High speed quantitative digital beta autoradiography using a multistep avalanche detector and an Apple II microcomputer

The development of an electronic, digital beta autoradiography system is described. Using a multistep avalanche/multiwire proportional counter (MSA/MWPC) detector system fitted with delay line readout, high speed digital imaging is demonstrated with submillimeter spatial resolution. In the case of autoradiography with a tritium label, image acquisition requires about one hour compared with several weeks for conventional film techniques. Good proportionality of observed counting rate relative to the known tritium activity is demonstrated. The application of the system to autoradiography in immunoelectrophoresis, histopathology and DNA sequencing is described (using 125I, 14C and 35S labels in addition to 3H).