While the majority of radiation therapy courses are currently delivered with photon therapy, including 3-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), proton therapy (PT) has emerged as a way to reduce dose to normal tissues and potentially allow safer escalation of the biologically effective dose of treatment, delivery of trimodality therapy, and reirradiation treatments (1). Until the mid-to late-2000s, PT was a limited radiation modality only available at a handful of institutions in the United States (2). An earlier iteration of proton technology, passive scattering proton therapy (PS-PT), utilized the unique immediate stopping power of heavy charged particles to reduce or eliminate irradiation dose to tissues along the beam path beyond the intended target volume. However, PS-PT had several major inherent challenges, including imprecise dose deposition with scattered proton beams, inability to modulate or sculpt dose resulting in limited dose