Radiation imaging apparatus, radiation imaging system, and method of operating radiation imaging apparatus

A method of operating a radiation imaging apparatus comprising a pixel array having a plurality of pixels arrayed to form a plurality of rows and a plurality of columns, a scanning circuit configured to scan the plurality of rows of the pixel array in accordance with a selected mode of a plurality of modes, and a readout circuit configured to read out signals from pixels on a selected row in scanning by the scanning circuit,

• Wherein the plurality of modes include a first mode of performing image capturing at a first frame rate and a second mode of performing image capturing at a second frame rate lower than the first frame rate, and
• the number of times of scanning on the plurality of rows by the scanning circuit in one frame period in the second mode is larger than the number of times of scanning on the plurality of rows by the scanning circuit in one frame period in the first mode.