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The Influence of Shielding Reinforcement in a Vault with Limited Dimensions on the Neutron Dose Equivalent in Vicinity of Medical Electron Linear Accelerator

BACKGROUND: High energy electron linear accelerators (LINACs) producing photon beams with energies higher than 10 MeV are widely used in radiation therapy. In these beams, fast neutrons are generated, which results in undesired contamination of the therapeutic beam. In this study, measurements and M...

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Autores principales: Ivkovic, Ana, Faj, Dario, Kasabasic, Mladen, Sovilj, Marina Poje, Krpan, Ivana, Branilovic, Marina Grabar, Brkic, Hrvoje
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Sciendo 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7276637/
https://www.ncbi.nlm.nih.gov/pubmed/32374291
http://dx.doi.org/10.2478/raon-2020-0024
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author Ivkovic, Ana
Faj, Dario
Kasabasic, Mladen
Sovilj, Marina Poje
Krpan, Ivana
Branilovic, Marina Grabar
Brkic, Hrvoje
author_facet Ivkovic, Ana
Faj, Dario
Kasabasic, Mladen
Sovilj, Marina Poje
Krpan, Ivana
Branilovic, Marina Grabar
Brkic, Hrvoje
author_sort Ivkovic, Ana
collection PubMed
description BACKGROUND: High energy electron linear accelerators (LINACs) producing photon beams with energies higher than 10 MeV are widely used in radiation therapy. In these beams, fast neutrons are generated, which results in undesired contamination of the therapeutic beam. In this study, measurements and Monte Carlo (MC) simulations were used to obtain neutron spectra and dose equivalents in vicinity of linear accelerator. MATERIALS AND METHODS: LINAC Siemens Oncor Expression in Osijek University Hospital is placed in vault that was previously used for (60)Co machine. Then, the shielding of the vault was enhanced using lead and steel plates. Measurements of neutron dose equivalent around LINAC and the vault were done using CR-39 solid state nuclear track detectors. To compensate energy dependence of detectors, neutron energy spectra was calculated in measuring positions using MC simulations. RESULTS: The vault is a source of photoneutrons, but a vast majority of neutrons originates from accelerator head. Neutron spectra obtained from MC simulations show significant changes between the measuring positions. Annual neutron dose equivalent per year was estimated to be less than 324 μSv in the measuring points outside of the vault. CONCLUSIONS: Since detectors used in this paper are very dependent on neutron energy, it is extremely important to know the neutron spectra in measuring points. Though, patient dosimetry should include neutrons, estimated annual neutron doses outside the vault were far below exposure limit of ionizing radiation for workers.
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spelling pubmed-72766372020-06-09 The Influence of Shielding Reinforcement in a Vault with Limited Dimensions on the Neutron Dose Equivalent in Vicinity of Medical Electron Linear Accelerator Ivkovic, Ana Faj, Dario Kasabasic, Mladen Sovilj, Marina Poje Krpan, Ivana Branilovic, Marina Grabar Brkic, Hrvoje Radiol Oncol Research Article BACKGROUND: High energy electron linear accelerators (LINACs) producing photon beams with energies higher than 10 MeV are widely used in radiation therapy. In these beams, fast neutrons are generated, which results in undesired contamination of the therapeutic beam. In this study, measurements and Monte Carlo (MC) simulations were used to obtain neutron spectra and dose equivalents in vicinity of linear accelerator. MATERIALS AND METHODS: LINAC Siemens Oncor Expression in Osijek University Hospital is placed in vault that was previously used for (60)Co machine. Then, the shielding of the vault was enhanced using lead and steel plates. Measurements of neutron dose equivalent around LINAC and the vault were done using CR-39 solid state nuclear track detectors. To compensate energy dependence of detectors, neutron energy spectra was calculated in measuring positions using MC simulations. RESULTS: The vault is a source of photoneutrons, but a vast majority of neutrons originates from accelerator head. Neutron spectra obtained from MC simulations show significant changes between the measuring positions. Annual neutron dose equivalent per year was estimated to be less than 324 μSv in the measuring points outside of the vault. CONCLUSIONS: Since detectors used in this paper are very dependent on neutron energy, it is extremely important to know the neutron spectra in measuring points. Though, patient dosimetry should include neutrons, estimated annual neutron doses outside the vault were far below exposure limit of ionizing radiation for workers. Sciendo 2020-05-02 /pmc/articles/PMC7276637/ /pubmed/32374291 http://dx.doi.org/10.2478/raon-2020-0024 Text en © 2020 Ana Ivkovic, Dario Faj, Mladen Kasabasic, Marina Poje Sovilj, Ivana Krpan, Marina Grabar Branilovic, Hrvoje Brkic, published by Sciendo http://creativecommons.org/licenses/by-nc-nd/3.0 This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.
spellingShingle Research Article
Ivkovic, Ana
Faj, Dario
Kasabasic, Mladen
Sovilj, Marina Poje
Krpan, Ivana
Branilovic, Marina Grabar
Brkic, Hrvoje
The Influence of Shielding Reinforcement in a Vault with Limited Dimensions on the Neutron Dose Equivalent in Vicinity of Medical Electron Linear Accelerator
title The Influence of Shielding Reinforcement in a Vault with Limited Dimensions on the Neutron Dose Equivalent in Vicinity of Medical Electron Linear Accelerator
title_full The Influence of Shielding Reinforcement in a Vault with Limited Dimensions on the Neutron Dose Equivalent in Vicinity of Medical Electron Linear Accelerator
title_fullStr The Influence of Shielding Reinforcement in a Vault with Limited Dimensions on the Neutron Dose Equivalent in Vicinity of Medical Electron Linear Accelerator
title_full_unstemmed The Influence of Shielding Reinforcement in a Vault with Limited Dimensions on the Neutron Dose Equivalent in Vicinity of Medical Electron Linear Accelerator
title_short The Influence of Shielding Reinforcement in a Vault with Limited Dimensions on the Neutron Dose Equivalent in Vicinity of Medical Electron Linear Accelerator
title_sort influence of shielding reinforcement in a vault with limited dimensions on the neutron dose equivalent in vicinity of medical electron linear accelerator
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7276637/
https://www.ncbi.nlm.nih.gov/pubmed/32374291
http://dx.doi.org/10.2478/raon-2020-0024
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