A correction plate has the same plane size as a small region obtained by equally dividing an image detection region. In addition, the correction plates whose number is equal to the number of small regions are prepared. In a maintenance mode, a plurality of correction plates are laid in the image detection region such that the entire image detection region is covered with the plurality of correction plates. In this state, scanning is performed and a correction image signal obtained by detecting fluorescent light from the correction plate is output. An acquisition unit of a console acquires a correction image signal and a creation unit creates a correction image on the basis of the correction image signal. A correction unit performs shading correction on the basis of the correction image.