JP2013017500A - Scattering-body switching device and particle beam treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a scattering-body switching device capable of avoiding increase in size, turbulence of irradiation and a collision between scattering bodies, so as to accurately replacing the scattering bodies.SOLUTION: The scattering-body switching device includes: a vacuum chamber 42 housing a plurality of scattering bodies 2; a drive mechanism 3 which has drive rods 3b each extending into the vacuum chamber 42 toward a center axis Xfrom different directions outside the vacuum chamber 42 on a first plane vertical to the center axis Xand having the scattering bodies 2 connected to the leading end thereof, thereby linearly driving the scattering bodies 2 to either of a use position or a retracted position separated from the use position; and stoppers 5 connected to the drive rods 3b corresponding to the respective scattering bodies 2 for cooperating with the scattering bodies, so as to prevent the collision of the scattering body with the other scattering body. The respective drive regions of the stoppers 5 are set outside the vacuum chamber 42 parallel to the first plane and separated from the center axis X.

Description

  The present invention relates to a particle beam therapy apparatus for irradiating and treating a diseased part of a patient with a particle beam, and in particular, a scatterer switching apparatus capable of accurately switching a scatterer for adjusting a beam diameter. It relates to what it has.

  Particle beam therapy is performed by irradiating the affected area to be treated with a charged particle beam (particle beam) and damaging the affected tissue. In order to give a sufficient dose, it is necessary to control the irradiation shape according to the shape of the affected tissue. In the particle beam therapy system, methods for controlling the irradiation shape are roughly classified into two. Forming an irradiation shape by scanning a small irradiation area with a scanning electromagnet, which is called a broad irradiation type that irradiates a predetermined area at once with an irradiation nozzle composed of a wobbler electromagnet, a scatterer, a range modulator, etc. It is called a scanning irradiation type.

  In the case of the broad irradiation type, the irradiation shape can be easily formed by a limiter that reproduces a physical transmission shape such as a multi-leaf collimator provided downstream of the irradiation nozzle. On the other hand, the scanning irradiation type requires complicated control, but directly forms the irradiation shape by scanning the particle beam, so that the resolution is high and the shape of the affected part can be faithfully reproduced. In view of this, a universal particle beam therapy system has been developed that is equipped with a restrictor or the like necessary for broad irradiation and that can also cope with scanning irradiation that directly forms an irradiation shape by scanning.

  On the other hand, since the required beam diameter differs between broad irradiation and scanning irradiation, when switching the irradiation method, the optimal scatterer is selected from the multiple scatterers with different scattering characteristics that adjust the beam diameter. Need to be placed. At this time, in the universal particle beam therapy system, it is necessary to arrange the scatterers in a vacuum atmosphere in order to perform accurate scanning control in scanning irradiation, and a plurality of scatterers including those for switching are placed in the vacuum chamber. Must be stored. In order to prevent malfunction due to electromagnetic waves or the like, a fluid type actuator (drive mechanism) that linearly drives by supplying fluid such as air pressure or water pressure to the cylinder is used for switching the scatterers. However, since the fluid-type actuator is turned on / off in one direction of protrusion or retraction, a scatterer switching device having a driving mechanism corresponding to each scatterer is required to switch the scatterer. Necessary.

  Here, in order to keep the thickness of the scatterer switching device in the beam axis direction thin or to keep the scattering starting point constant, it is necessary to drive each scatterer in the same plane. For this reason, if each drive mechanism operates erroneously, the scatterers may collide and be damaged. Therefore, there is a device (see, for example, Patent Document 1) in which a stopper is provided at the tip of the traveling direction of the magnet to be protected, and the stopper hits before the magnet to avoid collision of the magnet, and this technique is applied to the scatterer. It is possible to do.

JP-A-9-161996 (paragraph 0014, FIG. 4)

  However, the scatterer is arranged in the beam irradiation path centered on the beam axis. As described above, if the stopper is arranged in advance in the traveling direction, the beam hits the stopper and the irradiation is disturbed. was there.

  The present invention has been made to solve the above-described problems, and avoids collision between scatterers without causing an increase in the size in the beam axis direction or disturbance of irradiation, so that a scatterer is obtained. It is an object of the present invention to provide a scatterer switching device that can be accurately replaced, and a particle beam therapy device that can be irradiated with an appropriate beam diameter according to an irradiation mode using the scatterer switching device.

  The scatterer switching device of the present invention is a scatterer switching device that switches a scatterer that adjusts the beam diameter of a charged particle beam in a particle beam therapy apparatus, and a plurality of scatterers having different scattering characteristics are disposed, A vacuum chamber installed so as to align a central axis with a beam axis of the charged particle beam; and a first plane perpendicular to the central axis, the outer side of the vacuum chamber and from different directions to the central axis. A drive rod having a scatterer connected to each of the extended tips, and the connected scatterer being retracted away from the use position including the central axis or away from the use position. A driving mechanism that drives to any one of the positions, and a driving rod corresponding to each of the scatterers, and by interlocking with the scatterers, And a stopper that prevents the scatterer from colliding with each other, and each drive region of the stopper is set outside the vacuum chamber that is parallel to the first plane and away from the central axis. And

  According to the scatterer switching device of the present invention and the particle beam therapy system equipped with the scatterer, the stopper that is linked to the scatterer is arranged outside the vacuum chamber with respect to the scatterer driven in the vacuum chamber. A scatterer switching device that can accurately replace scatterers by avoiding collisions between scatterers without causing an increase in size in the beam axis direction or disturbance of irradiation, and depending on the irradiation mode using this Thus, a particle beam therapy system capable of irradiation with an appropriate beam diameter can be obtained.

It is a figure for demonstrating the structure of the particle beam therapy apparatus concerning Embodiment 1 of this invention. It is a figure for demonstrating the structure of the scatterer switching apparatus concerning Embodiment 1 of this invention. It is a figure for demonstrating the structure of the drive mechanism of a scatterer in the scatterer switching apparatus concerning Embodiment 1 of this invention. It is a figure for demonstrating the positional relationship of a scatterer and a stopper in the scatterer switching apparatus concerning Embodiment 1 of this invention. It is a figure for demonstrating operation | movement in the scatterer switching apparatus concerning Embodiment 1 of this invention. It is a figure for demonstrating the structure of the drive mechanism of a scatterer in the scatterer switching apparatus concerning Embodiment 2 of this invention. It is a figure for demonstrating operation | movement in the scatterer switching apparatus concerning Embodiment 2 of this invention. It is a figure for demonstrating the structure of the drive mechanism of a scatterer in the scatterer switching apparatus concerning Embodiment 3 of this invention.

