 30 includes an angle display unit that displays the rotation angle of the cylindrical case 31. The angle display unit in the first embodiment consists of a scale 38 provided on the periphery of the cylindrical bottom surface (side surface) of the cylindrical case 31, and a reading unit 39 provided on the base 32 that serves as a reference when reading the scale 38. In this way, the operator can confirm the rotation angle of the cylindrical case 31 by the scale 38. For example, the scale 38 is provided in increments of 0.5 degrees. Its accuracy is within ±0.5 degrees.

[0044] The reading section 39 is, for example, an arrow or a triangle mark. The numbers on the scale 38 located at the position of the reading section 39 represent the rotation angle of the cylindrical case 31.

[0045] The cylindrical case 31 houses the water-equivalent phantom 40 and the radiation detector 41 (Figure 9).

[0046] The radiation measuring instrument 41 of the first embodiment consists of a two-dimensional detector in which a plurality of detection elements are arranged two-dimensionally to form a plate shape. In this way, radiation can be measured over a range that extends two-dimensionally.

[0047] In the first embodiment, a solid, plate-shaped water equivalent phantom 40 (Figure 7) is used as the phantom. The water equivalent phantom 40 is made of, for example, acrylic resin. Multiple water equivalent phantoms 40 are stacked on top of each other, and these water equivalent phantoms 40 and the radiation measuring instrument 41 are arranged side by side and housed inside a cylindrical case 31.

[0048] The thickness of each water-equivalent phantom 40 does not have to be the same; for example, multiple water-equivalent phantoms 40 of different thicknesses can be used. These water-equivalent phantoms 40 are combined to form a phantom of the desired thickness. For example, the total thickness of multiple water-equivalent phantoms 40 can be adjusted within a range of 2 mm to 300 mm. The water-equivalent phantoms 40 should be stacked so that there are no gaps between them.

[0049] Inside the cylindrical case 31, a holding section 44 is formed to hold multiple water-equivalent phantoms 40 and a radiation measuring instrument 41. In this way, by adjusting the number of water-equivalent phantoms 40, the total thickness can be adjusted, and the transmittance of radiation (particle beam 7) can be arbitrarily adjusted. In other words, radiation can be measured under predetermined arbitrary measurement conditions.

[0050] Furthermore, a groove 43 is formed inside the cylindrical case 31, extending from the holding portion 44 toward the entrance window 33. The cable 42 extending from the radiation measuring instrument 41 is led out of the cylindrical case 31 along this groove 43.

[0051] As shown in Figure 7, the radiation measuring instrument support device 30 of the first embodiment includes a frame unit 50 for attaching and detaching the water equivalent phantom 40 and the radiation measuring instrument 41 to the cylindrical case 31 in an integrated state. This makes it easy to attach and detach the water equivalent phantom 40 and the radiation measuring instrument 41 to the cylindrical case 31.

[0052] The frame unit 50 is formed by combining multiple frames to create a rectangular prism shape. For example, the water equivalent phantom 40 and the radiation detector 41 are inserted into the frame unit 50 from above.

[0053] The radiation detector support device 30 of the first embodiment (Figures 2 to 3) is used to position the radiation detector 41 in a location that coincides with the horizontal axis 9 (Figure 1) of the rotating gantry 5. For example, the cylindrical axis of the cylindrical case 31 is positioned to coincide with the horizontal axis 9 of the rotating gantry 5. By rotating the cylindrical case 31, the radiation detector 41 can be directed in any direction while maintaining its alignment with the horizontal axis 9. Note that the radiation detector 41 does not necessarily need to be positioned in a location that coincides with the horizontal axis 9 of the rotating gantry 5; it may be positioned slightly offset from the incident direction of the particle beam 7.

