Approaches to improving the detection sensitivity of optical modulation based radiation detection method for positron emission tomography

In this paper, two approaches to improving the detection sensitivity of the optical modulation based radiation detection method for positron emission tomography (PET) have been investigated utilizing BSO, CdTe and PbBiGa as detector crystals. We first explored the magic angle of our two-crossed-polarizers based setup, of which the detection sensitivity could be improved by 15% at the magic angle. We then investigated the dependence of the detection sensitivity on the electric field distribution as well as on the crystal bias voltage with CdTe and PbBiGa crystals. Both the electric field distribution (i.e., electrode pattern) and applied bias voltage could affect the magnitude of the modulation signal and thus affect the setup's detection sensitivity. From our findings, we can conclude that a more concentrated electric field distribution (or a smaller electrode) could contribute to a better detection sensitivity. Besides, the detection sensitivity increases linearly with the bias voltage for all detector crystals and thus we could improve the detection sensitivity by adding higher bias voltage to the detector crystal.