BETAview:: a digital β-imaging system for dynamic studies of biological phenomena

We present a digital autoradiography (DAR) system, named BETAview, based on semiconductor pixel detectors and a single particle counting chip, for quantitative analysis of beta-emitting radioactive tracers in biological samples. The system is able to perform a real time monitoring of time-dependent biological phenomena. BETAview could be equipped either with GaAs or with Si semiconductor pixellated detectors. In this paper, we describe the results obtained with an assembly based on a Si detector, 300 pin thick, segmented into 64 x 64 170 mum size square pixels. The detector is bump-bonded to the low threshold, single particle counting chip named Medipix1, developed by a CERN-based European collaboration. The sensitive area is about 1 cm(2). Studies of background noise and detection efficiency have been performed. Moreover, time-resolved cellular uptake studies with radiolabelled molecules have been monitored. Specifically, we have followed in vivo and in real time, the [C-14]L-leucine amino acid uptake by eggs of Octopus vulgaris confirming the preliminary results of a previous paper. This opens the field of biomolecular kynetic studies with this new class of semiconductor DAR systems, whose evolution (using the Medipix2 chip, 256 x 256 pixels, 55 mum pixel size) is soon to come. (C) 2002 Elsevier Science B.V. All rights reserved.