Abstract: An MRI apparatus equipped with a magnetic shield structure to reduce flux leakage. The MRI apparatus includes: a pair of static magnetic magnets that are disposed on opposite sides of an imaging space; and a pair of gradient coils that are disposed on opposite sides of the imaging space. Each static magnetic magnet has a disk-shaped magnetic material pole 201 and a ring-shaped magnetic material pole 202. Each gradient coil has a first coil 204 that applies a magnetic field gradient in a Z axis direction in an imaging region, and a laminate 301 that shields the disk-shaped magnetic material pole from magnetic flux produced in the first coil. The laminate has a smaller thickness in the Z axis direction on the ring-shaped magnetic material pole side than that in a center portion of the imaging space.

Abstract: A correlation between a CT value and a water equivalent thickness ratio distribution for each patient can be corrected without increasing a treatment time, and more accurate treatment can be realized. A treatment planning system 112 which generates a treatment plan for irradiating an irradiation target with a particle beam calculates a correction amount of a water equivalent thickness ratio of a first treatment plan created in advance, calculates a water equivalent thickness ratio distribution based on the correction amount and the first treatment plan, and creates a second treatment plan from the water equivalent thickness distribution.

Abstract: A treatment planning system that generates treatment planning for irradiating a target with a particle beam, includes an arithmetic processing device that sets at least two or more irradiation patterns for one treatment planning, calculates a plurality of predicted dose distributions for each irradiation pattern based on a target dose set for each region for at least one region including a region of the target, and calculates an index for evaluating validity of the irradiation pattern based on the plurality of predicted dose distributions.

Abstract: An open-type MRI apparatus includes a pair of static magnetic field magnets and a pair of gradient magnetic field coils. Each static magnetic field magnet includes a discoid magnetic pole configured to generate a static magnetic field in a Z axis direction in which the pair of static magnetic field magnets are opposed each other, and an annular magnetic pole configured to generate a static magnetic field on an X-Y plane perpendicular to the Z axis direction. Each gradient magnetic field coil includes a Z coil configured to provide a magnetic field being gradient in the Z axis direction in the imaging region, a magnetic material block configured to shield the discoid magnetic pole from a magnetic flux generated from the Z coil, and a correction coil configured to shield the annular magnetic pole from the magnetic flux generated from the Z coil.

Abstract: An open-type MRI apparatus includes a pair of static magnetic field magnets and a pair of gradient magnetic field coils. Each static magnetic field magnet includes a discoid magnetic pole configured to generate a static magnetic field in a Z axis direction in which the pair of static magnetic field magnets are opposed each other, and an annular magnetic pole configured to generate a static magnetic field on an X-Y plane perpendicular to the Z axis direction. Each gradient magnetic field coil includes a Z coil configured to provide a magnetic field being gradient in the Z axis direction in the imaging region, a magnetic material block configured to shield the discoid magnetic pole from a magnetic flux generated from the Z coil, and a correction coil configured to shield the annular magnetic pole from the magnetic flux generated from the Z coil.

Abstract: There is provided a treatment planning system and a particle therapy system. In the related art, it is unable to determine optimum beam intensity in irradiation for which discrete spot irradiation and continuous beam irradiation coexist. There is provided a treatment planning system that includes a spot determination unit that divides an irradiation region to be irradiated with a charged particle beam into a plurality of layers in an advancing direction of the charged particle beam and disposes a plurality of irradiation spots, which becomes irradiation points of the charged particle beam, in the layers and a beam intensity determination unit that determines beam intensity for each of the layers by evaluating the irradiation time by changing the beam intensity in a range of a condition of change in dose distribution which is set in advance.

Abstract: Provided are a radiation treatment planning system and a radiation treatment system that are capable of achieving time shortening and labor saving of treatment planning making when a radiation treatment is planned. A predicted DVH calculation portion 4034 of an arithmetic processing device 403 in a radiation treatment planning system 400 anisotropically enlarges a target region 501 in an irradiated body image which is input to the radiation treatment planning system 400, and calculates an overlap volume OV with an organ-at-risk region 502 per the number of times of enlargement. A DVH (Dose Volume Histogram) is predicted from a volume of the calculated OV, and a dose histogram in the OV per the number of times of enlargement which is calculated from a past treatment planning data group, and is displayed on a display device 401.

