WO2003074126A1 - Tracking type radiation shielding apparatus and radiation irradiation apparatus - Google Patents

Abstract

A tracking type radiation shielding apparatus comprising a shielding block (14) having transmitted radiation for determining a radiation field, a pedestal (50) for placing the shielding block thereon, and a slide means for allowing the pedestal to slide in the moving direction of an irradiation part of the radiation. The slide means comprises an arc-shaped guide part (63) in which a moving locus of the shielding block depicts an arc, and a drive unit (53) for providing a moving force to the pedestal based on the external control signal. Since the shielding block is moved in an arc shape, the radiation passing through block pores is hardly subjected to irregular reflection, the radiation field is prevented from scattering at the irradiation part of the radiation, and the radiation field is not expanded excessively. The irradiation field is allowed to follow the irradiation part without expanding the radiation field.

Description

 Tracking type radiation shielding device and radiation irradiation device

 The present invention relates to a tracking radiation shielding device and a radiation irradiation device using the same. Specifically, when the irradiation area is moving, the shielding block that determines the radiation field is moved in an arc in accordance with the movement of the irradiation area.

With this, it is possible to correctly irradiate the irradiated area without scattering the irradiation field.

In addition, by moving the shielding block in synchronization with breathing, even if the irradiation area moves, the irradiation can be performed without removing the target irradiation area and without scattering the irradiation field. It was done. Conventional technology

 '' In a treatment device using radiation, as shown in Fig. 14, the part to be irradiated with normal radiation (the affected part) 11 is fixed, and the radiation 13 emitted from the radiation source 12 is irradiated here. . At this time, the radiation field is determined by the aperture (radiation passing light) 14a of the shielding block 14 arranged on the radiation path.

 However, if the tumor is in the lungs, the affected area moves with the patient's breathing. That is, as shown in FIG. 15, the affected part 11 moves right and left in this example of drawing in synchronization with respiration. The affected area when moved to the left most is 11a, and the affected area when moved to the far right is 11b.

 On the other hand, since the shielding block 14 is generally fixed, the maximum irradiation field at this time is the hole diameter of the radiation passing light 14a of the shielding block 14 and the thickness of the block. It is decided by such things. Since the hole diameter of the radiation passing light 14a is uniquely determined by the size of the affected area, depending on the depth of respiration, it may deviate from the irradiation field of radiation 13 as shown in Fig. 15. Occur.

Since the depth of respiration and the amount of movement of the affected area 11 are almost proportional, if the irradiation field moves away from the affected area, as in the example in Fig. 15, even normal cells (healthy tissue) are radiated. It is irradiating the line. It is, of course, necessary to ensure that normal cells are not exposed to radiation as much as possible. The radiation treatment plan itself must be reviewed.

 To solve such a problem, the irradiation position of the radiation 13 may be moved in the moving direction (horizontal direction) of the diseased part 11 in synchronization with respiration. Techniques from this point of view have already been presented (for example, Japanese Patent Application Laid-Open No. 2000-27641 (Japanese Patent Application No. 91059/2000)). .

 Briefly explaining the contents disclosed in this publication, as shown in Fig. 16Α, when the affected part 11 moves to the left, the shielding block 14 is moved in a predetermined amount in the direction of arrow a in synchronization with the movement. By only moving, the radiation field of radiation 13 shifts to the left following the affected part 11.

 Similarly, as shown in FIG. 16B, when the affected part 11 moves to the right, the shielding block 14 is moved by a predetermined amount in the direction of the arrow b in synchronization with the movement, thereby following the affected part 11. The irradiation field of radiation 13 shifts to the right.

 By moving the shielding block 14 itself so as to follow the movement of the diseased part 11 in this way, the irradiation field 16 does not come off the diseased part, and there is no risk that even normal cells will be irradiated with radiation. It will also be possible to deliver a prescribed amount of radiation to the affected area.

 FIG. 17 is a simple conceptual diagram for realizing the movement of the shielding block. The patient 22 is lying on his / her back on the gantry 2 1. A radiation generator 24 is located right above the pedestal 21, from which radiation 13 is irradiated. Both the emission position and the direction of the radiation source 12 are fixed.

