DOSE DISTRIBUTION-MEASURING APPARATUS FOR RADIOTHERAPY, AND CALIBRATION METHOD OF SCATTERED RADIATION DETECTOR IN DOSE DISTRIBUTION-MEASURING APPARATUS FOR RADIOTHERAPY

摘要

PROBLEM TO BE SOLVED: To calibrate the position and the detection sensitivity of a scattered radiation detector in a measuring apparatus for detecting scattered radiation during the radiotherapy.

SOLUTION: A marker plate including a plurality of scattering bodies for scattering a treatment beam is mounted on a bed 14, and the scattered radiation detector 21 detects scattered radiation from the scattering bodies generated based on the treatment beam. A position calculating part 41 calculates the position of the scattered radiation detector 21 based on the result of the detection and the image in the scattered radiation detector 21 obtained from the setting positions of the scattering bodies. An area calculating part 45 calculates the area within the marker plate with a possibility of the scattered radiation entering the scattered radiation detector 21 based on the position of the scattered radiation detector 21 and the setting positions of the scattering bodies. An attributed data calculating part 46 calculates the attributed data of the incident scattered radiation based on the calculated area and the positions and material of the scattering bodies. A correction coefficient calculating part 47 calculates a correction coefficient for correcting the detection sensitivity based on the actually measured value and the calculated attributed data.

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