[0054] As shown in Figure 9, the frame unit 50 is fitted into the holding portion 44 of the cylindrical case 31. For example, the cylindrical case 31 consists of a main body 45 and a lid 46 connected by a hinge portion 47. By swinging the lid 46 to open the main body 45, the holding portion 44 is exposed. The worker then fits the frame unit 50 into this holding portion 44 and closes the lid 46 again, thereby housing the water equivalent phantom 40 and the radiation measuring instrument 41 inside the cylindrical case 31.

[0055] The water-equivalent phantom 40 and the radiation detector 41 are positioned within the frame unit 50 towards the entrance window 33 (the direction of radiation incidence). For example, when the side facing the entrance window 33 is considered the front side of the radiation detector 41, a space is provided behind the radiation detector 41. The gap between the rear surface of the water-equivalent phantom 40 at the rearmost position and the front surface of the radiation detector 41 is set to 1 mm or less.

[0056] As shown in Figure 5, the operator can confirm the position of the internal radiation measuring instrument 41 through a slit 34 opened in the cylindrical bottom surface (side) of the cylindrical case 31. In this way, the position of the radiation measuring instrument 41 can be aligned with the isocenter 28 (Figure 1), which is a virtual point where radiation is irradiated.

[0057] For example, when performing radiation measurement, the worker looks through the slit 34 to confirm the position of the radiation measuring instrument 41. The worker then adjusts the position of the treatment table 17 or the stand 29, adjusts the orientation of the base 32, and adjusts the rotation angle of the cylindrical case 31 so that the position of the radiation measuring instrument 41 visible through the slit 34 aligns with the position of the isocenter 28 (Figure 1).

[0058] During this alignment process, a visible light laser is shone into the treatment space 16. For example, lasers are shone from each of the three dimensions (one vertical direction and two horizontal directions). The position where these lasers intersect is indicated as the isocenter 28. The operator aligns the radiation measuring instrument 41 to the position of the isocenter 28 indicated by the lasers. A spirit level may be used to confirm the horizontal position of the radiation measuring instrument support device 30.

[0059] Alternatively, the operator may adjust the position of the treatment table 17 or the stand 29, adjust the orientation of the base 32, and adjust the rotation angle of the cylindrical case 31 so that the multiple reference lines 35 drawn on the surface of the cylindrical case 31 coincide with the laser irradiation position.

[0060] For example, if the irradiation port 13 is directly above the isocenter 28, that is, if the irradiation port 13 is at the 0-degree position, the operator rotates the cylindrical case 31 so that the incident window 33 is directly above, i.e., at a rotation angle of 0 degrees, as shown in Figure 8. Then, the radiation (particle beam 7) is measured at this rotation angle.

[0061] Furthermore, when the rotating gantry 5 is rotated and the irradiation port 13 is at a 90-degree position, the operator rotates the cylindrical case 31 so that it is at a 90-degree rotation angle, as shown in Figure 9. The radiation (particle beam 7) is then measured at this rotation angle. If the rotating gantry 5 is rotated and the irradiation port 13 is at a 270-degree position, the base 32 is rotated 180 degrees horizontally while the cylindrical case 31 is at a 90-degree rotation angle. This causes the entrance window 33 to face the irradiation port 13.

[0062] Furthermore, when the rotating gantry 5 has rotated and the irradiation port 13 is at a 135-degree position, the operator rotates the cylindrical case 31 so that the rotation angle is 135 degrees, as shown in Figure 10. Since the base 32 has a U-shape when viewed from below, even at this rotation angle, the incident window 33 will face the irradiation port 13. Then, radiation (particle beam 7) is measured at this rotation angle.

[0063] Furthermore, when the rotating gantry 5 is rotated and the irradiation port 13 is at a 180-degree position, the operator rotates the cylindrical case 31 so that it is at a 180-degree rotation angle, as shown in Figure 11. The base 32 has a U-shape when viewed from below and is open on the bottom side, so even at this rotation angle, the incident window 33 faces the irradiation port 13. Then, radiation (particle beam 7) is measured at this rotation angle.

