Sample data (53) is stored in a console (24) of an electronic cassette (image detection panel) (21, 107). The sample data corresponds to a model of the electronic cassette and includes sample images captured using different doses before a shipment of the electronic cassette. In initial setting processing of an imaging condition including the dose, the sample data is read out and a dose selection screen (81) in which the sample images are arranged is displayed on a display (48). In the dose selection screen, the sample images are arranged in a tiled manner in an ascending or descending order of their doses (densities). A user compares the sample images to select the sample image with the density suitable for diagnosis. The dose corresponding to the selected sample image is set as an initial value.
