JP4717859B2 - Multi-leaf collimator and radiotherapy apparatus - Google Patents

Description

  The present invention relates to a multi-leaf collimator that sets an irradiation range of radiation according to the shape of a lesion such as cancer in a patient's body, and radiation that treats the lesion by irradiating the lesion with radiation such as a proton beam. The present invention relates to a treatment device.

  In the treatment of lesions such as cancer with a radiotherapy device, radiation should be applied so that the surrounding normal tissue is not affected irreversibly and a lethal dose is concentrated only on the lesion. Is ideal. However, the shape of the lesion is usually different for each patient.

Therefore, conventionally, a pair of leaf plate groups constituted by a plurality of leaf plates, a plurality of L-shaped metal fittings provided respectively on each leaf plate, and each L-shaped metal fitting connected via a feed screw, respectively. There is known a multi-leaf collimator that includes a plurality of motors and can set the radiation irradiation range for each patient by driving each motor (see, for example, Patent Document 1).
JP-A-7-204284

  As described above, since radiation is irradiated only on a lesion, it is desired to set the radiation irradiation range as accurately as possible. Here, in order to accurately reproduce the outer shape of the lesion with a large number of leaf plates, it is preferable that the leaf plate be as thin as possible.

  However, in the conventional multi-leaf collimator, since the motors are arranged so as to be alternately displaced, when attempting to make the leaf plate thinner, the motors interfere with each other, making it difficult to arrange the motors. There was a problem of becoming.

  An object of the present invention is to provide a multi-leaf collimator and a radiation therapy apparatus capable of setting a radiation irradiation range with high accuracy.

  The multi-leaf collimator according to the present invention is a multi-leaf collimator that sets a radiation irradiation range according to the shape of a lesion in a patient's body, and the leaf plates are arranged along a virtual axis orthogonal to the radiation irradiation axis. A plurality of leaf plate groups arranged in this manner, and drive means for driving the leaf plates along the direction orthogonal to the irradiation axis and orthogonal to the imaginary axis are connected to the leaf plates in a one-to-one relationship along the irradiation axis. And a drive unit having a plurality of drive means rows arranged in a row.

  In the multi-leaf collimator according to the present invention, the drive unit has a plurality of drive means rows arranged so that the drive means are arranged along the irradiation axis. For this reason, the driving means are arranged without interfering with each other, so that the leaf plate can be made thinner. As a result, the radiation irradiation range can be set with high accuracy.

  Moreover, it is preferable that a plurality of drive units are arranged so that the drive means row is arranged along the drive direction of the leaf plate. In this way, the arrangement density of the drive means row in the drive unit can be increased, so that the multi-leaf collimator can be made compact.

  Moreover, it is preferable that a plurality of drive units are configured so that the drive means row is arranged along the virtual axis. In this way, since the arrangement density of the drive means row in the drive unit can be further increased, the multi-leaf collimator can be further reduced in size.

  Further, the first rotation member that is rotatable along the driving direction of the leaf plate and is disposed at one end side of the leaf plate in the direction along the irradiation axis, and along the driving direction of the leaf plate The leaf plate further includes at least two second turning members arranged on the other end side of the leaf plate in the direction along the irradiation axis, the leaf plate including the first turning member and the second turning member. It is preferably supported by a member. If it does in this way, while being able to support a leaf board reliably, it becomes possible to drive a leaf board smoothly in the drive direction.

  Further, the plate thickness of the leaf plate located in the central portion of the leaf plate group in the direction along the virtual axis is thinner than the plate thickness of the leaf plate located in both side portions of the leaf plate group in the direction along the virtual axis. It is preferable. Since the accuracy of the radiation irradiation range is mainly determined by the thickness of the leaf plate located in the central portion of the leaf plate group in the direction in which the plurality of leaf plates constituting the leaf plate group are arranged, by doing this, It is possible to set the radiation irradiation range with higher accuracy.

  Moreover, it is preferable that the drive unit is arrange | positioned in the position near the radiation source which irradiates a radiation rather than the leaf board group. In this way, the proximity of the multi-leaf collimator to the patient is not hindered by the drive unit. Here, since the radiation has a property of spreading in a direction orthogonal to the irradiation axis, the multi-leaf collimator can be brought close to the patient as described above, thereby setting the irradiation range of the radiation with high accuracy. Will be able to.

