A novel hermetic detector composed of 200 bismuth germanium oxide crystal scintillators and 393 channel silicon photomultipliers has been developed for positronium (Ps) annihilation studies. This compact 4π detector is capable of simultaneously detecting γ-ray decay in all directions, enabling not only the study of visible and invisible exotic decay processes but also tumor localization in positron emission tomography for small animals. In this study, we investigate the use of a convolutional neural network (CNN) for the localization of Ps annihilation synonymous with tumor localization. Two-γ decay systems of the Ps annihilation from 22Na and 18F radioactive sources are simulated using a GEANT4 simulation. The simulated datasets are preprocessed by applying energy cutoffs. The spatial error in the XY plane from the CNN is compared to that from the classical weighted k-means algorithm centroiding, and the feasibility of CNN-based Ps annihilation reconstruction with tumor localization is discussed.

A hermetic novel detector composed of 200 Bismuth germanium oxide crystal scintillators and 393 channel silicon photomultipliers has been developed for positronium (Ps) annihilation study. This compact 4π detector is capable of simultaneously detecting γ-ray decay in all directions, enabling not only the study of visible and invisible exotic decay processes but also tumor localization in positron emission tomography for small animals. In this study, we investigate the use of a convolutional neural network (CNN) for the localization of the Ps annihilation synonymous with tumor localization. The 2-γ decay systems of the Ps annihilation from the 22Na and 18F radioactive sources are simulated using GEANT4. The simulated data sets are preprocessed by applying energy cuts. The spatial error in the XY plane from CNN is compared to that from the classical centroiding, weighted k-means algorithm. The feasibility of the CNN-based Ps an-nihilation reconstruction with tumor localization is discussed.

A precise measurement of radiation energy corresponding to position is important in radiation monitoring as well as proton therapy technique utilizing a particle accelerator. Proton Bragg peak makes it possible to modulate dose distribution in target by charged particle energy loss. We develop and test a real-time system using radio-photoluminescence (RPL) glass for accelerator particle beam tuning. The RPL glass has promising characteristics, such as a linear dosimeter equivalent to ionizing irradiation, no fading, data accumulation, and repeatability through thermal treatment. Utilizing this system, the energy deposit of the proton beam irradiated RPL glass is measured under an ultraviolet (UV) excitation source in real-time. 45 MeV and 100 MeV proton beams are generated from a cyclotron and a linear accelerator respectively. The proton Bragg curve corresponding to the proton energy and RPL is verified by GEANT4 simulation. This system promises to provide useful information on beam tuning techniques and quality verification through real-time radiation monitoring and recordings of the accumulated dose on repeatable RPL glass.