Patent ID: 7409034

Claim:
A radiation tomography apparatus comprising: an X-ray irradiation device for irradiating an X-ray while scanning helically around an imaging area of an imaging object on a body axis of said imaging object; an X-ray detection array comprising X-ray detection elements arranged in an array for detecting said X-ray and for generating detection data according to said X-ray detected by said X-ray detection elements; an irradiation range adjustment device disposed between said X-ray irradiation device and said X-ray detection array for shielding said X-ray to adjust an irradiation range of said X-ray so that said X-ray is not irradiated to a specified area of said X-ray detection array; a controller for controlling at least said irradiation range adjustment device; and a tomographic image generation device for generating a tomographic image of said imaging area of said imaging object based on said detection data; wherein said detection data of said X-ray detection array comprises first and second detection data, said first detection data results from said X-ray detected by said X-ray detection element corresponding to an area not shielded by said irradiation range adjustment device, and said second data results from said X-ray detected by said X-ray detection element corresponding to an area shielded by said irradiation range adjustment device during at least one of a beginning and an end of said helical scanning; an opening of said irradiation range adjustment device is adjustable during said helical scanning to shield said X-ray during at least one of the beginning and the end of said helical scanning to shield at least a part of an area outside of said imaging area along the body axis, wherein said opening is adjusted by said controller during said helical scanning such that, upon helical scanning of said imaging area from a first end to an opposing second end in a direction along said body axis, said irradiation range adjustment device makes the irradiation range of said X-ray wider than an irradiation range during at least one of the beginning and the end of said helical scanning; and said tomographic image generation device correcting said first detection data by using said second detection data from said X-ray detected during at least one of the beginning and the end of said helical scanning, and generating said tomographic image based on a corrected first detection data.