| 摘要 |
PURPOSE: To realize a calibration method using single circular phantom placed at a shifted position against the rotation axis of a scanner, by measuring each attenuation corresponding to the angle position of the scanner for each channel, calculating the distance that X-ray passed in the phantom, and incorporating an operation to obtain polynominal approximation of the calculated values based on a specified eccentricity rule. CONSTITUTION: In calibration of an X-ray scanner provided with N pieces of detectors or an N channels detection unit supported on a structural body rotating around an X-ray source and an rotation axis, using a circular phantom, the phantom is placed at a specified position where the center of the phantom deviates from the rotation axis of the scanner. Measurements of attenuation Yij corresponding to each channel i and scanner angle positionβj are repeated m times by moving the scanner. The distance Xij that X-ray passed through the phantom is calculated for each Yij measurement. The coefficient Aik of the n order polynominal for each channel i is calculated, and polynominal approximation of the calculated value Xij is obtained based on a specified eccentricity rule.
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