A dual-ended readout PET detector module based on GAPDs with large-area microcells

초록

The use of a dual-ended readout PET detector module based on Geiger-mode avalanche photodiodes (GAPDs) with large-area microcells was proposed to obtain high photon detection efficiency (PDE) and overcome energy non-linearity problems. A simulation study was performed and experimental measurement were taken for the single- and dual-ended PET detector modules consisting of the two types of GAPDs with 50 x 50 mu m(2) and 100 x 100 mu m(2) microcells. A Monte Carlo simulation was conducted to predict the number of incident photons impinging on the GAPD entrance surface to estimate the light collection efficiency (LCE) and energy linearity performance. A depth of interaction (DOI) ratio histogram was also obtained. An experimental study was performed to acquire the spectra of different energy gamma-rays, and the energy linearity was evaluated by analyzing the photo-peak channels. The simulation results showed that the LCE and energy linearity of the dual-ended PET detector modules were considerably improved compared to the single-ended one, with 100 x 100 mu m(2) microcell GAPDs. We also estimated that the proposed method can provide accurate (3-4 mm) and uniform DOI resolution. In the experimental measurement, the 511 keV photo-peak channels of the dual-ended PET detector modules were increased 26% and 71% compared to the single-ended one, with 50 x 50 mu m(2) and 100 x 100 mu m(2) microcell GAPDs, respectively. The coefficients of determination (R(2)) were increased from 0.97 to 0.99 and from 0.86 to 0.93 with 50 x 50 mu m(2) and 100 x 100 mu m(2) microcell GAPDs, respectively. The results of this study demonstrate that the dual-ended readout scheme using GAPDs with large-area microcells provides high LCE and DOI information with minimized energy non-linearity. This will enable investigators to configure PET detector modules with high sensitivity and resolution.

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