CN105056405B - Particle-beam therapeutic apparatus - Google Patents

Abstract

An object of the present invention is to obtain a multi-leaf collimator and a particle beam therapy apparatus that are not affected by the penumbra and that can form an irradiation field with high contrast. The multi-leaf collimator includes: a blade row (5 _C ), the blade row (5 _C ) aligns one end surface (E _L ) of a plurality of blade plates (5 _L ) and arranges them in the thickness direction; and blades Plate driving mechanism (5 _D ), the blade plate driving mechanism (5 _D ) drives each blade plate (5 _L ) in such a way that one end surface (EL) approaches or moves away from the beam axis (X _{B )} , for each The vane plate (5 _L ), the opposite surface (PL) of the vane plate and the vane plate adjacent to the vane plate in the thickness direction is formed including the first axis (A _sa ) on the beam axis (X _B ) In the plane ( _{P Sa} ), the vane plate driving mechanism (5 _D ) drives the _{vane plate} (5 _L ), the second axis (A _sb ) is perpendicular to the beam axis (X _B ) and the first axis (A _sa ).

Description

Particle radiation therapy device

The application of the present invention is the international application number PCT/JP2010/063874, the international application date is August 17, 2010, the application number entering the Chinese national phase is 201080068421.8, and the name is "multi-leaf collimator, particle beam therapy device and therapeutic A divisional application of the invention patent application for "planning device".

technical field

The present invention relates to a multi-leaf collimator, a particle beam therapy device using the multi-leaf collimator, and a treatment planning device for determining the operating conditions of the particle beam therapy device, and the multi-leaf collimator is suitable for using charged particle beams An irradiation field is formed in a particle beam therapy device.

Background technique

Particle beam therapy is a method of treatment by irradiating charged particle beams to the affected area as the treatment target to destroy the affected tissue. A particle beam therapy device that accurately controls the irradiation dose and the irradiation range (hereinafter referred to as the irradiation field). Among the particle beam therapy devices, in a so-called wide-area irradiation type particle beam therapy device that uses an irradiation nozzle including a scanning electromagnet such as a swing electromagnet, the irradiation field is enlarged by the irradiation nozzle, and the irradiation nozzle is placed in the enlarged irradiation field for use. Through the shape-changing multi-leaf collimator, an irradiation field corresponding to the shape of the affected area is formed.

A multi-leaf collimator is arranged so that two rows of blades laminated with blades in the thickness direction face each other, and the blades are driven to move toward or away from the opposing blade, thereby forming a multi-leaf collimator. Predetermined see-through shape. Therefore, it is possible to easily form an irradiation field by controlling the physical position of each blade plate. However, in the case of linearly driving the vane plate, a charged particle beam at an angle to the diffusion direction is irradiated to a part of the end face of the vane plate at a contour portion away from the center of the irradiation field, resulting in continuous occurrence of dose of the charged particle beam. Sexual attenuation, which produces the so-called penumbra. Therefore, considering the spread of the beam, a so-called conical multi-leaf collimator is proposed. The conical multi-leaf collimator drives the blades in a circular track, and the blades are formed in the shape of an arc or a cone. A shape obtained by dividing the side surface (for example, refer to Patent Document 1 or 2).

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. Sho 60-063500 (upper right on page 2, lower right on page 2 to upper left on page 3, Fig. 2, Fig. 4)

Patent Document 2: Japanese Patent Application Laid-Open No. 63-225199 (bottom right of page 3 to top right of page 4, bottom left to bottom right of page 7, Figures 1 to 3, and Figures 12 to 13)

Patent Document 3: Japanese Patent Application Laid-Open No. 10-255707 (paragraphs 0009 to 0020, FIG. 1 and FIG. 5 )

Patent Document 4: Japanese Patent Laid-Open No. 2006-166947 (paragraphs 0015-0016, FIG. 1 )

Contents of the invention

The problem to be solved by the invention

However, for the above-mentioned cone multi-leaf collimator, it is assumed that a beam diffused from a point source is used. In other words, when it is assumed that a volumetric light source is used, the different diffusion methods due to different directions are not considered. On the other hand, in order to expand the irradiation field in a particle beam device using a charged particle beam, as shown in Patent Documents 3 and 4, an electromagnet that scans a relatively thin beam supplied from an accelerator is required. Furthermore, since electromagnets provided in two directions, such as x-direction electromagnets and y-direction electromagnets, are required in a plane perpendicular to the beam axis, the diffusion in the x-direction and in the y-direction The starting point becomes different. Therefore, even if the above-mentioned multi-leaf collimator is applied to a particle beam therapy apparatus, there is a problem that the beam spreading method does not match the transmission shape of the multi-leaf collimator, thereby causing a penumbra.

The present invention was made to solve the above problems, and an object of the present invention is to obtain a multi-leaf collimator and a particle beam therapy apparatus that are not affected by the penumbra and that can form an irradiation field with high contrast.

means of solving problems

The multi-leaf collimator of the present invention is arranged in the particle beam irradiated in order to expand the irradiation field, and forms the above-mentioned irradiation field in a manner consistent with the irradiation object, and the multi-leaf collimator includes: a blade row, the the blade row is arranged in the thickness direction so that one end surface of the plurality of blade plates is aligned; and the blade plate driving mechanism moves the one end surface closer to or away from the beam axis of the particle beam A plurality of the above-mentioned vane plates are respectively driven in the manner of the beam axis, and the multi-leaf collimator is characterized in that the opposite surface of each of the above-mentioned vane plates and the adjacent vane plates in the thickness direction is formed on a plane including the first axis On the inner plane, the first axis is set at the first position on the above-mentioned beam axis and is perpendicular to the beam axis, and the above-mentioned vane plate driving mechanism is driven along a circular track centered on the second axis In the vane plate, the second axis is set at a second position on the beam axis and is perpendicular to the beam axis and the first axis.

In addition, the particle beam therapy apparatus of the present invention includes: an irradiation nozzle that scans a particle beam supplied from an accelerator using two electromagnets with different scanning directions, and performs irradiation to expand the irradiation field; and the above-mentioned multi-leaf collimator The multi-leaf collimator is arranged in the particle beam irradiated by the above-mentioned irradiation nozzle, and the particle beam therapy device is characterized in that the above-mentioned first axis and the scanning axis of one of the above-mentioned two electromagnets The above-mentioned multi-leaf collimator is arranged so that the above-mentioned second axis coincides with the scanning axis of the other electromagnet.

In addition, the treatment planning device of the present invention is characterized by including: a three-dimensional data generating unit that generates three-dimensional data from image data of an irradiation target; and an irradiation condition setting unit based on the generated three-dimensional data to set the irradiation conditions; and a control data generation unit, the control data generation unit based on the set irradiation conditions, to generate the The three-dimensional data generating unit generates the three-dimensional data using at least a deflection angle of the beam centered on the first axis and a deflection angle of the beam centered on the second axis.

Invention effect

According to the multi-leaf collimator, particle beam therapy device, and treatment planning device of the present invention, when the multi-leaf collimator forms a transmission shape, the surface of the blade plate formed as an outline and the particles near the surface can be transmitted. The diffusion direction of the beam is consistent, so it is not affected by the penumbra and forms an irradiation field with high contrast.

Description of drawings

FIG. 1 is a diagram for explaining the configuration of an irradiation system of a particle beam therapy apparatus including a multileaf collimator according to Embodiment 1 of the present invention.

2 is a side view seen from two directions perpendicular to the center of the beam for explaining the configuration of the irradiation system of the particle beam therapy apparatus including the multileaf collimator according to Embodiment 1 of the present invention.

3 is a diagram for explaining a beam state of a charged particle beam in an irradiation system of the particle beam therapy apparatus according to Embodiment 1 of the present invention.

4 is a diagram showing a fully closed state for explaining the structure of the multi-leaf collimator and blade plates according to Embodiment 1 of the present invention.

5 is a diagram showing a state in which an irradiation field of a predetermined shape is formed for explaining the configuration of the multi-leaf collimator and blade plates according to Embodiment 1 of the present invention.

