Abstract: In beam monitoring for detecting annihilation radiations produced by radiation irradiation in radiation therapy for cancer which is performed by irradiating the affected area by X-rays, gamma rays, or particle beams, a detector-shift type combined radiation therapy/PET apparatus is provided with an open PET device that includes a plurality of shiftable multi-ring detector rings; and a radiation irradiation device that is capable of irradiation with a radiation beam through between the detector rings. The apparatus changes the positions of the detector rings, performs irradiation with the radiation beam through between the detector rings, and then performs radiation measurement.

Abstract: In beam monitoring for detecting annihilation radiations produced by radiation irradiation in radiation therapy for cancer which is performed by irradiating the affected area by X-rays, gamma rays, or particle beams, a detector-shift type combined radiation therapy/PET apparatus is provided with an open PET device that includes a plurality of shiftable multi-ring detector rings; and a radiation irradiation device that is capable of irradiation with a radiation beam through between the detector rings. The apparatus changes the positions of the detector rings, performs irradiation with the radiation beam through between the detector rings, and then performs radiation measurement.

Abstract: In an open-type PET scanner including a plurality of detector rings having multiple rings arrayed in the body axis direction, radiation measurement is performed while at least one detector ring is relatively moved with respect to a subject in the body axis direction, thereby dispersing simultaneous radiation in an open region to suppress a local reduction in sensitivity. The detector rings are optimized in constitution, moving direction and/or moving speed, thus making it possible to reduce the variation of distribution of sensitivity and expand a clearance in the open region and a field-of-view in the body axis direction.

Abstract: When a repeatedly periodically moving site of a to-be-examined subject in a gantry is subjected to computed tomography and is reconstructed, the gantry is rotated in synchronization with the movement of the periodically moving site, and a dynamic image showing a transient phenomenon is obtained in which the periodic movement of the moving site has been stopped. As a result, the flow of a contrast agent or the like can be observed in a state of stopping the movement of an internal organ that moves repeatedly periodically.

Abstract: When a repeatedly periodically moving site of a to-be-examined subject in a gantry is subjected to computed tomography and is reconstructed, the gantry is rotated in synchronization with the movement of the periodically moving site, and a dynamic image showing a transient phenomenon is obtained in which the periodic movement of the moving site has been stopped. As a result, the flow of a contrast agent or the like can be observed in a state of stopping the movement of an internal organ that moves repeatedly periodically.

Abstract: A heel effect compensation filter is configured to have a thickness distribution that uniforms an X-ray intensity angular distribution that is nonuniform in the body axis direction of a subject in an X-ray flux irradiated space. The space is formed by an X-ray flux diverging from an anode in a body width direction of the subject and diverging in a shape of an approximate sector in the body axis direction due to the heel effect, when the X-ray flux generated on the anode by irradiating a thermoelectron beam flux from a cathode to the anode is irradiated on the subject. The thickness distribution can be obtained using a predetermined formula.

Abstract: An X-ray flux irradiation intensity distribution which is nonuniform due to a heel effect can be made uniform, and a subject can be prevented from being unnecessarily exposed. In addition, image quality of image data obtained with an X-ray CT scanner can be made uniform and improved in a body axis direction. A heel effect compensation filter is configured to have a thickness distribution that uniforms an X-ray intensity angular distribution that is nonuniform in the body axis direction of a subject in an X-ray flux irradiated space. The space is formed by an X-ray flux diverging from an anode in a body width direction of the subject and diverging in a shape of an approximate sector in the body axis direction due to the heel effect, when the X-ray flux generated on the anode by irradiating a thermoelectron beam flux from a cathode to the anode is irradiated on the subject. The thickness distribution can be obtained using a predetermined formula.