TITLE
Spatial resolution evaluation with a pair of two four-layer DOI detectors for small animal PET scanner: jPET-RD
AUTHORS
Fumihiko Nishikido, Tomoaki Tsuda, Eiji Yoshida, Naoko Inadama, Kengo Shibuya, Taiga Yamaya, Keishi Kitamura, Kei Takahashi, Atsushi Ohmura, and Hideo Murayama
SOURCE
NUCLEAR INSTRUMENTS AND METHODS IN PHYSICS RESEARCH A 584 (1): 212-218 JAN 1 2008
(doi:10.1016/j.nima.2007.10.001)

NIM_A

ABSTRACT
We are developing a small animal PET scanner, “jPET-RD” to achieve high sensitivity as well as high spatial resolution by using four-layer depth-of-interaction (DOI) detectors. The jPET-RD is designed with two detector rings. Each detector ring is composed of six DOI detectors arranged hexagonally. The diameter of the field-of-view (FOV) is 8.8 cm, which is smaller than typical small animal PET scanners on the market now. Each detector module consists of a crystal block and a 256-channel flat panel position-sensitive photomultiplier tube. The crystal block, consisting of 32×32×4 crystal (4096 crystals, each 1.46 mm×1.46 mm×4.5 mm) and a reflector, is mounted on the 256ch FP-PMT.

In this study, we evaluated the spatial resolution of reconstructed images with the evaluation system of two four-layer DOI detectors which consist of 32×32×4 LYSO (Lu: 98%, Y: 2%) crystals coupled on the 256ch FP-PMT by using RTV rubber. The spatial resolution of 1.5 mm was obtained at the center of the FOV by the filtered back projection. The spatial resolution, better than 2 mm in the whole FOV, was also achieved with DOI while the spatial resolution without DOI was degraded to 3.3 mm.

Fig.7

Fig. 7. Parts of the reconstructed image for the 68Ge–Ga line source obtained by the FBP method (a) without DOI and (b) with DOI.