Embodiment 1 FIG.
1 to 5 are diagrams for explaining the configuration of a scatterer switching device according to a first embodiment of the present invention and a particle beam therapy device including the scatterer switching device, and FIG. 1 is an entire irradiation system of the particle beam therapy device. FIG. 2 is a diagram for explaining the configuration of the scatterer switching device provided in the particle beam therapy system. FIG. 2A is a plan view seen from the upstream side in the beam direction. 2 (b) is a diagram showing a configuration in which a part of the housing is seen through or partly opened in the plan view of FIG. 2 (a), and FIG. 2 (c) is seen from a direction perpendicular to the beam direction. It is a side view, Comprising: As shown in FIG.2 (b), the structure at the time of seeing through a part of housing | casing or partly opening is shown. 3A and 3B are diagrams for explaining the configuration of the scatterer driving mechanism in the scatterer switching device. FIG. 3A is a plan view of the driving mechanism viewed from the upstream side in the beam direction, and FIG. FIG. 3C is a side view seen from a direction perpendicular to the beam direction, and FIG. 3C is a diagram showing a cooperative relationship with stoppers corresponding to the three scatterers. FIG. 4 is a diagram for explaining the relationship between the drive locus of each scatterer and the arrangement of the stopper in the plane direction perpendicular to the beam direction, and FIG. 4A is a diagram showing the drive range of each scatterer. FIG. 4B is a diagram showing the size and arrangement of each stopper. Further, FIG. 5 is a diagram for explaining the operation in the scatterer switching device, and FIGS. 5A to 5C show other scatterers when each scatterer is driven to the use position. It shows the operation of eliminating intrusion.

  The greatest feature of the particle beam therapy system according to the first embodiment of the present invention is that it is irradiated with a scatterer for adjusting the beam diameter in a universal type particle beam therapy system capable of selectively irradiating broad irradiation and scanning irradiation. It is the structure provided with the scatterer switching device which can be switched exactly according to a system. However, as a premise for detailed description of the features, the overall configuration of the irradiation system of the universal particle beam therapy system will be described.

  As shown in FIG. 1, the particle beam therapy system 10 scans a charged particle beam B supplied from an accelerator (not shown) according to an irradiation method, thereby scanning a broad irradiation nozzle or a direct irradiation shape for expanding an irradiation range. A scanning electromagnet 1 that functions as a scanning irradiation nozzle, and a scatterer (Scatterer) 2 that adjusts the beam diameter by scattering the charged particle beam B, and aluminum. Accordingly, the depth (irradiation depth) of the affected part Tc from the body surface of the patient K of the affected part Tc, which is composed of a ridge filter (Ridge Filter) 6 for expanding the width of the Bragg peak and acrylic resin or the like. Depending on the range, a range shifter 7 for changing the energy (range) of the charged particle beam B and a plurality (multi-leaf) Lee that can be set at an arbitrary position. A multi-leaf collimator 8 that functions as a restrictor for limiting the transmission shape to match the shape of the affected part Tc and the depth shape of the irradiation target are provided. Thus, a bolus 9 for adjusting the range of the charged particle beam B is provided.

Then, it is deflected by at least the scanning electromagnet 1 of the charged particles for accurately scanning control of the beam B, beam path around the beam axis X _B of the charged particle beam B in response to the illumination profile at the time of scanning irradiation The vacuum chamber 4 is provided so that the part and the part scattered by the scatterer 2 become a vacuum atmosphere. Of the vacuum chamber 4, the portion 41 corresponding to the scanning electromagnet 1, the portion 42 which is arranged to fit to the beam axis X _B of the gap oppositely disposed scanning magnet 1 so as to sandwich, corresponding to the scatterer 2 Three scatterers 2 are housed inside, and each of the scatterers 2 is connected to the extended end of the drive rod 3b of the drive mechanism 3 extended from the atmosphere through the airtight sliding portion 4S. Has been.

The details of the portion 42 corresponding to the scatterer 2 of the vacuum chamber 4 and the drive mechanism 3 will be described later, and the operation during the broad irradiation and scanning irradiation in the irradiation system will be described first.
Here, for the sake of clarity, the x direction and the y direction are defined. The traveling direction along the beam axis X _B of the charged particle beam B to be supplied to the irradiation system is a positive direction of the z-axis, the x-axis and y-axis and z-axis, is expressed by right-handed coordinate axes orthogonal to each other. The scanning electromagnet 1 is arranged so as to face the x direction across the center of the beam (beam axis X _B ), and so as to face the y direction electromagnet 1 y that deflects the charged particle beam B in the y direction. disposed, the charged particle beam B to be two sets of x-direction electromagnet 1x for deflecting in the x-direction, each of the electromagnets 1y, 1x are arranged so as to be continued along the beam axis X _B of the charged particle beam B Yes. Further, the charged particle beam B accelerated by an accelerator (not shown) and supplied to the irradiation system via the transport system is in a so-called pencil beam state having a diameter of several millimeters or less.

  In the case of broad irradiation, the scanning electromagnet 1 scans the charged particle beam B so as to draw a circular orbit like a wobbler electromagnet, for example, and scatters it by the scatterer 2 having scattering characteristics corresponding to the thickness. That is, by expanding the beam irradiation range (in the xy plane) with the scanning electromagnet 1 and adjusting the beam diameter with the scatterer 2, the distribution of the beam irradiation amount within the irradiation range is adjusted. The scanning trajectory in the broad irradiation is exemplified by the circular trajectory. However, the scanning trajectory is not limited to the circular trajectory and may be a spiral trajectory or other trajectories as long as the irradiation range is widened.

  Next, the charged particle beam B passes through the ridge filter 6. The ridge filter 6 is formed, for example, so that a large number of conical bodies and triangular plates having a triangular cross section are arranged in the plane, and the beam passage area (xy plane) is divided into a large number of small areas, for example. There are charged particle beams B passing through different thicknesses. In the figure, the triangular prisms are arranged in a horizontal direction for easy understanding. As a result, the Bragg peak is expanded and has a predetermined SOBP (Spread-Out Bragg Peak) width. In other words, the irradiation range is expanded in the z direction by the ridge filter 6. The charged particle beam B whose irradiation range has been expanded passes through the range shifter 7. The range shifter 7 is a device for changing the energy of the charged particle beam B. By adjusting the range by the range shifter 7, the charged particle beam B can be irradiated (given dose) to a desired body depth. Note that the spread of the irradiation range includes not only the surface direction (x, y) but also the thickness direction (z) as described in the ridge filter 6, but hereinafter, unless otherwise specified, in this specification Will describe only the irradiation range in the plane direction (x, y).