Abstract: The invention provides a particle therapy system in which whether to perform any one irradiation method of a raster scanning method and a discrete spot scanning method can also be selected based on previous selection depending on a target volume 41 of a patient 4 to be irradiated, and either of the irradiation methods of the raster scanning method and the discrete spot scanning method is configured to be capable of being performed by one irradiation apparatus 500. Therefore, a small particle therapy system capable of achieving both higher accuracy irradiation and high dose rate improvement is provided.

Abstract: The object of the invention is to estimate a causal relation between predetermined data at high precision and at ease, taking nonlinearity between the data into consideration. A work improvement support device is comprised of a nonlinear term adding unit for calculating a nonlinear value as for respective working data in the working data group and adding the nonlinear value to a working data group, a multiple regression analysis unit for calculating a regression formula as for respective working data according to the multiple linear regression analysis, a data group setting unit for determining whether there is a linear term in the calculated regression formula and setting the predetermined data comprising the linear term and the objective variable of the regression formula as the same group, and an explanatory variable candidate selecting unit for selecting the working data, excluding the predetermined data, as the explanatory variable candidates for the multiple linear regression analysis.

Abstract: A radiation therapy planning apparatus performs dose calculation at high speed and with high accuracy for radiation therapy in a scanning irradiation method. The apparatus includes a display, an arithmetic processing apparatus, a memory, and a data server, which is connected to a particle beam irradiation apparatus. A dose calculation unit of the arithmetic processing apparatus calculates dose distribution by a simplified Monte Carlo algorithm, and corrects the dose distribution by a decreasing rate stored in a particle number decreasing rate table of the memory, and stores the corrected dose distribution in an integrated dose distribution table. By using the simplified Monte Carlo algorithm and the particle number decreasing rate that corrects the simplified Monte Carlo algorithm, the dose distribution is calculated, and thereby, it is possible to realize a radiation therapy planning apparatus that performs dose calculation at a high speed with high accuracy.

Abstract: The particle therapy system includes a particle beam generator for generating a particle beam; an irradiation nozzle arranged in a treatment room and irradiating a target with the particle beam; a particle beam transport system communicating the particle beam generator with the irradiation nozzle; an X-ray imaging device arranged in the treatment room and imaging the position of the target through irradiation with X-rays; a dosimeter arranged at a position passed by the particle beam in the irradiation nozzle; and a control apparatus performing control to exclude the measurement result of the X-rays from the measurement result obtained using the dosimeter when the X-rays are emitted during treatment.

Abstract: The invention provides a particle therapy system in which whether to perform any one irradiation method of a raster scanning method and a discrete spot scanning method can also be selected based on previous selection depending on a target volume 41 of a patient 4 to be irradiated, and either of the irradiation methods of the raster scanning method and the discrete spot scanning method is configured to be capable of being performed by one irradiation apparatus 500. Therefore, a small particle therapy system capable of achieving both higher accuracy irradiation and high dose rate improvement is provided.

Abstract: There is provided a treatment planning system and a particle therapy system. In the related art, it is unable to determine optimum beam intensity in irradiation for which discrete spot irradiation and continuous beam irradiation coexist. There is provided a treatment planning system that includes a spot determination unit that divides an irradiation region to be irradiated with a charged particle beam into a plurality of layers in an advancing direction of the charged particle beam and disposes a plurality of irradiation spots, which becomes irradiation points of the charged particle beam, in the layers and a beam intensity determination unit that determines beam intensity for each of the layers by evaluating the irradiation time by changing the beam intensity in a range of a condition of change in dose distribution which is set in advance.