FIG. 6 is a diagram showing an example of beam scanning trajectories in the particle beam therapy system according to Embodiment 2 of the present invention.

7 is a diagram showing another example of beam scanning trajectories in the particle beam therapy system according to Embodiment 2 of the present invention.

8 is a diagram for explaining the configuration of a particle beam therapy system and a multi-leaf collimator according to Embodiment 5 of the present invention.

FIG. 9 is a diagram for explaining the flow of medical actions.

FIG. 10 is a block diagram illustrating the configuration of a treatment planning device according to Embodiment 6 of the present invention.

detailed description

Implementation mode 1.

Next, configurations of the multileaf collimator and the particle beam therapy apparatus according to Embodiment 1 of the present invention will be described. 1 to 5 are diagrams for explaining the configuration of a multi-leaf collimator and a particle beam therapy apparatus according to Embodiment 1 of the present invention, and FIG. 1 shows a diagram of a particle beam therapy apparatus including a multi-leaf collimator. The diagram of the configuration of the irradiation system, FIG. 2 is a diagram viewed from a direction perpendicular to the center (z direction) of the charged particle beam in FIG. 1 in order to show the configuration of the particle beam therapy device and the multi-leaf collimator, FIG. 2 (a) is a side view seen from the y direction, and FIG. 2(b) is a side view seen from the x direction. Fig. 3 is a diagram for explaining the shape of the beam in the irradiation system of the particle beam irradiation device, and Fig. 3(a) is a diagram showing the overall appearance of the beam; Fig. 3(b) and Fig. 3(c) are View from a direction perpendicular to the center (z-direction) of the charged particle beam in Fig. 3(a), Fig. 3(b) is a side view from the y-direction, and Fig. 3(c) is from the x-direction Observed side view. In addition, FIGS. 4 and 5 are diagrams viewed from various directions in order to explain the structure of the multi-leaf collimator and the blade plate which is a main component of the multi-leaf collimator.

As a prerequisite for describing the configuration of the multi-leaf collimator in detail, first, an irradiation system of a particle beam therapy apparatus including the multi-leaf collimator will be described. As shown in Figures 1 and 2, the particle beam therapy device 10 includes: a oscillating electromagnet 1 (upstream 1a, downstream 1b), the oscillating electromagnet 1 plays the role of the irradiating mouth. The so-called pencil-shaped charged particle beam B provided by the accelerator is scanned to expand the irradiation field; the ridge filter 2 is used to expand the width of the Bragg peak according to the thickness of the irradiated object; the range shift The range shifter 3 is used to change the energy (range) of the charged particle beam B according to the depth of the irradiated object (irradiation depth); the block collimator (blockcollimator) 4 is used for the block collimator 4 To limit the expanded irradiation field within a specified range to prevent unnecessary irradiation of normal tissues; the multi-leaf collimator 5 is composed of a plurality of blade plates and blades driving each blade plate A drive mechanism for restricting the irradiation field so as to conform to the shape of the affected part; and a block 6 for restricting the range of the charged particle beam B so as to conform to the depth shape of the irradiated object.

Next, the operation and principle of the irradiation system in which the irradiation field is enlarged by the irradiation nozzle using the swing method will be described.

The charged particle beam B is accelerated by an accelerator not shown, and introduced into the irradiation system via a transport system as a so-called pencil beam having a diameter of several mm or less. The oscillating electromagnet 1 scans the beam introduced into the irradiation system so that it traces a circular trajectory. The swing electromagnet 1 generally includes an x-direction electromagnet 1a and a y-direction electromagnet 1b as shown in the figure, and the two electromagnets are arranged so that they are connected along the central axis _XB of the charged particle beam B. Here, for clarity of description, an x direction and a y direction are defined. The coordinate system can be defined according to various standards, and this specification defines the coordinate system according to the following standards. Let the advancing direction of the charged particle beam B be the positive direction of the z-axis. The x-axis and the y-axis are axes orthogonal to the z-axis, and the x-axis and the y-axis are orthogonal to each other. Also, the xyz coordinate system is a right-handed coordinate system. In the example of FIGS. 1 and 2 , the upstream oscillating electromagnet 1 a scans the beam in the x direction and the downstream oscillating electromagnet 1 b scans the beam in the y direction. By scanning the two electromagnets 1a and 1b, the irradiation field is expanded in the xy direction (planar direction).

The charged particle beam B after expanding the irradiation field passes through the ridge filter 2 . If the ridge filter is formed by arranging a plurality of pyramidal bodies or plates with a triangular cross-section in the plane, if the irradiation field is divided into a plurality of small areas, for example, there will be holes with different thicknesses for each small area. beam. In the figure, for easy understanding, the cones are described as being arranged like a mountain of swords. Accordingly, the width of the Bragg peak, SOBP (Spread-Out Bragg Peak), is enlarged. That is, the ridge filter 2 also diffuses the irradiation field in the z direction. Next, the charged particle beam B after expanding the irradiation field passes through the range shifter 3 . The range shifter 3 is a device for changing the energy of the charged particle beam B. The expanded irradiation field can be irradiated to a desired depth in the body by the range shifter 3 . Next, the beam passing through the range shifter 3 passes through the block collimator 4 . The stopper collimator 4 is a metal block or the like provided with a through hole PH, and limits the diffusion of the irradiation field in the planar direction (xy plane). This is because unnecessary irradiation of normal tissues can be prevented by limiting the irradiation range in advance.

Next, the charged particle beam passes through the multi-leaf collimator 5 . As will be described in detail later, the multi-leaf collimator 5 is used to limit the irradiation field to match the shape of the affected part using the transmission shape PS formed according to the positions of the plurality of leaf plates _5L . That is, the irradiation field is limited and shaped in the xy direction by the multi-leaf collimator 5 . In addition, the multi-leaf collimator 5 includes at least a blade plate 5 _L (as a whole, a blade group 5 _G ) and a blade drive mechanism 5 _D . However, the structure of the blade drive mechanism _5D itself is not important if it can represent the drive track of the blade. In addition, since it is difficult to show the structure of the blade plate _5L if the blade drive mechanism _5D itself is described in the figure, in the above Figures 1 and 2 and the following drawings, in order to simplify it, In the multi-leaf collimator 5 , only the leaf plate 5 _L or the leaf plate group 5 _G obtained by combining the leaf plates 5 _L is extracted and described.

Finally, the charged particle beam B passes through the block 6 . The block 6 is a stopper made of resin or the like, and has a shape of the depth of the affected part, for example, formed to compensate for the shape of the distal end (Distal) of the affected part. The terminal shape refers to the concave-convex shape of the deepest part. Here, the energy of the irradiation field is confined (shaped in the z-direction) and has the same shape as the tip shape. That is, the irradiation field is restricted and shaped in the z direction by the block 6 .

The role of the irradiation system of the particle beam therapy apparatus is to form an irradiation field to be irradiated so that it coincides with the affected part. As this method, the particle beam therapy apparatus according to Embodiment 1 employs a swing method in which the irradiation field is enlarged only by the swing electromagnet 1 . A specific example of this method is, for example, the "method of realizing large-area and uniform irradiation by helical beam scanning" shown in Patent Document 3, which is also called the helical wobble method in the wobble method. In short, the helical wobble method is a method of expanding an irradiation field by scanning a beam in a helical shape, and ensures flatness by improving a scanning trajectory (scanning trajectory) in the irradiation field. In addition, for the scanning trajectory of the beam formed by the helical wobble method, see FIG. 1 of Patent Document 3 and the like.

On the other hand, the oscillating method generally refers to the single-circle oscillating method, and in this case, the flatness is ensured by a scatterer when expanding the irradiation field. Therefore, even in the same wobble method, there are cases where a scatterer is used and cases where a scatterer is not used, and the directivity of the beam differs depending on the presence or absence of a scatterer. In the case of using a scatterer, since the beam spreads over the entire surface of the scatterer, a width is generated in the irradiation direction of the beam passing a certain point. On the other hand, the scatterer is not used like the spiral swing method, and only the scanning electromagnet is used to diffuse the beam. In this case, the irradiation direction of the beam passing a certain point is mainly determined by the position away from the scanning electromagnet. a certain direction.