The charged particle beam B whose irradiation range has been expanded passes through the multi-leaf collimator 8. Multi-leaf collimator 8 is a leaf string obtained by laminating a plate-like leaf plate in the thickness direction (y-direction), placed opposite in pairs so as to sandwich the beam axis X _B of the charged particle beam B. In in the direction (x) orthogonal to each leaf plate in the thickness direction are positioned on the predetermined position of the separating or approaching direction with respect to the beam axis X _B, to form the desired opening shape. Then, the charged particle beam B that has passed through the multi-leaf collimator 8 is limited in the irradiation range according to the shape of the affected area by the opening shape that matches the shape of the affected area Tc. That is, the irradiation range expanded by the scanning electromagnet 1 and the scatterer 2 is limited and shaped according to the shape of the affected area by the multi-leaf collimator 8.

  Finally, the charged particle beam B passes through the bolus 9. The bolus 9 is a restrictor made of a resin or the like, and is formed in a form that compensates for a distal shape of the affected part, for example, as a depth shape of the affected part. Here, the energy distribution within the irradiation range is limited (shaped in the z direction), and has the same shape as the distal shape. That is, the irradiation range is limited and shaped in the z direction by the bolus 9.

  On the other hand, in the case of scanning irradiation, the scanning electromagnet 1 controls the scanning trajectory and range so that the irradiation range is in accordance with the shape of the affected part Tc. The charged particle beam B controlled by the scanning electromagnet 1 is scattered by a scatterer 2 having a predetermined thickness corresponding to the scanning locus. That is, the distribution of the beam irradiation amount in the irradiation shape is adjusted by shaping the beam with the scanning electromagnet 1 into the shape of the affected part (in the xy plane) and adjusting the beam diameter with the scatterer 2.

  The ridge filter 6 and the range shifter 7 are the same as in the broad irradiation. However, in the case of scanning irradiation, the multi-leaf collimator 8 is not used to directly shape the irradiation shape. For this reason, the leaf is used as a restrictor that allows the leaf to pass through a predetermined range in order to prevent the irradiation of the leaf to a fully open state or a certain range including the affected part Tc.

  Finally, the charged particle beam B passes through the bolus 9, the energy distribution within the irradiation shape is limited (shaped in the z direction), and has the same shape as the distal shape. In scanning irradiation, instead of installing the bolus 9, the irradiation time (dose density) and energy (kinetic energy of charged particle beam) are changed according to the deflection angle (beam scanning position) by the scanning electromagnet 1. You may control.

  Thus, in the particle beam therapy system 10 according to the present embodiment, by providing a limiter such as the multi-collimator 8 necessary for broad irradiation, broad irradiation is possible, and scanning irradiation is performed as necessary. It can function as a universal-type particle beam therapy apparatus that can be switched. Here, as a universal type particle beam therapy system, not only the scanning electromagnet 1 portion but also the scatterer 2 provided immediately downstream of the scanning electromagnet 1 includes a vacuum chamber 4 in order to accurately perform scanning control and beam diameter adjustment. The scatterer switching device 20 is provided so that the scatterer 2 can be reliably switched within the vacuum chamber 4.

Scatterer switching device 20 is centered three scatterer 2A, 2B, 2C (collectively scatterer 2) is selected the center of one of the scatterer 2 only a beam path of the beam axis X _B It switches so that it may drive to a use position. As a result, the charged particle beam B incident on the scatterer switching device 20 in the form of a so-called pencil beam is in any one of the three stages (four stages in addition to the case where the scatterer 2 is not installed at the use position). It is an apparatus which adjusts and emits. The scatterer switching device 20 drives the scatterers 2 and the vacuum chamber 42 corresponding to the scatterers 2 in the vacuum chamber 4, the scatterers 2 stored in the vacuum chamber 42. The drive mechanism 3 is provided.

Vacuum chamber 42, as shown in FIG. 2, the opening for the upstream side of the beam B deflected by the scanning magnet 1 enters the beam axis X _B direction (z direction), the beam is below the An opening (collectively an opening 42a) for emitting a charged particle beam having an adjusted diameter is formed. The axis connecting the centers of essentially vertical opening and the central axis X ₄₂ of the vacuum chamber 42, is arranged so as charged particle beam central axis X ₄₂ to the beam axis X _B of the B match, between the upper and lower openings 42a The substantially cylindrical space to be connected becomes the beam path of the charged particle beam B. Then, the central axis X ₄₂ perpendicular plane (xy plane) scatterers on one side in the x direction on both sides in the y direction in the 2A, 2B, 2C the drive mechanism 3A, each linearly driven in one direction in the xy plane 3B and 3C (collectively the drive mechanism 3) are connected.

The drive mechanism 3 is mainly composed of an air cylinder that is an actuator that linearly drives with compressed air supplied from a high-pressure supply source (not shown) as power, and as shown in FIGS. 2 (b) and 2 (c), a vacuum chamber is provided. A housing 3c fixedly connected to 42 (in the figure, the housing of the driving mechanism 3A is referred to as 3cA), and extends from the housing so as to be stretchable and connected, and the scatterer 2 is connected to the tip, and the connected scatterer 2 Drive rod 3b (in the figure, the drive rod of the drive mechanism 3A is denoted as 3bA). Then, each of the driving mechanism 3, the driving rod 3b is the central axis X ₄₂ in ₍₌ beam axis X _B) perpendicular to the same plane, and the tip is connected to the vacuum chamber 42 to face the central axis X ₄₂ ing.

Further, the intermediate portion of the drive rod 3b passes through the gas (vacuum-proof) sealable sliding portion 4s disposed in the connection portion between the vacuum chamber 42 and the housing 3c, and extends the drive rod 3b (proximity direction). the extent substantial center of the scatterer 2 is coincident with the beam axis X _B is (use position), reduce side when driving in (retracting direction) than the sliding portion 4s of the vacuum chamber 42 side when the driven The direction and stroke of the drive rod 3b are adjusted so that they do not enter the drive range of other scatterers 2 (retracted positions). Accordingly, the scatterer 2 is in the same plane, scatterer 2A and 2C is a linear drive between a use position and a retracted position in the x-axis direction so as to face each other across the central axis X _42, scatterers. 2B It is linearly driven between a use position and a retracted position in the y-axis direction toward the central axis X _42. In order to accurately drive the scatterer 2 in a straight line, a slide guide or the like is actually installed in the atmospheric part or vacuum part, but the illustration is omitted for simplification.

  Further, as shown in FIG. 3, a portion exposed to the atmosphere side of the drive rod 3b of each drive mechanism 3 is connected to a stopper via a connecting body 5b (the connecting body for the driving mechanism 3A is indicated as 5bA in the figure). 5 (in the figure, the stopper for the drive mechanism 3A is denoted as 5A). At this time, the stopper 5 is positioned in a plane parallel to the plane that is the driving range of the scatterer 2 in the vacuum chamber 42 in the atmosphere outside the vacuum chamber 42, and is linearly linked to the scatterer 2. To drive. As long as the drive rod 3b and the connecting body 5b interposed between the scatterer 2 and the stopper 5 function as a rigid body, the movement of the stopper 5 is as shown in FIG. The movement of the scatterer 2 can be explained only by ignoring the connection body 5b, and conversely, the movement of the scatterer 2 can be explained only by the movement of the stopper 5.

