초록 ▼

When the IMRT technology for a radiation therapy system utilizing an X-ray or the like is applied as it is to a particle beam therapy system having a conventional wobbler system, there is posed the problem that it is required to utilize two or more boluses. The objective of the present invention is

When the IMRT technology for a radiation therapy system utilizing an X-ray or the like is applied as it is to a particle beam therapy system having a conventional wobbler system, there is posed the problem that it is required to utilize two or more boluses. The objective of the present invention is to solve the problem of excess irradiation in IMRT by a particle beam therapy system. More specifically, the problem of excess irradiation in IMRT by a particle beam therapy system is solved by raising the irradiation flexibility in the depth direction, without utilizing a bolus. There is provided a particle beam irradiation apparatus (58) having a scanning irradiation system (34) that performs scanning with a charged particle beam (1) accelerated by an accelerator and being mounted in a rotating gantry for rotating the irradiation direction of the charged particle beam (1); the particle beam irradiation apparatus (58) comprises a columnar-irradiation-field generation apparatus (4) that generates a columnar irradiation field by enlarging the Bragg peak of the charged particle beam (1).

대표청구항 ▼

1. A particle beam irradiation apparatus having a scanning irradiation system that performs scanning with a charged particle beam accelerated by an accelerator and being mounted in a rotating gantry for rotating the irradiation direction of the charged particle beam, the particle beam irradiation ap

