Prism Mirror Light Guide for Enhanced Gamma Ray Localization in PET

Depth-of-interaction (DOI) readout in PET has traditionally been performed using dual-ended readout where a scintillator is sandwiched between two readout arrays. In recent years, researchers have explored the efficacy of replacing the second readout array with a light guide at the entrance layer of a multicrystal scintillator array, which introduces depth-dependent intercrystal light sharing, in order to reduce cost and make depth-encoding more practical. However, single-ended readout depth-encoding modules have worse overall spatial performance compared with dual-ended readout modules, which is in part due to the noisy DOI signal created by the random light sharing characteristics of the light guides being used. In this paper, we introduce Prism-PET, a segmented light guide composed of an array of prism mirrors that introduce deterministic intercrystal light sharing, which enhances the crystal identification and depth-encoding signals. We characterized the expected spatial performance of PET modules with our light guide using Monte Carlo simulations. Our results demonstrate that Prism-PET improves the DOI and crystal localization performances of multicrystal single-ended readout depth-encoding PET modules and can be used to develop cost-effective high resolution PET systems.