Xenon-Doped Liquid Argon Scintillation for Positron Emission Tomography

Positron Emission Tomography (PET) is used to observe metabolic processes within patients. It works by reconstructing the annihilation origin of incident gamma rays produced by a positron emitting tracer. However, inefficiencies of current PET technology, such photomultiplier tubes, can result in poor imaging. We propose 3Dπ: a full body, Time of Flight (TOF) PET scanner using Silicon Photomultipliers (SiPM) coupled with a xenon-doped Liquid Argon (Lar+Xe) scintillator. We simulated this design using Geant4 while following the National Electrical Manufacturers Association’s evaluation tests for performance assessment. We will present results that highlight a 200-fold increase in sensitivity, spatial resolutions comparable to commercial PET scanners and produce PET images from 15-30 second scans faster than traditional 30-35-minute scans. Further studies will involve optimizing the layer thickness of Lar+Xe. Moreover, scintillation induced ionization electrons can produce Cherenkov radiation along with the Lar+Xe scintillation light. We will discuss strategies to characterize this other signal in Geant4 to improve the timing resolution of our scanner. With the Lar+Xe scintillator and SiPMs of 3Dπ, we can use the precise TOF info of gamma rays to improve the localization of individual positron annihilations and provide low-dose PET scans for patients who may be at high risk for exposure to radiation.