Potential role of intensity modulated proton beams in prostate cancer radiotherapy.

摘要: Purpose: The present study was undertaken to assess the potential benefit of intensity modulated (IM) proton beams in optimizing dose distribution safely escalate tumor prostate cancer radiotherapy. Methods and Materials: Four treatment plans were compared a patient aiming deliver 81 Gy target: 1) conformal 18 MV X-rays, 6-fields; 2) 214 MeV protons, 2-fields; 3) IM 15 5-fields; 4) 177–200 Mev 5-fields as Plan 3. In addition, methods used further 99 Gy. Dose-volume histograms (DVH) physically compare plans. DVH data also obtain normal tissue complication probabilities (NTCP) for rectum, bladder, femoral heads, control probabilities. Results: Although planning target volume satisfactory with four plans, homogeneity slightly reduced both X-ray (IM standard) low-to-medium doses delivered all organs at risk, other tissues significantly by For prescribed Gy, only succeeded predicting an acceptably low NTCP rectum (<5%, Grade 3). integral nontarget (i.e., 3.1, 1.3, 1.7 times less than Plans 1, 2, 3, respectively). When escalating no additional improvement between protons observed. Conclusions: Both able optimize comply goal delivering highest while reducing risk severe morbidity acceptable levels. main advantage X-rays that achieved small (PTV) heterogeneity.