JP2001066397A - Radiation-treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an accurate irradiation field by equipping a member for guiding and retaining the track of a constriction block in a track groove being provided opposingly on the proximity surface of the constriction block that orthogonally crosses the direction of radiation and approaches so that it can travel. SOLUTION: The irradiation field of radiation from a radiation source S is determined by constriction bodies 10A and 10B and constriction bodies 11A and 11B. The constriction bodies 10A, 10B, 11A, and 11B are composed by the combination of a plurality of constriction blocks 12 nearly in a plate shape. A ball bearing is arranged on the opposing surfaces of the constriction blocks 12, the opposing positions of the adjacent constriction blocks 12 are supported by the ball beating slidably. The constriction blocks 12 are driven by a drive motor 23 with an encoder 24 for detecting a position individually.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiotherapy apparatus in which a radiation irradiation range can be arbitrarily changed by a stop block, and more particularly to a support structure for a multi-segment stop block.

[0002]

2. Description of the Related Art A schematic configuration of a conventional radiotherapy apparatus is shown in FIG.

[0003] The configuration of a radiation therapy apparatus that has been conventionally used includes a fixed gantry 1, a rotatable gantry 2 supported on the fixed gantry 1, an irradiation head 3 incorporated at the tip of the gantry 2, and an irradiation head 3. Squeezing device 4 to be incorporated, treatment table 5
And so on as the main components.

Since the rotary gantry 2 and the irradiation head 3 rotate around rotation axes orthogonal to each other, in this rotating state, the direction in which gravity acts on the operating direction of an aperture block (not shown) included in the aperture device 4. Changes in every direction. Therefore, a mechanism for supporting the aperture block is required so that the aperture block can operate even when the direction in which gravity acts changes.

A diaphragm device consisting of a single block forming a rectangular irradiation field can be easily implemented because only two pairs of vertical and horizontal diaphragm blocks need to be supported, but an irregularly shaped irradiation field (irregular irradiation field) can be formed. In the multi-segment aperture apparatus, the aperture blocks divided into a large number of pieces operate independently. And, the larger the number of divisions of the aperture block, the narrower the width of the aperture block alone, and the gap between the aperture blocks is as small as possible, for example, 0.05 to 5 to prevent radiation leakage from between adjacent aperture blocks. 0.1mm
Must be about.

As the aperture shape of this type of conventional multi-segment aperture apparatus, as shown in FIGS.
A and 110B are provided so as to move in the X direction on a concentric circle including the radiation source S as a center and approach and separate from each other. Further, in the Y direction, a pair of aperture bodies 111
Similarly, A and 111B are provided so as to move in the Y direction on a concentric circle including the radiation source S as a center and approach and separate from each other. Apertures 110A, 110B, 111A, 1
11B is realized by a combination of a substantially plate-shaped aperture block 112.

The aperture blocks 112 are provided on adjacent surfaces with groove rails that fit together, and the fitting of the groove rails restricts the movement of each other to perform a predetermined movement. As shown in FIG. 5, for example, a convex projection is fitted into the concave rail and the groove rail is guided in the groove rail. These aperture blocks 112 are driven by a drive motor 113.

[0008] As shown in FIG.
An aperture having a predetermined shape can be formed around the radiation source S by individually moving the plurality of aperture blocks 112 of the multi-aperture aperture bodies 111A and 111B to a predetermined position and combining them. Drive motor 1
13 are arranged for driving the respective aperture blocks 112, the individual aperture blocks 112 are moved, and an opening having a predetermined shape is formed by a combination of the individual movements.

FIG. 7 shows the movement trajectories of the diaphragms 111A and 111B. For example, the diaphragms 111A and 111B move in a circular arc around the radiation source S in the Y direction. For radiation emission from the radiation source S, aperture bodies 111A and 111B having linear ends parallel to the trajectory of the radiation are used.