  On the other hand, a radiation therapy apparatus according to the present invention includes a radiation source that irradiates radiation, and a multi-leaf collimator that is arranged in an irradiation direction of radiation irradiated from the radiation source and sets a radiation irradiation range to a predetermined shape. A multi-leaf collimator, which is a treatment device, includes a plurality of leaf plates arranged along a virtual axis orthogonal to a radiation irradiation axis and a pair of leaf plates connected to the leaf plate in a one-to-one manner and an irradiation axis. Drive means for driving the leaf plate along a direction perpendicular to the virtual axis and a drive unit having a plurality of drive means rows arranged so as to be aligned along the irradiation axis. Features.

  In the radiotherapy apparatus according to the present invention, the drive unit of the multi-leaf collimator has a plurality of drive means rows arranged so that the drive means are arranged along the irradiation axis. For this reason, the driving means are arranged without interfering with each other, so that the leaf plate can be made thinner. As a result, the radiation irradiation range can be set with high accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, the multileaf collimator and radiation therapy apparatus which can set the irradiation range of a radiation with high precision can be provided.

  Preferred embodiments of the present invention will be described with reference to the drawings.

  First, with reference to FIG.1 and FIG.2, the structure of the radiotherapy apparatus 100 is demonstrated. As shown in FIG. 1, the radiation treatment apparatus 100 includes a treatment table 102, a rotating gantry 104 surrounding the treatment table 102, a radiation irradiation device 106, and a cyclotron (particle accelerator) 108.

  The radiation irradiation device 106 is a device that irradiates a radiation R for treatment to a lesion F such as cancer in the body of a patient P on the treatment table 102. The radiation irradiation device 106 is attached to the rotating gantry 104 and can be moved around the treatment table 102 by the rotating gantry 104 (see FIG. 1). As shown in FIG. 2, the radiation irradiation apparatus 106 includes a scatterer 110 and a multi-leaf collimator 1.

  The scatterer 110 expands the thin radiation R generated by the cyclotron 108 and sent to the radiation irradiation apparatus 106 through a transport device (not shown) in a direction orthogonal to the irradiation axis A of the radiation R (FIG. 2). reference). As the scatterer 110, for example, a lead plate or an aluminum plate having a thickness of several mm can be used. Here, in the present embodiment, the radiation R is α-ray, β-ray, γ-ray, molecular beam, atomic beam, neutron beam, electron beam, proton beam, X-ray, heavy particle beam, ion beam, heavy ion beam, etc. In the field of radiation therapy, proton beams, heavy particle beams, X-rays, and neutron beams are particularly preferably used.

  The multi-leaf collimator 1 determines the irradiation range of the radiation R according to the shape of the lesion part F in the body of the patient P. As shown in FIG. 2, the multi-leaf collimator 1 is arranged in the radiation R irradiation direction (X-axis direction) with respect to the scatterer 110 in the radiation irradiation device 106.

  Next, the configuration of the multi-leaf collimator 1 will be described in detail with reference to FIGS. As shown in FIGS. 2 and 3, the multi-leaf collimator 1 is disposed at a position on the upstream side of the radiation R (the cyclotron 108 side that is a radiation source) with respect to the pair of leaf plate groups 10 and the leaf plate group 10. And a pair of drive units 12.

  The pair of leaf plate groups 10 are arranged to face each other in the Y-axis direction (a direction perpendicular to the X-axis and perpendicular to the Z-axis). The leaf plate group 10 includes a plurality (32 in the present embodiment) of leaf plates 14A and a plurality (20 in the present embodiment) of leaf plates 14B in a direction (Z-axis direction) orthogonal to the irradiation axis A of the radiation R. ) Are arranged along the line. Specifically, in this embodiment, the leaf plate group 10 includes 10 leaf plates 14B and 32 leaf plates 14A and 10 along a direction (Z-axis direction) orthogonal to the irradiation axis A of the radiation R. A plurality of leaf plates 14B are arranged in this order.

