A simulation study of in-beam visualization system for proton therapy by monitoring scattered protons

Recently, in-beam positron emission tomography (PET) has been actively researched for reducing biological washout effects and dose monitoring during irradiation. However, the distribution does not precisely reflect since production ionization are completely different physical processes. Thus, a novel system was proposed to determine proton range by measuring scattered protons with dozens of scintillation detectors surrounding body surface. While previous studies conducted preliminary experiment simple phantom, we simulated more complex situations in this paper. Especially, three stepwise simulation demonstrate feasibility method. First, rectangular phantom reproduced on irradiated obtaining current values Monte Carlo (MC) dose. Next, trained deep learning model estimate 2-dimensional-dose (2D-DL dose) from measured (A). We plastic scintillators as measure protons. Second, an air layer used, 3D-DL estimated (B). Finally, cylindrical that mimics human used confirming estimation quality (C). Consequently, position Bragg peak error 1.0 mm In addition, layer, well verifying 2.1 mm, successfully Although 12.6 (C), further improved 9.3 incorporating mass density obtained computed (CT). These results demonstrated potential as-proposed verification system. Additionally, effectiveness CT utilization estimating DL also indicated.