title: A depth-of-interaction PET detector using a stair-shaped reflector arrangement and a single-ended scintillation light readout.
abstract: Positron emission tomography (PET) detectors with the ability to encode depth-of-interaction (DOI) information allow us to simultaneously improve the spatial resolution and sensitivity of PET scanners. In this study, we propose a DOI PET detector based on a stair-pattern reflector arrangement inserted between pixelated crystals and a single-ended scintillation light readout. The main advantage of the proposed method is its simplicity; DOI information is decoded from a flood map and the data can be simply acquired by using a single-ended readout system. Another potential advantage is that the two-step DOI detectors can provide the largest peak position distance in a flood map because two-dimensional peak positions can be evenly distributed. We conducted a Monte Carlo simulation and obtained flood maps. Then, we conducted experimental studies using two-step DOI arrays of 5  ×  5 Lu1.9Y0.1SiO5:Ce crystals with a cross-section of 1.7  ×  1.7 mm2and different detector configurations: an unpolished single-layer (US) array, a polished single-layer (PS) array and a polished stacked two-layer (PT) array. For each detector configuration, both air gaps and room-temperature vulcanization (RTV) silicone gaps were tested. DetectorsUS andPT showed good peak separation in each scintillator with an average peak-to-valley ratio (PVR) and distance-to-width ratio (DWR) of 2.09 and 1.53, respectively. DetectorPSRTVshowed lower PVR and DWR (1.65 and 1.34, respectively). The configuration of detectorPTAiris preferable for the construction of time-of-flight-DOI detectors because timing resolution was degraded by only about 40 ps compared with that of a non-DOI detector. The performance of detectorsUSAirandPSRTVwas lower than that of a non-DOI detector, and thus these designs are favorable when the manufacturing cost is more important than timing performance. The results demonstrate that the proposed DOI-encoding method is a promising candidate for PET scanners that require high resolution and sensitivity and operate with conventional acquisition systems.
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-744, Korea. Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-744, Korea.
authors.forename: Jeong-Whan
authors.initials: JW
authors.lastname: Son
authors.forename: Min Sun
authors.initials: MS
authors.lastname: Lee
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Lee
mesh_terms: D003198:Computer Simulation; D006801:Humans; D008027:Light; D009010:Monte Carlo Method; D049268:Positron-Emission Tomography / Q000295:instrumentation* / Q000379:methods*; D012588:Scintillation Counting / Q000295:instrumentation* / Q000379:methods*