JP4100653B2 - Radiation therapy equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a support structure for a multi-division diaphragm block, particularly in a radiation therapy apparatus in which the radiation irradiation range can be arbitrarily changed by the diaphragm block.
[0002]
[Prior art]
FIG. 6 shows a schematic configuration of a conventional radiotherapy apparatus.
[0003]
The configuration of the radiotherapy apparatus that has been conventionally used includes a fixed base 1, a rotatable rotary base 2 that is supported by the fixed base 1, an irradiation head 3 that is built into the tip of the rotary base 2, and a diaphragm that is built into the irradiation head 3. The apparatus 4, the treatment table 5, and the like are included as main components.
[0004]
Since the rotary mount 2 and the irradiation head 3 rotate around rotation axes that are orthogonal to each other, in this rotation state, the direction in which gravity acts is any direction with respect to the operation direction of a diaphragm block (not shown) included in the diaphragm device 4. To change. Therefore, a mechanism for supporting the aperture block is required so that the aperture block can be operated even if the direction in which the gravity acts changes.
[0005]
An aperture device composed of a single block that forms a rectangular field can be easily implemented because it only needs to support two pairs of vertical and horizontal aperture blocks, but it can be divided into multiple parts that form an irregularly shaped field (irregular field). In the diaphragm device, the diaphragm blocks divided into a large number operate independently. The larger the number of aperture blocks divided, the narrower the aperture block itself, and in order to prevent radiation leakage between adjacent aperture blocks, the gap between the aperture blocks is as small as possible, for example, 0.05 to Must be about 0.1 mm.
[0006]
As shown in FIGS. 5 to 9, a pair of apertures 110A and 110B move in the X direction on a concentric circle including the radiation source S as a center and approach each other as shown in FIGS. , Provided to be separated. Similarly, with respect to the Y direction, the pair of diaphragms 111A and 111B is also 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. Each of the diaphragms 110A, 110B, 111A, and 111B is configured by a combination of substantially plate-like diaphragm blocks 112.
[0007]
These diaphragm blocks 112 are provided with groove rails that are fitted to each other on the surfaces adjacent to each other, and the movement of the groove rails is regulated by the fitting of the groove rails to perform a predetermined motion. As shown in FIG. 5, for example, a convex protrusion is fitted into the concave rail to guide the groove rail. These diaphragm blocks 112 are driven by a drive motor 113.
[0008]
As shown in FIG. 6, a pair of diaphragms 110A and 110B and a plurality of diaphragm blocks 112 of the multi-particulate diaphragms 111A and 111B are individually moved to a predetermined position and combined to thereby center the radiation source S. An opening having a predetermined shape can be formed. Drive motors 113 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.
[0009]
FIG. 7 shows the movement trajectories of the diaphragms 111A and 111B. For example, the diaphragms 111A and 111B move so as to draw an arc around the radiation source S in the Y direction. For radiation radiation from the radiation source S, diaphragms 111A and 111B having linear end portions parallel to the radiation locus are used.
[0010]
FIG. 8 shows an aperture U formed by the apertures 111A and 111B and an irradiation field T obtained by the aperture U. Since the end portion of the aperture block 112 appears in a step shape, the irradiation field T does not have an arc-shaped end portion as shown in FIG. By providing the aperture block 112 in a more divided manner, a smooth end shape is obtained.
[0011]
As a load supporting method for operating the aperture block 112 as described above, there is a method of supporting each aperture block with a grooved roller as described in Japanese Patent Publication No. 210012. For example, FIG. 9 shows a load support mechanism applied to the multi-division diaphragm device in the radiotherapy apparatus described in Japanese Patent Publication No. 210012. In this structure, a square step D1 is provided on the outer periphery of each throttle block 31, and a roller 32 (one on the inner peripheral portion of the throttle block 31 and two on the outer peripheral portion) is fitted to the step. The load of the block 31 (aperture block group 30) is supported. The aperture block group 30 is supported by a bearing 33 through these rollers 32.
[0012]
Further, for example, a conventional multi-leaf collimator has a cross-sectional structure shown in FIGS. As can be seen from this cross-sectional view, each squeezing block (leaf) 41 is supported at the edge by a set of three grooved rollers 42.
[0013]
Among these rollers 42, a pair of rollers 42 are arranged so as to be separated from each other along the inner edge of the diaphragm block 41, and the remaining one roller 42 is arranged in direct contact with the outer edge of the diaphragm 41. Regardless of the posture of the head, it is held so that it can be displaced directly.
[0014]
[Problems to be solved by the invention]
However, the conventional techniques have the following problems.
[0015]
The method of supporting the throttle block with a grooved roller is rolling contact in the radial direction, but there is a problem of wear due to sliding friction in the thrust direction.
[0016]
In addition, since the aperture block is made of heavy metal such as tungsten, it is necessary to have a large shaft diameter to support the load of the aperture block group with one support shaft at one place, and it is fitted to this shaft. Since the roller becomes large, the diaphragm device is extended in the direction of the patient, and the feeling of pressure received by the patient is increased.