1. A particle beam irradiation apparatus having a scanning irradiation system that performs scanning with a charged particle beam accelerated by an accelerator and being mounted in a rotating gantry for rotating the irradiation direction of the charged particle beam, the particle beam irradiation apparatus comprising: a columnar-irradiation-field generation apparatus for generating a columnar irradiation field by enlarging the Bragg peak of the charged particle beam, said columnar irradiation-field generation apparatus including: at least one pair of upstream deflection electromagnets and at least one pair of downstream deflection electromagnets, wherein (i) a first deflection electromagnet of the pair of upstream deflection electromagnets deflects the charged particle beam at a predetermined angle with respect to an original beam path and (ii) a second electromagnet of the pair of upstream deflection electromagnets deflects the deflected charged particle beam such that it is parallel with respect to the original beam path,an energy changing apparatus for changing the energy of the charged particle beam,a depth-direction irradiation field enlargement apparatus for enlarging the Bragg peak of the charged particle beam, anda controller that controls the energy changing apparatus in conjunction with the depth-direction irradiation field enlargement apparatus so that the columnar irradiation field of the charged particle beam, entering an irradiation subject from any one of a plurality of different directions, is generated at a depth of the irradiation subject that conforms to a shape of a distal end portion of the irradiation subject. 2. The particle beam irradiation apparatus according to claim 1, wherein the the energy of the charged particle beam is changed by the accelerator. 3. The particle beam irradiation apparatus according to claim 1, wherein the energy changing apparatus comprises: a range shifter whose thicknesses in directions in which the charged particle beam passes change depending on portions thereof and that reduces the energy of the charged particle beam that passes therethrough, in accordance with the thickness;a pair of upstream deflection electromagnets, from the at least one pair of upstream deflection electromagnets, that move the passing position, of the charged particle beam, in the range shifter;a pair of downstream deflection electromagnets, from the at least one pair of downstream deflection electromagnets, that return the orbit of the charged particle beam toward a beam axis along which the charged particle beam has entered the energy changing apparatus; anda change control apparatus that controls the pair of upstream deflection electromagnets and the pair of downstream deflection electromagnets in such a way that the charged particle beam passes through a predetermined thickness of the range shifter. 4. The particle beam irradiation apparatus according to claim 1, wherein the depth-direction irradiation field enlargement apparatus comprises; a ridge filter having a thickness distribution in which energy that the charged particle beam loses differs depending on the position thereon through which the charged particle beam passes;a pair of upstream deflection electromagnets, from the at least one pair of upstream deflection electromagnets, that move the passing position, of the charged particle beam, in the ridge filter;a pair of downstream deflection electromagnets, from the at least one pair of downstream deflection electromagnets, that return the orbit of the charged particle beam toward a beam axis along which the charged particle beam has entered the depth-direction irradiation field enlargement apparatus; andan irradiation-field enlargement control apparatus that controls the pair of upstream deflection electromagnets and the pair of downstream deflection electromagnets in such a way that the charged particle beam passes through a predetermined thickness distribution of the ridge filter. 5. The particle beam irradiation apparatus according to claim 1, wherein the depth-direction irradiation field enlargement apparatus comprises; a plurality of ridge filters, each having a different thickness and each of which changing the energy range of the charged particle beam in accordance with the thickness thereof through which the charged particle beam passes;a plurality of driving devices for driving the ridge filters respectively; andan irradiation-field enlargement control apparatus for driving the driving devices so as to control the whole thickness of the ridge filters through which the charged particle beam passes. 6. The particle beam irradiation apparatus according to claim 1, wherein the columnar-irradiation-field generation apparatus comprises; a range shifter whose thicknesses in directions in which the charged particle beam passes change depending on portions thereof and that reduces the energy of the charged particle beam that passes therethrough, in accordance with the thickness;a ridge filter that is disposed at the downstream side of the range shifter and has a thickness distribution in which energy that the charged particle beam loses differs depending on the position thereon through which the charged particle beam passes;a pair of upstream deflection electromagnets, from the at least one pair of upstream deflection electromagnets, that move the passing positions, of the charged particle beam, in the range shifter and the ridge filter;a pair of downstream deflection electromagnets, from the at least one pair of downstream deflection electromagnets, that return the orbit of the charged particle beam toward a beam axis along which the charged particle beam has entered the columnar-irradiation-field generation apparatus; anda change control apparatus that controls the pair of upstream deflection electromagnets and the pair of downstream deflection electromagnets in such a way that the charged particle beam passes through respective predetermined thickness distributions of the range shifter and the ridge filter. 7. The particle beam irradiation apparatus according to claim 1, wherein the depth-direction irradiation field enlargement apparatus comprises;an RMW apparatus that changes the position thereof, through which the charged particle beam passes, so as to vary the energy of the charged particle beam; andan irradiation-field enlargement control apparatus that controls the RMW apparatus,wherein the RMW apparatus comprises;an RMW that has an energy absorber in which a plurality of pedestals, the respective axis-direction thicknesses of which are stepwise different from one another, are arranged in the circumferential direction thereof and that varies the energy thereof as the charged particle beam passes through the plurality of pedestals; anda rotation drive device that rotates the RMW,wherein the irradiation-field enlargement control apparatus controls the rotation drive device in such a way that the charged particle beam passes through the plurality of pedestals. 8. The particle beam irradiation apparatus according to claim 7, wherein the depth-direction irradiation field enlargement apparatus comprises an angle sensor that detects a rotation angle of the RMW, andwherein the irradiation-field enlargement control apparatus controls the rotation drive device in such a way that the RMW continues to rotate, and controls the emission start and the emission stop of the charged particle beam, based on the rotation angle detected by the angle sensor, so that the charged particle beam passes through the plurality of pedestals. 