PROBLEM TO BE SOLVED: To suppress deterioration of image quality due to deviation of synchronization between a radiation irradiation period in a radiation source and a charge accumulation period in a radiation imaging apparatus. According to a control unit (22) of an FPD cassette (3) in a radiation imaging system (100), a plurality of radiation detection elements (7) are read out to generate a frame image of a moving image, and then a plurality of charges are read out. The charges are read out again from a part of the radiation detection element 7, and it is determined whether or not the radiation is irradiated outside the charge accumulation period of the radiation detection element 7 based on the read-out charge amount of the radiation detection element 7. When it is determined that the radiation is irradiated outside the charge accumulation period of the radiation detection element 7, the charge accumulation period is adjusted so that the radiation is irradiated within the charge accumulation period in the generation of the next frame image. [Selection diagram] Fig. 4【課題】放射線源における放射線照射期間と放射線撮影装置における電荷蓄積期間の同期のずれによる画質劣化を抑制する。【解決手段】放射線撮影システム１００におけるＦＰＤカセッテ３の制御部２２によれば、動画像の一のフレーム画像の生成のために複数の放射線検出素子７からの電荷の読み出しを行った後、複数の放射線検出素子７の一部から電荷の再読み出しを行い、再読み出しされた放射線検出素子７の電荷量に基づいて、放射線検出素子７の電荷蓄積期間外に放射線が照射されたか否かを判断し、放射線検出素子７の電荷蓄積期間外に放射線が照射されたと判断した場合は、次のフレーム画像の生成において電荷蓄積期間内に放射線が照射されるように電荷蓄積期間を調整する。【選択図】図４