FIG. 3 is a schematic diagram showing a beam diffusion method (beam F _B shape) generated by the two-stage scanning electromagnet 1 in the irradiation system of the particle beam therapy apparatus 10 according to the first embodiment. In the helical oscillating method, the beam spreads as shown in Figure 3, rather than as a point source. For ease of description, the beam spreading method shown in FIG. 3 is referred to as "two-stage scanning spreading". When the beam is not a point source and is diffused in two-stage scanning, it is necessary to design a suitable limiter.

Here, some detailed descriptions of the two-stage scanning diffusion are added.

As shown in FIG. 3 , the beam B is irradiated from above to below (z direction). Beam B is originally provided in a thinner state known as a pencil beam. On the beam axis _XB , a reference point CPa and a reference point CPb are set. The reference point CPa can be regarded as the position where the upstream oscillating electromagnet 1a (strictly speaking, the scanning axis A _sa ) is arranged. Similarly, the reference point CPb can be regarded as the position where the downstream oscillating electromagnet 1b (strictly speaking, the scanning axis A _sb ) is arranged. s position.

The upstream oscillating electromagnet 1a arranged at the reference point CPa scans the beam with reference to the reference point CPa. The scanning direction of the beam of the upstream oscillating electromagnet 1a is the direction of scanning in the plane (xz plane) of Figure 3 (b), and passes through the reference point CPa on the beam axis X _B , perpendicular to the beam axis X _B The axis A _sa becomes the action axis (scanning axis) of the upstream oscillating electromagnet 1a. In addition, the downstream oscillating electromagnet 1b arranged at the reference point CPb scans the beam with reference to the reference point CPb. The scanning direction of the beam of the downstream oscillating electromagnet 1b is the direction of scanning in the plane (yz plane) of Fig. 3 (c), and passes through the reference point CPb on the beam axis X _B , and the beam axis X _B and The axis _Asb perpendicular to the axis _Asa becomes the action axis (scanning axis) of the downstream swing electromagnet 1b. That is, the scanning direction (x) of the upstream oscillating electromagnet 1a and the scanning direction of the downstream oscillating electromagnet 1b

(y) is perpendicular to the beam axis _XB , and the scanning direction (y) of the downstream oscillating electromagnet 1b is perpendicular to the scanning direction (x) of the upstream oscillating electromagnet 1a.

In addition, the shape of the above-mentioned beam F _B will be described geometrically using FIG. 3 .

As shown in Fig. 3(b), a vertical (z-direction) line segment with the reference point CPa as the upper end point is drawn, and a reference point CPb is set at a position other than the reference point CPa on the line segment. Rotate the line segment by only ±α degrees with the reference point CPa as the center, and at this time obtain the sector Fsa through which the line segment passes. This sector Fsa corresponds to the spread of the beam when only the upstream oscillating electromagnet 1a is used. Next, the sector Fsa is divided into an upper half and a lower half by the reference axis _Asb passing through the reference point CPb. Rotate the lower half of the sector Fsa by only ±β degrees with respect to the reference axis _Asb , and at this time obtain the area through which the lower half of the sector Fsa passes. In FIG. 3( c ), this region can be seen as the region of the sector Fsb, which shows how the beam spreads (the region through which the beam can pass: beam F _B ). That is, the shape of the beam F _B subjected to two-stage scanning diffusion is formed into a fan shape with different curvature radii in the x direction and the y direction.

The embodiment of the present invention considers the shape of the beam F _B obtained by expanding the irradiation field by using the two scanning electromagnets 1a and 1b with different scanning directions as described above, and after performing two-stage scanning diffusion of the beam. The multi-leaf collimator 5 involved is used to correctly form a high-contrast radiation field without being influenced by the penumbra. That is, in the multi-leaf collimator 5 according to Embodiment 1 of the present invention, each leaf plate 5 _L and the actual facing surface _PL of the leaf plate adjacent to it in the thickness direction are formed in one plane, This plane is on the beam axis X _B of the electron particle beam B and includes the scanning axis A _sa of the scanning electromagnet 1a set on the reference point CPa, along the reference set on the beam axis X _B The scanning axis _Asb of the scanning electromagnet 1b on the point CPb is a circular orbit centered on each blade plate 5L, and the scanning axis _Asb of the scanning electromagnet 1b is perpendicular to the beam axis X _B and the _scanning axis _Asa .

Next, a detailed description will be given using FIGS. 4 and 5 . Fig. 4 is a diagram showing the state of the blades in the fully closed state for explaining the structure of the multi-leaf collimator and the blade plate driven in the multi-leaf collimator, and Fig. 4(a) is a multi-leaf collimator Figure 4 (b) is a perspective view of the upper surface observed from the P direction of Figure 4 (a), and Figure 4 (c) is observed from the F direction of Figure 4 (a) Figure 4(d) is a side perspective view of the left half of the multi-leaf collimator viewed from the S direction of Figure 4(a). In addition, FIG. 5 is a diagram showing the state of forming an irradiation field of a predetermined shape, and FIG. 5(a) is an overall appearance view of the leaf group of the multi-leaf collimator; The perspective view of the upper surface observed from the direction of Fig. 5 (c) is the front perspective view observed from the direction F of Fig. 5 (a), and Fig. Side perspective view of the blade column in the left half of the straightener.

As shown in Figures 4 and 5, the multi-leaf collimator 5 _{has two rows of blades (5 c1 ,} 5 _c2 : collectively _referred to as 5 _c ), and includes: blade group _5G , which blade group _5G is configured such that one end surface EL of blade rows _5c1 and _{5c2 faces} each other; and a blade plate driving mechanism not shown, which drives Each vane plate 5 _L is made to be close to or away from its opposite vane plate. The shape of each vane plate 5 _L is the actual shape of the main surface of the plate as each vane plate, that is, it is formed with the opposite surface _PL of the adjacent vane plate. on a plane including the scanning axis A _sa of the scanning electromagnet 1a that expands the charged particle beam B in the x direction. That is to say, the main surface of the plate is formed on two planes including the scanning axis _Asa of the scanning electromagnet 1a, and the thickness of the cross-section after cutting the blade plate in the plane including the irradiation direction and the plate thickness direction varies with The thickness increases from the upstream side toward the downstream side in the irradiation direction of the charged particle beam B.

And, let the driving track (direction in the yz plane) of each blade 5 _L be a circular track _OL corresponding to the distance from the scanning _{axis Asb of} the downstream electromagnet 1b, which The charged particle beam B is expanded in the y direction, and among the four end faces of the vane plate 5 _L , the shape of the incident side end face P _I adjacent to one end face _EL and the shape of the exit side end face P _X The shapes are respectively formed as circular arcs centered on the scanning axis _Asb , that is, by forming a part of a circle centered on the scanning axis Asb, so that even if the blade plate 5 _L is driven along the circumferential orbit _OL , along the charged The depth dimension in the irradiation direction of the particle beam B also does not change.

Thus, _regardless of where the _{vane plate 5L} is driven, for example, as shown in FIG. The irradiation direction of the particle beam B is parallel so that no penumbra is generated. In addition, the opposing surface _PL of the vane plate 5 _L forming the outline of the transmission shape PS in the y direction is parallel to the irradiation direction of the charged particle beam B passing near the opposing surface _PL so that no penumbra occurs. That is, no penumbral zone is formed in the outline of the transmission shape PS formed by the multi-leaf collimator 5 , so that an accurate irradiation field suitable for the shape of the affected part can be formed.