FIG. 8 shows an aperture U formed by the aperture bodies 111A and 111B and an irradiation field T obtained by the aperture U. Since the end of the aperture block 112 appears stepwise, the irradiation field T does not have a strictly arcuate end as shown in FIG. By dividing the aperture block 112 into more parts,
Obtains a smooth end shape.

As a load supporting method for operating the aperture block 112 as described above, there is a method in which each aperture block is supported by a grooved roller as described in Japanese Patent Laid-Open Publication No. 210012/1994. . For example, FIG. 9 shows a load support mechanism applied to a multi-segment diaphragm device in a radiation therapy apparatus described in Japanese Patent Application Laid-Open No. 210012/1994. In this structure, a rectangular step D1 is provided on the outer periphery of each of the aperture blocks 31, and the rollers 32 (one at the inner peripheral portion and two at the outer peripheral portion of the aperture block 31) are fitted with the steps to restrict the aperture. It supports the load of the block 31 (aperture block group 30). The aperture block group 30 is supported by bearings 33 via these rollers 32.

Further, for example, a conventional multi-leaf collimator has a sectional structure shown in FIGS. As can be seen from this sectional view, each aperture block (leaf) 41 is supported at the edge by a set of three grooved rollers 42.

Of these rollers 42, a pair of rollers 42
Are arranged apart from each other along the inner edge of the aperture block 41, and the other roller 42 is arranged in direct contact with the outer edge of the aperture 41, and can be directly displaced irrespective of the posture of the head. Is to be held.

[0014]

However, the prior art has the following problems.

In the method of supporting the drawing block with the grooved roller, rolling contact occurs in the radial direction, but sliding friction occurs in the thrust direction, and there is also a problem of wear.

Further, since the aperture block is made of a heavy metal such as tungsten, a large shaft diameter is required to support the load of the aperture block group with one support shaft at each location. Since the size of the fitted roller is large, the squeezing device is extended in the direction of the patient, and the feeling of pressure received by the patient is increased.

It is also difficult to ensure that there is sufficient space between the radiation source and the patient as needed to accommodate standard auxiliary equipment, such as block trays.

Further, when the squeezing block is subdivided, three or more grooved rollers must be arranged in each squeezing block, so that a large number of rollers are arranged.
The drawback is that it takes up space and is difficult to assemble and adjust.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to hold an aperture block smoothly and reliably while preventing an increase in the size of an aperture device, and to provide a highly accurate irradiation field. Is to provide a multi-segment stop device which can obtain the following.

[0020]

According to a first aspect of the present invention, there is provided a radiotherapy apparatus having a multi-segment stop mechanism for arbitrarily changing a radiation irradiation range. A diaphragm block composed of a plurality of plate-like bodies provided movably and in proximity to each other in a direction substantially orthogonal to the radiation direction, and a diaphragm block provided in opposition to a close surface of each of the diaphragm blocks. A radiotherapy apparatus is provided as a solution means, comprising: a track groove for guiding a track; and a sliding support member in the track groove for guiding and holding the tracks of the plurality of aperture blocks to each other.

Further, in the present invention described in claim 2,
The radiotherapy apparatus according to claim 1, wherein the sliding support member is constituted by a bearing member including a plurality of sliding members having a spherical shape or a substantially cylindrical shape.

Further, in the present invention according to claim 3,
3. The radiation according to claim 2, wherein the bearing member is positioned and supported at a predetermined position in the raceway groove by the positioning means comprising an elastic support member disposed in the raceway groove. The treatment device is the solution.

Further, in the present invention described in claim 4,
The positioning means has a pair of end sealing members mounted opposite to both ends of the elastic support means, and guides the retraction direction of the elastic support member to seal the bearing member. The radiotherapy apparatus according to claim 3 is a solution.

