GaAs pixel arrays for β imaging in medicine and biology

We present an autoradiography system (BETAview) for a quantitative analysis of radioactive markers in biological samples; this system is also able to monitor a dynamic process. It is based on a solid-state pixel array detector, bump bonded to low threshold, integrated electronics developed for medical applications (Medipix). The present assembly is equipped with a 200 μm thick GaAs square detector, about 1 cm side, segmented into 64×64 170-μm size square pixels; simulation and experimental studies show good linearity and high sensitivity to β sources. Imaging tests with β sources of medical and biological interest such as 14C, 35S, 32P are reported.