  Therefore, the driving range of the scatterer 2 and the arrangement of the stopper 5 will be described with reference to FIG. In FIG. 4, each of the scatterers 2A to 2C is assumed to be in the respective retracted position, and will be described only with a two-dimensional size and position in the xy plane direction unless otherwise specified.

<Position relationship of scatterers>
As shown in FIG. 4 (a), the scatterer 2A than being driven between a use position around the beam axis X _B is the center of the current retracted position and the beam path, it forms a driving range RMA, scattering The body 2B is driven between the current retraction position and the use position to form a drive range RmB, and the scatterer 2C is driven between the current retraction position and the use position to form a drive range RmC. At this time, the region where the driving range overlaps is the exclusive region R _x2 , and when one scatterer 2 enters the exclusive region R _x2 and another scatterer 2 enters the exclusive region R _x2 , Will collide. In other words, if one scatterer 2 is in the exclusive region R _x2 and other scatterers 2 cannot enter the exclusive region R _x2 , collision between the scatterers 2 can be avoided. Can do.

Scatterer 2A and 2C in the driving direction perpendicular to a direction of the width _{L EXV,} the vertical width in the driving direction of the scatterer 2B and _{L exH,} the size of the exclusion area _{R x2} is, y direction length L _{It is} a square of _exV × x direction length L _exH (a square when the aspect ratio of the scatterer 2 is the same (L _exV = L _exH )). Here, among the three scatterers, the scatterers 2A and 2C opposed to each other on a straight line can be approached to an interval shorter than the width of the exclusive region _Rx2 , but the drive directions intersect with each other. and between 2B, and 2B and 2C between the when one enters the exclusive area R _x2 even partially, the other collides as soon penetrated into the exclusive area R _x2. Therefore, in consideration of safety, set the surface opposite to the scattering body 2A of the exclusive area R _x2, face towards 2C, and the surface facing the scatterer 2B widened by margin L of the restricted area R _p2. In other words, the limited region R _p2 having a margin L wide is set from the exclusive region R _x2 to both sides in the x direction and toward the scatterer 2B in the y direction.

Then, a drive length to enter the restricted area _{R p2} from the retracted position of the scatterer 2A, intervals _{G 2A} of the exclusive area _{R x2} (= scatterer 2A stroke _DmA-L exH -L), similar restricted area when the scatterer. 2B interval _{G 2B} the restricted area _{R p2} when in the retracted position (= stroke _{DmB-L exV} -L scatterers 2B), the scatterer 2C is in the retracted position _{R p2} And G _2C (= stroke DmC−L _exH −L of scatterer 2C). In other words, it enters a restricted area _{R p2} if distance _{G 2A} moving scatterers 2A width _{L EXV} from the retracted position, enters a restricted area _{R p2} if distance _{G 2B} movement scatterer 2B of width _{L exH} from the retracted position, so that the scatterer 2C width _{L EXV} enters the distance _{G 2C} if movement restriction region _{R p2} from the retracted position.

<Composition and arrangement of stopper>
Basically, when one scatterer is in the restricted region R _p2 for the scatterers that form a pair whose driving directions intersect, the other scatterer does not enter the restricted region R _p2 and the exclusive region The stopper 5 is configured so that it cannot contact _Rx2 . Further, regarding the arrangement of the stopper 5, as shown in FIG. 4B, the range in which the stopper 5 and the connecting body 5b are driven does not cover the beam path of the charged particle beam B, the outer wall 42w of the vacuum chamber 42, and the like. The exclusive region R _x5 translated from the exclusive region R _x2 of the scatterer 2 in the z direction and the xy plane direction is used as a reference. Further, based on the exclusive region R _x5 of the translated stopper 5, the connecting body 5 b prevents the stopper 5 and the connecting body 5 b from hitting the housing 3 c of the scatterer driving mechanism 3, the outer wall 42 w of the vacuum chamber 42, and the like. And the connecting position with the drive rod 3b are determined.

<Stopper 5B>
The stopper 5B sets the position of the surface 5f _BF facing the exclusive region R _x5 so that the distance G _BF from the exclusive region R _x5 becomes G _2B when driven to the retracted position. Then, the length L _5BF in the direction (x direction) perpendicular to the driving direction of the stopper 5B is set to L _exH + 2L which is 2L longer than the length of the exclusive region R _x5 facing the surface 5f _BF , and the stopper 5B is in the exclusive region R _x5 . When entering, the positions in the x direction are adjusted so that the surfaces 5f _BR and 5f _BL facing the stopper 5A and the stopper 5C come out from both ends of the exclusive region _Rx5 , respectively. Thus, the surface _{5f BF} facing the exclusive region _{R x5} is perpendicular to the driving direction, upon entering the exclusive area _{R x5,} stoppers 5A, opposite to 5C surfaces _{5f BL} and surface _{5f BR} serves as a stopper. Of the surfaces functioning as stoppers, both end surfaces 5f _BR and 5f _BL also function in terms of a theoretically non-area area, so there is no need to define the length, and basically the opposite surfaces 5f _BF What is necessary is just to prescribe | regulate length and a position.

<Stopper 5A>
Stopper 5A is, considering only the stopper 5B driving directions cross (scatterer 2B), when driven to the retracted position, so that the distance G _AF from the exclusive region R _x5 is G _2A, the exclusive area What is necessary is just to set the position of surface 5f _AF which opposes _Rx5 . Further, the driving direction is to avoid approaching the stopper 5C (scatterer 2C) that is collinear, the distance _{G AF} from the exclusive region _{R x5} is set to a predetermined amount shorter _{G 2A-.alpha.} than _{G 2A.} The length L _5AF in the direction perpendicular to the driving direction of the stopper 5A (y direction) is set to L _exV + L which is longer than the length of the exclusive area R _x5 facing the surface 5f _AF , and the stopper 5A is in the exclusive area R _x5 . when entering, the end face 5f _AL facing the stopper 5B is align the y-direction position out of the end of the stopper 5B side of the exclusive area R _x5. Thus, the surface _{5f AF} facing the exclusive region _{R x5} is perpendicular to the driving direction, upon entering the exclusive area _{R x5,} end face _{5f AL} facing the stopper 5B functions as a stopper. Of the surfaces that function as stoppers, the end surface 5f _AL functions theoretically even at a point that does not have an area. Therefore, the length may be set only by mechanical strength, and basically the opposing surface 5f _AF. What is necessary is just to prescribe | regulate the length and position.

