A new pixelated prompt gamma imaging detector (PPGID) was developed for prompt gamma spectrum and gamma source position measurement. The PPGID prototype is composed of 30 independent pixelated scintillator detectors that can simultaneously obtain the gamma spectrum. The prototype has two \(\text {LaBr}_{3}\) scintillator modules for gamma ray spectrum measurement with good performance in terms of energy resolution and one BGO module with high efficiency in high-energy detection. Therefore, in this study, a compound advanced imaging device based on energy spectrum detection was designed, assembled, and tested with radioactive sources. This device is called a pixelated prompt gamma imaging detector system (PPGID). The PPGID can correctly measure the source position as predicted by the FOV mathematical model. Both \(\text {LaBr}_{3}\) and BGO can reproduce the gamma spectrum of the radioactive source. The tested energy response of \(\text {LaBr}_{3}\) is 0.03–2.6 MeV, and that of BGO is 1–2.6 MeV with \(^{22}\text {Na}\) and \(^{232}\text {Th}\) . Dedicated data acquisition software was developed for energy calibration and gamma count histogram distribution. The gamma count histogram can be transformed into a thermal map which is the basis of the image.