The leaf plates 14A and 14B have a rectangular shape and can be formed by processing a material (for example, copper, tantalum, molybdenum) having a density of 8 g / cm ³ or more that can shield radiation. . The plate thickness T (width in the Z-axis direction) of the leaf plate 14A is different from the plate thickness T of the leaf plate 14B. In this embodiment, the plate thickness T of the leaf plate 14A is set to about 3 mm, and the leaf plate 14B The plate thickness T is set to about 5 mm. In this embodiment, the length (width in the Y-axis direction) L of the leaf plates 14A and 14B is set to about 180 mm, and the height (width in the X-axis direction) H of the leaf plates 14A and 14B is Both are set to about 120 mm. Therefore, the thickness T of the leaf plate 14A located at the central portion of the leaf plate group 10 in the direction orthogonal to the irradiation axis A of the radiation R (Z-axis direction) is orthogonal to the irradiation axis A of the radiation R (Z-axis). Direction), the leaf plate 14B located at both end portions of the leaf plate group 10 is thinner than the plate thickness T.

As shown in FIGS. 4 and 5, the leaf plates 14 </ _b > A and 14 </ _b > B have groove portions 16 extending in the length L direction on a pair of side surfaces S ₁ and S ₂ facing each other in the height H direction. Is formed. Leaf plate 14A, the groove 16 of the side surface _{S 1} side of 14B, and one miniature bearing (first rotation member) 18 is engaged in the groove 16 in the leaf plate 14A, 14B side _{S 2} of the Two miniature bearings (second rotating members) 18 are engaged with each other while being separated from each other in the Y-axis direction (see FIG. 4). Therefore, the leaf plates 14A and 14B are supported by the three miniature bearings 18 and are slidable in the length L direction.

The leaf plates 14A and 14B, as shown in detail in FIG. 5 in particular, are a pair of side surfaces S ₃ and S ₄ facing each other in the plate thickness T direction, and have a length L at a central portion in the height H direction. It has a stepped portion 20 extending in the direction. Further, the gap G between the adjacent leaf plates 14A and 14B is set to be smaller than the height D of the stepped portion 20. This is to prevent the radiation R from passing through the gap between the adjacent leaf plates 14A and 14B. In the present embodiment, the height D of the stepped portion 20 is set to about 1 mm, and the interval G between the adjacent leaf plates 14A and 14B is set to about 0.2 mm.

Returning to FIG. 3, the pair of drive units 12 are arranged to face each other in the Y-axis direction (a direction perpendicular to the X-axis and perpendicular to the Z-axis). The drive unit 12 includes a plurality (six in this embodiment) of first to sixth drive mechanism rows 22A _{1 to} 22A ₆ and a plurality (six in this embodiment) of first to sixth drive mechanism rows 22B _1. and a ~22B _6. The first to sixth drive mechanism rows 22A _{1 to} 22A ₆ and the first to sixth drive mechanism rows 22B _{1 to} 22B ₆ are arranged along a direction (Z-axis direction) orthogonal to the irradiation axis A of the radiation R, respectively. Is arranged. The first to sixth drive mechanism rows 22A _{1 to} 22A ₆ and the first to sixth drive mechanism rows 22B _{1 to} 22B ₆ are arranged along the length direction (Y-axis direction) of the leaf plates 14A and 14B. It is arranged such, the first to sixth driving mechanism columns _22B 1 _{~22B 6} on the leaf plate group 10 is positioned farther than the first to sixth driving mechanism columns _22A 1 _{~22A 6.}

The first, second, fifth, and sixth drive mechanism rows 22A ₁ , 22A ₂ , 22A ₅ , 22A ₆ and the first, second, fifth, and sixth drive mechanism rows 22B ₁ , 22B ₂ , 22B ₅ , 22B ₆ is configured such that a plurality (four in the present embodiment) of drive mechanisms 24 are arranged along the irradiation axis A of the radiation R. In addition, the third and fourth drive mechanism rows 22A ₃ and 22A ₄ and the third and fourth drive mechanism rows 22B ₃ and 22B ₄ are plural (the number of the drive mechanisms 24 is aligned along the irradiation axis A of the radiation R). In the embodiment, 5) are arranged. The drive mechanism 24 constituting the respective drive mechanisms column _{22A 1 ~22A 6, 22B 1 ~22B} 6 is a rib provided on the frame for accommodating the leaf plate group 10 (not shown) (not shown) It is fixed.

