Capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy

The capabilities of electret ion chambers to measure non-target absorbed dose during radio- therapy treatment was investigated for the first time. During radiotherapy, non-target doses can be classified as one of three approximate dose levels: high doses, intermediate doses and low doses. Low doses...

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Autores principales:	Clouvas Alexandros, Makridou Anna, Chatzimarkou Michalis
Formato:	article
Lenguaje:	EN
Publicado:	VINCA Institute of Nuclear Sciences 2021
Materias:	electret ion chambers radiation therapy absorbed dose Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
Acceso en línea:	https://doaj.org/article/c9d2b165411a4da18b93be9c1f33142a
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spelling	oai:doaj.org-article:c9d2b165411a4da18b93be9c1f33142a2021-11-22T11:03:07ZCapabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy1451-39941452-818510.2298/NTRP201113015Chttps://doaj.org/article/c9d2b165411a4da18b93be9c1f33142a2021-01-01T00:00:00Zhttp://www.doiserbia.nb.rs/img/doi/1451-3994/2021/1451-39942100015C.pdfhttps://doaj.org/toc/1451-3994https://doaj.org/toc/1452-8185The capabilities of electret ion chambers to measure non-target absorbed dose during radio- therapy treatment was investigated for the first time. During radiotherapy, non-target doses can be classified as one of three approximate dose levels: high doses, intermediate doses and low doses. Low doses (<5 % of the prescription dose) are not generally considered during treatment planning, due to the fact that is difficult to measure, characterize, or model them in the planning system. In this work were performed measurements with electret ion chambers of absorbed dose outside the treated volume (<5 % of the prescription dose), during external photon radiation therapy in an Elekta Infinity Linear Accelerator of Theagenio Cancer Hospital of Thessaloniki, Greece. The absorbed dose values for distances 8-100 cm from the borders of the irradiated volume varied from 0.3 to 17 mGy which corresponds to 0.01 % up to % of the prescription dose (2660 mGy). Near the irradiation volume the absorbed dose values were greater than the upper detection limit of the electret ion chambers (threshold 40 mGy). The results are compared with the calculated ones by the Monaco treatment planning system – TPS (Elekta Monaco at November 5, 2003) in three positions distanced at 8 cm and about 30 cm from the border of the irradiation zone. In the position at 8 cm from the irradiation zone, where Monaco TPS calculates (within uncertainty of about 15 %) the absorbed dose, measured and calculated doses are the same within experimental uncertainties. On the contrary for the other two positions, where leakage radiation becomes the dominant source of out-of-field dose the absorbed dose values calculated by the TPS are seriously underestimated ( by a factor of 4) due to the fact that TPS does not take into account the leakage radiation. However, adding to the TPS values an estimated dose due to leakage radiation, the difference between measured and calculated doses are about 30 %.Clouvas AlexandrosMakridou AnnaChatzimarkou MichalisVINCA Institute of Nuclear Sciencesarticleelectret ion chambersradiation therapyabsorbed doseNuclear and particle physics. Atomic energy. RadioactivityQC770-798ENNuclear Technology and Radiation Protection, Vol 36, Iss 2, Pp 197-204 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	electret ion chambers radiation therapy absorbed dose Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
spellingShingle	electret ion chambers radiation therapy absorbed dose Nuclear and particle physics. Atomic energy. Radioactivity QC770-798 Clouvas Alexandros Makridou Anna Chatzimarkou Michalis Capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy
description	The capabilities of electret ion chambers to measure non-target absorbed dose during radio- therapy treatment was investigated for the first time. During radiotherapy, non-target doses can be classified as one of three approximate dose levels: high doses, intermediate doses and low doses. Low doses (<5 % of the prescription dose) are not generally considered during treatment planning, due to the fact that is difficult to measure, characterize, or model them in the planning system. In this work were performed measurements with electret ion chambers of absorbed dose outside the treated volume (<5 % of the prescription dose), during external photon radiation therapy in an Elekta Infinity Linear Accelerator of Theagenio Cancer Hospital of Thessaloniki, Greece. The absorbed dose values for distances 8-100 cm from the borders of the irradiated volume varied from 0.3 to 17 mGy which corresponds to 0.01 % up to % of the prescription dose (2660 mGy). Near the irradiation volume the absorbed dose values were greater than the upper detection limit of the electret ion chambers (threshold 40 mGy). The results are compared with the calculated ones by the Monaco treatment planning system – TPS (Elekta Monaco at November 5, 2003) in three positions distanced at 8 cm and about 30 cm from the border of the irradiation zone. In the position at 8 cm from the irradiation zone, where Monaco TPS calculates (within uncertainty of about 15 %) the absorbed dose, measured and calculated doses are the same within experimental uncertainties. On the contrary for the other two positions, where leakage radiation becomes the dominant source of out-of-field dose the absorbed dose values calculated by the TPS are seriously underestimated ( by a factor of 4) due to the fact that TPS does not take into account the leakage radiation. However, adding to the TPS values an estimated dose due to leakage radiation, the difference between measured and calculated doses are about 30 %.
format	article
author	Clouvas Alexandros Makridou Anna Chatzimarkou Michalis
author_facet	Clouvas Alexandros Makridou Anna Chatzimarkou Michalis
author_sort	Clouvas Alexandros
title	Capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy
title_short	Capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy
title_full	Capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy
title_fullStr	Capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy
title_full_unstemmed	Capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy
title_sort	capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy
publisher	VINCA Institute of Nuclear Sciences
publishDate	2021
url	https://doaj.org/article/c9d2b165411a4da18b93be9c1f33142a
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Capabilities of electret ion chambers to measure absorbed dose outside the treated volume, during external-photon radiation therapy

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