Possibility analysis of a GSO PET/SPECT detector

Light output of GSO is about twice of that of BGO. In addition, GSO does not contain any natural radioisotope. Thus, GSO may be a possible material for a detector that can be used for annihilation photons (511 keV gamma photons) and gamma photons for SPECT. In addition, it may be able to be used for a block detector for PET/SPECT system such as hybrid gamma camera. For this purpose, the author measured the energy response of GSO for gamma photons for PET (511 keV) and SPECT (122 keV). The author also fabricated GSO block detector and measured the position response. The energy resolution were 9.9% FWHM and 19.5% FWHM for 511 keV and 122 keV gamma photons, respectively. Though the GSO block of 8×8 matrix was perfectly resolved in 2 dimensional distributions for 511 keV gamma photons, the block was not resolved for 122 keV gamma photons. The GSO block of 6×6 was almost resolved for 122 keV gamma photons. These results indicated that GSO is suitable for PET/SPECT detectors for a non-imaging radiation detector if the energy resolution of around 20% FWHM is accepted for SPECT application. For the PET/SPECT block detector application, the block was limited in 6×6 matrix that may limit the cost effectiveness of the system. Thus, it is suggested that GSO block detector is suitable for PET only application