  The drive mechanism 24 is for driving the leaf plates 14A and 14B in the length L direction (Y-axis direction). As shown in FIG. 6, the drive mechanism 24 includes a ball screw 26, a motor 28, an encoder 30, and a housing 32.

  The ball screw 26 includes a screw shaft 26a and a nut body 26b. The screw shaft 26 a is attached to the housing 32 so as to be rotatable by a pair of bearings 33. The nut body 26b is screwed with the screw shaft 26a. The nut body 26b is provided with a plate-like member 34 that protrudes outward from a slit 32b of the casing 32 described later (see FIGS. 3, 4, and 6). In FIGS. 3 and 4, some of the plate-like members 34 and connection plates 38 and 42 and a connecting member 40 described later are omitted.

  The shaft of the motor 28 is coupled to one end of the screw shaft 26 a by a coupling member (coupling) 36. The encoder 30 is attached to the motor 28 and measures the rotation angle of the motor 28.

  The casing 32 has a rectangular parallelepiped shape, and accommodates the ball screw 26 therein. A slit 32b extending in the longitudinal direction (Y-axis direction) of the housing 32 is formed in the side wall 32a of the housing 32 (see FIG. 4).

The drive mechanism 24 having the above configuration is connected to the leaf plates 14A and 14B on a one-to-one basis in order to drive the leaf plates 14A and 14B. Specifically, as shown in FIG. 4, the drive mechanism 24 and the leaf plates 14 </ b> A and 14 </ b> B constituting the drive mechanism rows 22 </ b> A _{1 to} 22 </ b> A ₆ are connected one-on-one by a connection plate 38. One end of the connection plate 38 is connected to the plate-like member 34 protruding from the slit 32b, and the other end is connected to the leaf plates 14A and 14B. The connection plate 38 extends downward along the radiation R irradiation direction (X-axis direction) from one end to the other end, bends at the bent portion 38a, and then returns to the leaf plates 14A and 14B. It extends downward along the irradiation direction (X-axis direction). The connection plate 38 is a thin plate having a rectangular shape, and can be formed by processing a stainless plate. In the present embodiment, the thickness of the connection plate 38 is set to about 0.5 mm.

Further, as shown in FIG. 4, the drive mechanism 24 and the leaf plates 14 </ b> A and 14 </ b> B constituting the drive mechanism rows 22 </ b> B _{1 to} 22 </ b> B ₆ are connected one-to-one by a connecting member 40 and a connection plate 42. The connecting member 40 has one end connected to the plate-like member 34 protruding from the slit 32 b and the other end connected to one end of the connection plate 42, and connects the plate-like member 34 and the connection plate 42. The connecting member 40 extends linearly along the Y-axis direction from one end to the other end toward the leaf plates 14A and 14B. The connecting member 40 is a thin plate having a rectangular shape, and can be formed by processing an aluminum plate. In the present embodiment, the plate thickness of the connecting member 40 is set to about 3 mm.

  The connection plate 42 has one end connected to the other end of the connecting member 40 and the other end connected to the leaf plates 14A and 14B. The connection plate 42 extends downward along the radiation R irradiation direction (X-axis direction) from one end to the other end, bends at the bent portion 42a, and then returns to the leaf plates 14A and 14B. It extends downward along the irradiation direction (X-axis direction). The connection plate 42 is a thin plate having a rectangular shape, and can be formed by processing a stainless plate. In the present embodiment, the thickness of the connection plate 42 is set to about 0.5 mm.

