CT IMAGING METHOD AND X-RAY CT DEVICE

摘要

PROBLEM TO BE SOLVED: To shorten the filtering processing time when a CT image is formed and dispense with a pre-scan using a reference phantom. ;SOLUTION: The ideal projection data R_ij,_s to be obtained when multiple ideal phantoms different in size are scanned are calculated by simulation and held, the ideal projection data R_ij,_s of the ideal phantom most approximate to a testee in size are selected (B2), the selected data are subtracted from the projection data Proj_ij obtained when the testee is scanned (B4), and the filtering process (B5-B7) and back protection process (B8) are applied to the difference projection data P'roj_ij. No low-frequency component is left in the difference projection data P'roj_ij, no cupping occurs on a CT image when the number of FFT points is decreased in the filtering process, and the calculating time can be shortened. The ideal projection data are obtained by simulation, and a pre-scan using a reference phantom is not required.;COPYRIGHT: (C)1998,JPO