Patent ID: 7750309

Claim:
A radiation imaging apparatus, comprising; a flat panel detector including picture elements arranged in a matrix of rows and columns on a substrate, each picture element having a conversion element for converting radiation into an electrical signal, a signal wiring connected to the picture elements in a column, and a read-out circuit unit connected to the signal wiring; a holding unit for holding said flat panel detector; and a control unit for controlling said flat panel detector, wherein said flat panel detector can be connected to and disconnected from said holding unit, and wherein connecting state radiographing can be performed with the flat panel detector connected to the holding unit, and non-connecting state radiographing can be performed with the flat panel detector disconnected from the holding unit, and wherein said control unit controls said flat panel detector so that a power supply voltage applied to said read-out circuit unit in the non-connecting state radiographing is lower than that of applied to said read-out circuit unit in the connecting state radiographing, and so that a change in characteristics of said read-out circuit unit due to a change of the power supply voltage is compensated for.