How do tangent-based IMRT and VMAT compare when planning breast IMRT? This study compared treatment plans for each technique using the mCycle automated planning system within the Monaco treatment planning system. It included 65 patients receiving standard, adjuvant whole breast RT. The prescription was 40.05 Gy in 15 fractions with a 13.35 Gy boost in 5 fractions. Static-field IMRT used standard tangent beam arrangements whereas the VMAT plans used two 60-degree partial arcs (290-350 and 160-100 on the left; 70-10 and 200-260 on the right). The automated planning systemic used multi-criteria optimization and local planning goals to generate each plan. VMAT provided slightly better target coverage, and it also had better lung and heart dosimetry. However, IMRT plans had superior contralateral OAR dosimetry. Even though the same flash was used for both planning techniques, tangent IMRT plans had more robust target coverage when accounting for potential anatomic changes compared to VMAT. | Marrazzo, Adv Radiat Oncol 2025
