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Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters

PURPOSE: Brachytherapy procedure may result in acute tissue reactions like edema, causing deviations between planned and measured doses. The rationale for in vivo dosimetry in interstitial brachytherapy is to assess the accuracy of the delivered dose in comparison with the dose calculated by the tre...

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Autores principales: Melchert, Corinna, Soror, Tamer, Kovács, György
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Termedia Publishing House 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6052378/
https://www.ncbi.nlm.nih.gov/pubmed/30038643
http://dx.doi.org/10.5114/jcb.2018.76748
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author Melchert, Corinna
Soror, Tamer
Kovács, György
author_facet Melchert, Corinna
Soror, Tamer
Kovács, György
author_sort Melchert, Corinna
collection PubMed
description PURPOSE: Brachytherapy procedure may result in acute tissue reactions like edema, causing deviations between planned and measured doses. The rationale for in vivo dosimetry in interstitial brachytherapy is to assess the accuracy of the delivered dose in comparison with the dose calculated by the treatment planning system (TPS). MATERIAL AND METHODS: One single computer tomography (CT) dataset was used for brachytherapy planning, taken within 24 hours after implantation. In vivo interstitial measurements with micro-MOSFET-detectors (metal oxide semiconductor field effect transistor) were performed in 12 patients with different anatomic locations of cancers, including thorax-wall, head and neck, breast, and different types of implantations (monoplanar, loops, and multiplanar). RESULTS: Measured values for the thorax-wall tumor patient showed a good agreement with the calculated data, with average deviation of –2.7% in 8 mm distance to the closest dwell position of the source. The deviation of the measured dose value of the head and neck patient was +55.6% in the first fraction and +8.5% in the last fraction. In the ten breast cancer patients, measured doses depended on the proximity of the detector to the irradiated volume PTV. CONCLUSIONS: The deviations between planned and measured dose values were markedly influenced by the proximity of the detector to the PTV because where the edema exerts, the greatest influence on the tube applicator geometry. The positioning of the patient during irradiation must correspond to the positioning in the planning CT. Further studies are needed to investigate the role of in vivo dosimetry during interstitial brachytherapy as a routine procedure.
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spelling pubmed-60523782018-07-23 Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters Melchert, Corinna Soror, Tamer Kovács, György J Contemp Brachytherapy Original Paper PURPOSE: Brachytherapy procedure may result in acute tissue reactions like edema, causing deviations between planned and measured doses. The rationale for in vivo dosimetry in interstitial brachytherapy is to assess the accuracy of the delivered dose in comparison with the dose calculated by the treatment planning system (TPS). MATERIAL AND METHODS: One single computer tomography (CT) dataset was used for brachytherapy planning, taken within 24 hours after implantation. In vivo interstitial measurements with micro-MOSFET-detectors (metal oxide semiconductor field effect transistor) were performed in 12 patients with different anatomic locations of cancers, including thorax-wall, head and neck, breast, and different types of implantations (monoplanar, loops, and multiplanar). RESULTS: Measured values for the thorax-wall tumor patient showed a good agreement with the calculated data, with average deviation of –2.7% in 8 mm distance to the closest dwell position of the source. The deviation of the measured dose value of the head and neck patient was +55.6% in the first fraction and +8.5% in the last fraction. In the ten breast cancer patients, measured doses depended on the proximity of the detector to the irradiated volume PTV. CONCLUSIONS: The deviations between planned and measured dose values were markedly influenced by the proximity of the detector to the PTV because where the edema exerts, the greatest influence on the tube applicator geometry. The positioning of the patient during irradiation must correspond to the positioning in the planning CT. Further studies are needed to investigate the role of in vivo dosimetry during interstitial brachytherapy as a routine procedure. Termedia Publishing House 2018-06-28 2018-06 /pmc/articles/PMC6052378/ /pubmed/30038643 http://dx.doi.org/10.5114/jcb.2018.76748 Text en Copyright: © 2018 Termedia Sp. z o. o. http://creativecommons.org/licenses/by-nc-sa/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) License, allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material, provided the original work is properly cited and states its license.
spellingShingle Original Paper
Melchert, Corinna
Soror, Tamer
Kovács, György
Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters
title Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters
title_full Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters
title_fullStr Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters
title_full_unstemmed Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters
title_short Quality assurance during interstitial brachytherapy: in vivo dosimetry using MOSFET dosimeters
title_sort quality assurance during interstitial brachytherapy: in vivo dosimetry using mosfet dosimeters
topic Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6052378/
https://www.ncbi.nlm.nih.gov/pubmed/30038643
http://dx.doi.org/10.5114/jcb.2018.76748
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