[0064] In the radiation measurement method of the first embodiment, first, the operator rotates the rotating gantry 5 to move the irradiation port 13 to any position to be measured. Next, the operator installs the radiation measuring instrument support device 30 inside the rotating gantry 5 of the particle beam therapy system 1. Next, the operator rotates the cylindrical case 31 in accordance with the rotation of the rotating gantry 5 to adjust the orientation of the radiation measuring instrument 41. Then, the radiation (particle beam 7) emitted from the irradiation port 13 of the rotating gantry 5 is measured by the radiation measuring instrument 41. Note that these steps are at least a part of the radiation measurement method, and other steps may also be included in the radiation measurement method.

[0065] (Second Embodiment) Next, a second embodiment will be described with reference to Figure 12. Note that components identical to those shown in the previously described embodiment are denoted by the same reference numerals, and redundant descriptions are omitted.

[0066] In the radiation measuring instrument support device 30A (radiation measuring instrument) of the second embodiment, when the cylindrical case 31 has the side facing the incident window 33 as the front side of the radiation measuring instrument 41, water equivalent phantoms 40 are provided on both the front and rear sides of the radiation measuring instrument 41. In this way, it is possible to evaluate not only the radiation (particle beam 7) incident on the radiation measuring instrument 41 from the front, but also the radiation incident on the radiation measuring instrument 41 from the rear, that is, to include the contribution of backscattering.

[0067] (Third embodiment) Next, a third embodiment will be described using Figure 13. Note that components identical to those shown in the previously described embodiments are denoted by the same reference numerals, and redundant descriptions are omitted.

[0068] In the third embodiment of the radiation measuring instrument support device 30B (radiation measuring instrument), liquid water is used as the phantom. Here, the radiation measuring instrument support device 30B includes a container 51 for holding water, placed alongside the radiation measuring instrument 41. For example, within the frame unit 50, containers 51 filled with water are provided on both the front and back sides of the radiation measuring instrument 41. In this way, since water is used as the phantom, the phantom can be constructed inexpensively. Alternatively, a container 51 filled with water may be provided only on the front side of the radiation measuring instrument 41.

[0069] (Fourth Embodiment) Next, a fourth embodiment will be described using Figure 14. Note that components identical to those shown in the previously described embodiments are denoted by the same reference numerals, and redundant descriptions are omitted.

[0070] The radiation measuring instrument support device 30C (radiation measuring instrument) of the fourth embodiment includes an ion chamber 52 instead of the radiation measuring instrument 41 consisting of the aforementioned two-dimensional detector. The ion chamber 52 is a device having a gas-filled chamber (not shown) and an electrode (not shown) for detecting the ionization of the gas. In this way, a device for measuring radiation can be constructed at low cost. The ion chamber 52 is fixed to the water equivalent phantom 40 at a predetermined position inside the frame unit 50 by a predetermined jig (not shown).

[0071] (Fifth embodiment) Next, the fifth embodiment will be described with reference to Figures 15 to 16. Note that components identical to those shown in the previously described embodiments are denoted by the same reference numerals, and redundant descriptions are omitted.

[0072] As shown in Figure 15, the radiation measuring instrument support device 30D (radiation measuring instrument) of the fifth embodiment includes an angle detection sensor 53, a drive unit 54, and a control computer 55.

[0073] An angle detection sensor 53 is mounted on the base 32 and detects the rotation angle of the cylindrical case 31. The drive unit 54 includes a roller that contacts the outer surface of the cylindrical case 31 and a motor that rotates this roller. This drive unit 54 is controlled by a control computer 55. In this way, the cylindrical case 31 can be automatically rotated to adjust the orientation of the radiation measuring instrument 41.

[0074] The control computer 55 is a computer that has hardware resources such as a CPU, ROM, RAM, and HDD, and in which the CPU executes various programs, software-based information processing is realized using the hardware resources.

[0075] As shown in Figure 16, the control computer 55 includes at least a processing circuit 56, a storage unit 57, and a display 58. The control computer 55 may also include components other than those listed above.

