Distal edge determination precision for a multi-slat promptgamma camera: a comprehensive simulation and optimization of the detection system

TL;DR

This study uses comprehensive simulations, including optical photon modeling, to optimize a multi-slat prompt-gamma camera for precise distal edge detection in proton therapy, achieving a 2.1 mm accuracy.

Contribution

It introduces a detailed simulation including optical photons and optimizes the detector configuration for improved edge detection precision in proton therapy.

Findings

Achieved 2.1 mm precision in distal edge detection.

Optimized collimator configuration for best performance.

Included optical photon simulation in system modeling.

Abstract

Multi-slat prompt-gamma camera is a promising tool for range monitoring during proton therapy. We report the results of a comprehensive simulation study analyzing the precision which is possible to reach with this camera in determination of the position of the distal edge of the Bragg peak. For the first time we include simulation of optical photons. The proton beam (single pencil beam, 130 MeV, 10 ns bunch period, total of 10^8 protons) is interacting with a polymethyl methacrylate (PMMA) phantom, which is a cylinder of 200 mm in diameter and length. The prompt gamma rays generated in the phantom are collimated with a multi-slat collimator and detected using a combination of yttrium aluminum perovskite (YAP) scintillators, installed in the collimator apertures, and light sensors. Two scintillator packing schemes, with one and with two scintillator plates per aperture, are considered. The collimator configuration (the septal thickness, aperture and height), resulting in the best precision, is determined using two methods of detector optimization. Precision of 2.1 mm (full width at half maximum) in the edge position determination is demonstrated.