On this radiation path, a shielding block 14 is attached via a sliding means 26. The occlusion block 14 moves in the direction of the arrow p based on the output of detecting the patient's breathing. The arrow p direction is a direction parallel to the surface of the gantry 21. The shielding block 14 is a cube as shown in FIG. 18, and a radiation passage hole 14a is formed in the center thereof. The radiation passage hole 14a has a hole diameter of about 5 mm to 30 mm depending on the size of the affected part 11. Depending on the radiation dose, the use of lead blocks In this case, the thickness H is usually 100 mm or more. In the case of 100 mm, a radiation dose of about 10 Gray (Gy) can be shielded.

 By the way, even if the shielding block 14 is moved in accordance with the respiration of the patient 22 in this way, since the radiation direction of the radiation source 12 is fixed, the manner of moving the shielding block 14 is the same as in the prior art. In the same horizontal direction as the gantry 21, it is not always possible to irradiate the affected part with an appropriate irradiation field. This will be described with reference to FIG.

 FIG. 19 is a conceptual diagram showing an irradiation locus of the radiation 13 when the shielding block 14 is moved to the maximum in the direction of the arrow b. Due to the relatively large thickness H of the shielding block 14 and the large size of the affected area 11 and the need for the radiation passage hole 14a to increase accordingly, (Radiation flux) No longer completely orthogonal to 13.

 As a result, as shown in FIG. 19, a part of the radiation 13 hits the inner wall of the radiation passage hole 14a, so that the radiation 13 is diffused and diffused to the irradiation field 16 or more. That is, the irradiation field 16 at the affected part 11 is scattered and expanded like the irradiation field 16 ′.

 Enlargement of the irradiation field 16 is not preferable. This is because even normal cells are exposed to radiation. Of course, it is difficult to irradiate the affected area with the prescribed radiation dose, which makes planning radiation treatment difficult. When the radiation dose is required to be 1 OGy or more as described above, the shielding block 14 itself has to have a thickness H larger than that in the above-described example, so that the scattering of radiation is further increased.

 Therefore, the present invention solves such a conventional problem. In particular, when the shielding block is moved in accordance with an external control signal, the shielding block is moved in an arc shape, thereby causing irregular reflection of radiation at the shielding block. The present invention proposes a tracking type radiation shielding device and a radiation irradiating device that prevent the irradiation field from scattering. Disclosure of the invention

In order to solve the above-mentioned problems, a tracking-type radiation shielding apparatus according to the present invention described in claim 1 is a mobile radiation shielding apparatus provided on a radiation irradiation path, A shielding block having radiation transmitted light for determining the irradiation field of the radiation, a pedestal on which the shielding block is mounted,

 In order to slide the pedestal in the direction of movement of the radiation-irradiated part, the slide means includes an arc-shaped guide portion so that the movement locus of the shielding block draws an arc shape, and the pedestal based on an external control signal. A driving unit for applying a moving force.

 In the radiation irradiating apparatus according to the present invention described in claim 6, a tracking type radiation shielding apparatus which is provided immediately below the radiation source and is configured to be movable, and detects respiration of a patient placed on a gantry And a movement control device that moves the radiation shielding device in synchronization with the output of the respiration detection device.

 The tracking type radiation shielding device has a shielding block for determining an irradiation field of the radiation,

 The shielding block is provided immediately below the radiation source, and moves in an arc in synchronization with the patient's breathing.

 In the present invention, the shielding block is moved in an arc shape. At this time, scattering of the irradiation field at the radiation irradiation site is prevented by selecting the movement locus so that the radiation passing through the radiation passage hole is not irregularly reflected. This prevents the irradiation field from becoming larger.

 In addition, by linking the shielding block with the movement of respiration, the irradiation field can be moved according to the movement of the affected area. Even in such a case, the shielding block is moved in an arc shape so that the radiation passing through the radiation passage hole is not irregularly reflected. This makes it possible to achieve ideal radiation therapy. Strictly speaking, the size of the arc differs depending on the size and thickness of the shielding block, but the largest contributor is the mounting position of the shielding block. Usually, it is placed at a position about half the distance from the affected area. So that scattering does not occur at the mounting position

 'The radius of the trajectory is selected. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a conceptual diagram of a waist showing an embodiment of a radiation irradiation apparatus according to the present invention. FIG. 2 is a plan layout diagram.

FIG. 3 is a use state diagram of the tracking radiation shielding device according to the present invention. FIG. 4 is a central longitudinal sectional view of the tracking radiation shielding apparatus.

FIG. 5 is a partial longitudinal sectional view of FIG.

FIG. 6 is a diagram illustrating a moving state of the side plate.