Abstract: Provided are a radiation treatment planning system and a radiation treatment system that are capable of achieving time shortening and labor saving of treatment planning making when a radiation treatment is planned. A predicted DVH calculation portion 4034 of an arithmetic processing device 403 in a radiation treatment planning system 400 anisotropically enlarges a target region 501 in an irradiated body image which is input to the radiation treatment planning system 400, and calculates an overlap volume OV with an organ-at-risk region 502 per the number of times of enlargement. A DVH (Dose Volume Histogram) is predicted from a volume of the calculated OV, and a dose histogram in the OV per the number of times of enlargement which is calculated from a past treatment planning data group, and is displayed on a display device 401.

Abstract: A structure configuring a ridge filter has line symmetry about a line vertical to a depth direction passing the center of the structure. A small structure obtained in such a way that the structure is divided by this line has a bilaterally asymmetric shape about a center line in an iterative direction, and has a point symmetric shape about an intersection between the center line in the iterative direction and the center line in the depth direction. Thicknesses in the iterative direction of an uppermost stream surface and a lowermost stream surface in the depth direction are equal to each other. The structure is configured so that a thick portion in the iterative direction of the uppermost stream surface and the lowermost stream surface is not present in the depth direction.

Abstract: A radiation therapy planning apparatus performs dose calculation at high speed and with high accuracy for radiation therapy in a scanning irradiation method. The apparatus includes a display, an arithmetic processing apparatus, a memory, and a data server, which is connected to a particle beam irradiation apparatus. A dose calculation unit of the arithmetic processing apparatus calculates dose distribution by a simplified Monte Carlo algorithm, and corrects the dose distribution by a decreasing rate stored in a particle number decreasing rate table of the memory, and stores the corrected dose distribution in an integrated dose distribution table. By using the simplified Monte Carlo algorithm and the particle number decreasing rate that corrects the simplified Monte Carlo algorithm, the dose distribution is calculated, and thereby, it is possible to realize a radiation therapy planning apparatus that performs dose calculation at a high speed with high accuracy.

Abstract: A structure configuring a ridge filter has line symmetry about a line vertical to a depth direction passing the center of the structure. A small structure obtained in such a way that the structure is divided by this line has a bilaterally asymmetric shape about a center line in an iterative direction, and has a point symmetric shape about an intersection between the center line in the iterative direction and the center line in the depth direction. Thicknesses in the iterative direction of an uppermost stream surface and a lowermost stream surface in the depth direction are equal to each other. The structure is configured so that a thick portion in the iterative direction of the uppermost stream surface and the lowermost stream surface is not present in the depth direction.

Abstract: The present invention provides a particle therapy system including an irradiation compensating device made up of an energy absorber, a first collimator, and a second collimator for use in a short-range region. The irradiation compensating device is characterized by a mechanism for attaching and detaching the first energy absorber, first collimator, and second collimator. The first collimator is located upstream where the beam diameter is small with a view to suppressing the width of the compensating device, thereby contributing to making the compensating device small and lightweight. The second collimator is located downstream to improve penumbrae.

Abstract: There is provided a particle therapy system including: a particle beam generator for generating a particle beam; an irradiation nozzle arranged in a treatment room and irradiating a target with the particle beam; a particle beam transport system 6 communicating the particle beam generator with the irradiation nozzle; an X-ray imaging device arranged in the treatment room and imaging the position of the target through irradiation with X-rays; a dosimeter 8 arranged at a position passed by the particle beam in the irradiation nozzle; and a control apparatus 400 performing control to exclude the measurement result of the X-rays from the measurement result obtained using the dosimeter 8 when the X-rays are emitted during treatment.

Abstract: The present invention provides a particle therapy system including an irradiation compensating device made up of an energy absorber, a first collimator, and a second collimator for use in a short-range region. The irradiation compensating device is characterized by a mechanism for attaching and detaching the first energy absorber, first collimator, and second collimator. The first collimator is located upstream where the beam diameter is small with a view to suppressing the width of the compensating device, thereby contributing to making the compensating device small and lightweight. The second collimator is located downstream to improve penumbrae.