  In the present embodiment as described above, in the drive mechanism 24, the rotational motion of the motor 28 is converted into a linear motion by the ball screw 26, and the nut body 26b and the leaf plates 14A and 14B constituting the ball screw 26 are connected to the connection plate 38. Therefore, the leaf plates 14A and 14B are driven along the extending direction (Y-axis direction) of the screw shaft 26a constituting the ball screw 26. Since the drive mechanism 24 and the leaf plates 14A and 14B are connected in a one-to-one relationship, the leaf plates 14A and 14B are driven by the drive mechanisms 24 to allow the radiation R to pass therethrough (see FIG. 2), and the position and shape of the opening 44 can be freely changed. Therefore, the radiation R incident on the multi-leaf collimator 1 passes through the opening 44, is shielded by the leaf plates 14A and 14B existing around the opening 44, and is cut off along a contour corresponding to the shape of the opening 44. Therefore, in the multi-leaf collimator 1, it is possible to change the irradiation range of the radiation R according to the shape of the lesion part F in the body of the patient P.

In the present embodiment, the drive unit 12 includes drive mechanism rows 22A _{1 to} 22A ₆ and drive mechanism rows 22B _{1 to} 22B ₆ , and the drive mechanism rows 22A _{1 to} 22A ₆ and the drive mechanism row 22B _1. -22B ₆ has a plurality of drive mechanisms 24 arranged so as to be aligned along the irradiation axis A of the radiation R. For this reason, the drive mechanisms 24 are arranged without interfering with each other, so that the leaf plates 14A and 14B can be made thinner.

In the present embodiment, the drive mechanism rows 22A _{1 to} 22A ₆ and the drive mechanism rows 22B _{1 to} 22B ₆ are arranged so as to be aligned along a direction (Z-axis direction) perpendicular to the irradiation axis A of the radiation R, respectively. The drive mechanism rows 22A _{1 to} 22A ₆ and the drive mechanism rows 22B _{1 to} 22B ₆ are arranged along the length direction (Y-axis direction) of the leaf plates 14A and 14B. Therefore, it is possible to increase the arrangement density of the drive mechanism columns _22A 1 _{~22A 6} and the drive mechanism columns _22B 1 _{~22B 6} in the drive unit 12, and can be made compact multi-leaf collimator 1.

  Further, in the present embodiment, the drive unit 12 is disposed upstream of the radiation R from the leaf plate group 10 (on the cyclotron 108 side). Therefore, when the multi-leaf collimator 1 is intended to be close to the patient, the drive unit 12 does not hinder the proximity of the multi-leaf collimator 1 to the patient P. As a result, the irradiation range of the radiation R can be set with high accuracy.

In the present embodiment, the leaf plate 14A, the groove portions 16 in one miniature bearing 18 at the side surface _{S 1} of 14B and engages two miniature bearing groove 16 in the leaf plate 14A, 14B side _{S 2} of 18 is engaged. Therefore, the leaf plates 14A and 14B are supported by the three miniature bearings 18, and the miniature bearing 18 is driven in the drive direction (Y-axis direction) of the leaf plates 14A and 14B as the drive mechanism 24 drives the leaf plates 14A and 14B. Therefore, the leaf plates 14A and 14B can be smoothly driven in the driving direction (Y-axis direction).

  In the present embodiment, the thickness T of the leaf plate 14A located in the central portion of the leaf plate group 10 in the direction orthogonal to the irradiation axis A of the radiation R (Z-axis direction) is equal to the irradiation axis A of the radiation R. In the orthogonal direction (Z-axis direction), it is thinner than the plate thickness T of the leaf plate 14B located at both end portions of the leaf plate group 10. Since the accuracy of the irradiation range of the radiation R is mainly determined by the plate thickness T of the leaf plate 14A located in the central portion of the leaf plate group 10 in the direction orthogonal to the irradiation axis A of the radiation R (Z-axis direction). By doing so, it is possible to set the irradiation range of the radiation R with higher accuracy.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments. For example, a leaf plate 14A, 1 single miniature bearing 18 in the grooves 16 of the side surface _{S 1} and 14B is engaged, the leaf plate 14A, the groove 16 into two miniature bearing 18 at the side surface _{S 2} of 14B is in engagement However, at least one miniature bearing 18 is disposed on one of the side surfaces S ₁ and S ₂ of the leaf plates 14A and 14B, and at least two miniature bearings 18 are disposed on the other of the side surfaces S ₁ and S ₂ of the leaf plates 14A and 14B. It only has to be arranged.

