PROBLEM TO BE SOLVED: To easily and quickly set a measurement area for AEC (Automatic Exposure Control).SOLUTION: A measurement area selection circuit 75 has an irradiation field determination unit 120, an object area determination unit 121, and a measurement area determination unit 123. The irradiation field determination unit 120 determines an irradiation field of an imaging surface 47 of an FPD 45 on the basis of a collimator angle of an irradiation field limiter 17 and positional relation between an X-ray source and an electronic cassette 13. The object area determination unit 121 determines an object area from a comparison result between a first expected received dose of a directly exposed area calculated by a first expected received dose calculation unit 122 and dose detection signals of detection pixels 65 situated in the irradiation field. The measurement area determination unit 123 determines a measurement area, which corresponds to a region of interest to which attention should be paid the most at the time of diagnosis, from a comparison result between a second expected received dose of the measurement area and the dose detection signals of the detection pixels 65 situated in the irradiation area and the object area. The dose detection signals of the detection pixels 65 situated in the measurement area are used for AEC. With this configuration, the measurement area for AEC can be easily and quickly set.SELECTED DRAWING: Figure 9COPYRIGHT: (C)2016,JPO&INPIT【課題】AECの採光野を簡便かつ高速に設定する。【解決手段】採光野選択回路75は、照射野特定部120、被写体領域特定部121、および採光野領域特定部123を有する。照射野特定部120は、照射野限定器17のコリメータ角度、およびX線源と電子カセッテ13の位置関係に基づき、FPD45の撮像面47の照射野を特定する。被写体領域特定部121は、第一到達予測線量算出部122で算出された素抜け領域の第一到達予測線量と照射野の検出画素65の線量検出信号の比較結果から被写体領域を特定する。採光野領域特定部123は、診断時に最も注目すべき関心領域にあたる採光野領域の第二到達予測線量と照射野かつ被写体領域の検出画素65の線量検出信号の比較結果から採光野領域を特定する。採光野領域と特定された検出画素65の線量検出信号がAECに使用される。これにより、AECの採光野を簡便かつ高速に設定することができる。【選択図】図9