FIG. 7 is a system diagram illustrating an example of a control unit of the radiotherapy apparatus.

8A and 8B are waveform diagrams showing the amplitude relationship between respiration and occlusion blocks. FIG. 9 is a diagram showing a relationship between a shielding block and an affected part for explaining the principle of the present invention.

FIG. 10 is a diagram showing a relationship with the shielding block when the affected part moves to the left. FIG. 11 is a diagram illustrating a relationship with the shielding block when the affected part moves to the right. FIG. 12 is a diagram showing the relationship between the shielding block and the radiation flux.

FIG. 13 is a perspective view of a shielding block that can be used in the present invention.

FIG. 14 is a diagram showing a relationship with the shielding block when the irradiation site is fixed.

FIG. 15 is a diagram showing the relationship between the irradiation area and the irradiation field when the irradiation area moves. FIG. 16A and FIG. 16B are diagrams showing a relationship between the irradiation part and the movement of the irradiation part when the irradiation part moves right and left.

FIG. 17 is a conceptual diagram of the radiation therapy apparatus.

FIG. 18 is a perspective view of the irradiation site.

FIG. 19 is a diagram showing the relationship of the radiation flux in the radiation passage hole when the irradiation site is moved horizontally. BEST MODE FOR CARRYING OUT THE INVENTION

 Next, an embodiment of a tracking radiation shielding apparatus and a radiation irradiation apparatus according to the present invention will be described in detail with reference to the drawings.

FIG. 1 et seq. Show an embodiment of a radiation irradiation device according to the present invention equipped with a tracking type radiation shielding device according to the present invention. To facilitate understanding of the present invention, refer to FIG. 9 et seq. Let us start with the principle description of the present invention. According to the present invention, the radiation shielding device is moved in synchronization with the movement of the radiation irradiation site. In particular, in the present invention, the movement is not a simple movement in the horizontal direction but an arc-like movement.

 FIG. 9 is a conceptual diagram for explaining this, in which the shielding block 14 is moved so that a circle having a radius R centered on the radiation source 12 is used as a scanning trajectory. In other words, when the radiation irradiation site (affected part) 11 moves to the left (arrow c), the shielding block 14 moves along the radius R in synchronization with the movement of the radiation irradiation site 11 as shown in FIG. move. Similarly, when the irradiation area 11 moves to the right (arrow d), the shielding block 14 moves along the radius R in synchronization with the movement of the irradiation area 11 as shown in FIG. .

 In this way, even if the irradiation site moves to the position of 11a or 11b, the irradiation field of the radiation 13 does not deviate from the irradiation site 11. In addition, since the shielding block 14 is slightly inclined, it faces the radiation irradiating part 11 in the direction of the radiation irradiating part 11, and the radiation blocking hole 14 of the shielding block 14 is formed. The radiation flux is almost parallel.

 As a result, as shown in FIG. 12, when the radiation flux passes through the radiation passage hole 14a, the probability of irregular reflection on the inner wall thereof is extremely reduced, and the scattering of the irradiation field 16 can be suppressed. Therefore, since the irradiation field 16 does not greatly exceed the irradiation field designed in advance, the radiation irradiation site 11 can be irradiated with a predetermined radiation dose. Therefore, even if the irradiated area 11 is a tumor such as a lung cancer, and the irradiated area 11 moves in the negative direction with respiration, it synchronizes with the movement of the affected area. By adopting a tracking method in which the shielding block 14 is moved in an arc shape, it is possible to always irradiate the affected area with radiation, and the irradiation field 16 is not greatly expanded. FIG. 13 shows an example of a shielding block 14 that can be used in the present invention. In this example, a resin molded from a special resin capable of absorbing radiation is used as described later. In this case, the thickness can be made thinner than the lead block.

Next, the case where the tracking type radiation shielding apparatus according to the present invention and the radiation irradiation apparatus including the same are applied to a radiation therapy apparatus will be described with reference to FIG. I do.

 FIG. 1 shows an embodiment of the radiation therapy apparatus 30. The radiotherapy device 30 includes a lentogen device 3OA and a radiotherapy unit 30B. The tracking radiation shielding device 20 described above is mounted on both the X-ray device 3OA and the radiotherapy unit 30B, and the tracking radiation shielding devices 20 are controlled so as to move synchronously. Therefore, the same configuration is used for the X-ray apparatus 3OA and the radiotherapy unit 30B. The difference is in the radiation dose emitted from each. This is because the X-ray apparatus 30A is used to obtain a projection image of the affected part 11 with a reduced radiation dose.

