PROBLEM TO BE SOLVED: To constantly take photographs using the best dose without need for much time and efforts.SOLUTION: The X ray photographing system takes one X-ray photograph as a set of a pre-photograph and a main photograph. In pre-photography, X-ray dose transmitting a subject is detected by detection pixels 65, and the integrated dose value is compared with a predetermined irradiation stop threshold value. Upon the integrated values reaching the irradiation stop threshold value, an electronic cassette AEC 67 executes the automatic exposure control to stop the X ray irradiation. A main photographing condition decision section decides the irradiation time or tube current time product, based on the irradiation time or tube current time product in pre-photography, the dose detected by the detection pixels 65 during pre-photography, and the dose necessary for the main photography. In this photography, X rays are irradiated using the irradiation time or tube current time product that is decided.COPYRIGHT: (C)2013,JPO&INPIT【課題】手間を掛けずに常に最適な線量で撮影を行う。【解決手段】X線撮影システムでは、一回のX線撮影をプレ撮影と本撮影のセットで行う。プレ撮影では被検体を透過したX線の線量を検出画素65で検出して、線量の積算値と予め設定した照射停止閾値を比較し、積算値が照射停止閾値に達したらX線の照射を停止させる自動露出制御を電子カセッテのAEC部67で行う。プレ撮影時の照射時間あるいは管電流時間積、プレ撮影時に検出画素65で検出された線量、および本撮影で必要な線量に基づき、本撮影条件決定部で本撮影の照射時間あるいは管電流時間積を決定する。本撮影では決定された照射時間あるいは管電流時間積でX線を照射する。【選択図】図4
