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内容記述 |
For brain dedicated positron emission tomography (PET), time-of-flight (TOF) and depth-of-interaction (DOI) information is essential to improve PET image quality. In addition, signal multiplexing is required to reduce the number of data acquisition channels thereby reducing cost. Last year, we developed a TOF-PET detector with a diode-based row-column multiplexing (RC mux) circuit. However, the detector lacks DOI information, and the crystal pitch was large (3.2 mm). Here, we present the CLS (crosshair light sharing) detector with diode-based multiplexing for brain-dedicated TOF-DOI PET development. The CLS detector consists of fast-LGSO crystal 14×14 array (crystal pitch=1.6 mm, thickness=15 mm) and SiPM 8×8 array (S14160-3050HS, pixel pitch=3.2 mm) (Fig. 1(a)). Custom-made RC mux circuits were used to reduce the SiPM channels from 64 into 16 (8 x-position + 8 y-position) with diode and resistor materials, respectively (Fig. 1(b-c)). The multiplexed analog signals were digitized by using PETsys TOFPET2 ASIC modules with an energy window of 440-560 keV (Fig. 2(a)). The effects of the RC mux circuits on the CTR were evaluated (Fig. 2(b)), and the diode-based multiplexing did not degrade the CTR (378 ps), whereas the resistor-based multiplexing degraded the CTR by 34% (572 ps). In conclusion, the diode-based RC multiplexing is a cost-effective solution for the development of brain-dedicated TOF-DOI PET systems. |
