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Title: Postoperative Irradiation of Gynecologic Malignancies: Improving Treatment Delivery Using Aperture-Based Intensity-Modulated Radiotherapy

Purpose: To evaluate dosimetric and treatment delivery advantages of aperture-based intensity-modulated radiotherapy (AB-IMRT) for the treatment of patients receiving whole pelvic radiotherapy for gynecologic malignancies. Methods and Materials: Nineteen patients undergoing pelvic radiotherapy after resection of endometrial cancers were selected. A 45-Gy dose was prescribed to the target volume delineated on a planning CT scan. An in-house inverse planning system, Ballista, was used to develop a treatment plan using aperture-based multileaf collimator segments. This approach was compared with conventional four-field, enlarged four-field, and static beamlet-based IMRT (BB-IMRT) techniques in terms of target coverage, dose-volume histogram statistics for surrounding normal tissues, and numbers of segments and monitor units (MU). Results: Three quarters (76.4%) of the planning target volume received the prescription dose with conventional four-field plans. With adequate target coverage, the Ballista plans significantly reduced the volume of bowel and bladder irradiated at the prescribed dose (p < 0.001), whereas the two approaches provided equivalent results for the rectum (p 0.5). On the other hand, AB-IMRT and BB-IMRT plans showed only small differences in dose-volume histogram statistics of unknown clinical impact, whereas Ballista plan delivery required on average 73% and 59% fewer segments and MU, respectively. Conclusion: With respect to conventionalmore » techniques, AB-IMRT for the treatment of gynecologic malignancies provides dosimetric advantages similar to those with BB-IMRT but with clear treatment delivery improvements.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ;  [4] ;  [3] ;  [3] ;  [4]
  1. Departement de physique, de genie physique et d'optique, Universite Laval, Quebec, QC (Canada) and Departement de radio-oncologie et Centre de recherche de l'Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Hotel-Dieu de Quebec, Quebec, QC (Canada). E-mail: sylvainn@rrsb.nb.ca
  2. Departement de radio-oncologie et Centre de recherche de l'Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Hotel-Dieu de Quebec, Quebec, QC (Canada)
  3. Departement de physique, de genie physique et d'optique, Universite Laval, Quebec, QC (Canada)
  4. (Canada)
Publication Date:
OSTI Identifier:
20951683
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 68; Journal Issue: 2; Other Information: DOI: 10.1016/j.ijrobp.2007.01.046; PII: S0360-3016(07)00196-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; APERTURES; BLADDER; CARCINOMAS; COLLIMATORS; COMPUTERIZED TOMOGRAPHY; IRRADIATION; PATIENTS; RADIATION DOSES; RADIOTHERAPY; RECTUM