A large field-of-view angled panel detector for the development of a plant PET system

In plant research, positron emission tomography (PET) is sometimes employed for physiological studies of plants. However, due to the generally high cost of PET systems, their application in plant research centers can be challenging. Furthermore, the configurations of commercial PET systems might not always align well with the requirements of plant research. To address these issues, we have taken the initial steps towards a solution by developing a large field-of-view (LFOV) angled panel detector intended for the development of a plant PET system. This panel detector is composed of two gadolinium orthosilicate (GSO) scintillator blocks, an angled light guide, and four flat panel photomultiplier tubes (FP-PMTs). The GSO pixel size used in the scintillator block measures 2.65 mm (radial)x2.85 mm (axial)x15.0 mm, arranged in a configuration of 16 (radial)x32 (axial) to form a scintillator block with overall dimensions of 44.0 mm (radial)x94.4 mm (axial)x15 mm (depth). By implementing an angled light guide, the two scintillator blocks were positioned at a 22.5-degree angle, resulting in the creation of a LFOV angled panel detector. This specific angle allowed for the arrangement of 16 scintillator blocks in a hexadecagonal shape using 8 panel detectors when arranged in a circular configuration. We successfully constructed a panel detector with an approximate field-of -view of 10 cm x 10 cm and conducted a comprehensive performance evaluation. Upon irradiating the panel detector with 511 keV gamma photons, nearly all 1024 GSO pixels were accurately resolved in the position histogram, displaying minimal distortion, and exhibiting an average peak-to-valley ratio of 5.0. Additionally, the energy resolution achieved was 14% full width at half maximum (FWHM). The resulting LFOV angled panel detector holds considerable promise for the use within a cost-effective, user-friendly as well as high performance plant PET system.