[0076] The processing circuit 56 is, for example, a circuit equipped with a CPU (Central Processing Unit), a dedicated or general-purpose processor. This processor realizes various functions by executing various programs stored in the memory unit 57. The processing circuit 56 may also be composed of hardware such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). Various functions can also be realized by this hardware. Furthermore, the processing circuit 56 can realize various functions by combining software processing by the processor and programs with hardware processing.

[0077] Furthermore, the memory unit 57 of the control computer 55 stores various information necessary for performing radiation measurement. In addition, the display 58 outputs predetermined information. This display 58 displays the rotation angle of the cylindrical case 31.

[0078] The display 58 may be separate from the computer body or integrated into it. Additionally or alternatively, the control computer 55 may control the images displayed on displays 58 of other computers connected via the network.

[0079] The angle display unit of the fifth embodiment consists of an angle detection sensor 53 and a display 58 of a control computer 55. The control computer 55 acquires the rotation angle of the cylindrical case 31 based on the signal output by the angle detection sensor 53. The control computer 55 then performs control to display this rotation angle on the display 58. In this way, the operator can check the rotation angle of the cylindrical case 31 on the display 58.

[0080] Alternatively, the control computer 55 may acquire the rotation angle of the cylindrical case 31 based on the control signal of the drive unit 54, without using the angle detection sensor 53.

[0081] Alternatively, the control computer 55 may control the drive unit 54 to rotate the cylindrical case 31 so that it reaches a preset target rotation angle, based on the rotation angle of the cylindrical case 31 acquired by the angle detection sensor 53.

[0082] The control computer 55 comprises a control unit with highly integrated processors such as an FPGA (Field Programmable Gate Array), GPU (Graphics Processing Unit), CPU (Central Processing Unit), and dedicated chips; storage devices such as ROM (Read Only Memory) and RAM (Random Access Memory); external storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive); a display device such as a display 58; input devices such as a mouse and keyboard; and a communication interface. This control computer 55 can be realized using a hardware configuration that utilizes a standard computer.

[0083] The program to be executed by the control computer 55 is provided pre-installed in ROM or similar media. Alternatively, this program may be provided as an installable or executable file stored on a computer-readable non-temporary storage medium such as a CD-ROM, CD-R, memory card, DVD, or flexible disk (FD).

[0084] Furthermore, the program executed by this control computer 55 may be stored on a computer connected to a network such as the Internet and provided for download via the network. Alternatively, this control computer 55 can be configured by combining separate modules, each independently performing its respective function, which are interconnected via a network or dedicated line.

[0085] Although a radiation measuring instrument support device, a radiation measuring device, and a radiation measuring method are described based on the first to fifth embodiments, a configuration applied in any one embodiment may be applied to another embodiment, or the configurations applied in each embodiment may be combined.

[0086] According to at least one embodiment described above, by providing a base 32 that supports the cylindrical case 31 so that it can rotate in the circumferential direction with the cylindrical axis facing horizontally, and fixes the cylindrical case 31 at any rotation angle in the circumferential direction, the operation of setting up the radiation measuring instrument 41 according to the position of the irradiation port 13 can be easily performed in the particle beam therapy system 1 in which the position of the irradiation port 13 changes.

[0087] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, modifications, and combinations are possible without departing from the spirit of the invention. These embodiments or their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0088] 1…Particle beam therapy system, 5…Rotating gantry, 6…Vacuum duct, 7…Particle beam, 8…Patient, 9…Horizontal axis, 10…Structure, 11…End ring, 12…Rotating drive unit, 13…Irradiation port, 14…Transport unit, 15…Superconducting magnet, 16…Treatment space, 17…Treatment table, 18…Treatment room, 19…Main body, 20…Inner wall, 21…Support rail, 22…Track rail, 23…Reverse rotation synchronous motor, 24…Support rod, 25…Building side structure, 26…Moving floor, 28…Isocenter, 29…Stand, 30(30A,30B,30C,30D)…Broadcasting Radiation measuring instrument support device, 31...Cylindrical case, 32...Base, 33...Induction window, 34...Slit, 35...Reference line, 36...Round section, 37...Adjuster, 38...Scale, 39...Reading section, 40...Water equivalent phantom, 41...Radiation measuring instrument, 42...Cable, 43...Groove section, 44...Holding section, 45...Main body section, 46...Lid section, 47...Hinge section, 50...Frame unit, 51...Container, 52...Ion chamber, 53...Angle detection sensor, 54...Drive unit, 55...Control computer, 56...Processing circuit, 57...Storage unit, 58...Display.