That is, only the shape of each blade plate 5 _L in the thickness direction of the multi-leaf collimator 5 according to Embodiment 1 of the present invention and the diffusion shape of the driving orbit _OL and the beam F _B of the charged particle beam B Just the same. That is, it is a range that can pass when the scanning angles of the two-stage scanning electromagnets 1a and 1b are respectively limited. It can even be said to be the position of the charged particle beam within a certain range of the beam propagation distance from the beam source. Since the multi-leaf collimator 5 is obtained by laminating the leaf plates 5 _L , the formed transmission shape PS is also the diffused shape of the beam F _B of the charged particle beam. In addition, thus, the opening (contour) forming the transmission shape PS does not depend on the shape of the opening, and the end surface E _L facing the center of the irradiation field of the blade plate 5 _L as the wall surface of the opening, and the wall surface facing the adjacent blade plate The plane _PL coincides with the irradiation direction of the charged particle beam passing through the vicinity of the plane. Therefore, it is possible to solve the penumbra problem caused when two-stage scanning electromagnets 1a, 1b are used. In addition, when irradiation is performed using a scatterer for the purpose of improving flatness, a width is generated in the above-mentioned two-stage scanning type irradiation direction distribution. Therefore, even in the case of using the multi-leaf collimator 5, a part of the charged particle beam will be irradiated on the end surface _{EL or the opposite surface PL of} the blade plate, and it is less likely than the case of not using the scatterer. The effect of the shadow band is somewhat reduced, but the effect of suppressing the penumbral band can be obtained compared with the conventional multi-leaf collimator with a simple cone.

In addition, in the multileaf collimator 5 according to Embodiment 1, the shape in the thickness direction is set based on the position of the upstream electromagnet 1a, and the drive is set based on the position of the downstream electromagnet 1b. Orbit O _L , but not limited thereto, and the reverse setting is also possible. Therefore, the upstream electromagnet 1a scans in the x-direction, and the downstream electromagnet 1b scans in the y-direction, but the reverse is also possible. In addition, although the angles between the opposing surfaces _PL which define the thickness of each vane plate 5 _L are shown to be equal in the figure, it is not limited to this. Even if they are not equal, the above-mentioned effect of suppressing the penumbra can be obtained. In addition, the use of "substantially" to express the opposite surface is because the opposite surface is stacked in the thickness direction and is used to distinguish it from the substantially adjacent blade. For example, even if there is formed in the opposite surface for Grooves, grooves, and the like forming the driving track are also formed in a plane including the scanning axis _Asa of the scanning electromagnet 1a set on the reference point CPa. In addition, the blades 5 _L of the blade rows 5 _C1 and 5 _C2 are in a paired state of one to one, but they are not necessarily paired. In addition, the blade row does not have to be two rows. For example, in the case of only one row, as long as the end surface EL of the blade plate is _closest to the beam axis X _B , it can be in close contact with the fixed surface and block the beam B. . In addition, it is also possible to have several columns.

In addition, as a method of enlarging the irradiation field, the helical wobble method in which the scanning trajectory is helical has been described, but as described in the embodiments described later, other helical wobble methods can also be used, and the method is not limited to the helical wobble. Law. In addition, the electromagnet functioning as the irradiation nozzle is not limited to the swing electromagnet 1, and any irradiation nozzle can expand the irradiation field by using two electromagnets with different scanning directions.

As described above, according to the multileaf collimator 5 according to Embodiment 1, the multileaf collimator is arranged in the charged particle beam B irradiated to expand the irradiation field by the scanning electromagnet 1, and is used for An irradiation field suitable for the shape of the affected part that is the irradiation object is formed, and the multi-leaf collimator 5 includes: a blade row 5 _C that _aligns one end surface _EL of a plurality of blade plates 5 _L and arranges them on In the thickness direction; and the vane plate driving mechanism 5 _D , the vane plate driving mechanism 5 _D drives each vane plate 5 _L so that one end surface _EL is relative to the beam axis X _B of the particle beam B, or relative to the opposite side The vanes are close to or far away from each other. Among the respective vanes 5L, the opposing faces _PL of the vanes and the vanes adjacent to the vane in the thickness direction (x direction ₎ are formed on a plane _{PSa that} includes The first axis is the scanning axis A _sa , the first axis is set at the first position on the beam axis X _B of the charged particle beam B, that is, the reference point CPa, and is perpendicular to the beam axis X _B , the blade plate driving mechanism 5 _D drives the vane plate 5 _L along a circular orbit _OL centered on the second axis, that is, the scanning axis _Asb , which is set at the second position on the beam axis X _B , that is, the reference point CPb, and is consistent with The beam axis X _B and the first axis A _sa are vertical. Since the multileaf collimator 5 has such a structure, the opposite surface _PL or the end surface E _L of the outline of the transmission shape PS of the multileaf collimator 5 is formed. The direction of is consistent with the diffusion method of the beam F _B of the charged particle beam B, so that the influence of the penumbra can be suppressed and an accurate irradiation field can be formed according to the shape of the irradiation object.

In addition, among the main four end faces of the vane plate 5 _L , the end face P _I on the incident side of the charged particle beam B and the end face P _X on the exit side of the charged particle beam B adjacent to one end face E _L are formed in the shape of the second end face P X. Since the two axes, that is, the scanning axis Asb, are circular arc-shaped, the vane plate 5 _L can be easily driven along the circular orbit _OL . In addition, no matter how the blade plate _5L is driven, the depth dimension along the irradiation direction of the charged particle beam B does not change, so that the distance for shielding the charged particle beam does not change.

In addition, the particle beam therapy apparatus 10 according to Embodiment 1 of the present invention includes a oscillating electromagnet 1 that performs a charged particle beam B supplied from an accelerator using two electromagnets 1a and 1b having different scanning directions. Scan and irradiate to expand the irradiation field; and the above-mentioned multi-leaf collimator 5, the multi-leaf collimator 5 is arranged in the charged particle beam B (ie beam F _B ) irradiated by the irradiation nozzle 1, and the multi-leaf collimator The first axis of the straightener 5 is consistent with the scanning axis (A _sa or _{Asb) of one of the above two electromagnets, and the second axis is consistent with the scanning axis (A sb or} A _sa ) of the other electromagnet , according to such a configuration, it is possible to suppress the influence of the penumbra and irradiate charged particle beams with an irradiation field corresponding to the shape of the irradiation target.

Implementation mode 2.

In Embodiment 1, the application of the helical wobble method of scanning the beam in a helical shape was explained. However, the shape of the scanning trajectory (scanning trajectory) of the beam in the irradiation field is not limited to the technical idea of the present invention, and the effect of two-stage scanning diffusion can also be exhibited in other beam scanning trajectory. Therefore, in Embodiment 2, the case will be explained by applying the multileaf collimator of the present invention to an irradiation system having another typical beam scanning trajectory.

First, the beam scanning trajectory obtained by the helical wobble method used in Embodiment 1 will be described. As described in Patent Document 3, the spiral scanning trajectory is obtained by Equation (1) including the following three equations.

(mathematical formula 1)

Here, the radius at time t=0 is R _min , the radius at time t=T is R _max , and the number of scans is N. In addition, r(t) is the coordinate in the radial direction; θ(t) is the coordinate in the angular direction, which is represented by the polar coordinate system.

The beam scanning trajectory obtained according to the above formula (1) is in a spiral shape, which is an effective shape for scanning the beam in a circular area and obtaining a uniform dose distribution. However, in order to obtain a uniform dose distribution, it is not necessary to limit the beam scanning trajectory to a helical shape. It is considered that beam scanning trajectories for obtaining a uniform dose distribution by scanning two electromagnets can be classified into several typical patterns.

The oscillating method is a method of continuously scanning the beam to form a uniform dose distribution. That is, it is preferable that the beam scanning trajectory in the wobble method is continuous and periodic. Therefore, a pattern in which r(t) and θ(t) are continuously and periodically changed by expressing the beam trajectory using the polar coordinate system will be discussed.

<Typical pattern 1>

In the first pattern, r(t) and θ(t) are defined as functions that change continuously and periodically as shown below.

r(t) = continuous and periodic function (period T ₁ )

θ(t) = continuous and periodic function (period T ₂ ),

In addition, different values may be used for the periods of r(t) and θ(t) at this time. In addition, pay attention to the angle θ, 360 degrees can be regarded as 0 degrees obtained after one rotation. In other words, 360 degrees and 0 degrees are continuous. If expressed in radians, 2π can be regarded as 0.