 In using the radiotherapy apparatus 30, first, the movement of the affected area 11 is imaged by the X-ray apparatus 3OA, and the respiration movement of the patient (therapist) 22 is detected. The purpose of detecting the movement of respiration is to move the radiation shielding device 20 in synchronization with the movement of the diseased part 11, and to image the movement of the diseased part 11, how much the diseased part moves in synchronization with respiration The purpose of this study is to examine the relationship between the radiation and the respiration, and to check at what amplitude the radiation shielding device, specifically the shielding block 14, should be moved in conjunction with the respiration.

 For example, when the amplitude of respiration is represented by a curve La as shown in FIG. 8A, the movement of the affected part 11 of a certain patient also moves in synchronization with it, so when the amount of movement of the affected part 11 is small, the chain line The motion characteristics are as shown in Lb. However, some patients may move significantly more than the proportion of the respiratory amplitude. For example, another patient may have the movement shown in Figure 8B. In this case, the amount of movement of the shielding block 14 must be adjusted according to the amount of movement of the affected part 11 of the patient.

 The actual radiotherapy section 30B is controlled based on the amplitude of the respiration obtained by the X-ray apparatus 30A and the data corresponding to the amount of movement of the affected area 11. That is, the shielding block 14 mounted on the radiotherapy unit 30B moves in conjunction with the patient's breathing. At this time, the amount of movement is adjusted to suit the patient.

The X-ray apparatus 3 OA will be described first. The X-ray apparatus 3 OA has a substantially U-shaped apparatus main body 31, and a radiation source 33 is provided at a predetermined position of a head 32 of the apparatus main body 31. X-rays) 13 are irradiated. The concave portion 32 a provided on the lower surface of the head 32 is formed so as to include the radiation source 33, and at an appropriate position on the radiation path of the radiation 13, in this example, the concave portion 32 a is closed. At the position, the above-mentioned tracking radiation shielding device 20 is detachably attached. An embodiment of the tracking type radiation shielding device 20 will be described later. A rotatable base 34 is placed directly below the radiation source 33, where the patient 22 is laid on his / her back. Thus, the affected area 11 of the patient 22 faces the radiation source 33 via the tracking-type radiation shielding device 20.

 An X-ray force measurment 36 is fixed below the gantry 34, and an X-ray image around the affected area 11 is captured. Based on this imaging output, the amount of movement of the affected part 11 is detected as described above. The X-ray camera 36 is fixed to the apparatus main body 31 side.

 In connection with the gantry 34, a length measuring element 38 is attached at a predetermined position on the upper surface side of the gantry 34 at a predetermined distance from the gantry 34. In this example, a laser displacement meter is used as the length measuring element 38, and the laser displacement meter 38 is connected to the indicator rod 40 via the elevating means 39. The indicator rod 40 is fixed to the gantry 34.

 The position of the laser displacement meter 38 is adjusted by the lifting / lowering means 38 so as to be at a predetermined distance (for example, 100 to 200 mm) from the gantry 34. At this adjustment position, the displacement of the body surface due to the respiration of the patient 22 is measured. The result is the curve A in FIG. 8A. In the case of abdominal breathing, when you inhale, the abdomen expands and becomes convex, and when you exhale, the abdomen becomes concave and concave, so a signal (sinusoidal respiratory signal) that matches this patient's breathing is called. Obtained as absorption characteristics. The respiratory signal controls the shielding block 14 of the tracking radiation shielding device 20. For example, control is performed such that the shielding block 14 is advanced, for example, so as to follow the diseased part 11 when inhaling, and the shielding block 14 is retracted when exhaling.

 The gantry 34 is configured to be freely rotatable and advanceable and retractable as described above. After the respiratory signal of the patient 22 is detected by the X-ray apparatus 3 OA and the amount of movement of the affected part 11 is detected, the gantry 34 is Is rotated 90 ° as also shown in FIG.

By rotating the gantry 34 by 90 ° and further moving it back and forth, the radiotherapy unit 30B is located immediately above the gantry adjustment position as shown in FIG. The radiotherapy section 30B is configured in the same manner as the X-ray apparatus 30A as described above. The detailed explanation is omitted.

