Postmastectomy radiation therapy technique and cardiopulmonary sparing: A dosimetric comparative analysis between photons and protons with free breathing versus deep inspiration breath hold

For left-sided PMRT, passively scattered or PBS protons with or without DIBH improves homogeneity and cardiopulmonary sparing without compromise in target coverage compared with PWTF photons with DIBH. Furthermore, the addition of DIBH to proton therapy did not provide a significant dosimetric benefit.