<Stopper 5C>
The stopper 5C is a relationship controls the stopper 5A, concept is the same as the stopper A, when driven to the retracted position, so that the distance G _CF from the exclusive region R _x5 is G _2C-.alpha., The position of the surface 5f _CF facing the exclusive area R _x5 is set. Then, the length L _5CF in the direction (y direction) perpendicular to the driving direction of the stopper 5C is set to L _exV + L which is longer than the length of the exclusive region R _x5 facing the surface 5f _CF , and the stopper 5C is in the exclusive region R _x5 . When entering, the y-direction position is adjusted so that the end surface 5f _CR facing the stopper 5B is placed on the end of the exclusive region _{Rx5 on} the stopper 5B side. Thus, the surface _{5f CF} facing the exclusive region _{R x5} in the driving direction perpendicular, upon entering the exclusive area _{R x5,} end face _{5f CR} facing the stopper 5B functions as a stopper. Of the surfaces that function as stoppers, the end surface 5f _CR also functions in terms of a theoretically small area, so the length may be set only by mechanical strength. Basically, the opposing surface 5f _CF What is necessary is just to prescribe | regulate the length and position.

Next, the operation of the scatterer switching device 20 configured as described above will be described with reference to FIG.
<When using scatterer 2A>
As shown in FIG. 5A, when the scatterer 2A is used, the other scatterers 2B and 2C are in the retracted position, and the scatterer 2A is driven from the retracted position toward the use position on the right side in the figure. Can do. At this time, in any position within a range of from the portion where the scattering body 2A enters the restricted area R _p2 until it reaches the use position, the end face 5f _AL stopper 5A faces the stopper 5B exclusive area R _x5 It exists in any position on the side. Therefore, be driven toward the use position incorrectly scatterers 2B, the opposing surface 5f _BF of the stopper 5B just before scatterer 2B enters the restricted area R _p2 is hit the end face 5f _AL, stopper 5B and to Driving of the interlocking scatterer 2B is prevented. Thereby, the scatterer 2B does not enter the restricted region _Rp2 , and the scatterer 2B can be prevented from colliding with the scatterer 2A.

At this time, even if the scatterer 2C is erroneously driven toward the use position, the opposing surface of the stopper 5C is left first by leaving a distance of 2 (α + L) until the scatterer 2C collides with the scatterer 2A. The 5f _CF hits the opposing surface 5f _AF of the stopper 5A. Thereby, the driving of the stopper 5C and the scatterer 2C interlocked with the stopper 5C is prevented, and the scatterer 2C can be prevented from colliding with the scatterer 2A.

<When using scatterer 2B>
As shown in FIG. 5B, when the scatterer 2B is used, the other scatterers 2A and 2C are in the retracted position, and the scatterer 2B is driven from the retracted position toward the lower use position in the figure. be able to. At this time, the end face 5f _AR of the stopper 5B faces the stopper 5A of the exclusive region R _x5 at any position within the range from the portion where the scatterer 2B enters the restricted region _Rp2 to the use position. It exists somewhere on the side. The end face 5f _AL will be present at any position on the line moved parallel to the outside from the side opposite to the stopper 5C exclusive region R _x5. Therefore, be driven toward the use position incorrectly scatterers 2A, opposing surface 5f _AF of the stopper 5A immediately prior to the scattering body 2A enters the restricted area R _p2 is hit the end face 5f _BR, stoppers 5A and thereto The driving of the interlocking scatterer 2A is prevented. Thereby, the scatterer 2A does not enter the restricted region _Rp2 , and the scatterer 2A can be prevented from colliding with the scatterer 2B.

At this time, be driven toward the use position incorrectly scatterers 2C, the opposing surface _{5f CF} of the stopper 5C just before scatterer 2C enters the restricted area _{R p2} is hit the end face _{5f BL,} the stopper 5C And the drive of the scatterer 2C interlock | cooperating to this is blocked | prevented. Thereby, the scatterer 2C does not enter the restricted region _Rp2 , and the scatterer 2C can be prevented from colliding with the scatterer 2B.

<When using scatterer 2C>
As shown in FIG. 5C, when the scatterer 2C is used, the other scatterers 2A and 2B are in the retracted position, and the scatterer 2C is driven from the retracted position toward the use position on the left side in the drawing. Can do. At this time, the end face 5f _CR of the stopper 5C faces the stopper 5B of the exclusive region R _x5 at any position within the range from the portion where the scatterer 2C enters the restricted region _Rp2 to the use position. It exists at any position on the straight line translated outward from the side. Therefore, be driven toward the use position incorrectly scatterers 2B, the opposing surface 5f _BF of the stopper 5B just before scatterer 2B enters the restricted area R _p2 is hit the end face 5f _CR, stopper 5B and to Driving of the interlocking scatterer 2B is prevented. Thereby, the scatterer 2B does not enter the restricted region _Rp2 , and the scatterer 2B can be prevented from colliding with the scatterer 2C.

At this time, even if the scatterer 2A is erroneously driven toward the use position, a distance of 2 (α + L) is left before the scatterer 2A collides with the scatterer 2C, so as to face the stopper 5A first. The surface 5f _AF hits the facing surface 5f _CF of the stopper 5C. As a result, the driving of the stopper 5A and the scatterer 2A interlocked therewith is prevented, and the scatterer 2A can be prevented from colliding with the scatterer 2C.

That is, when one scatterer 2 enters the restricted region R _p2 including the use position, the other scatterers 2 do not enter the restricted region R _p2 , so that the drive mechanism 3 of the other scatterer 2 is Even if it is driven toward the use position by mistake, the scatterers 2 do not collide with each other and suffer damage. Furthermore, since the stopper 5 connected to the scatterer 2 is driven in cooperation with the scatterer 2 outside the vacuum chamber 42, the operation of the scatterer 2 can be easily monitored from the outside without searching the inside of the vacuum chamber 42. be able to.

As described above, according to the scatterer switching device 20 according to the first embodiment, the scatterer switching device 20 that switches the scatterer 2 that adjusts the beam diameter of the charged particle beam B in the particle beam therapy system 10. Te, scattering characteristics different scatterers 2A-2C (collectively 2) (in a vacuum atmosphere) while being disposed, is disposed so as to align the center axis X ₄₂ to the beam axis X _B of the charged particle beam B that the vacuum chamber 42, in a first plane perpendicular to the central axis X _42, an outer vacuum chamber 42 (in the air), toward the central axis X ₄₂ from different directions (housing 3c) with each other stretched vacuum chamber 42, provided with a respective scatterer 2A-2C a stretched tip is connected a driving rod 3b (3bA~3bC), the connected scatterer 2A-2C, respectively the central axis X Use containing ₂ position, or a driving mechanism 3 for driving either one of the retracted position away from the use position, the scatterer respectively (the outer portion of the vacuum chamber 42 of) the driving rod 3bA~3bC corresponding to the 2A~2C And a stopper 5 (5A to 5C) that prevents the scatterer from colliding with another scatterer by interlocking with the scatterer. Since it is configured to be set outside the vacuum chamber 42 that is parallel to the plane 1 and away from the central axis X ₄₂ , the size of the apparatus, particularly the irradiation system portion, in the direction of the beam axis X _B is increased or irradiated. Without causing any disturbance, the collision of the scatterers 2 can be avoided and the scatterers 2 can be accurately replaced. In addition, since the driving state of the scatterer 2 that is stored in the vacuum chamber 42 and cannot normally be easily checked can be easily checked from the outside, one of the scatterers 2 (the driving mechanism 3) malfunctions. Even so, an appropriate response can be taken.

