A Prototype PET Scanner with DOI-Encoding Detectors

Detectors with depth-encoding allow a PET scanner to simulta-neously achieve high sensitivity and high spatial resolution. Methods: A prototype PET scanner, consisting of depth-encoding detectors constructed by dual-ended readout of lutetium oxyorthosilicate (LSO) arrays with 2 position-sensitive avalanche photodiodes (PSAPDs), was developed. The scanner comprised 2 detector plates, each with 4 detector modules, and the LSO arrays consisted of 7 · 7 elements, with a crystal size of 0.9225 · 0.9225 · 20 mm and a pitch of 1.0 mm. The active area of the PSAPDs was 8 · 8mm. The performance of individual detec-tor modules was characterized. A line-source phantom and a hot-rod phantom were imaged on the prototype scanner in 2 dif-ferent scanner configurations. The images were reconstructed using 20, 10, 5, 2, and 1 depth-of-interaction (DOI) bins to dem-onstrate the effects of DOI resolution on reconstructed imag