The solution according to the present invention having the above-described structure enables the diaphragm blocks to be favorably moved without increasing the size of the diaphragm device, and at the same time, secure holding between the diaphragm blocks. , The gap between the aperture blocks can be held at a predetermined position without adjusting the gap, ensuring a low cost and good reliability with a simple configuration, increasing the number of aperture block divisions, and achieving high-precision segmentation. It is an object of the present invention to provide a radiation therapy apparatus including a diaphragm device capable of coping with a diaphragm block that has been set.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic block diagram of a multi-segment diaphragm according to an embodiment of the present invention.

The radiation from the radiation source S is applied to the diaphragm 10A,
The irradiation field is determined by 10B and the aperture bodies 11A and 11B. Drawing bodies 10A and 10B and drawing bodies 11A and 1
Reference numeral 1B denotes a combination of a plurality of substantially plate-shaped aperture blocks 12. This respective aperture block 12
The ball bearings 14 are arranged on the surfaces facing each other. The ball bearings 14 support the adjacent positions of the adjacent aperture blocks 12 and allow the blocks to slide.

The aperture blocks 12 are separately driven by a drive motor 23. The drive motors 23 used for this drive each have an encoder 24 for position detection, and are controlled by operation control means (not shown). Further, a driving force is transmitted to the aperture block 12 by the drive gears 21a and 21b and the drive gears 22a and 22b.

In this embodiment, an example is shown in which the drive shaft for transmitting power from the drive motor 23 to, for example, the drive gears 21a and 22a has a double shaft structure. However, the present invention is not limited to this example. In addition, even if the respective drive shafts are independent from each other, no change occurs in the configuration and effect of the present invention.

FIG. 2 is a schematic view of a sliding support means according to an embodiment of the present invention.

In FIG. 2, a plurality of sectional or U-shaped grooves 1 are formed on opposite sides of each aperture block 12.
3a, 13b, a plurality of ball bearings 14, a plurality of retainers 15, and springs 16 at both ends are arranged in the grooves 13a, 13b, so that the adjacent aperture blocks 1
The two members are slidably supported by each other. That is, the opposing surfaces of the adjacent drawing blocks 12 are supported by the rolling contact of the ball bearings 14, and the retainer 15 prevents the ball bearings 14 from contacting each other and locking. The ball bearings 14 and the retainers 15 are alternately arranged in the grooves 13a and 13b.

Grooves 13a and 13b are located opposite to the mating surfaces of two adjacent aperture blocks 12, respectively. For this reason, the groove 1 is located between the two aperture blocks 12 that are fitted together.
A track hole is formed by opposing the 3a and 13b. A ball bearing 14 is inserted therein, and one hemispherical portion of the ball bearing 14 supports one aperture block 12, and the other hemispherical portion supports another aperture block 12.

In order to prevent the ball bearing 14 from being displaced from a predetermined position, the groove 13
The spring 16 is arranged between the ball bearings 14 and the stoppers 17a, 17b provided at both ends of the a, 13b. Caps 18 are attached to both ends of the spring 16 to prevent the ball bearing 14 from biting, and have a structure shown in FIG. When the spring 16 is compressed and contracted to the maximum, the cap 18 comes into contact with the opposite ends of the cap 18 fitted in the spring 16. Such contact may cause the spring 16 to shrink, for example, beyond the maximum compression length, to break, or to cause the grooves 13a, 13a.
It is possible to prevent biting into b. FIG. 3 shows a state in which the spring 16 is contracted to the maximum compression length and the opposite ends of the cap 18 are in contact with each other. For the sake of explanation, only the spring 16 is shown in a sectional view.

The trajectory guide shapes of the grooves 13a and 13b can be set in accordance with the design intention, for example, a linear shape or an arc shape in accordance with the shape of the predetermined movement trajectory of the aperture block 12. Also, the cross-sectional shape of the grooves 13a and 13b can be implemented in the same manner whether the shape is a letter shape or a U-shape.
Similar effects can be obtained by using a roller-shaped bearing member (not shown) instead of the roller member 4.

