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Title: Quantifying intra- and inter-fractional motion in breast radiotherapy

The magnitude of intra- and inter-fractional variation in the set up of breast cancer patients treated with tangential megavoltage photon beams was investigated using an electronic portal imaging device (EPID). Daily cine-EPID images were captured during delivery of the tangential fields for ten breast cancer patients treated in the supine position. Measurements collected from each image included the central lung distance (CLD), central flash distance (CFD), superior axial measurement (SAM) and the inferior axial measurement (IAM). The variation of motion within a fraction (intra-fraction) and the variation between fractions (inter-fraction) was analysed to quantify set up variation and motion due to respiration. Altogether 3775 EPID images were collected from 10 patients. The effect of respiratory motion during treatment was <0.1 cm standard deviation (SD) in the anterior–posterior (AP) direction. The inter-fraction movement caused by variations in daily set up was larger at 0.28 cm SD in the AP direction. Superior–inferior (SI) variation was more difficult to summarise and proved unreliable as the measurements were taken to an ambiguous point on the images. It was difficult to discern true SI movement from that implicated by AP movement. There is minimal intra-fractional chest wall motion due to respiration during treatment. Inter-fractional variationmore » was larger, however, on average it remained within departmental tolerance (0.5 cm) for set up variations. This review of our current breast technique provides confidence in the feasibility of utilising advanced treatment techniques (field-in-field, intensity modulated radiotherapy or volumetric modulated arc therapy) following a review of the current imaging protocol.« less
Authors:
 [1] ;  [2] ; ;  [1]
  1. Division of Cancer Services, Radiation Oncology Mater Centre, Princess Alexandra Hospital, Brisbane (Australia)
  2. Division of Cancer Services, Princess Alexandra Hospital, Brisbane (Australia)
Publication Date:
OSTI Identifier:
22402364
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Medical Radiation Sciences (Print); Journal Volume: 62; Journal Issue: 1; Other Information: PMCID: PMC4364805; PMID: 26229666; OAI: oai:pubmedcentral.nih.gov:4364805; 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-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
Australia
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; CHEST; DELIVERY; EQUIPMENT; IMAGES; LUNGS; MAMMARY GLANDS; MOTION; NEOPLASMS; PATIENTS; PHOTON BEAMS; RADIOTHERAPY; RESPIRATION; REVIEWS; TOLERANCE