Proton Computed Tomography and Proton Radiography with a Fast Monolithic Proton Imaging System F DeJongh, E DeJongh, I Polnyi , V Rykalin M Pankuch G Coutrakon, K Duffin, N Karonis, C Ordonez, J Winans, C Sarosiek J Welsh ProtonVDA LLC Northwestern Medicine Chicago Proton Center Northern Illinois University Stritch School of Medicine Loyola University Chicago Proton spot positions on one tracking plane INTRODUCTION Reconstructing images in isocenter coordinates RESULTS Proton Imaging can help reduce range uncertainties by directly measuring proton stopping power We aim to: Develop a proton imaging system based on wellestablished fast scintillator technology → High-performance, low-cost measurements Achieve lower dose to the patient relative to equivalent x-ray images Produce spatially sharp images Images free of artifacts from high-Z implants Multidisciplinary team of detector physicists, medical physicists, computer scientists, and radiation oncologists: Customized pediatric head phantom with cm cubic cavity CONCLUSIONS • Prototype proton radiography system is fully functional, clinically realistic • Automatic pRad reconstruction with display in isocenter coordinates • Sensitive to very small variations and changes in range • Spatial resolution of