Patent ID: 7535008

Claim:
A radiation imaging system comprising a camera part capable of rotating around a first rotation center axis as a center, the camera part including a collimator in which a plurality of radiation passages are formed on its incident plane side; and a plurality of radiation detectors of detecting radiations passing in the radiation passage for the respective radiation passages, wherein: the radiation passage of the collimator has an aperture section so that a section toward the radiation detector side is shaped to get broadened; the radiation detectors with a predetermined size are arranged in plurality in the rotation direction toward the respective radiation passages; and the camera part which is configured to radio-graph in a plurality of angle positions for the first rotation center axis set corresponding with the size of the radiation detector in the rotation direction upon radio-graphing a projection image from one direction, wherein the radiation passage of the collimator comprises: a fan-like opening angle φp on the circumferential direction side of the radiation passage that is not more than φp=2×tan −1 (Wp/D) with width Wp being the width of the detector in the circumferential direction of the radiation detector and the depth length D being a length of the detector in a direction perpendicular to the circumferential direction of the radiation detector.