Further, among the plurality of scatterers 2A to 2C, the driving directions of at least two scatterers (2A and 2B, 2B and 2C) are orthogonal, and stoppers (5A and 5B, 5B and 5C) are configured to be set on the basis of an exclusive region R _x5 obtained by translating a rectangular exclusive region R _{x2 in} which the driving trajectories of the corresponding scatterers in the first plane are overlapped. Therefore, the stopper 5 does not block the charged particle beam B. In addition, when one of the scatterers 2 whose drive directions are orthogonal to each other enters the exclusive region R _x2 , the other scatterer 2 cannot enter the exclusive region R _x2 because the corresponding stopper first hits one of the stoppers. The collision between the scatterers 2 can be reliably prevented.

  Further, according to the particle beam therapy system 10 according to the first embodiment, the scanning electromagnet 1 that scans the charged particle beam B supplied from the accelerator (not shown) with the two electromagnets 1x and 1y having different scanning directions, and the scanning electromagnet 1, the scatterer switching device 20 described above, and a scanning mode switching device (not shown) for switching the scanning mode of the scanning electromagnet 1 to either scanning irradiation or broad irradiation. Is configured to switch the scatterer driven to the use position based on the switched scanning mode, so that a (universal type) particle beam therapy system capable of irradiation with an appropriate beam diameter according to the irradiation mode is obtained. be able to.

Embodiment 2. FIG.
In the first embodiment, the case where the driving directions of the scatterers 2 are orthogonal or collinear is described. In the present embodiment, the driving directions of the three scatterers are configured to intersect each other at 120 degrees in the same plane. Other configurations are basically the same as those in the first embodiment.

  6 and 7 are for explaining the configuration of the scatterer switching device according to the second embodiment of the present invention, and FIG. 6 is a vacuum chamber for explaining the configuration of the drive mechanism in the scatterer switching device. FIG. 6A is a plan view of the scatterer switching device viewed from the upstream side in the beam direction, and FIG. 6B is a diagram illustrating each scattering in a plane direction perpendicular to the beam direction. It is a figure for demonstrating the relationship between the driving locus of a body and a restriction | limiting area | region. Further, FIG. 7 is a diagram for explaining the operation in the scatterer switching device. FIGS. 7A to 7C are diagrams showing other scatterers when each scatterer is driven to the use position. It shows the operation of eliminating intrusion.

As shown in FIG. 6 (a), in the scatterer switching device according to the second embodiment, three scatterers 2A, 2B, and 2C are beams when the central axis X ₄₂ (= particle beam therapy system 10 is installed). In the same plane perpendicular to the axis X _B ), the driving directions intersect each other at 120 degrees. Then, as in the first embodiment, among the three scatterers 2A-2C, it can be used to move the position of use only one scatterers around the center axis X _42. The stopper 5 for avoiding a collision between the scatterers 2 is arranged so as not to be applied to the beam path of the charged particle beam B and the outer wall 42w of the vacuum chamber 42.

In order to arrange and configure the stopper 5, an exclusive region _Rx2 as shown in FIG. 6B was set. The driving directions of the scatterers 2A to 2C intersect with each other, and among them, two pairs of scatterers (2A and 2B, 2B and 2C) are selected to set exclusive regions R _{x2AB and} R _X2BC for each set. . As shown in the figure, for the scatterers 2A and 2B, a parallelogram exclusive region _Rx2AB , which is an overlap of the respective drive loci, is extracted, and the sides of the exclusive region _Rx2AB facing the scatterers are _defined as the central axis X. A region that has been moved L by a margin L from _{42 is} defined as a restricted region R _p2AB . This is also performed for the pair of scatterers 2B and 2C, and the common area between them is _Rp2 , and, as in the first embodiment, there is a range in which the stopper 5 and the connecting body connecting the stopper 5 and the scatterer 2 are driven. The exclusive region R _x5 translated from the exclusive region R _x2 of the scatterer 2 in the z direction and the xy plane direction is set so as not to affect the beam path of the charged particle beam B, the outer wall 42w of the vacuum chamber 42, and the like. Further, the shape of the connecting body 5b and the connecting position with the driving rod 3b so that the stopper 5 and the connecting body 5b do not hit the housing 3c of the scatterer driving mechanism 3 and the outer wall 42w of the vacuum chamber 42 which are not shown. Etc.

<Stopper 5B>
The length of the stopper 5B in the direction perpendicular to the driving direction is a width that is widened by a margin L from the width of the exclusive region _Rx5 in the same direction, and when the scatterer 2B enters the restriction region _Rp2 , It arrange _| positions so that 5B may approach into the near part in the drive direction of exclusive area _| region _Rx5 . Accordingly, the surface facing the exclusive region R _x5 is perpendicular to the driving direction, upon entering the exclusive area R _x5, both end faces in the direction perpendicular to the driving direction to function as a stopper. Of the surfaces that function as stoppers, both end surfaces theoretically function even at points that do not have an area, so there is no need to define the length; basically, if the length and position of the opposing surface are defined. Good.

<Stopper 5A, 5C>
For the stoppers 5A and 5C, the driving distance is decomposed into a component parallel to the driving direction of the scatterer B (y direction) and a vertical direction (x direction) to set the configuration. If only the stopper 5B (scattering body 2B) is considered, when the scattering body 2A enters the restricted region _R2p , the stopper 5A may be placed on the exclusive region _Rx5 . However, in consideration of the collision with the stopper 5C (scattering body 2C), the stopper 5A is further brought closer to the exclusive region R _x5 by α in the x direction. Then, the y-direction cross-sectional length in the y-direction length of the exclusion area R _x5 stopper 5A Satoshi, when the stopper 5A enters into an exclusive region R _x5, the end face facing the stopper 5B is an exclusive area R _x5 stopper The y-direction position is adjusted so as to cover the end on the 5B side. The same applies to the stopper 5C.

