| 摘要 |
PURPOSE:To achieve a higher pulse rate, by a method wherein the residue of ionized charge is determined from secular changes in the ionized charge of a xenon detector in the calibration mode and the correction factor is determined from the results to correct the data corresponding to transmission radiation dose in the normal mode. CONSTITUTION:An object 12 to be inspected is exposed to a fan beam X rays FB from an X rays tube 11 and the beam is detected with an xenon detector 13. A signal current of the ionized charge outputted from the detector 13 is integrated with a data collecting section 14 and a discharging is done to obtain an X rays absorption data corresponding to time value. In the calibration mode, a reference material is exposed to the beam and the ratio of the residue of ionized charge is determined corresponding to the pulse rate in the radiation exposure from secular changed of the ionized charge of the xenon detector left in a single radiation pulse exposure. A correction factor is found from the results to determine the true signal value for each radiation pulse exposure. Then, in the normal mode, a data corresponding to transmission radiation dose is multiplied by the correction factor to correct with a computer 15 to perform a reconstruction image processing. Thus, the correction is made at the image reconstruction using the correction factor obtained at the calibration thereby enabling a higher pulse rate. |