[0017]
In addition, it is difficult to ensure a sufficient space between the radiation source and the patient as needed to accommodate standard auxiliary equipment such as a block tray.
[0018]
In addition, when the aperture block is subdivided, each aperture block has to be provided with three or more grooved rollers, so a large number of rollers are allocated, and it takes up space and is difficult to assemble and adjust. There is a drawback.
[0019]
The present invention has been made to solve the above-described problems, and can smoothly and reliably hold the aperture block while preventing an increase in the size of the aperture device, thereby obtaining a highly accurate irradiation field. It is to provide a multi-division diaphragm device.
[0020]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the present invention described in claim 1, a radiation therapy apparatus having a multi-division diaphragm mechanism for arbitrarily changing a radiation irradiation range, a direction substantially orthogonal to the radiation direction. An aperture block made up of a plurality of plate-like bodies each of which is movable and provided close to each other;
A raceway groove that is provided opposite to each adjacent surface of the aperture block and guides the trajectory of the aperture block;
A radiation therapy apparatus comprising a sliding support member that guides and holds the trajectories of the plurality of aperture blocks in the trajectory groove is used as a solution means.
[0021]
Moreover, in this invention of Claim 2, the said sliding support member is
The radiotherapy apparatus according to claim 1, wherein the solution means comprises a bearing member comprising a plurality of sliding members having a spherical shape or a substantially cylindrical shape.
[0022]
Moreover, in this invention of Claim 3, the said sliding support member is
The radiotherapy apparatus according to claim 2, wherein the bearing member is positioned and supported at a predetermined position in the track groove by positioning means comprising an elastic support member disposed in the track groove. To do.
[0023]
According to a fourth aspect of the present invention, the positioning means includes a pair of end sealing members mounted to face both end portions of the elastic support member, and the contraction direction of the elastic support member is determined. The radiotherapy apparatus according to claim 3, wherein the solution is guided to seal the bearing member.
[0024]
The solution according to the present invention configured as described above can move the aperture blocks well without increasing the size of the aperture device, and at the same time, can reliably hold the aperture blocks together.
The gap between the aperture blocks can be held in place without adjusting the gap,
To provide a radiotherapy apparatus equipped with a diaphragm device that secures low cost and good reliability with a simple configuration, increases the number of divisions of the diaphragm block, and is compatible with a highly accurate segmented diaphragm block. It is aimed.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic configuration diagram of a multi-division diaphragm apparatus according to an embodiment of the present invention.
[0026]
The irradiation field of the radiation from the radiation source S is determined by the diaphragms 10A and 10B and the diaphragms 11A and 11B. The apertures 10A and 10B and the apertures 11A and 11B are composed of a combination of a plurality of substantially plate-like aperture blocks 12. Ball bearings 14 are arranged on the mutually opposing surfaces of the respective throttle blocks 12. The ball bearings 14 support the opposing positions of the adjacent throttle blocks 12 and allow them to slide.
[0027]
Each of these aperture blocks 12 is driven by a drive motor 23 separately. Each drive motor 23 used for this drive has an encoder 24 for position detection, and is controlled by an operation control means (not shown). The driving force is transmitted to the aperture block 12 by the driving gears 21a and 21b and the driving gears 22a and 22b.
[0028]
In the present embodiment, an example 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 is shown, but the present invention is not limited to this example. Even if the drive shafts are independent of each other, no change occurs in the configuration and effect of the present invention.
[0029]
FIG. 2 is a schematic view of the sliding support means according to the embodiment of the present invention.
[0030]
In FIG. 2, a plurality of cross-sectional (5) -shaped or U-shaped grooves 13a and 13b are provided on opposite side surfaces of each diaphragm block 12, and a plurality of ball bearings 14 and a plurality of retainers are provided in the grooves 13a and 13b. 15 and springs 16 are arranged at both ends so as to be slidably supported by the adjacent throttle blocks 12. That is, the opposing surfaces of the adjacent throttle blocks 12 are supported by the rolling contact of the ball bearings 14, and the retainer 15 prevents the ball bearings 14 from contacting and locking. The ball bearing 14 and the retainer 15 are alternately arranged in the grooves 13a and 13b.
[0031]
Grooves 13a and 13b are positioned to face the mating surfaces of the two adjacent diaphragm blocks 12, respectively. For this reason, a raceway hole is formed by the grooves 13a and 13b facing each other between the two aperture blocks 12 that have been combined. A ball bearing 14 is inserted therein, and one hemispherical portion of the ball bearing 14 supports one aperture block 12, and the remaining hemispherical portion supports another aperture block 12.
