| 摘要 |
PROBLEM TO BE SOLVED: To calculate a distance between an irradiation field center and the surface of a patient and to optimize an exposure dose by setting a measure straight line extended from a radiation virtual source on an axial image onto a transmissive image plane to the center position of an irradiation field on the transmissive image plane and setting an end point marker on the measure straight line to the front surface of the patient. SOLUTION: When a breast tangential irradiation is executed by using a half field technique irradiation method, the axial image 120 displayed on a monitor is observed and the position and size of a tumor 130 are recognized. Then, the measure straight line 161 extended from the radiation virtual source 141 set on the image 120 to the optional position of the transmissive image plane 160 is displayed and also a start point marker 162 indicating a position where the straight line 161 is crossed with the plane 160 is displayed. The straight line 161 is moved to the optional position of the plane 160 on the axial image 120, the end point marker 163 is displayed at the optional position on the straight line 161, the distance from the start point marker 162 is calculated and the exposure dose is adjusted. |