  In the present embodiment, the miniature bearing 18 is used, but various rotating members can be used as long as they can rotate in the drive direction (Y-axis direction) of the leaf plates 14A and 14B.

  Further, in the present embodiment, the plate thickness T of the leaf plate 14A positioned at the central portion of the leaf plate group 10 in the direction orthogonal to the irradiation axis A of the radiation R (Z-axis direction) is orthogonal to the irradiation axis A of the radiation R. In the direction (Z-axis direction), the plate thickness T of the leaf plates 14B positioned at both ends of the leaf plate group 10 is smaller than the thickness T of the leaf plates 14B. It may be the same.

  In the present embodiment, the drive unit 12 is disposed upstream of the leaf plate group 10 on the upstream side of the radiation R (the cyclotron 108 side). However, the drive unit 12 is located at the same position (leaf) as the leaf plate group 10 in the X-axis direction. It may be arranged next to the plate group.

FIG. 1 is a perspective view showing a radiotherapy apparatus according to this embodiment. FIG. 2 is a schematic diagram for explaining the configuration of the radiotherapy apparatus according to the present embodiment. FIG. 3 is a perspective view showing a multi-leaf collimator. FIG. 4 is a perspective view showing a part of the multi-leaf collimator. FIG. 5 is an enlarged side view showing the leaf plate. FIG. 6 is a cross-sectional view showing the drive mechanism.

Explanation of symbols

1 ... multileaf collimator, 10 ... Leaf plate group, 12 ... drive unit, 14A, 14B ... Leaf plate, 18 ... Miniature Bearings (first rotating member, a second rotating _{member), 22A 1 ~22A 6, 22B} 1 -22B ₆ ... drive mechanism array (drive means array), 24 ... drive mechanism (drive means), 100 ... radiation therapy apparatus.

Claims (6)

A multi-leaf collimator that sets the irradiation range of radiation according to the shape of the lesion in the patient's body,
A plurality of leaf plates arranged such that the leaf plates are arranged along a virtual axis orthogonal to the radiation irradiation axis;
A plurality of drive means connected to the leaf plate in a one-to-one manner and driving the leaf plate along a direction orthogonal to the irradiation axis and orthogonal to the imaginary axis are arranged along the irradiation axis. A drive unit having a plurality of drive means rows ,
The multi-leaf collimator is characterized in that a plurality of the drive units are arranged so that the drive means row is arranged along the drive direction of the leaf plate . The drive unit is a multi-leaf collimator according to claim 1, characterized in that it is constituted by a plurality of arranged such that the drive means rows are arranged along the virtual axis. A first rotating member that is rotatable along the driving direction of the leaf plate and at least one disposed on one end side of the leaf plate in the direction along the irradiation axis;
A second rotation member that is rotatable along the driving direction of the leaf plate and at least two second rotation members disposed on the other end side of the leaf plate in the direction along the irradiation axis;
The leaf plate, multi-leaf collimator according to any one of claims 1 or claim 2, characterized in that it is supported by the first rotating member and the second rotating member. The plate thickness of the leaf plate located at the central portion of the leaf plate group in the direction along the virtual axis is thinner than the plate thickness of the leaf plate located at both side portions of the leaf plate group in the direction along the virtual axis. multi-leaf collimator as claimed in any one of claims 1 to 3, characterized in that is. The multi-leaf collimator according to any one of claims 1 to 4 , wherein the drive unit is disposed at a position closer to a radiation source that emits radiation than the leaf plate group. A radiation source that emits radiation;
A radiation therapy apparatus comprising a multi-leaf collimator arranged in a radiation direction of radiation irradiated from the radiation source and setting a radiation irradiation range to a predetermined shape,
The multi-leaf collimator is
A group of leaf plates in which a plurality of leaf plates are arranged along a virtual axis perpendicular to the radiation irradiation axis;
A plurality of drive means connected to the leaf plate in a one-to-one manner and driving the leaf plate along a direction orthogonal to the irradiation axis and orthogonal to the imaginary axis are arranged along the irradiation axis. A drive unit having a plurality of drive means rows ,
The radiotherapy apparatus according to claim 1, wherein a plurality of the drive units are arranged so that the drive means row is arranged along the drive direction of the leaf plate .

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