[0032]
Further, in order to prevent the ball bearing 14 from being displaced from a predetermined position, springs 16 are arranged between the stoppers 17 a and 17 b provided at both ends of the grooves 13 a and 13 b of the aperture block 12 and the ball bearing 14. Caps 18 are attached to both ends of the spring 16 to prevent the ball bearing 14 from being caught, and has a structure shown in FIG. The cap 18 is configured such that when the spring 16 is compressed and contracted to the maximum, opposing ends of the cap 18 fitted into the spring 16 come into contact with each other. By contacting in this way, it is possible to prevent the spring 16 from being contracted and damaged, for example, beyond the maximum compression length, or being caught in the grooves 13a and 13b. FIG. 3 shows a state where the spring 16 is contracted to the maximum compression length and the opposite ends of the cap 18 are in contact with each other, and only the spring 16 is shown as a cross-sectional view for explanation.
[0033]
The trajectory guide shapes of the grooves 13a and 13b can be set in accordance with the design intention, for example, in a linear shape or an arc shape according to the shape of a predetermined movement trajectory of the aperture block 12. Further, the cross-sectional shapes of the grooves 13a and 13b can be implemented in the same manner as in the (5) shape or the U shape, and the same effect can be obtained with a roller-shaped bearing member (not shown) instead of the ball bearing 14.
[0034]
The retainer 15 may not be an independent member, but may be provided with a round hole into which the ball bearing 14 is fitted, for example, in a plate-like member, or a retainer 15 having a square hole if it is a roller-shaped bearing member. The effect of can be obtained. The installation position of the ball bearing 14 or the roller-shaped bearing member (not shown) is not limited to the both side surfaces of the aperture block 12, and the same effect can be obtained even if grooves are provided in the inner edge portion and the outer edge portion.
[0035]
Further, as an auxiliary, small-diameter rollers 19a, 19b, and 19c are arranged at predetermined intervals in the radial direction of the aperture block 12. With this arrangement, the diaphragm block 12 can be used as a complementary support means from the inside and outside of the diaphragm block 12 and combined with the ball bearing 14 to slidably support the diaphragm block 12 at a predetermined position.
[0036]
As described above, according to the present invention, the diaphragm block 12 can be effectively supported only by rolling contact while preventing the diaphragm apparatus included in the radiotherapy apparatus from being enlarged, so that the diaphragm block 12 can be moved smoothly. Can be provided at the same time. Since the clearance of the aperture block 12 can be ensured with processing accuracy, the clearance adjustment in the prior art is not necessary, and the configuration is simple, inexpensive and highly reliable. For example, the number of divisions of the aperture block 12 can be increased, It is also possible to deal with an accurate subdivided aperture block 12.
[0037]
The embodiment described above is described in order to facilitate understanding of the present invention, and is not described in order to limit the present invention. Therefore, each element disclosed in the above embodiment includes all design changes and equivalents belonging to the technical scope of the present invention.
[0038]
【The invention's effect】
According to the radiotherapy apparatus according to the present invention,
It is possible to move the aperture block well without increasing the size of the aperture device, and at the same time, it is possible to securely hold between the aperture blocks,
The gap between the aperture blocks can be held in place without adjusting the gap,
To provide a radiotherapy apparatus equipped with a diaphragm device that secures low cost and good reliability with a simple configuration, increases the number of divisions of the diaphragm block, and is compatible with a highly accurate segmented diaphragm block it can.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a diaphragm in an embodiment of the present invention.
FIG. 2 shows an example of an aperture block in the embodiment of the present invention.
FIG. 3 shows an example of the 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 the configuration of a conventional diaphragm.
FIG. 6 shows an example of a configuration in a conventional aperture block.
FIG. 7 shows an example of a radiation stop by a conventional stop block.
FIG. 8 shows an example of an aperture opening and an irradiation field by an aperture body.
FIG. 9 shows an example of a support structure in a conventional diaphragm block.
FIG. 10 shows an example of a support structure in a conventional diaphragm block.
FIG. 11 shows an example of a support structure in a conventional diaphragm block.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 12 ... Diaphragm block, 13a, 13b ... Groove, 14 ... Ball bearing, 15 ... Retainer, 16 ... Spring, 18 ... Cap, S ... Radiation source, T ... Irradiation field, U ... Diaphragm opening

Claims (4)

A radiotherapy apparatus having a multi-part diaphragm mechanism for arbitrarily changing a radiation irradiation range,
A diaphragm block composed of a plurality of plate-like bodies that are respectively movable and close to each other in a direction substantially perpendicular to the radiation direction;
A raceway groove that is provided opposite to each adjacent surface of the aperture block and guides the trajectory of the aperture block;
A radiation therapy apparatus comprising: a sliding support member that guides and holds the tracks of the plurality of aperture blocks in each other in the track groove. The sliding support member is
The radiotherapy apparatus according to claim 1, comprising a bearing member including a plurality of sliding members having a spherical shape or a substantially cylindrical shape. The sliding support member is
The radiotherapy apparatus according to claim 2, wherein the bearing member is positioned and supported at a predetermined position in the track groove by positioning means including an elastic support member disposed in the track groove. The positioning means includes
Having a pair of end sealing members mounted facing both ends of the elastic support member;
The radiotherapy apparatus according to claim 3, wherein the bearing member is sealed by guiding a contraction direction of the elastic support member.

Images