3D-Conformal Versus Intensity-Modulated Postoperative Radiotherapy of Vaginal Vault: A Dosimetric Comparison
- Medical Physics Unit, Department of Oncology, 'John Paul II' Center for High Technology Research and Education in Biomedical Sciences, Catholic University, Campobasso (Italy)
- Radiotherapy Unit, Department of Oncology, 'John Paul II' Center for High Technology Research and Education in Biomedical Sciences, Catholic University, Campobasso (Italy)
- Gynaecologic Oncology Unit, Department of Oncology, 'John Paul II' Center for High Technology Research and Education in Biomedical Sciences, Catholic University, Campobasso (Italy)
- Department of Radiation Oncology, The Lacks Cancer Center Saint Mary's Health Care, Grand Rapids, MI (United States)
- Gynaecology/Obstetrics Department, Policlinico A. Gemelli, Catholic University, Rome (Italy)
We evaluated a step-and-shoot IMRT plan in the postoperative irradiation of the vaginal vault compared with equispaced beam arrangements (3-5) 3D-radiotherapy (RT) optimized plans. Twelve patients were included in this analysis. Four plans for each patient were compared in terms of dose-volume histograms, homogeneity index (HI), and conformity index (CI): (1) 3 equispaced beam arrangement 3D-RT; (2) 4 equispaced beam arrangement 3D-RT; (3) 5 equispaced beam arrangement 3D-RT; (4) step-and-shoot IMRT technique. CI showed a good discrimination between the four plans. The mean scores of CI were 0.58 (range: 0.38-0.67) for the 3F-CRT plan, 0.58 (range: 0.41-0.66) for 4F-CRT, 0.62 (range: 0.43-0.68) for 5F-CRT and 0.69 (range: 0.58-0.78) for the IMRT plan. A significant improvement of the conformity was reached by the IMRT plan (p < 0.001 for all comparisons). As expected, the increment of 3D-CRT fields was associated with an improvement of target dose conformity and homogeneity; on the contrary, in the IMRT plans, a better conformity was associated to a worse target dose homogeneity. A significant reduction in terms of D{sub mean}, V90%, V95%, V100% was recorded for rectal and bladder irradiation with the IMRT plan. Surprisingly, IMRT supplied a significant dose reduction also for rectum and bladder V30% and V50%. A significant dosimetric advantage of IMRT over 3D-RT in the adjuvant treatment of vaginal vault alone in terms of treatment conformity and rectum and bladder sparing is shown.
- OSTI ID:
- 21333981
- Journal Information:
- Medical Dosimetry, Vol. 35, Issue 2; Other Information: DOI: 10.1016/j.meddos.2009.04.003; PII: S0958-3947(09)00047-8; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0958-3947
- Country of Publication:
- United States
- Language:
- English
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