 As shown in FIG. 1, the tracking type radiation shielding device 20 is detachably attached to the radiotherapy unit 30B, so that the relative positional relationship is exactly the same as that of the X-ray device 30A. Therefore, radiation therapy can be started immediately by simply moving the gantry 34. In accordance with the radiation treatment plan, the affected part 11 is irradiated with radiation at a predetermined radiation dose and irradiation time, and radiation treatment of the affected part is performed.

 As shown in FIGS. 3 and 4, an embodiment of the tracking type radiation shielding apparatus 20 includes a pedestal 50 on which the shielding block 14 is mounted, and a guide portion for sliding the pedestal 50. 6 and a driving unit 53 for sliding the pedestal 50. Further, the pedestal 50, the driving part 53 and the guide part 63 are fixed so that the pedestal 50 can be moved in the housing 46 as shown in FIG. The box-shaped housing 46 is connected to a top plate 46 A, which also functions as a guide plate, and four side plates 46 C, which are provided so that a bottom plate 46 B surrounds the periphery. It is fixed to the top plate 46A.

 On the other hand, a pair of guide blocks 45 A and 45 B having guide grooves are opposed to the lower surface of the head 32 and the left and right end surfaces of the recess 32 a such that the respective guide grooves face each other. It is attached and fixed in the state where it was set. The left and right end surfaces of the top plate 46A slightly protrude from the left and right side surfaces as shown in FIG. 4, and the protrusions are fitted along the guide grooves. After fitting to the end, the case 46 is fixed to the head 32 using screws or the like. If a hook or the like is used, the housing 46 can be fixed to the head 32 without screws. Therefore, the tracking radiation shielding device 20 is detachable. The reason why the tracking type radiation shielding device 20 is easily replaceable is that the tracking type radiation shielding device 20 can be easily replaced.

The drive section 53 described above has a drive motor 54 as shown in FIG. As the drive motor 54, an AC drive motor that has good tracking performance to external control signals and is easy to control is used. The drive motor 54 is fixed to the bottom plate 46B as shown in FIG. A rack 55 is connected to the drive motor 54, and a pinion gear 56 is screwed into the rack 55, and the circular motion of the rack 55 is converted into a linear motion by the pinion gear 56. The other end of the rack 55 is fixed to a fixing plate 56. Fixing plate 5 6 is bottom Fixed to plate 4 6 B.

 As shown in FIGS. 4 and 5, an auxiliary block 56a for height adjustment is attached to the pinion gear 56, and a transmission shaft 57 is supported by the auxiliary block 56a. On the other hand, a side plate 51 is provided on the lower surface of the pedestal 50 and facing the transmission shaft 57, and a long hole 51a provided in the side plate 51 (see FIGS. 5 and 6) The relationship between the side plate 51 and the pinion gear 56 is selected so that the transmission shaft 57 is engaged with the transmission shaft 57. Position sensors 59 a and 59 b are provided at predetermined positions along the rack 55 with the pinion gear 56 interposed therebetween, so that the movement amount of the pinion gear 56 can be regulated.

 A guide 63 is provided on the right side of the pedestal 50. The guide portion 63 is an arcuate guide rail 64 having a predetermined arc shape as shown in FIG. 3, and in this example, as shown in FIG. 4 and FIG. This is the case where a V-groove sandwiching guide rail with a and 64 formed is used. A steel material is used as the guide rail 64, and the sliding pieces 65 are fitted so as to sandwich these V grooves 64a and 64b. Therefore, the sliding piece 65 is provided with a pair of ridges 65a and 65b that engage with the V-grooves 64a and 64b, thereby making the sliding piece 65 less rugged. It has been made possible to slide. To achieve smoother sliding, grease or the like may be applied to the V-grooves 64a and 64b.

 The guide rail 64 is fixed to a fixing plate 67 along the guide rail 64 with screws or the like. The fixing plate 67 itself is firmly fixed to the bottom plate 46B. The sliding piece 65 itself is fixed to a side plate 52 fixed to the pedestal 50.

 The guide 63 is provided with a position sensor 70 for detecting the reference point when the slide piece 66 is located at the center position. For this purpose, the sliding piece 66 is provided with a detector 70a of the position sensor and a detection body 70b for detecting the detector 70a. As the detection body 70b, a transmission type is used. By using this position sensor 70, the initial position of the pedestal 50 can be fixed at the center position.

