PROBLEM TO BE SOLVED: To perform an AEC without difficulty by shooting conditions and the irradiation prohibition threshold value of abundant variation of a radiation image detector side when the variation of the shooting conditions and the irradiation prohibition threshold value set by a radiation source controller side is fewer than that of the radiation image detector side.SOLUTION: A comparison circuit 78 of an AEC unit 67 of an electronic cassette compares the accumulated value of a detection signal from a detection pixel of the electronic cassette with an irradiation prohibition threshold value on the electronic cassette. When the accumulated value of the detection signal reaches the irradiation prohibition threshold value on the electronic cassette, a detection signal having the same voltage value as the irradiation prohibition threshold value of the radiographing condition on the source control device paired with the radiographing condition on the electronic cassette is output from a detection signal I/F 80 of the electronic cassette toward a detection signal I/F 26 of the source control device.COPYRIGHT: (C)2013,JPO&INPIT【課題】線源制御装置側で設定される撮影条件および照射停止閾値が放射線画像検出装置側のそれらよりもバリエーションが少ない場合に、労せずして放射線画像検出装置側のバリエーション豊富な撮影条件および照射停止閾値でAECを行う。【解決手段】電子カセッテのAEC部67の比較回路78は、電子カセッテの検出画素からの検出信号の積算値と、電子カセッテ側の照射停止閾値とを比較する。検出信号の積算値が電子カセッテ側の照射停止閾値に達したときに、電子カセッテ側の撮影条件と対をなす線源制御装置側の撮影条件の照射停止閾値と等しい電圧値の検出信号を電子カセッテの検出信号I/F80から線源制御装置の検出信号I/F26に向けて出力する。【選択図】図18
