Performance of Dual-Ended Readout PET Detectors Based on BGO Arrays and BaSO₄ Reflector

The performance of two dual-ended readout positron emission tomography detectors based on 15
$\times $
15 bismuth germanate (BGO) arrays was compared. The crystal elements of one BGO array have polished lateral surfaces, while the crystal elements of the other BGO array have unpolished lateral surfaces. The two ends of the BGO elements are polished. The two BGO arrays both have a pitch size of 1.6 mm and thickness of 20 mm, and BaSO
₄
with a thickness of 80
$\mu \text{m}$
was used as the reflector. Hamamatsu S14161-3050-08 SiPM arrays were used as photodetectors. All the measurements were performed at a bias voltage of 41.0 V and a temperature of 23.5 °C. The flood histograms show that all the crystal elements in the two BGO arrays were clearly resolved. The detector based on the BGO array with polished lateral surfaces provides an energy resolution of 16.9 ± 1.3%, timing resolution of 3.2 ± 0.2 ns, and depth-of-interaction (DOI) resolution of 18.4 ± 2.2 mm. In comparison, the detector based on the BGO array with unpolished lateral surfaces provides an energy resolution of 17.7 ± 2.0%, timing resolution of 3.5 ± 0.3 ns, and DOI resolution of 3.2 ± 0.2 mm.