| 摘要 |
PROBLEM TO BE SOLVED: To provide a tomography apparatus that is drastically speeded up by simplifying arcsin calculation. SOLUTION: The apparatus decides a projection data phase range which can be backprojected by each reforming voxel by means of used data phase range calculation, calculates an approximate straight line to a curve that indicates a location of a radiation source against a channel direction location of parallel beam projection data obtained by a parallel beam in a parallel form when viewed from the direction of an orbit axis released from the radiation source by means of approximate straight line calculation, and has a means of a parallel beam three-dimensional backprojection that three-dimensionally backprojects filter-processed parallel beam projection data, which are prepared by means of a filter calibration based on the decided projection data range which can be backprojected, in a backprojection area corresponding to an area of interest along with an approximate irradiation path of an irradiation beam calculated with the approximate straight line by means of the approximate straight line calculation. COPYRIGHT: (C)2004,JPO&NCIPI
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