# Feasibility of the J-PET to monitor range of therapeutic proton beams

## TL;DR

This study evaluates the potential of the J-PET scanner for monitoring proton therapy range using Monte Carlo simulations, identifying promising geometries with adequate sensitivity and sub-millimeter precision for clinical use.

## Contribution

It introduces a feasibility assessment of various J-PET geometries for proton range monitoring through detailed simulation, highlighting the most promising configurations for clinical implementation.

## Key findings

- Double-layer cylindrical and triple-layer dual-head geometries are most promising.
- Scanner sensitivity is around 10^-5 coincidences per primary proton.
- Range assessment precision is below 1 mm for simulated plans.

## Abstract

Objective: The aim of this work is to investigate the feasibility of the Jagiellonian Positron Emission Tomography (J-PET) scanner for intra-treatment proton beam range monitoring. Approach: The Monte Carlo simulation studies with GATE and PET image reconstruction with CASToR were performed in order to compare six J-PET scanner geometries (three dual-heads and three cylindrical). We simulated proton irradiation of a PMMA phantom with a Single Pencil Beam (SPB) and Spread-Out Bragg Peak (SOBP) of various ranges. The sensitivity and precision of each scanner were calculated, and considering the setup's cost-effectiveness, we indicated potentially optimal geometries for the J-PET scanner prototype dedicated to the proton beam range assessment. Main results: The investigations indicate that the double-layer cylindrical and triple-layer double-head configurations are the most promising for clinical application. We found that the scanner sensitivity is of the order of 10$^{-5}$ coincidences per primary proton, while the precision of the range assessment for both SPB and SOBP irradiation plans was found below 1 mm. Among the scanners with the same number of detector modules, the best results are found for the triple-layer dual-head geometry. Significance: We performed simulation studies demonstrating that the feasibility of the J-PET detector for PET-based proton beam therapy range monitoring is possible with reasonable sensitivity and precision enabling its pre-clinical tests in the clinical proton therapy environment. Considering the sensitivity, precision and cost-effectiveness, the double-layer cylindrical and triple-layer dual-head J-PET geometry configurations seem promising for the future clinical application. Experimental tests are needed to confirm these findings.