As an example of realizing the above pattern, a beam scanning trajectory shown in equation (2) including the following three equations can be cited.

r(τ)＝r ₁ +r ₂ sin(ω _r τ+φ _r )

θ(τ)=ω _θ τ···

(2)τ=τ(t)

Here, τ(t) is a parameter of the above formula (2) represented by a parameter, and is a function of time. ω _r is the angular velocity that determines r(t), whose period is 2π/ω _r . φ _r is the initial phase. ω _θ is the angular velocity that determines θ(t), the period of θ(t) is 2π/ω _θ .

As shown in FIG. 6 , an example of the beam scanning trajectory ST1 generated by Equation (2) is shown. FIG. 6 is a diagram showing a scanning trajectory in a certain plane perpendicular to the beam axis, with x on the horizontal axis and y on the vertical axis, and x and y are respectively standardized. In addition, in formula (2), the reason why the parameter is not set as time t is that the drawing speed can be changed according to different situations. For example, in Fig. 6, the coordinates (0, 0) are used as the center of the beam axis. Since the beam scanning is more concentrated and the density is higher near the center of the beam axis, the trajectory of the beam near the center Concentrated parts, trying to speed up the scanning speed, etc., thus obtaining a uniform dose distribution.

<Typical pattern 2>

In the second pattern, multiple functions defining the trace pattern are combined to form the beam scanning trajectory. For example, combine a function that draws a larger circle with a function that draws a smaller circle. Equation (3) including the following 3 equations shows one example thereof.

x(τ)＝r ₁ cos(ω ₁ τ+φ ₁ )+r ₂ cos(ω ₂ τ+φ ₂ )

y(τ)＝r ₁ sin(ω ₁ τ+φ ₁ )+r ₂ sin(ω ₂ τ+φ ₂ )···

(3)

τ=τ(t)

Wherein, x(τ) and y(τ) are the x-coordinate and y-coordinate of the beam scanning trajectory respectively, and are an orthogonal coordinate system. An example of the beam scanning trajectory generated by the mathematical formula (3) is shown in FIG. 7 . FIG. 7 is the same as FIG. 6 , showing the scanning trajectory in a certain plane perpendicular to the beam axis, with x on the horizontal axis and y on the vertical axis, and x and y are respectively standardized.

There is a prop in the toy, a gear-shaped disc is set in a circular hole formed with teeth inside it, and a pen tip is inserted into a small hole at a specified position in the disc, so that the disc moves along the A geometric pattern is drawn by rotating it around a circular hole, and geometric patterns made from this prop also fall into this category. In addition, the curve drawn by this prop is called hypotrochoid, which is defined geometrically as follows, that is, when a circle with radius r is used as the active circle and the distance from the active When a point whose distance from the center of a circle is Ir is used as a fixed point, the circle of radius r is inscribed to a circle of radius kr, and is obtained by rotating the active circle with respect to the circle of radius r without sliding track. In addition, in most stirring devices, this pattern is used as a driving pattern of the stirring unit. Also, as in the previous example, the reason why the parameter is not set to time t is to allow the drawing speed to be changed depending on the situation.

As described above, in the method of drawing a continuous and periodic pattern (line pattern) using the oscillating electromagnet, the pattern is not limited to a spiral shape. However, the idea of realizing large-area and uniform irradiation by designing beam trajectories without using scatterers comes from the "spiral wobble method", so these methods shown in Embodiment Mode 2 are also called generalized wobble Law. Moreover, in these generalized spiral swing methods, the diffusion method of the beam is not a point source type, but a two-stage scanning type.

That is, in the particle beam therapy apparatus of the second embodiment having the irradiation system using the generalized helical swing method, the multi-leaf collimator shown in the first embodiment is applied, so that the thickness of each leaf plate can be made The shape in the direction and the drive trajectory are the same as the spread shape of the beam F _B of the charged particle beam B. Therefore, the formed transmission shape PS is also the diffused shape of the beam F _B of the charged particle beam B, and the opening forming the transmission shape PS does not depend on the shape of the opening, but the wall surface facing the blade plate The end surface of the center of the irradiation field and the surface opposite to the adjacent blade plate are consistent with the irradiation direction of the charged particle beam. Therefore, the penumbra problem caused when using two-stage scanning electromagnets can be solved.

Implementation mode 3.

In Embodiments 1 and 2 above, the case where irradiation is performed using the swing method has been described. However, as described above, the irradiation method itself is not an essential part of the present invention, nor does it limit the technical idea of the present invention. In a particle beam therapy apparatus, a spot scanning method has been proposed which scans a charged particle beam using a two-stage scanning electromagnet and performs spot irradiation on an irradiated object in a point drawing manner. In the case of spot scanning, the spread of the beam is also two-stage scanning. Therefore, even when a multi-leaf collimator is used for spot scanning, the effect of suppressing the above-mentioned penumbra and forming an irradiation field with high contrast can be exhibited.

Implementation mode 4.

In Embodiment 3, a case where the point scanning method is applied to the multi-leaf collimator according to the embodiment of the present invention is described. Like the spot scanning method, there is also a raster scanning method in which a beam is scanned using two-stage scanning electromagnets and raster irradiation is performed on an irradiation target in a one-stroke writing manner. In the case of raster scanning, the spread of the beam is also two-stage scanning. Therefore, when a multi-leaf collimator is used for raster scanning, the multi-leaf collimator 5 according to the above-described embodiment of the present invention exhibits an effect. In other words, when the irradiation field is enlarged by a scanning method such as point scanning or raster scanning, if the multi-leaf collimator 5 according to the embodiment of the present invention is used, the above-mentioned penumbra can be suppressed and the contrast can be achieved. The effect of a higher irradiation field.

Implementation mode 5.

In a particle beam therapy apparatus, for example, as described in Patent Document 4, a proposal has been made in which one of the two scanning electromagnets is omitted by designing a control method of the deflection electromagnet. However, since in such an irradiation system, the deflection electromagnet for changing the track direction (direction of the beam axis) scans the charged particle beam instead of the omitted scanning electromagnet, the beam also undergoes two-stage Scanning diffusion, so that the multi-leaf collimator in the above embodiment can exert the effect of suppressing the penumbra.

Fig. 8 is a diagram showing a portion of an irradiation system including a multi-leaf collimator in a particle beam therapy apparatus according to Embodiment 5. In the figure, for the charged particle beam B supplied from the horizontal direction (x direction), the deflection electromagnet 201a is used to deflect the beam axis to the vertical direction, and after passing through the scanning electromagnet 201b, it passes through the ridge shape as in Embodiment 1. The filter 2, the range shifter 3, the ring collimator 4, the multi-leaf collimator 205 and the agglomerate 6 irradiate the irradiation object. Furthermore, the difference between the structure of the particle beam therapy apparatus 210 in the fifth embodiment and the first embodiment is that: a deflection electromagnet 201a is provided instead of the scanning electromagnet 1a in the particle beam therapy apparatus 10 of the first embodiment; The shape of the leaf plate of the leaf collimator 205 and the setting standard of the track are different.

In the figure, the beam axis P _X of the charged particle beam B supplied from the horizontal direction is deflected in the z direction while drawing an arc inside the deflection electromagnet 201 a. At this time, generally, when using the deflection electromagnet, control is performed so that the magnetic field does not change, so that the beam of the charged particle beam B does not spread. However, in the case of using the deflection electromagnet 21, the deflection electromagnet The iron 21 can scan the charged particle beam B in the x direction by changing the magnetic field periodically so that the beam spreads from P _E1 to P _E2 in the x direction. That is, the deflection electromagnet 201a functions as the upstream scanning electromagnet 1a in the first embodiment. Subsequent parts are basically the same as in Embodiment 1, and the scanning electromagnet 201b diffuses the beam diffused in the x direction to the y direction.

