Depth-encoding detectors with single-ended readout provide a practical, cost-effective approach for constructing high-resolution and high sensitivity PET scanners. However, the current iteration of such
detectors utilize a uniform glass light guide to achieve depth-encoding, resulting in non-uniform performance throughout the detector array due to suboptimal intercrystal light sharing. We introduce Prism-PET, a singleended readout PET detector module with a segmented light guide composed of an array of prismatoids that introduces enhanced, deterministic light sharing. High resolution PET detector modules were fabricated with a single-ended readout of polished multicrystal lutetium yttrium orthosilicate (LYSO) scintillator arrays directly coupled 4-to-1 and 9-to-1 to arrays of 3.2 × 3.2 mm2 silicon photomultiplier pixels. Each scintillator array was coupled at the non-readout side to a light guide (one 4-to-1 module with a uniform glass light guide, one 4-to-1 Prism-PET module, and one 9-to-1 Prism-PET module) to introduce intercrystal light sharing, which closely mimics the behavior of dual-ended readout with the additional benefit of improved crystal identification. Flood histogram data were acquired using a 3 MBq Na-22 source to characterize crystal identification and energy resolution. Lead collimation was used to acquire data at specific depths to determine depth-of-interaction (DOI) resolution. The flood histogram measurements showed excellent and uniform crystal separation throughout the Prism-PET modules while the uniform glass light guide module had performance degradation at the edges and corners. A DOI resolution of 5.0 mm full width at half maximum (FWHM) and energy resolution of 13% was obtained in the uniform glass light guide module. By comparison, the 4-to-1 coupled Prism-PET module achieved 2.5 mm FWHM DOI resolution and 9% energy resolution.
Publications:
- A. LaBella, X. Cao, E. Petersen, R. Lubinsky, A. Biegon, W. Zhao, and A. H. Goldan, “High Resolution Depth-Encoding PET Detector Module with Prismatoid Light Guide Array” J. Nucl. Med., 61, p. 1528 (2020). Paper link
- A. LaBella, W. Zhao, R. Lubinsky, and A. H. Goldan, “Prismatoid light guide array for enhanced gamma ray localization in PET: a Monte Carlo simulation study of scintillation photon transport,” Phys. Med. Biol. 65, 18LT01 (2020). Paper link