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Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins

PURPOSE: The purpose of the study was to evaluate the patient set-up error of different anatomical sites, to estimate the effect of different frequencies of online verifications on the patient set-up accuracy, and to calculate margins to accommodate for the patient set-up error (ICRU set-up margin,...

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Autores principales: Rudat, Volker, Hammoud, Mohamed, Pillay, Yogin, Alaradi, Abdul Aziz, Mohamed, Adel, Altuwaijri, Saleh
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3201019/
https://www.ncbi.nlm.nih.gov/pubmed/21864393
http://dx.doi.org/10.1186/1748-717X-6-101
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author Rudat, Volker
Hammoud, Mohamed
Pillay, Yogin
Alaradi, Abdul Aziz
Mohamed, Adel
Altuwaijri, Saleh
author_facet Rudat, Volker
Hammoud, Mohamed
Pillay, Yogin
Alaradi, Abdul Aziz
Mohamed, Adel
Altuwaijri, Saleh
author_sort Rudat, Volker
collection PubMed
description PURPOSE: The purpose of the study was to evaluate the patient set-up error of different anatomical sites, to estimate the effect of different frequencies of online verifications on the patient set-up accuracy, and to calculate margins to accommodate for the patient set-up error (ICRU set-up margin, SM). METHODS AND MATERIALS: Alignment data of 148 patients treated with inversed planned intensity modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3D-CRT) of the head and neck (n = 31), chest (n = 72), abdomen (n = 15), and pelvis (n = 30) were evaluated. The patient set-up accuracy was assessed using orthogonal megavoltage electronic portal images of 2328 fractions of 173 planning target volumes (PTV). In 25 patients, two PTVs were analyzed where the PTVs were located in different anatomical sites and treated in two different radiotherapy courses. The patient set-up error and the corresponding SM were retrospectively determined assuming no online verification, online verification once a week and online verification every other day. RESULTS: The SM could be effectively reduced with increasing frequency of online verifications. However, a significant frequency of relevant set-up errors remained even after online verification every other day. For example, residual set-up errors larger than 5 mm were observed on average in 18% to 27% of all fractions of patients treated in the chest, abdomen and pelvis, and in 10% of fractions of patients treated in the head and neck after online verification every other day. CONCLUSION: In patients where high set-up accuracy is desired, daily online verification is highly recommended.
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spelling pubmed-32010192011-10-26 Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins Rudat, Volker Hammoud, Mohamed Pillay, Yogin Alaradi, Abdul Aziz Mohamed, Adel Altuwaijri, Saleh Radiat Oncol Research PURPOSE: The purpose of the study was to evaluate the patient set-up error of different anatomical sites, to estimate the effect of different frequencies of online verifications on the patient set-up accuracy, and to calculate margins to accommodate for the patient set-up error (ICRU set-up margin, SM). METHODS AND MATERIALS: Alignment data of 148 patients treated with inversed planned intensity modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3D-CRT) of the head and neck (n = 31), chest (n = 72), abdomen (n = 15), and pelvis (n = 30) were evaluated. The patient set-up accuracy was assessed using orthogonal megavoltage electronic portal images of 2328 fractions of 173 planning target volumes (PTV). In 25 patients, two PTVs were analyzed where the PTVs were located in different anatomical sites and treated in two different radiotherapy courses. The patient set-up error and the corresponding SM were retrospectively determined assuming no online verification, online verification once a week and online verification every other day. RESULTS: The SM could be effectively reduced with increasing frequency of online verifications. However, a significant frequency of relevant set-up errors remained even after online verification every other day. For example, residual set-up errors larger than 5 mm were observed on average in 18% to 27% of all fractions of patients treated in the chest, abdomen and pelvis, and in 10% of fractions of patients treated in the head and neck after online verification every other day. CONCLUSION: In patients where high set-up accuracy is desired, daily online verification is highly recommended. BioMed Central 2011-08-24 /pmc/articles/PMC3201019/ /pubmed/21864393 http://dx.doi.org/10.1186/1748-717X-6-101 Text en Copyright ©2011 Rudat et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research
Rudat, Volker
Hammoud, Mohamed
Pillay, Yogin
Alaradi, Abdul Aziz
Mohamed, Adel
Altuwaijri, Saleh
Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins
title Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins
title_full Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins
title_fullStr Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins
title_full_unstemmed Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins
title_short Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins
title_sort impact of the frequency of online verifications on the patient set-up accuracy and set-up margins
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3201019/
https://www.ncbi.nlm.nih.gov/pubmed/21864393
http://dx.doi.org/10.1186/1748-717X-6-101
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