We are currently developing a small animal PET scanner with a design goal of 1 mm3 image resolution. We have built three pairs of detectors and tested performance in terms of crystal identification, spatial, energy and timing resolution. The detectors consisted of 12 × 12 arrays of 1 × 1 × 10mm LSO crystals (1.15 mm pitch) coupled to Hamamatsu H7546 64 channel PMTs via 5cm long coherent glass fiber bundles. Optical fiber connection is necessary to allow high packing fraction in a ring geometry scanner. Fiber bundles with and without extramural absorber (EMA) were tested. The results demonstrated an intrinsic spatial resolution of 1.12 mm (direct coupled LSO array), 1.23 mm (bundle without EMA) and 1.27 mm (bundle with EMA) using a ∼500 micron diameter Na-22 source. Using a 330 micron line source filled with F-18, intrinsic resolution for the EMA bundle improved to 1.05 mm. The respective timing and energy resolution values were 1.96 ns, 21% (direct coupled), 2.20 ns, 23% (bundle without EMA) and 2.99ns, 30% (bundle with EMA). Peak-to-valley ratio in the flood histograms was better with EMA (5:1) compared to the bundle without EMA (2.5:1). These detectors substantially improve on the performance characteristics of the detectors in our current microPET scanner.
|State||Published - 2000|
|Event||2000 IEEE Nuclear Science Symposium Conference Record - Lyon, France|
Duration: Oct 15 2000 → Oct 20 2000
|Conference||2000 IEEE Nuclear Science Symposium Conference Record|
|Period||10/15/00 → 10/20/00|