Feasibility study of a highly sensitive LaBr3 PET scanner based on the DOI-dependent extended-energy window

Conventionally, positron emission tomograph (PET) scanners use scintillators which have a high effective atomic number. Recently, novel scintillators like LaBr3 have been developed which have excellent timing and energy resolutions. LaBr3 has a high performance for PET scanner use, but its effective atomic number is lower than that of lutetium oxyorthosilicate (LSO). As an alternative, we have developed a scatter reduction method using depth-of-interaction (DOI) information and energy information to increase the sensitivity. The sensitivity of the PET scanner with LaBr3 can be improved using the DOI-dependent extended-energy window (DEEW) method. In this work, our method is applied to the whole-body LSO/LaBr3 PET scanner using the GATE simulation toolkit. Simulation results show the number of true coincidences can be increased while minimizing the scatter and random coincidences by using the DEEW method. Noise equivalent count rate (NECR) can be improved by 20–70% for the whole-body DOI-PET scanner. Sensitivity of the PET scanner with a scintillator of low-effective atomic number can be improved by the DEEW method.