Next, the operation of the scatterer switching device 20 configured as described above will be described with reference to FIG.
<When using scatterer 2A>
As shown in FIG. 7A, when the scatterer 2A is used, the other scatterers 2B and 2C are at the retracted position, and the scatterer 2A is moved from the retracted position toward the use position at 30 degrees on the upper right in the figure. Can be driven. At this time, the end face of the stopper 5A facing the stopper 5B is the stopper 5B of the exclusive region R _x5 regardless of the position within the range from the portion where the scatterer 2A enters the restricted region _Rp2 to the use position. It exists in any position on the line translated to the outside. Therefore, even if the scatterer 2B is erroneously driven toward the use position, immediately before the scatterer 2B enters the restriction region _Rp2 , the opposing surface of the stopper 5B collides with the end surface of the stopper 5A, and interlocks with the stopper 5B. The scatterer 2B is prevented from being driven. Thereby, the scatterer 2B does not enter the restricted region _Rp2 , and the scatterer 2B can be prevented from colliding with the scatterer 2A.

  At this time, even if the scatterer 2C is erroneously driven toward the use position, the stopper 5A of the stopper 5C is left first, leaving a distance of 2 (α + L) before the scatterer 2C collides with the scatterer 2A. The surface that faces the surface of the stopper 5A hits the surface of the stopper 5A that faces the stopper 5C. Thereby, the driving of the stopper 5C and the scatterer 2C interlocked with the stopper 5C is prevented, and the scatterer 2C can be prevented from colliding with the scatterer 2A.

<When using scatterer 2B>
As shown in FIG. 7B, when the scatterer 2B is used, the other scatterers 2A and 2C are in the retracted position, and the scatterer 2B is driven from the retracted position toward the lower use position in the figure. be able to. At this time, the end face of the stopper 5B facing the stopper 5A is the stopper 5A of the exclusive region _Rx5 regardless of the position within the range from the portion where the scatterer 2B enters the restricted region _Rp2 to the use position. It exists at any position on the line translated to the outside. Further, the end surface of the stopper 5B facing the stopper 5C is present at any position on the line obtained by translating the side facing the stopper 5C of the exclusive region _Rx5 outward. Therefore, be driven toward the use position incorrectly scatterers 2A, the surface facing the stopper 5C of the stopper 5A immediately prior to the scattering body 2A enters the restricted area R _p2 is hit the end face of the stopper 5B, the stopper 5A And the drive of the scatterer 2A interlock | cooperating with this is blocked | prevented. Thereby, the scatterer 2A does not enter the restricted region _Rp2 , and the scatterer 2A can be prevented from colliding with the scatterer 2B.

At this time, be driven toward the use position incorrectly scatterers 2C, the surface facing the stopper 5A of the stopper 5C just before scatterer 2C enters the restricted area R _p2 is hit the end face of the stopper 5B The stopper 5C and the scatterer 2C interlocked with the stopper 5C are prevented from being driven. Thereby, the scatterer 2C does not enter the restricted region _Rp2 , and the scatterer 2C can be prevented from colliding with the scatterer 2B.

That is, when one scatterer 2 enters the restricted region R _p2 including the use position, the other scatterers 2 do not enter the restricted region R _p2 , so that the drive mechanism 3 of the other scatterer 2 is Even if it is driven toward the use position by mistake, the scatterers 2 do not collide with each other and suffer damage. Furthermore, since the stopper 5 connected to the scatterer 2 is driven in cooperation with the scatterer 2 outside the vacuum chamber 42, the operation of the scatterer 2 can be easily monitored from the outside without searching the inside of the vacuum chamber 42. be able to.

In the second embodiment, the surface of the stopper 5B that faces the exclusive region _Rx5 is a single surface that extends in the direction perpendicular to the driving direction, but the present invention is not limited to this. For example, the surface in the z direction is shifted between the surface parallel to the driving direction of the stopper 5A as the surface corresponding to the end surface of the stopper 5A and the surface parallel to the driving direction of the stopper 5C as the surface corresponding to the end surface of the stopper 5C. You may make it form. In this case, the distance that the stopper 5B can be driven does not change regardless of the depth of entry of the stoppers 5A and 5C in the exclusive region _Rx5 , so that the stroke of the stopper 5B does not need to be excessively long and can be formed compactly. .

In the second embodiment, with reference to the stopper disposed in the first embodiment, so as to be symmetrical with respect to the straight line including the center axis X ₄₂ parallel to the driving direction of the scatterer 2B, horizontally and vertically decomposition Although the stopper is configured on the basis of the driving component, the present invention is not limited to this. As to the second embodiment, the same driving angles of the three scatterers 2A-2C, the case of 3-fold symmetry of the central axis X ₄₂ axis of symmetry, a plane stopper 5 also extends in a direction perpendicular to the driving direction It is also possible to form a three-fold symmetrical arrangement with the center of the exclusive region R _{x5 as} the axis of symmetry.

As described above, according to the scatterer switching device 20 according to the second embodiment, the driving directions of at least two scatterers (2A and 2B, 2B and 2C) among the plurality of scatterers 2A to 2C intersect. The driving regions of the stoppers (5A and 5B, 5B and 5C) corresponding to the two scatterers are parallelograms obtained by overlapping the driving tracks of the corresponding scatterers in the first plane. Since the exclusive region R _x2 is set based on the exclusive region R _x5 obtained by translating the exclusive region R _x2 , the stopper 5 does not block the charged particle beam B. In addition, when one of the scatterers 2 whose drive directions are orthogonal to each other enters the exclusive region R _x2 , the other scatterer 2 cannot enter the exclusive region R _x2 because the corresponding stopper first hits one of the stoppers. The collision between the scatterers 2 can be reliably prevented.

Embodiment 3 FIG.
In the first embodiment, the case where there are three scatterers has been described. In this embodiment, the driving directions of the four scatterers are different by 90 degrees in the same plane. Other configurations are basically the same as those in the first embodiment.

  FIG. 8 is a diagram for explaining the configuration of the scatterer switching device according to the third exemplary embodiment of the present invention. Like FIG. 6 of the second exemplary embodiment, the illustration of the outer wall portion and the like of the vacuum chamber is omitted. 8A is a plan view of the scatterer switching device viewed from the upstream side in the beam direction, FIG. 8B is a side view of the scatterer switching device viewed from the line bb in FIG. 8A, and FIG. (c) is the side view seen from the cc line part in Fig.8 (a).

As shown in FIG. 8A, in the scatterer switching device according to the third embodiment, when the four scatterers 2A, 2B, 2C, and 2D are installed on the central axis X ₄₂ (= particle beam therapy device 10). In the same plane perpendicular to the beam axis X _B ), the drive direction is shifted by 90 degrees. Then, as in the first embodiment, among the four scatterer 2A-2D, it may be used to move the position of use only one scatterers around the center axis X _42. The stopper 5 for avoiding a collision between the scatterers 2 is arranged so as not to be applied to the beam path of the charged particle beam B and the outer wall 42w of the vacuum chamber 42.