The diffusion mode of the beam can be regarded as that there is a scanning axis of the upstream scanning electromagnet _201a on the equivalent reference point E _As in FIG. ) is scanned in the x-direction, spreading from E _E1 to E _E2 in the x-direction. In addition, in the deflection electromagnet 201a, as the beam advances, the beam axis is gradually deflected. Therefore, the beam axis on the entrance side is different from the beam axis on the exit side (=beam axis E _X ), and the scanning axis _EAS is located away from the main body of the deflection electromagnet 201a. However, since the beam axis incident into the multi-leaf collimator 205 is the beam axis EX, it can be understood that the reference point _CPa that defines the position of the scanning axis _EAS is at the position of the beam incident into the multi-leaf collimator 205. On the beam axis of the beam, it can also be understood that the scan axis E _AS is perpendicular to the beam axis of the beam incident into the multi-leaf collimator 205 . Therefore, in the irradiation system that uses one electromagnet also as a deflection electromagnet as described above, the beam axis of the beam incident into the multi-leaf collimator can be used as a reference to calculate from the beam diffusion method The equivalent scan axis E _As is the same as in Embodiment 1. The shape and trajectory of the blades of the multi-leaf collimator 205 are set using the equivalent scan axis E _As and the scan axis _Asb (reference point CPb).

As can be seen in Figure 8, the irradiation system omits a scanning electromagnet, and uses a deflection electromagnet 201a that bends the track to replace the omitted scanning electromagnet. The distance between the reference point CPa and the reference point CPb that define the equivalent scanning axis E _As (equivalent) becomes larger than that of a normal irradiation system that scans according to the method 1 (1a, 1b). Therefore, in a multi-leaf collimator that assumes a beam spreading method of a point light source type, the problem of penumbra generation is particularly conspicuous. However, no matter what kind of transmission shape is formed, the multi-leaf collimator 205 according to Embodiment 5 of the present invention is set so that the surface forming the outline of the transmission shape is the same as the direction in which the beam spreads. The shape and track of each blade plate. Therefore, the relatively prominent penumbra problem that occurs in an illumination system that omits a single scanning electromagnet can be easily resolved.

As described above, in the particle beam therapy apparatus 210 according to Embodiment 5, when scanning two directions x and y, one of them (x Or y) scan, and set the beam axis of the set reference point CPa, _CPb as the beam axis EX of the beam incident in the multi-leaf collimator 205, and carry out the configuration of the multi-leaf collimator 205 and configuration, therefore, it is possible to suppress the penumbra and form a high-contrast irradiation field.

Implementation mode 6.

In each of Embodiments 1 to 5 above, the configuration of the multi-leaf collimator and the irradiation system using the multi-leaf collimator, and the beam trajectory thereof have been described. In Embodiment 6, a treatment planning device for setting operation conditions of the multileaf collimator and the particle beam therapy apparatus according to the above-mentioned embodiments of the present invention will be described.

Here, before describing the treatment planning device, the diagnosis and treatment action, which is the premise of the treatment plan executed by the treatment planning device, will be described. Generally, it can be considered that the diagnosis and treatment behavior consists of several stages. FIG. 9 shows the stages (flow) of this medical treatment action, and shows devices used in each stage. The treatment flow will be described based on FIG. 9 .

Specifically, it can be said that diagnosis and treatment activities are roughly composed of the following stages: preventive diagnosis stage (MS1), diagnosis stage (MS2), treatment planning stage (MS3), treatment stage (MS4), and rehabilitation and follow-up observation stage ( MS5). In addition, especially when performing particle beam therapy or the like, the apparatus used in each of the above-mentioned stages is the apparatus shown on the right side of FIG. 9 . For example, the devices used in the diagnosis stage (MS2) are X-ray imaging devices, CT (Computed Tomography: computerized tomography), MRI (Magnetic Resonance Imaging: magnetic resonance imaging), etc., and in the treatment planning stage (MS3) The device used is what is known as a treatment planning device. Also, the device used in the treatment stage (MS4) is a radiation therapy device or a particle beam therapy device.

Next, each stage will be described.

The preventive diagnosis stage (MS1) refers to the stage in which preventive diagnosis is carried out regardless of the onset or absence. For example, regular physical examinations and medical examinations belong to this category. For cancer, methods using fluoroscopic images such as X-rays, PET (Positron Emission Tomography: Positron Emission Computed Tomography), PET/CT, etc. are known. A method of tomographic imaging, a method using genetic testing (immunoassay), and the like.

The diagnostic stage (MS2) refers to the stage where diagnosis is made on the premise of treatment after the onset of the disease. In the case of particle beam therapy, it is necessary to obtain three-dimensional information on the position and shape of an affected part in order to perform the therapy. Therefore, various CT and MRI apparatuses capable of obtaining three-dimensional data of an affected part are used.

The treatment planning stage (MS3) refers to a stage in which a treatment plan is set based on the above diagnosis results. In the case of performing particle beam therapy, a treatment plan is prepared using the treatment planning device according to Embodiment 6 at this stage. A detailed description of the treatment planning device will follow, and the description of the remaining stages will continue.

The treatment stage (MS4) refers to a stage in which actual treatment is performed based on the results of the above-mentioned treatment plan. In the case of performing particle beam therapy, a particle beam therapy device is used in this step. The multileaf collimator according to each of the above-described embodiments of the present invention is used to form an irradiation field in an irradiation system of a particle beam therapy apparatus. In addition, in the treatment phase, the treatment step may be completed after one irradiation, but it is usually necessary to perform multiple irradiations within a certain period.

As the literal meaning, rehabilitation and follow-up observation step (MS5) refers to the stage of rehabilitation or follow-up observation for recurrence. In the case of cancer, follow-up observations at this stage are the same as in the preventive diagnosis stage, and the following methods are used: methods using fluoroscopic images such as X-rays, methods using tomography such as PET and PET/CT, and methods using genetic testing ( immunoassay) methods, etc.

In the above diagnosis and treatment activities, the treatment plan is a series of operations performed after the diagnosis phase and before the treatment phase. Since the particle beam diagnostic device irradiates charged particle beams based on the treatment plan obtained by the treatment planning device, the treatment planning device in particle beam therapy generally includes means having the following functions.

Function A: A unit for generating three-dimensional data through pre-acquired image information of a plurality of irradiation objects.

Function B: means for generating optimal irradiation conditions (treatment plan) based on given conditions.

Action C: A unit that simulates the final dose distribution for the optimization result (treatment plan) and displays it.

That is, the treatment planning device plays the role of setting the irradiation conditions required for treatment based on the diagnosis results, and the treatment planning device also has the role of generating control data for the particle beam therapy device and the like based on the set conditions. unit.

In order to achieve the above functions, the treatment planning device also specifically has the following functions.

＜Action A＞

Function a: A function of generating three-dimensional data from the tomographic image obtained in the diagnosis stage.

Function b: A function to display generated 3D data from various angles of view like 3D CAD.

Function c: A function of distinguishing an affected part from a normal tissue in the generated three-dimensional data and storing it.

＜Action B＞

Function d: A function of setting parameters of a particle beam therapy apparatus used in a treatment step and simulating irradiation.

Function e: a function to optimize the irradiation under the conditions set by the user of the device.

＜Action C＞

Function f: A function to display the optimized irradiation result in a superimposed manner with the above-mentioned three-dimensional data.

＜Function D＞

Function g: A function to set the shapes of the multi-leaf collimator and the object in order to realize the above-mentioned optimized irradiation. (including multi-port irradiation assuming wide beam irradiation)

Function h: A function to set the irradiation trajectory of the beam in order to realize the above-mentioned optimized irradiation. (assuming the case of scanning irradiation)

Function i: a function for realizing the above-mentioned irradiation trajectory of the beam and generating a driving code of the particle beam therapy device.

＜Others＞

Function j: A function to store various data generated in the device.

Function k: A function that can reuse past information by reading various data stored in the past.

The system configuration of the treatment planning device for realizing the above-mentioned respective functions will be described. In recent years, manufacturers of treatment planning devices hardly design and manufacture unique hardware, and most of them are based on the Unix (registered trademark) operating platform or PC on the market, and most of the peripheral devices use general-purpose devices. That is, manufacturers of treatment planning devices focus on developing, manufacturing, and selling treatment planning software. In the treatment planning software, as a subroutine called by the main program, for example, a module realizing each function of function a to function k is prepared. The flow of functions a to k is omitted as necessary, or the conditions are changed and re-executed, so that the user of the treatment planning device can create a treatment plan while calling up necessary modules.

