β -Ga 2 O 3 -Based Radiation Detector for Proton Therapy

Intensity-modulated proton therapy (IMPT) is an advanced cancer treatment modality that offers advantages over conventional X-ray therapies, particularly in its ability to minimize radiation dose beyond the tumor target. This reduction in unnecessary irradiation exposure lowers the risk to surrounding healthy tissue and reduces side effects compared to conventional X-ray treatments. However, due to the high complexity of intensity-modulated proton therapy plans, each plan must be independently validated to ensure the safety 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 β-Ga2O3-based metal–semiconductor–metal detector was compared with a commercial ion chamber using a MEVION S250i proton accelerator. The β-Ga2O3detector 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. These results highlight the strong potential of β-Ga2O3as a detector material for dose verification in IMPT.