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Title: Is ExacTrac x-ray system an alternative to CBCT for positioning patients with head and neck cancers?

Purpose: To evaluate the usefulness of a six-degrees-of freedom (6D) correction using ExacTrac robotics system in patients with head-and-neck (HN) cancer receiving radiation therapy.Methods: Local setup accuracy was analyzed for 12 patients undergoing intensity-modulated radiation therapy (IMRT). Patient position was imaged daily upon two different protocols, cone-beam computed tomography (CBCT), and ExacTrac (ET) images correction. Setup data from either approach were compared in terms of both residual errors after correction and punctual displacement of selected regions of interest (Mandible, C2, and C6 vertebral bodies).Results: On average, both protocols achieved reasonably low residual errors after initial correction. The observed differences in shift vectors between the two protocols showed that CBCT tends to weight more C2 and C6 at the expense of the mandible, while ET tends to average more differences among the different ROIs.Conclusions: CBCT, even without 6D correction capabilities, seems preferable to ET for better consistent alignment and the capability to see soft tissues. Therefore, in our experience, CBCT represents a benchmark for positioning head and neck cancer patients.
Authors:
; ; ; ; ; ; ;  [1] ;  [2]
  1. Department of Radiation Oncology, IRCCS CROB, 1 Padre Pio Street, 85028 Rionero in Vulture, PZ (Italy)
  2. Laboratory of Preclinical and Translational Research, IRCCS CROB, 1 Padre Pio Street, 85028 Rionero in Vulture, PZ (Italy)
Publication Date:
OSTI Identifier:
22230759
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 40; Journal Issue: 11; Other Information: (c) 2013 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; COMPUTERIZED TOMOGRAPHY; CORRECTIONS; HEAD; JAW; NECK; NEOPLASMS; PATIENTS; POSITIONING; RADIOTHERAPY; X RADIATION