In the third embodiment, as compared with the first embodiment, only the scatterer 2D driven on the same straight line as the scatterer 2B is increased. Therefore, the exclusive region R _x2 and the limited region R _p2 of the scatterer ₂ are This can be set in the same manner as in the first form. However, the exclusive area R _x5 for arranging and configuring the stopper 5 is centered on the exclusive area R _x5B for the stopper group B including the stoppers 5A, 5B, and 5C intersecting the driving direction with the stopper 5B as the center, and the stopper 5D. Two exclusive regions _Rx5D for the stopper group D composed of the stoppers 5A, 5C, and 5D intersecting in the driving direction were set. Exclusive region _{R X5B} is the same as the exclusive area _{R x5} in the first embodiment, the exclusive region _{R X5d} exclusive area _{R X5B,} stoppers 5A includes a central axis _{X 42,} not shown parallel to the driving direction of the 5D The plane (hereinafter referred to as plane ACX) is a plane-symmetrical relationship. And the structure of each stopper 5 and the connection body 5b is also comprised so that it may become plane symmetry by plane ACX.

<Stopper 5B, 5D>
The stopper 5B avoids a collision between the scatterer 2D and the stopper 5B _S configured based on the exclusive region R _x5D , similarly to the stopper 5B in the first embodiment, in order to avoid a collision with the scatterers 2A and 2C. Therefore, it includes a stopper 5B _F configured independently of the exclusive region R _x5 and a connecting body 5bB that connects these to the drive rod 3bB. The stopper 5D is configured to be plane-symmetrical in terms ACX against the stopper 5B, the stopper 5B _S and symmetrical stopper 5D _S, a stopper 5B _F symmetrical stopper 5D _F, connecting body 5bB and symmetrical It consists of connected body 5bD. Then, as shown in FIGS. 8B and 8C, the stopper 5B _F and the stopper 5D _F are within a plane (a parallel plane at a distance) different from the plane where the exclusive region R _x5D is set. Driven and configured and arranged so that the interval in the drive direction (y direction) is shorter than the interval between the scatterers 2B and 2D.

<Stopper 5A, 5C>
The stopper 5A includes a stopper 5A _L corresponding to the stopper 5A in the first embodiment, a stopper 5A _R that is plane-symmetrical with the stopper 5A _L and the surface ACX, and a connecting body 5bA that couples these to the drive rod 3bA. . Similarly, the stopper 5C, a stopper _{5C LR} corresponding to the stopper 5C of the first embodiment, the stopper 5C _L as a plane symmetry with the stopper 5C _R and plane ACX, a connecting member 5bC connecting these to the drive rod 3bC Consists of.

Next, the operation of the scatterer switching device 20 configured as described above will be described.
<When using scatterer 2A>
When the scatterer 2A is used, the relationship between the scatterers 2B and 2C among the other scatterers 2B, 2C, and 2D is the same as that in the first embodiment. And for the scatterer 2D, by a stopper 5A _R and stopper 5D _S to be combined with plane symmetry between the stopper 5A _L and the stopper 5B _S, it can avoid collision.

In the case where the scatterer 2C is driven toward the use position by mistake, as with inter stopper 5A _L and the stopper 5C _L, also prevents the driving of the scatterer 2C between the stopper 5A _R and the stopper 5C _L, scatterers It is possible to avoid the collision of the scatterer 2C with 2A.

<When using scatterer 2B>
When the scatterer 2B is used, the relationship between the scatterers 2A and 2C among the other scatterers 2B, 2C, and 2D is the same as that in the first embodiment. And for the scatterer 2D, the stopper 5B _F and the stopper 5D _F before scatterer 2B and 2D collide because strikes earlier can avoid collisions.

<When using scatterers 2C and 2D>
When the scatterer 2C is used, the collision with the other scatterers 2A, 2B, and 2D can be avoided similarly to the scatterer 2A. Further, when the scatterer 2D is used, the collision with the other scatterers 2A, 2B, and 2C can be avoided similarly to the scatterer 2B.

That is, when one scatterer 2 enters the restricted region R _p2 including the use position, the other scatterers 2 do not enter the restricted region R _p2 , so that the drive mechanism 3 of the other scatterer 2 is Even if it is driven toward the use position by mistake, the scatterers 2 do not collide with each other and suffer damage. Furthermore, since the stopper 5 connected to the scatterer 2 is driven in cooperation with the scatterer 2 outside the vacuum chamber 42, the operation of the scatterer 2 can be easily monitored from the outside without searching the inside of the vacuum chamber 42. be able to.

1 scanning electromagnet (1x: x-direction scanning electromagnet, 1y: y-direction scanning electromagnet), 2 scatterer (2A: first scatterer, 2B: second scatterer, 2C: third scatterer), 3 air cylinder (drive) Mechanism (3b: drive rod, 3c: housing)), 4 vacuum chamber (41: scanning electromagnet corresponding part, 42: scatterer corresponding part), 5 stopper (5b: coupled body), 6 ridge filter, 7 range shifter, 8 Multi-leaf collimator, 9 bolus,
10 particle beam therapy device, 20 scatterer switching device,
B: charged particle beam, Rm: driving region of scatterer, R _p2 : restricted region of scatterer, R _x2 : exclusive region of scatterer (overlapping of driving region), R _x5 : exclusive region of stopper, X ₄₂ : scattering center of the body switching device, X _B beam axis (the center of the beam path)

Claims (4)

In a particle beam therapy system, a scatterer switching device that switches a scatterer that adjusts the beam diameter of a charged particle beam,
A plurality of scatterers having different scattering characteristics, and a vacuum chamber installed so as to align a central axis with a beam axis of the charged particle beam;
Within the first plane perpendicular to the central axis, the outer side of the vacuum chamber extends from the different directions toward the central axis toward the central axis, and scatterers are respectively connected to the extended tips. A drive mechanism that includes a drive rod and drives the connected scatterers to either a use position including the central axis or a retracted position away from the use position;
A stopper that is connected to a drive rod corresponding to each of the scatterers and prevents the scatterers from colliding with other scatterers by interlocking with the scatterers,
Each driving region of the stopper is set outside the vacuum chamber parallel to the first plane and away from the central axis;
A scatterer switching device characterized by that. Among the plurality of scatterers, the driving direction of at least two scatterers is a crossing direction,
The stopper drive regions corresponding to the two scatterers are set based on a second region obtained by translating the first region in which the drive loci of the corresponding scatterers in the first plane are overlapped. The scatterer switching device according to claim 1, wherein:   The scatterer switching device according to claim 2, wherein the driving directions of the two scatterers are orthogonal to each other. A scanning electromagnet that scans the charged particle beam supplied from the accelerator with two electromagnets having different scanning directions;
The scatterer switching device according to any one of claims 1 to 3, which is disposed downstream of the scanning electromagnet;
A scanning mode switching device that switches the scanning mode of the scanning electromagnet to either scanning irradiation or broad irradiation,
The scatterer switching device switches the scatterer to be driven to the use position based on the switched scanning mode.
A particle beam therapy system.

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