As the guide rail 64 itself, a rail curved in an arc shape as described above is used. The radius of curvature R depends on the position between the radiation source 33 and the gantry 34. It differs depending on whether the radiation shielding device 20 is arranged. For example, when the distance from the radiation source 33 to the gantry 34 is 100 cm and the distance from the radiation source 33 to the tracking radiation shielding device 20 is 50 cm, which is half of that, the curvature is The radius R is 50 cm, ie the radiation source 33 can be chosen as the center of the radius of curvature. 3 to 5, the through hole 50a provided in the pedestal 50 has a sufficiently larger diameter than the radiation passage hole 14a. And it is a long hole configuration along the moving direction of the shielding block 14. The top plate 46A is provided with a U-shaped notch that does not cause injury when the shielding block 14 is placed. The bottom plate 46B is also provided with a through hole 46b so as not to hinder the passage of radiation.

 In the above configuration, if the drive motor 54 is driven to rotate the rack 55 in a predetermined direction, the rotational force is transmitted to the pinion gear 55, so that the rotational motion is converted to a linear motion. Therefore, the pedestal 50 is given a moving force in the direction of the arrow p shown in FIG. Since the pedestal 50 is only fixed to the guide rail 64, when a force is applied to the pedestal 50, the pedestal 50 moves along the guide rail 64. Since the guide rails 64 are slightly curved, the pedestal 50 moves while slightly tilting up along the guide rails 64 as shown in FIG. Accordingly, if a shielding block 14 as shown in FIG. 6 is placed on the upper surface of the lever base 50, the shielding block 14 also moves while slightly tilting. Thus, the inclination of the radiation passage hole 14a of the shielding block 14 can be adjusted so as to be substantially parallel to the radiation flux. That is, the movement of the shielding block 14 as shown in FIGS. 10 and 11 can be realized.

 FIG. 6 shows the relationship between the side plate 51 and the transmission shaft 57 when the pedestal 50 has moved from the reference point (center position) to the maximum left and right movement points. Since the side plate 51 slightly moves up and down in this way, the shaft engaging hole 51a is formed as an elongated hole.

As a practical matter, the size of the affected area 11 varies from about 5 mm to about 30 mm for large ones, and depends on the size of the affected area 11, that is, the size of the irradiation field 16. Thus, the radiation passage hole 14a of the shielding block 14 is selected. The amount of movement of the shielding block 14 is determined by the irradiation field 16. For example, 100 cm up to the affected area 11 and the tracking radiation shielding device 20 is installed at half the position. When the affected area 11 has a diameter of 30 mm, the diameter of the radiation passage hole 14a of the shielding block 14 is about 15 mm, and the displacement of the shielding block 14 from the reference point is It may be set to ± 7.5 mm.

 Normally, when a lead block is used as the shielding block 14 as in the past, its thickness H is about 1 O Gy and about 10 O mm in thickness to absorb radiation. On the other hand, if a block made of a special resin that can absorb radiation is used, its thickness can be reduced to about 2/3. According to experiments, it can be reduced to about 70 mm at 10 Gy. The smaller the thickness H, the less the diffuse reflection of the radiation in the passage hole 14a, so that the scattering of the irradiation field 16 can be more effectively prevented.

 FIG. 7 shows an embodiment of the movement control device 80 provided in the radiotherapy device 30. The movement control device 80 is controlled by a computer, and includes a control unit 82 having a CPU as a central processing unit. All controls are performed via the control unit 82.

 First, the X-ray image of the diseased part 11 taken by the X-ray force camera 36 is displayed on the X-ray monitor 83 via the control part 82, and the X-ray monitor 73 shows how much the diseased part 11 moves. Therefore, the movement can be grasped. The respiratory signal detected by the laser displacement meter 38 is supplied to a respiratory monitor 75 via a control unit 82, and respiratory monitoring in the abdomen is monitored. Then, based on the amplitude of the respiration on the respiration monitor 85 and the movement of the diseased part 11, the control magnification of the extent to which the shielding block 14 should be moved is set.

 The motor control signal having the set control magnification is supplied to the AC drive motor 54 through the motor driver 87 of the X-ray apparatus 3OA, and the rotation control in the forward and reverse directions is performed according to the motor control signal. Done. The AC drive motor 54 has excellent control characteristics, and can realize forward / reverse rotation control following the motor control signal. The motor control signal is further supplied to a motor driver 87 provided in the radiotherapy unit 30B, and the movement of the shielding block 14 is controlled in synchronization with the movement of the shielding block 14 of the lentogen device 3OA. You.

