USE OF STORAGE PHOSPHOR IMAGING PLATES IN PORTAL IMAGING AND HIGH-ENERGY RADIOGRAPHY - THE INTENSIFYING EFFECT OF METALLIC SCREENS ON THE SENSITIVITY

The sensitivity of storage phosphor imaging plates (SPIP) at megavolt photon energies (Co-60, 6-, 10-, and 18-MV radiotherapy beams) is studied both experimentally and by Monte Carlo radiation transport calculations. In addition, the same techniques are used to investigate the intensifying effect of metal screens on the sensitivity of the SPIP. The results provide evidence that the sensitivity of the SPIPs is proportional to the absorbed energy in the phosphor layer per cGy. The spectral sensitivity is calculated for photon energies between 10 keV and 20 MeV for various SPIP-screen combinations.