Next, each function or a module realizing each function will be described, and the treatment planning device according to the embodiment of the present invention will be described.

Function a (module a) generates three-dimensional data from a series of tomographic images acquired during the diagnosis phase. When reading tomographic images, it can also be read from patient information such as patient ID and scan information (slice interval, slice thickness, FOV, tomographic conditions, etc.). Here, the three-dimensional data refers to information necessary for virtually and three-dimensionally recreating an imaging target including an affected part in a treatment planning device. In general, a method is adopted in which a virtual space in the treatment planning device is defined, points are arranged in a grid at equal intervals in the virtual space, and the material information obtained from the tomographic image corresponds to the point. The reason why this function is necessary is that one of the most important purposes of a treatment planning device is to simulate treatment, maintain, and reproduce the affected part and its surrounding tissues to be irradiated.

Function b (module b) displays generated three-dimensional data from various viewpoints like three-dimensional CAD.

Function c (module c) distinguishes and stores the affected part and normal tissue in the generated three-dimensional data. For example, assume that a tomographic image is obtained using X-ray CT. In this case, the "material information" used in the function a corresponds to the degree of difficulty of X-ray transmission. That is, the three-dimensional model reproduced in the virtual space based on the tomographic image is the shape of a three-dimensional object composed of substances with different degrees of X-ray transmission. This "texture information", that is, the degree of difficulty of X-ray transmission, is represented by changing, for example, color or brightness in the virtual space of the treatment planning device. In addition, based on this "material information", it is possible to obtain the following information: that is, in the three-dimensional model reproduced in the virtual space, the part corresponds to the bone part, or the part corresponds to the tumor part, and the diseased part can be distinguished from the normal part. organize. The result of distinguishing the affected part from the normal tissue can be stored in the storage device (hard disk, etc.) of the treatment planning device.

Function d (module d) sets parameters of the particle beam therapy apparatus used in the treatment phase, and simulates irradiation. The parameters of the particle beam therapy device refer to geometrical information of the particle beam therapy device and information related to the irradiation field. The geometrical information includes the position of the isocenter, the position of the bed, and the like. The above-mentioned "coordinates of the reference point CPa and reference point CPb" and the like are included in the information on the irradiation field. In addition, the width (thickness) of the blade plate 5 _L , the quantity of the blade plate 5 _L , and the moving distance (angle) of the blade plate 5 _L of the multi-leaf collimator 5 or 205 (only 5 is described below as a representative) are also included. and other parameters.

Function e (module e) optimizes the irradiation based on the conditions set by the user of the treatment planning device.

The function f (module f) is to display the optimized irradiation results in a way that overlaps with the above-mentioned three-dimensional data.

The function g (module g) sets the shapes of the multileaf collimator 5 and the block 6 in order to realize the above-mentioned optimized irradiation. This function assumes wide-beam irradiation, including multi-leaf irradiation.

Function h (module h) is to set the irradiation trajectory of the beam in order to realize the above-mentioned optimized irradiation. This function assumes that scanning such as point scanning or raster scanning is performed.

Function i (module i) generates the drive code of the particle beam therapy device in order to realize the above-mentioned irradiation trajectory of the beam. At this time, as described below, if the coordinate system corresponding to the two-stage scanning diffusion is adopted, the multileaf collimator 5 shown in the first to fifth embodiments above can easily generate a driving code. The code is used to realize the aperture shape (transmission shape SP) corresponding to the obtained optimal irradiation plan.

Function j (module j) stores various data set and generated in the device.

Function k (module k) can reuse past information by reading various data stored in the past.

<Coordinate system corresponding to two-stage scanning diffusion>

In conventional treatment planning devices, the three-dimensional data used in the above function a and subsequent functions are generally expressed in an orthogonal coordinate system (xyz coordinate system). In the case where the overall shape of the multi-leaf collimator is an existing cuboid, since its arrangement or the driving direction of the leaves is also represented by an orthogonal coordinate direction (for example, the x direction or the y direction), it is possible to use the orthogonal Coordinate system to represent three-dimensional data. The reason for this is to match the shape data for generating the shape of the opening from the shape of the affected part with the blade drive data.

On the other hand, when using the multi-leaf collimator 5 according to the present invention, since the drive of the blade plate 5 _L is curved, it is preferable to set the command value for driving the blade to an angle centered on the reference point. . That is, it is preferable that the shape data for generating the shape of the opening corresponding to the shape of the affected part include an angle centered on the reference point in the same format as the blade drive command value of the present invention.

Therefore, the treatment planning device according to Embodiment 6 of the present invention displays three-dimensional data of an affected part using a special coordinate system.

Specifically, the special coordinate system shown in (D1) is defined as follows.

[ψ _a ，ψ _b ，r _b ]·····(D1)

where ψ _a is the deflection angle of the beam centered on the reference axis (Asa), which is perpendicular to the beam axis _XB and passes through the reference point CPa, and ψ _b is the beam centered on the reference axis (Asb) The deflection angle of the beam, the reference axis (Asb) is perpendicular to the beam axis X _B and the reference axis Asa and passes through the reference point CPb, r _b is from the reference point CPb (or reference axis (Asb)) to the irradiation point distance.

Any point in the three-dimensional space can be uniquely represented by the above three pieces of information. Among them, the reference point CPa and the reference point CPb need to be determined in advance according to the arrangement of the scanning electromagnets 1a and 1b. In addition, instead of rb, the distance ra _or the like from the reference point CPa (or the reference axis (Asa)) to which the beam propagates to the irradiation point may be used.

Here, the xyz coordinates of the reference point CPa and the reference point CPb are assumed as follows, with the isocenter being the irradiation reference being the origin of the xyz coordinate system.

Reference point CPa: (0, 0, -l _a )

Reference point CPb: (0, 0, -l _b )

Furthermore, as shown in FIGS. 1 to 3 , the upstream scanning electromagnet 1 a is assumed to be an x-direction scanning electromagnet, and the downstream scanning electromagnet 1 b is assumed to be a y-direction scanning electromagnet. At this time, the coordinates of a certain point are obtained by defining [ψ _a , ψ _b , r _b ] represented by the special coordinate system shown in (D1). At this time, the xyz coordinates of this point are obtained by the following formula (4 )To represent.

(mathematical formula 2)

Here, if Rot _x (ψ _b ) and Rot _y (ψ _a ) in the formula (4) are defined as in (D2), the xyz coordinates of a certain point are obtained as in the formula (5).

(mathematical formula 3)

Conversely, the method of finding a special coordinate system from the xyz coordinate system is as follows.

Since l _b is a value specific to the irradiation system, ψ _b can be obtained from the relationship between y and z in Equation (5) as in Equation (6).

(mathematical formula 4)

In addition, since _la is also an inherent value of the irradiation system, it can also be defined by the relationship between y and z in formula (5) as in definition (D3),

Λ:＝y ² +(z+l _b ) ² +(l _a -l _b )···(D3)

＝(l _a ―l _b +r _b )cosψ _a

From the relationship and definition (D3) of z in the formula (5), ψ _a is obtained by using the formula (7).

(mathematical formula 5)

Finally, r _b can be calculated using Equation (8).

(mathematical formula 6)

The coordinate system [ψ _a , ψ _b , r _b ] corresponding to the above-mentioned two-stage scanning beam spread is used from the stage of function a. That is, in function a, or as an auxiliary function for executing function a, there is a coordinate system conversion function for conversion to a special coordinate system, which is performed assuming two-stage scanning.

For example, FIG. 10 is a block diagram showing the characteristic parts of the action (unit) and function (block) of the treatment planning device according to Embodiment 6 of the present invention. In the figure, the treatment planning device 20 includes: a three-dimensional data generating unit 21 that generates three-dimensional data from image data of an affected part to be irradiated; an irradiation condition setting unit 22 that generates Irradiation conditions are set based on the generated three-dimensional data; and a control data generation unit 23 that generates control data of the particle beam therapy apparatus based on the set irradiation conditions. In addition, as described above, since these units and modules are formed in the computer by software, they are not shown to be physically formed.

