An apparatus and method for detecting radiation are provided. The apparatus includes an upper electrode layer transmitting radiation; a first photoconductive layer becoming photoconductive upon exposure to the radiation and thus generating charges therein; a charge trapping layer trapping therein the charges generated in the first photoconductive layer; a second photoconductive layer becoming photoconductive upon exposure to rear light for reading out a radiation image; a lower transparent electrode layer charged with the charges trapped in the charge trapping layer; a micro lens layer disposed between the lower transparent electrode layer and a rear light emission unit and including a plurality of micro lenses respectively corresponding to a plurality of pixels; and the rear light emission unit applying the rear light to the second photoconductive layer via the micro lens layer and the lower transparent electrode layer in units of the pixels.