9. The particle beam irradiation apparatus according to claim 7, wherein the depth-direction irradiation field enlargement apparatus comprises;a plurality of RMW apparatuses; anda driving device that moves the RMW apparatus to a position through which the charged particle beam passes or a position through which the charged particle beam does not pass. 10. The particle beam irradiation apparatus according to claim 1, wherein the columnar-irradiation-field generation apparatus comprises;a range shifter whose thicknesses in directions in which the charged particle beam passes change depending on portions thereof and that reduces the energy of the charged particle beam that passes therethrough, in accordance with the thickness;an RMW apparatus that is disposed at the downstream side of the range shifter and changes the position thereof, through which the charged particle beam passes, so as to vary the energy of the charged particle beam;a pair of upstream deflection electromagnets, from the at least one pair of upstream deflection electromagnets, that move the incident position, of the charged particle beam, in the range shifter and the RMW apparatus;a pair of downstream deflection electromagnets, from the at least one pair of downstream deflection electromagnets, that return the orbit of the charged particle beam toward a beam axis along which the charged particle beam has entered the columnar-irradiation-field generation apparatus; anda change control apparatus that controls the pair of upstream deflection electromagnets and the pair of downstream deflection electromagnets in such a way that the charged particle beam passes through a predetermined thickness of the range shifter, and that performs control in such a way that the RMW apparatus varies the energy of the charged particle beam,wherein the RMW apparatus comprises;an RMW that has an energy absorber in which a plurality of pedestals, the respective axis-direction thicknesses of which are stepwise different from one another, are arranged in the circumferential direction thereof and that varies the energy thereof as the charged particle beam passes through the plurality of pedestals; anda rotation drive device that rotates the RMW,wherein in order to form a predetermined depth of SOBP, the change control apparatus performs control in such a way that the charged particle beam passes through the plurality of pedestals andwherein the range shifter is disposed at an upstream side of the RMW apparatus in such a way as to be situated between the rotation axle of an RMW and the outer circumference of the RMW. 11. A particle beam therapy system comprising: an ion beam generation apparatus that generates a charged particle beam and accelerates the charged particle beam by means of an accelerator until the charged particle beam acquires predetermined energy;an ion beam transport system that transports the charged particle beam accelerated by the ion beam generation apparatus;a particle beam irradiation apparatus that irradiates the charged particle beam transported by the ion beam transport system onto an irradiation subject; anda rotating gantry that rotates the irradiation direction of the particle beam irradiation apparatus, wherein the particle beam irradiation apparatus is the particle beam irradiation apparatus according to claim 1. 12. The particle beam therapy system according to claim 11, further comprises; a treatment planning apparatus that generates a treatment plan including the operation conditions of the particle beam irradiation apparatus and the rotating gantry, wherein the treatment planning apparatus comprises;an irradiation field arranging unit that arranges columnar irradiation fields in accordance with the distal form of an irradiation subject onto which the charged particle beam is irradiated, and arranges columnar irradiation fields in such a way that the columnar irradiation fields cover the inside of the irradiation subject; andan optimization calculation unit that adjusts the arrangement of the columnar irradiation fields in such a way that the irradiation dose onto the irradiation subject falls within a predetermined range, regarding, as the initial state, the state in which the columnar irradiation fields are arranged by the irradiation field arranging unit. 13. The particle beam therapy system according to claim 12, wherein, after arranging the columnar irradiation fields in accordance with the distal form of the irradiation subject, the irradiation field arranging unit arranges the columnar irradiation fields in accordance with the shape of an inner portion, of the irradiation subject, in which the columnar irradiation fields are not arranged. 14. The particle beam therapy system according to claim 12, wherein the irradiation field arranging unit utilizes a plurality of SOBP depths, which are the widths, in the irradiation direction, of the columnar irradiation fields. 15. A particle beam therapy system comprising: an ion beam generation apparatus that generates a charged particle beam and accelerates the charged particle beam by means of an accelerator until the charged particle beam acquires predetermined energy;an ion beam transport system that transports the charged particle beam accelerated by the ion beam generation apparatus;a particle beam irradiation apparatus that irradiates the charged particle beam transported by the ion beam transport system onto an irradiation subject; anda rotating gantry that rotates the irradiation direction of the particle beam irradiation apparatus, wherein the particle beam irradiation apparatus is the particle beam irradiation apparatus according to claim 2. 16. A particle beam therapy system comprising: an ion beam generation apparatus that generates a charged particle beam and accelerates the charged particle beam by means of an accelerator until the charged particle beam acquires predetermined energy;an ion beam transport system that transports the charged particle beam accelerated by the ion beam generation apparatus;a particle beam irradiation apparatus that irradiates the charged particle beam transported by the ion beam transport system onto an irradiation subject; anda rotating gantry that rotates the irradiation direction of the particle beam irradiation apparatus, wherein the particle beam irradiation apparatus is the particle beam irradiation apparatus according to claim 7. 17. A particle beam therapy system comprising: an ion beam generation apparatus that generates a charged particle beam and accelerates the charged particle beam by means of an accelerator until the charged particle beam acquires predetermined energy;an ion beam transport system that transports the charged particle beam accelerated by the ion beam generation apparatus;a particle beam irradiation apparatus that irradiates the charged particle beam transported by the ion beam transport system onto an irradiation subject; anda rotating gantry that rotates the irradiation direction of the particle beam irradiation apparatus, wherein the particle beam irradiation apparatus is the particle beam irradiation apparatus according to claim 8. 18. The particle beam irradiation apparatus according to claim 1, wherein the columnar-irradiation field generation apparatus generates at least two columnar irradiation fields having different SOBP depths and the particle beam irradiation apparatus irradiates the charged particle beam from any one of a plurality of directions in such a way as to generate a largest columnar irradiation field having a largest SOBP at a depth that conforms to the shape of the distal end portion of the irradiation subject.