X-ray intensifying screens greatly enhance the detection by autoradiography of the radioactive isotopes 32P and 125I

Detection of both γ-ray (¹²⁵I) and high energy β (³²P) particle-emitting radioisotopes by autoradiography is significantly enhanced by the use of X-ray intensifying screens. We have compared five commercially available intensifying screens (containing different inorganic phosphors) in combination with a number of films and exposure conditions. One calcium tungstate (Dupont, Cronex Lighting Plus intensifying screen produces an 8- to 10-fold enhancement in the detection of ³²P and a 30- to 40-fold enhancement in the detection of ¹²⁵I when an autoradiogram is made with Kodak RP ROYAL X-OMAT film at ?70°C. With one intensifying screen, 10 dpm of ³²P and 50 dpm of ¹²⁵I in an area of 10 mm² are readily detectable in a 20-hr exposure.