A Feasibility Study of In-Beam PET Imaging for Dose Verification in Carbon Therapy Using Free PET

In-beam PET imaging provides a noninvasive method to monitor the dose distribution in real-time for particle therapy such as carbon ion therapy and proton therapy. This work designed in-beam PET prototypes based on free PET including cylindrical, open-PET, C-shaped, dual-head plate and rectangular PET scanners and simulated in-beam PET imaging based on these scanners in GATE, a Monte Carlo simulation platform. The scanners were composed of 32 detector modules through free combination and had similar field of view, which could be used for dose monitoring in carbon therapy for the different part of human body and small animal. Each detector module was composed of LYSO array coupled with SiPM. The crystal array contained 20×20 crystals measuring 1.5 mm × 1.5 mm × 10 mm with 1.6 mm pitch. A PMMA phantom was irradiated by the periodic carbon ion pencil beam with an energy of 230 MeV/u and was monitored by the in-beam PET imaging using GATE macros. PET images of the generated positrons were reconstructed by using a