$\beta$-Ga$_2$O$_3$--Based Radiation Detector for Proton Therapy

TL;DR

This study evaluates a $eta$-Ga$_2$O$_3$-based detector for proton therapy, showing it can reliably measure doses with high sensitivity and stability, offering a promising alternative to traditional ion chambers for safe cancer treatment validation.

Contribution

The paper introduces a $eta$-Ga$_2$O$_3$-based detector for proton therapy dose verification, demonstrating its effectiveness and potential advantages over existing ion chambers.

Findings

Reliable detection of proton doses as low as 0.26 MU.

Linear charge-to-dose relationship across various conditions.

Measurement variability comparable to ion chambers, with improved sensitivity at higher bias voltages.

Abstract

Intensity modulated proton therapy (IMPT) is an advanced cancer treatment modality that offers significant advantages over conventional X-ray therapies, particularly in its ability to minimize radiation dose beyond the tumor target. This reduction in unnecessary irradiation exposure significantly lowers the risk to surrounding healthy tissue and reduces side effects compared to conventional X-ray treatments. However, due to the high complexity of IMPT plans, each plan must be independently validated to ensure the safety and efficacy of the radiation exposure to the patient. While ion chambers are currently used for this purpose, their limitations-particularly in angled-beam measurements and multi-depth assessments-hinder their effectiveness. Silicon-based detectors, commonly used in X-ray therapy, are unsuitable for IMPT due to their rapid degradation under proton irradiation. In this study, a $\beta$-Ga$_2$O$_3$-based metal-semiconductor-metal (MSM) detector was evaluated and compared with a commercial ion chamber using a MEVION S250i proton accelerator. The $\beta$-Ga$_2$O$_3$ detector demonstrated reliable detection of single-pulse proton doses as low as 0.26 MU and exhibited a linear charge-to-dose relationship across a wide range of irradiation conditions. Furthermore, its measurement variability was comparable to that of the ion chamber, with improved sensitivity observed at higher bias voltages. These results highlight the strong potential of $\beta$-Ga$_2$O$_3$ as a radiation-hard detector material for accurate dose verification in IMPT.