PURPOSE: Ventricular tachycardia (VT) is a life-threatening arrhythmia commonly treated with catheter ablation
however, some cases remain refractory to conventional treatment. Stereotactic arrhythmia radioablation (STAR) has emerged as a non-invasive option for such patients. While photon-based STAR has shown efficacy, proton therapy offers potential advantages due to its superior dose conformity and sparing of critical organs at risk (OARs), including the heart itself. This study aims to investigate and compare the dosimetry between proton and photon therapy for VT, focusing on target coverage and OAR sparing. METHODS: We performed a retrospective study on a cohort of 34 VT patients who received photon STAR. Proton STAR plans were generated using robust optimization in RayStation to deliver the same prescription dose of 25 Gy in a single fraction while minimizing dose to OARs. Dosimetric metrics, including D RESULTS: Proton and photon plans achieved comparable target coverage, with VAS D CONCLUSION: Proton therapy for STAR demonstrates significant dosimetric advantages in sparing the heart and other critical OARs compared to photon therapy for VT, while maintaining equivalent target coverage. These findings highlight the potential of proton therapy to reduce treatment-related toxicity and improve outcomes for VT patients.