And, three-dimensional data generating unit 21 includes: three-dimensional data generating module 21 _M1 , this three-dimensional data generating module 21 _M1 generates the three-dimensional data of affected part or body shape etc. according to image data as function a; coordinate conversion module 21 _M2 , this coordinate conversion module 21 _M2 converts the generated three-dimensional data into the data of the coordinate system [ψ _a , ψ _b , r _b ] shown in the definition (D1), which holds true under the assumption of two-stage scanning; a data generating module 21 _M3 , the display data generating module 21 _M3 generates display data based on the converted data as function b; and an irradiation target separation module 21 _M4 , the irradiation target separation module 21 _M4 based on the converted data To distinguish the affected part as the irradiation target from the normal tissue, and the three-dimensional data generation unit 21 forms three-dimensional data generated according to the coordinate system shown in definition (D1) as action A from the image information.

And, the irradiation condition generation unit 22 sets the optimum irradiation condition as action B by using the functions d and e based on the three-dimensional data generated according to the coordinate system shown in the definition (D1). _Furthermore , the control data generation unit 23 includes: a transmission shape setting module 23 _M1 that sets the transmission shape PS formed by the multi-leaf collimator 5 based on the set irradiation conditions. , as a function g; and a drive code generation module 23 _M2 , which generates a drive code for each leaf 5L of the multi-leaf collimator ₅ based on the set transmission shape as a function i, And, the control data generating unit 23 generates at least control data of the multi-leaf collimator 5 as action D by defining the coordinate system shown in (D1) based on the set irradiation conditions.

Thus, at least the deflection angle of the beam centered on the reference axis (Asa) and the deflection angle of the beam centered on the reference axis (Asb) are used in the three-dimensional data generation unit 21 or the irradiation condition setting unit 22 To specify the three-dimensional data used to determine the irradiation position and define the coordinate system shown in (D1), wherein the reference axis (Asa) is perpendicular to the beam axis X _B and passes through the reference point CPa, the reference axis (Asb ) is perpendicular to the beam axis X _B and the reference axis Asa and passes through the reference point CPb. Therefore, the driving code of the multileaf collimator 5 generated by the control data generating unit 23 is a driving code for realizing the aperture shape (transmission shape SP) obtained by the irradiation condition setting unit 22. corresponding to the optimal irradiation plan. That is, in the treatment planning device 20 according to Embodiment 6 of the present invention, among the functions (modules) for realizing the treatment planning function, there is a function of converting to a special coordinate system, and the special coordinate system is used The three-dimensional data is specified using a coordinate system, where this particular coordinate system is used assuming a two-level scan. Therefore, both the shape data for generating the shape of the opening corresponding to the shape of the affected part and the blade drive command value can be in the same form including the angle centered on the reference point (the angle used in the blade row _5C Among them, the blade plate 5 _L with the opposite surface _PL close to this angle is selected to represent. Therefore, it is possible to easily generate a drive code for optimum control of the multi-leaf collimator 5 in an irradiation system in which beams are diffused in a two-stage scanning manner.

Therefore, in the treatment planning device 20 according to Embodiment 6 of the present invention, the above-mentioned multileaf collimator 5 that can suppress the penumbra that occurs in the irradiation system that performs two-stage scanning diffusion of the particle beam is used , 205, in order to form the shape of the opening corresponding to the shape of the affected part, the particle beam therapy apparatus can directly use the three-dimensional data output from or input to the treatment planning device 20 to generate the drive command for the blades value.

As described above, according to the treatment planning device 20 according to the sixth embodiment, the three-dimensional data generating unit 21 which generates three-dimensional data from the image data of the affected part which is the irradiation target, and the irradiation condition setting unit 22 , the irradiation condition setting unit 22 sets irradiation conditions based on the generated three-dimensional data; and a control data generating unit 23, the control data generating unit 23 generates at least control data of the particle beam therapy device based on the set irradiation conditions In the control data of the multi-leaf collimator 5 according to Embodiments 1 to 5 above, since the three-dimensional data generation unit 21 uses the deflection angle ψ _a of the beam centered on the reference axis Asa, the reference axis (Asb) The above-mentioned three-dimensional data is generated in a coordinate system defined by the deflection angle ψ _b of the beam at the center and the distance r. Therefore, in order to form the shape of the opening in a manner corresponding to the shape of the affected part, the treatment planning device can directly use 20 The three-dimensional data input or output by the treatment planning device 20 generates the driving instruction value of the blade, wherein, the reference axis Asa is perpendicular to the beam axis X _B and passes through the reference point CPa; the reference axis (Asb) and the reference axis Asa and the beam axis X _B are perpendicular and pass through the reference point CPb; the distance r is the distance from the reference axis Asa or Asb, or the reference point CPa or CPb. In other words, in the control data generating unit 23, since the above-mentioned control data can be specified by using two deflection angles ψ _a and ψ _b , this particle beam therapy system can perform two-stage scanning diffusion of the particle beam in the irradiation system The penumbra is suppressed in the center, and high-contrast and high-quality beams are used for irradiation. For particle beam therapy equipment, high-contrast and high-precision irradiation can be performed.

Label description

1: Swing electromagnet (1a: x-direction (upstream) scanning electromagnet; 1b: y-direction (downstream) scanning electromagnet)

2: Ridge Filter

3: Range Shifter

4: Circular collimator

5: Multi-leaf collimator (5 _L : blade plate; 5 _G : blade group; 5 _D : blade drive unit)

6: Block

10: Particle beam therapy device

20: Treatment planning device

21: 3D data generation unit

22: Irradiation condition setting unit

23: Control data generation unit

Asa: Scanning axis (1st axis) of the upstream scanning solenoid (E _As : Assumed axis)

Asb: Scanning axis of the downstream scanning electromagnet (2nd axis)

CPa: the first reference point

CPb: 2nd datum point

E _L : an end face opposite to the vane plate

F _B : beam of particle beam (diffusion)

OL: drive rail of the vane plate

P _I : End face of the blade plate (adjacent to E _L ) on the beam incident side

P _L : The opposite surface in the thickness direction of the blade plate

PS: through the shape

P _X : End surface of the blade plate (adjacent to E _L ) on the side of the beam exit surface

ST: Scanning trajectory of the particle beam

_{X B} : beam axis of the particle beam (EX : beam axis of the beam incident on the multi-leaf collimator)

A numeral in the hundreds place represents a modified example according to the embodiment.

Claims (3)

1. A kind of 1. particle-beam therapeutic apparatus, it is characterised in that including：

   Mouth is irradiated, the irradiation mouth is scanned using 2 different electromagnet of scanning direction to the particle beams provided by accelerator, And it is irradiated；And

   Multi-diaphragm collimator, multi-diaphragm collimator configuration have in the path of the particle beams irradiated by the irradiation mouth：Leaf Piece is arranged, and the rows of blades is arranged in a thickness direction in a manner of an end face of multiple vane plates is alignd；And vane plate drives Motivation structure, the vane plate drive mechanism so that beam axis from one end face to the particle beams closer or far from the particle The mode of the beam axis of beam, to drive multiple vane plates respectively, and the multi-diaphragm collimator is with the shape with irradiation object The mode that shape is consistent limits or formed the irradiation field of the particle beams,

   The irradiation mouth irradiates the particle beams using scanning method,

   It is formed at by each vane plate and with the opposite face of its adjacent vane plate in a thickness direction including the 1st axle Plane on, the 1st axle is set in the 1st position on the beam axis, and vertical with the beam axis,

   The vane plate drive mechanism is that certain track drives the vane plate, the 2nd axle quilt along with the distance of the 2nd axle The 2nd position that the 1st position predetermined distance is left on the beam axis is set in, and is hung down with the beam axis and the 1st axle Directly.
2. 2. particle-beam therapeutic apparatus as claimed in claim 1, it is characterised in that multiple vane plates respective described one Individual end face is located in the plane comprising the 2nd axle.
3. 3. particle-beam therapeutic apparatus as claimed in claim 1, it is characterised in that entered using the vane plate drive mechanism Row driving, so that the respective one end face of multiple vane plates is located in the plane comprising the 2nd axle.