WE‐H‐207A‐01: Computational Evaluation of High‐Resolution 18F Positron Imaging Using Radioluminescence Microscopy with Lu2O3: Eu Thin‐Film Scintillator

Abstract

Purpose:Radioluminescence microscopy, an emerging and powerful tool for high resolution beta imaging, has been applied to molecular imaging of cellular metabolism to understand tumor biology. A novel thin‐film (10 µm thickness) scintillator made of Lu2O3: Eu has been developed to enhance the system performance. However the advances of radioluminescence imaging with Lu2O3scintillator compared with that using conventional scintillator have not been explored theoretically to date. To validate the advantages of the thin‐film scintillator, this study uses a novel computational simulation framework to evaluate the performance of radioluminescence microscopy using both conventional and thin‐film scintillators.Methods:Numerical models for different stages of positron imaging are established. Positron from 18F passing through the scintillator and its neighbor structures are modeled by Monte‐Carlo simulation using Geant4. The propagation and focus of photons by the microscope are modeled by convolution with a depth‐varying point spread function generated by the Gibson‐Lanni model. Photons focused on the detector plane are then captured and converted into electronic signals by an electron multiplication (EM) CCD camera, which is described by a photosensor model considering various noises and charge amplification.Results:The performance metrics of radioluminescence imaging with a thin‐film Lu2O3 and conventional CdWO4 scintillator are compared, including spatial resolution, sensitivity, positron track area and intensity. The spatial resolution of Lu2O3 system can achieve 10 µm maximally, a 12 µm enhancement from that obtained from CdWO4 system. Meanwhile, the system with Lu2O3 scintillator can provide a higher mean sensitivity: 40% compared with that (21.5%) obtained from CdWO4 system. Moreover, the simulation results are in good agreement with previous experimental measurements.Conclusion:This study provides a new theoretical understanding of our imaging system and has the potential to promote the development of radioluminescence microscopy for more reliable and robust application on the functional imaging of delicate biological structures.The authors acknowledge funding from NIH grant R01CA186275 and SBIR grant 1R43GM110888‐01.