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Title: A volumetric approach to path-length measurements is essential when treating radiotherapy with modulated beams

The established dosimetric benefits of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy have lead to their increased use in prostate radiotherapy. Complimenting these techniques, volumetric image guidance has supported increased positional accuracy. In addition, 3-dimensional image guidance has also allowed for assessment of potential dosimetric variation that can be attributed to a deformation of either internal or external structures, such as rectal distension or body contour. Compounding these issues is the variation of tissue density through which the new field position passes and also the variation of dose across a modulated beam. Despite the growing level of interest in this area, there are only a limited number of articles that examine the effect of a variation in beam path length, particularly across a modulated field. IMRT and volumetric-modulated radiation therapy (VMAT) fields are dynamic in nature, and the dose gradient within these fields is variable. Assessment of variation of path length away from the beam's central axis and across the entire field is vital where there is considerable variation of dose within the field, such as IMRT and VMAT. In these cases, reliance on the traditional central axis to focus skin distances is no longer appropriate. This article discussesmore » these more subtle challenges that may have a significant clinical effect if left unrecognized and undervalued.« less
Authors:
 [1] ;  [2] ;  [1]
  1. Discipline of Radiation Therapy, School of Medicine, Trinity College Dublin, Dublin (Ireland)
  2. Northern Sydney Cancer Centre, Royal North Shore Hospital, New South Wales (Australia)
Publication Date:
OSTI Identifier:
22395918
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Dosimetry; Journal Volume: 39; Journal Issue: 2; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; ACCURACY; ANIMAL TISSUES; IMAGES; PROSTATE; RADIATION DOSES; RADIOTHERAPY; RECTUM; SKIN