Filmless photon imaging sensor plates and apparatus which are particularly effective in medical radiology and industrial applications including, but not limited to high resolution mammography. In combination, the sensor plates and apparatus provide rapid production of high resolution images which exhibit higher sensitivity and wider dynamic range than contemporary X-ray systems. Novel sensor plate structures provide images having attributes of increased sensitivity; dual plate design providing increased pixel read-out speed and differential dual energy image production; and electrically isolated segments by which a plurality of pixels are read concurrently to reduce overall image processing time. Generally, the plates employ a homogeneous photoconductive material such as amorphous selenium and are read by exposing each pixel sized area to a small diameter scanning light beam. Using light beam scanning, resulting plate design promises low cost manufacture of both sensor plates and associated apparatus. Novel application of electric fields during plate preparation, exposure and read-out provides improved sensor plate performance. A plurality of precisely-positioned light beams are scanned across the sensor through the use of a novel optical system employing an elongated light source disposed within a rotating drum, the drum being generally opaque with a helical transparent pattern which in combination with a series of lenses and a slit provides the plurality of precisely-positioned scanning light beams. By changing slit and beam widths, variable resolution operation is achieved.