Claims

1. A cylindrical case that houses the phantom and radiation measuring instrument inside, A base that supports the cylindrical case so that it can rotate in the circumferential direction with the cylindrical axis facing horizontally, and fixes the cylindrical case at any rotation angle in the circumferential direction, An angle display unit that displays the rotation angle, Equipped with, Radiation measuring instrument support device.

2. The system includes a frame unit for attaching and detaching the phantom and the radiation measuring instrument to the cylindrical case in an integrated state. The radiation measuring instrument support device according to claim 1.

3. An incident window is opened in a part of the cylindrical surface of the aforementioned cylindrical case, into which radiation is incident. A holding section for holding the phantom and the radiation measuring instrument is formed inside the cylindrical case. When the side facing the entrance window is considered the front side of the radiation measuring instrument, the phantom is provided on both the front and rear sides of the radiation measuring instrument. A radiation measuring instrument support device according to claim 1 or claim 2.

4. A slit is opened in a part of the cylindrical bottom surface of the aforementioned cylindrical case to allow the position of the radiation measuring instrument to be confirmed from the outside. A radiation measuring instrument support device according to claim 1 or claim 2.

5. The angle display unit is, A scale provided on the periphery of the cylindrical base of the aforementioned cylindrical case, A reading unit is provided on the base and serves as a reference when reading the scale, including, A radiation measuring instrument support device according to claim 1 or claim 2.

6. The angle display unit is, A sensor for detecting the rotation angle, A computer display that displays the rotation angle based on the signal output by the sensor, including, A radiation measuring instrument support device according to claim 1 or claim 2.

7. A drive unit for rotating the cylindrical case, A computer that controls the aforementioned drive unit, Equipped with, A radiation measuring instrument support device according to claim 1 or claim 2.

8. The phantom is a solid water equivalent phantom, Multiple plate-shaped water-equivalent phantoms are stacked on top of each other, and a holding section for holding these water-equivalent phantoms and the radiation measuring instrument side by side is formed inside the cylindrical case. A radiation measuring instrument support device according to claim 1 or claim 2.

9. The aforementioned phantom is water, The container for holding the water is provided alongside the aforementioned radiation measuring instrument. A radiation measuring instrument support device according to claim 1 or claim 2.

10. The base can be installed on the upper surface of the frame, and adjusters are provided at least three locations on the bottom surface of the base. A radiation measuring instrument support device according to claim 1 or claim 2.

11. A radiation measuring instrument support device according to claim 1 or claim 2, The radiation measuring instrument comprises a two-dimensional detector in which multiple detection elements are arranged in two dimensions to form a plate shape, Equipped with, Radiation measuring device.

12. A radiation measuring instrument support device according to claim 1 or claim 2, The radiation measuring instrument comprises a gas-filled chamber and an ion chamber having electrodes for detecting the ionization of the gas, Equipped with, Radiation measuring device.

13. A method using the radiation measuring instrument support device described in claim 1 or claim 2, The aforementioned radiation measuring instrument support device is installed inside the rotating gantry of the particle beam therapy system. The cylindrical case is rotated in accordance with the rotation of the rotating gantry to adjust the orientation of the radiation measuring instrument. The radiation emitted from the irradiation port of the rotating gantry is measured by the radiation measuring instrument. Radiation measurement methods.

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