Solid state tritium detector for biomedical applications

Radioactive labeling of proteins is a very important technique used in biomedical research to identify, isolate, and investigate the expression and properties of proteins in biological systems. In such procedures, the preferred radiolabel is often tritium. Presently, binding assays involving tritium are carried out using inconvenient and expensive techniques which rely on the use of scintillation fluid counting systems. This traditional method involves both time-consuming laboratory protocols and the generation of substantial quantities of radioactive and chemical waste. The authors have developed a novel technology to measure the tritium content of biological specimens that does not rely on scintillation fluids. The tritiated samples can be positioned directly under a large area, monolithic array of specially prepared avalanche photodiodes which record the tritium activity distribution at each point within the field of view of the array. The 1 mm/sup 2/ sensing elements exhibit an intrinsic tritium beta detection efficiency of 27% with high gain uniformity and very low cross talk.<>