Development of a Portable Beta Particle Detector for Precision Cancer Detection Using GEM

Radio-PTT, which combines radiotherapy and photo-thermal therapy (PTT), can achieve better local depletion of cancer cells and inhibition of tumor recurrence and metastasis than a stand-alone therapy. The radiolabeled photosensitizer can serve as an imaging reporter for image-guided light delivery. Gamma-rays are usually used for tomographic imaging, but heavy metal collimation limits its application on portable imaging devices. On the other hand, beta particles' short range can be utilized for a compact design. In this study, we develop a Gas Electron Multiplier (GEM) detector for beta particle detection. The detector consists of a Kapton window, a drift foil, three GEM layers and a 128-channel anode readout board. The GEM detector, which amplifies weak signals by electron avalanches, is more sensitive to detect beta particles than gamma photons. Beta emitter, ¹³⁷Cs, is used to show that the constructed GEM detector can reliably detect beta particles. This study lays a foundation for further development of the portable GEM imaging detector through a scalable readout system, which will yield a highresolution beta imaging tool for Radio-PTT.