By performing such synchronous control (tracking control), the irradiation position when radiation is actually irradiated can be monitored in advance with the X-ray device 3OA. You.

 Regulation of the amount of movement of the shielding block 14, that is, control of the AC drive mode 54, is performed by sensor outputs from the detection sensors 69 a and 69 b. The output of the position sensor 70 is used to return the shielding block 14 to the initial position (the initial position of the pedestal 50). This is because the initial position of the base 50 is when the detector 70a crosses the detection body 70b.

 In addition, in this example, the lifting / lowering means 39 is controlled based on a control signal from the control unit 32 in order to adjust the position of the laser displacement meter 38. Position control, etc., can be performed from the remote control 84.

 In the above-described embodiment, the lung is exemplified as the moving part of the radiation irradiation. However, since the lung may be slightly moved if it is built-in, the irradiation may be performed in the evening. The present invention can also be applied to the present invention.

 As described above, in the tracking radiation shielding apparatus according to the present invention, the shielding block is moved so as to follow the movement of the radiation irradiation part, and the movement locus of the shielding block 14 is configured to be an arc. Things. In the radiation irradiating apparatus according to the present invention, the radiation irradiating apparatus is configured by using a tracking type radiation shielding apparatus. Industrial applicability

 According to the present invention, since the radiation irradiation field can be moved in synchronization with the movement of the radiation irradiation part, even if the radiation irradiation part moves, the radiation can be irradiated without coming off the irradiation part. Therefore, when the irradiation site is an affected area, radiation treatment can be realized without damaging normal tissues.

In addition, since the movement trajectory of the shielding block is arc-shaped, the position and inclination of the shielding block can be changed little by little as the radiation irradiation part moves. Thus, scattering of the radiation flux in the shielding block can be prevented. As a result, the scattering of the irradiation field can be suppressed, so that there is no possibility that the radiation is irradiated to the normal part. Along with this, the affected area can be irradiated with an appropriate radiation dose, which has the effect that the affected area can be treated with a dose almost as planned for radiation therapy. Therefore, the present invention is extremely suitable for application to a radiotherapy device or the like.

Claims

The scope of the claims 1A movable radiation shielding device provided on a radiation irradiation path, a shielding block having radiation transmitted light for determining the radiation irradiation field, and a pedestal on which the shielding block is mounted,  In order to slide this pedestal in the direction of movement of the radiation-irradiated part, a guide section that forms an arc so that the trajectory of the shielding block draws an arc, and a moving force is applied to the pedestal based on an external control signal A tracking type radiation shielding device, comprising: (2) The guide section has selected a movement locus thereof so as to prevent the radiation passing through the radiation passage hole from being irregularly reflected, thereby preventing the irradiation field from being scattered at the irradiation area. The tracking type radiation shielding device according to range 1. 3. The tracking type radiation shielding apparatus according to claim 1, wherein the guide section uses a V-groove sandwiching type guide rail. 4. The tracking type radiation shielding device according to claim 1, wherein the driving unit uses an AC motor. 5. The tracking type radiation shielding apparatus according to claim 1, wherein the external control signal is a signal related to respiration of a patient. (6) A tracking type radiation shielding device which is provided directly below the radiation source and is configured to be movable, respiration detection means for detecting the respiration of the patient placed on the gantry, and synchronized with the output of the respiration detection means And a movement control device for moving the radiation shielding device. The tracking type radiation shielding device has a shielding block for determining an irradiation field of the radiation, The radiation irradiating apparatus, wherein the shielding block is provided immediately below the radiation source, and moves in an arc in synchronization with respiration of the patient. 7 The tracking type radiation shielding device includes a pedestal on which the shielding block is placed,  In order to slide the pedestal in the direction of movement of the radiation-irradiated portion, the sliding means includes a guide portion having an arc shape so that the movement locus of the shielding block draws an arc shape, and a drive for applying a moving force to the pedestal. Part and  7. The radiation irradiation apparatus according to claim 6, wherein the driving unit is controlled by an external control signal from the movement control unit. 8. The radiation irradiation device according to claim 6, wherein the guide portion prevents scattering of the irradiation field by selecting a movement locus of the radiation so as to prevent the radiation passing through the radiation passage site from being irregularly reflected. apparatus. 9. The radiation irradiation apparatus according to claim 6, wherein the guide section uses a V-groove sandwiching type guide rail. 10. The radiation irradiation apparatus according to claim 6, wherein an AC motor is used as the driving unit.