Evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy

The aim of this research was to investigate the relationship between the collimator aperture and fast-neutron flux, neutron-energy spectrum and absorbed dose rate. For remote therapy, rather large fluxes of fast neutrons are needed which can create dose levels in the tissues of at least 0.1 Gy/min w...

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Autores principales:	A.M. Shehada, V.P. Krivobokov, V.M. Golovkov
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	Fast neutrons Collimation system Neutron therapy Absorbed dose rate MCNP simulations Science (General) Q1-390 Social sciences (General) H1-99
Acceso en línea:	https://doaj.org/article/fe6a461ae4f34d98abcfe2d6681bba53
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spelling	oai:doaj.org-article:fe6a461ae4f34d98abcfe2d6681bba532021-12-02T05:02:23ZEvaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy2405-844010.1016/j.heliyon.2021.e08274https://doaj.org/article/fe6a461ae4f34d98abcfe2d6681bba532021-11-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S240584402102377Xhttps://doaj.org/toc/2405-8440The aim of this research was to investigate the relationship between the collimator aperture and fast-neutron flux, neutron-energy spectrum and absorbed dose rate. For remote therapy, rather large fluxes of fast neutrons are needed which can create dose levels in the tissues of at least 0.1 Gy/min with a source-patient distance of 1 m. Advantageously for these purposes, the 9Be(d, n) reaction was investigated with deuteron energy of 13.6 MeV. The mean energy of the outgoing neutrons was obtained using the code PACE 4 (LISE++) which gave the value of about 5.2 MeV. The maximum neutron flux was at an energy of about 2.5 MeV. Samples activation analysis was deployed to measure the neutron flux in the energy-region [0–14 MeV]. The experimental works were carried out using Al, Fe, Cu and Cd foils which installed on the collimator apertures. To investigate the neutron spectrum, fluxes, and dose rates absorbed at the position of patients, experiments were conducted for four different neutron irradiation-field sizes, which can be modified by the removable-polyethylene parts. Simulation results obtained by the code MCNP-4C and PACE4 (LISE++) were comparable with the experimental data to some extent with consideration of some uncertainties of PACE4 results. It can be concluded that the neutron flux is depended on the irradiation-field size where the neutron flux output for bigger aperture size was about +25% comparing with the smaller ones. These results could play a significant role in improving the neutron flux and optimizing the collimation system utilized in fast neutron therapy. In addition, this can lead to optimization of irradiation canals installed in the nuclear reactors which employed for production of medical isotopes, material testing and many other applications.A.M. ShehadaV.P. KrivobokovV.M. GolovkovElsevierarticleFast neutronsCollimation systemNeutron therapyAbsorbed dose rateMCNP simulationsScience (General)Q1-390Social sciences (General)H1-99ENHeliyon, Vol 7, Iss 11, Pp e08274- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Fast neutrons Collimation system Neutron therapy Absorbed dose rate MCNP simulations Science (General) Q1-390 Social sciences (General) H1-99
spellingShingle	Fast neutrons Collimation system Neutron therapy Absorbed dose rate MCNP simulations Science (General) Q1-390 Social sciences (General) H1-99 A.M. Shehada V.P. Krivobokov V.M. Golovkov Evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy
description	The aim of this research was to investigate the relationship between the collimator aperture and fast-neutron flux, neutron-energy spectrum and absorbed dose rate. For remote therapy, rather large fluxes of fast neutrons are needed which can create dose levels in the tissues of at least 0.1 Gy/min with a source-patient distance of 1 m. Advantageously for these purposes, the 9Be(d, n) reaction was investigated with deuteron energy of 13.6 MeV. The mean energy of the outgoing neutrons was obtained using the code PACE 4 (LISE++) which gave the value of about 5.2 MeV. The maximum neutron flux was at an energy of about 2.5 MeV. Samples activation analysis was deployed to measure the neutron flux in the energy-region [0–14 MeV]. The experimental works were carried out using Al, Fe, Cu and Cd foils which installed on the collimator apertures. To investigate the neutron spectrum, fluxes, and dose rates absorbed at the position of patients, experiments were conducted for four different neutron irradiation-field sizes, which can be modified by the removable-polyethylene parts. Simulation results obtained by the code MCNP-4C and PACE4 (LISE++) were comparable with the experimental data to some extent with consideration of some uncertainties of PACE4 results. It can be concluded that the neutron flux is depended on the irradiation-field size where the neutron flux output for bigger aperture size was about +25% comparing with the smaller ones. These results could play a significant role in improving the neutron flux and optimizing the collimation system utilized in fast neutron therapy. In addition, this can lead to optimization of irradiation canals installed in the nuclear reactors which employed for production of medical isotopes, material testing and many other applications.
format	article
author	A.M. Shehada V.P. Krivobokov V.M. Golovkov
author_facet	A.M. Shehada V.P. Krivobokov V.M. Golovkov
author_sort	A.M. Shehada
title	Evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy
title_short	Evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy
title_full	Evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy
title_fullStr	Evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy
title_full_unstemmed	Evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy
title_sort	evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/fe6a461ae4f34d98abcfe2d6681bba53
work_keys_str_mv	AT amshehada evaluatingthedependencyofneutronspectraandabsorbeddoseratesonthecollimationfieldsizeinfastneutrontherapy AT vpkrivobokov evaluatingthedependencyofneutronspectraandabsorbeddoseratesonthecollimationfieldsizeinfastneutrontherapy AT vmgolovkov evaluatingthedependencyofneutronspectraandabsorbeddoseratesonthecollimationfieldsizeinfastneutrontherapy
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Evaluating the dependency of neutron spectra and absorbed dose rates on the collimation field size in fast neutron therapy

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