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Title: The effect of image-guided radiation therapy on the margin between the clinical target volume and planning target volume in lung cancer

Introduction: This study aimed to evaluate the effect of image-guided radiation therapy (IGRT) on the margin between the clinical target volume (CTV) and planning target volume (PTV) in lung cancer. Methods: The CTV and PTV margin were determined in three dimensions by four radiation oncologists using a standard method in 10 lung cancer patients, and compared to consensus values. Transfer error was measured using a rigid phantom containing gold markers. Systematic error and random error set up errors were calculated in three dimensions from pre-treatment and post-treatment cone beam CT scans. Finally, the margin between the CTV and PTV was corrected for set up error and calculated. Results: The margins between the CTV and PTV with IGRT (and without IGRT) were 0.88 cm (0.96 cm), 0.99 cm (1.08 cm) and 1.28 cm (1.82 cm) in the anterior and posterior (AP), left and right (LR) and superior and inferior (SI) directions, respectively. Images from two other patients verified the validity of the corrected margin. The target delineation errors of the radiation oncologists are considered to be the largest compared with the set up errors. The application of IGRT reduced the set up errors and the margins between CTV and PTV. Conclusions:more » The delineation errors of radiation oncologists are the most important factor to consider for the margin between CTV and PTV for lung cancer. IGRT can reduce the margins by reducing the set up errors, especially in the SI direction. Further research is required to assess whether the reduction in the margin is solely based on set up errors.« less
Authors:
; ; ; ; ; ; ; ; ; ; ; ;  [1]
  1. Department of Radiotherapy, Cancer Hospital, Chinese Academy of Medical Sciences, Beijing (China)
Publication Date:
OSTI Identifier:
22402338
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Medical Radiation Sciences (Print); Journal Volume: 61; Journal Issue: 1; Other Information: PMCID: PMC4175824; PMID: 26229633; OAI: oai:pubmedcentral.nih.gov:4175824; Copyright (c) 2014 The Authors. Journal of Medical Radiation Sciences published by Wiley Publishing Asia Pty Ltd on behalf of Australian Institute of Radiography and New Zealand Institute of Medical Radiation Technology; This is an open access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
Australia
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BEAMS; CONES; ERRORS; EXTERNAL BEAM RADIATION THERAPY; GOLD; IMAGES; LUNGS; NEOPLASMS; PATIENTS; PHANTOMS; PLANNING; REDUCTION