Figure 1.

Representative dose distributions of PRT versus Intensity Modulated Radiation Therapy (XRT). Proton beams were chosen to maximize dose limitation to cord, kidneys, and bowel based on prior radiation fields and anatomy. (A) Two beams, posterior and posterior-lateral oblique fields to spare bowel and kidney; (B) two beams, anterior-superior and anterior-lateral oblique to spare the cord, kidneys and bowel; (C) two beams, Anterior-lateral oblique and lateral fields to spare cord and liver; (D) three beams, posterior-lateral obliques and lateral fields to spare bowel. PRT, proton reirradiation.