We report on the investigations about the modification of optical properties induced by X-rays onto film detectors of cadmium tungstate (CdWO4), poly[2-methoxy-5(2'-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) and polystyrene (PS) This device takes advantage of reduction of spectral overlap between the radioluminescence (RL) of CdWO4 and the absorption of MEH-PPV as it is exposed to radiation, forming the basis of a new dosimeter that is capable of converting the orange-red radioluminescence of PS:MEH-PPV:CdWO4 into green. We propose an explanation of the optical processes occurring in MEH-PPV:CdWO4 in terms of the radiation hardness of CdWO4 combined to the RL-induced degradation of MEH-PPV. (c) 2012 Elsevier B.V. All rights reserved.