The retainer 15 may not be an independent member but may be provided with a round hole for fitting the ball bearing 14 in, for example, a plate-like member, or a roller member having a square hole in the case of a roller-shaped bearing member. The effect of the retainer 15 can be obtained. The installation position of the ball bearing 14 or a roller-shaped bearing member (not shown)
Similar effects can be obtained even if grooves are provided not only on both side surfaces of the aperture block 12 but also on the inner edge portion and the outer edge portion.

Further, rollers 19a, 19b and 19c having a small diameter are arranged at predetermined intervals in the radial direction of the aperture block 12 as an auxiliary. With this arrangement, the aperture block 12 can be slidably supported at a predetermined position in combination with the ball bearing 14 by using the aperture block 12 as a supplementary support means from inside and outside.

As described above, according to the present invention, the diaphragm block 12 can be effectively supported only by rolling contact while preventing the diaphragm device provided in the radiation therapy apparatus from being enlarged, so that the diaphragm block 12 can be smoothly moved. , And secure holding can be provided at the same time. Since the gap between the aperture blocks 12 can be ensured with the processing accuracy, the gap adjustment in the prior art is not required, and the configuration is simple, inexpensive and highly reliable. For example, the number of divisions of the aperture block 12 can be increased or even higher. It is possible to cope with the finely divided aperture block 12.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

[0038]

According to the radiotherapy apparatus of the present invention,
The aperture block can be moved favorably without increasing the size of the aperture device, and at the same time, the aperture blocks can be reliably held between the aperture blocks. Can be held,
With low cost and good reliability by simple configuration,
The number of divided aperture blocks can be increased, and a radiation therapy apparatus including an aperture device that can cope with highly accurate subdivided aperture blocks can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a diaphragm according to an embodiment of the present invention.

FIG. 2 shows one example of an aperture block according to the embodiment of the present invention.

FIG. 3 shows one example of a support means in the embodiment of the present invention.

FIG. 4 shows an example of a general configuration of a conventional radiotherapy apparatus.

FIG. 5 shows an example of a configuration of a conventional diaphragm.

FIG. 6 shows an example of a configuration of a conventional aperture block.

FIG. 7 shows an example of a radiation stop using a conventional stop block.

FIG. 8 shows an example of a stop aperture and an irradiation field by a stop body.

FIG. 9 shows an example of a support configuration in a conventional aperture block.

FIG. 10 shows an example of a support configuration in a conventional aperture block.

FIG. 11 shows an example of a support configuration in a conventional aperture block.

[Explanation of symbols]

Reference numeral 12: drawing block, 13a, 13b: groove, 14: ball bearing, 15: retainer, 16: spring, 1
8: Cap, S: Radiation source, T: Irradiation field, U: Stop aperture

Claims (4)

[Claims] 1. A radiotherapy apparatus having a multi-segment stop mechanism for arbitrarily changing a radiation irradiation range, wherein each of the plurality of radiotherapy apparatuses is provided so as to be movable and close to each other in a direction substantially orthogonal to the radiation direction. An orifice block made of a plate-shaped body of the above, an orbital groove provided to face each of the adjacent surfaces of the orifice block and guiding the orbit of the orifice block, and orbits of the plurality of orifice blocks in the orbital groove. And a sliding support member for guiding and holding each other. 2. The radiotherapy apparatus according to claim 1, wherein the sliding support member is constituted by a bearing member including a plurality of sliding members having a spherical shape or a substantially cylindrical shape. 3. The sliding support member, wherein the bearing member is positioned and supported at a predetermined position in the raceway groove by positioning means comprising an elastic support member disposed in the raceway groove. Item 2
A radiation therapy apparatus according to claim 1. 4. The positioning means has a pair of end sealing members mounted opposite to both ends of the elastic support means, and guides the retraction direction of the elastic support member to seal the bearing member. The radiation therapy apparatus according to claim 3, wherein the radiation therapy is stopped.