Charged Particle Stereotactic Body Radiation Therapy

In efforts to reduce the toxicities associated with photon-based stereotactic body radiation therapy (SBRT), increasing interest has emerged in the delivery of these ultra-high doses per fraction with proton therapy. Proton therapy allows energy to be deposited at a specific depth, termed the Bragg peak, and achieves a rapid energy falloff beyond this depth, thus allowing normal tissues on the distal side of the target volume to be spared. With these unique physical properties of proton therapy, SBRT delivered with proton therapy has the potential to more safely and effectively deliver dose to difficult-to-treat or recurrence tumor volumes and can reduce the irradiation doses to critical structures adjacent to the target volume, thus potentially reducing the risks treatment. This chapter reviews the rationale and current data for the use of proton SBRT across multiple disease sites, including thoracic, gastrointestinal, and genitourinary malignancies.