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Luitel K, Siteni S, Barron S, Shay JW. Simulated galactic cosmic radiation-induced cancer progression in mice. Life Sci Space Res (Amst) 2024; 41:43-51. [PMID: 38670651 DOI: 10.1016/j.lssr.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/29/2023] [Accepted: 01/28/2024] [Indexed: 04/28/2024]
Abstract
Prolonged manned space flight exposure risks to galactic comic radiation, has led to uncertainties in a variety of health risks. Our previous work, utilizing either single ion or multiple ion radiation exposure conducted at the NSRL (NASA Space Radiation Laboratory, Brookhaven, NY) demonstrated that HZE ion components of the GCR result in persistent inflammatory signaling, increased mutations, and higher rates of cancer initiation and progression. With the development of the 33-beam galactic cosmic radiation simulations (GCRsim) at the NSRL, we can more closely test on earth the radiation environment found in space. With a previously used lung cancer susceptible mouse model (K-rasLA-1), we performed acute exposure experiments lasting 1-2 h, and chronic exposure experiments lasting 2-6 weeks with a total dose of 50 cGy and 75 cGy. We obtained histological samples from a subset of mice 100 days post-irradiation, and the remaining mice were monitored for overall survival up to 1-year post-irradiation. When we compared acute exposures (1-2 hrs.) and chronic exposure (2-6 weeks), we found a trend in the increase of lung adenocarcinoma respectively for a total dose of 50 cGy and 75 cGy. Furthermore, when we added neutron exposure to the 75 cGy of GCRsim, we saw a further increase in the incidence of adenocarcinoma. We interpret these findings to suggest that the risks of carcinogenesis are heightened with doses anticipated during a round trip to Mars, and this risk is magnified when coupled with extra neutron exposure that are expected on the Martian surface. We also observed that risks are reduced when the NASA official 33-beam GCR simulations are provided at high dose rates compared to low dose rates.
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Affiliation(s)
- Krishna Luitel
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Silvia Siteni
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Summer Barron
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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2
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Chasapoglou S, Kokkoris M, Vlastou R, Diakaki M, Michalopoulou V, Kalamara A, Gkatis G, Stamatopoulos A, Axiotis M, Harissopulos S, Lagoyannis A, Savva MI, Vasilopoulou T, Lederer-Woods C, Patronis N, Kaperoni K. On the accuracy of cross-section measurements of neutron-induced reactions using the activation technique with natural targets: The case of Ge at E n=17.9 MeV. Appl Radiat Isot 2024; 203:111077. [PMID: 37925902 DOI: 10.1016/j.apradiso.2023.111077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 11/07/2023]
Abstract
Several cross-section measurements of neutron-induced reactions on Ge found in literature, are performed utilizing natGe targets. The production of the same residual nucleus as the measured one might occur as a result of the unavoidable presence of neighboring isotopes in the same target, acting as a contamination. Corrections must be made based on theoretical calculations and models in order to resolve this problem. The accuracy and limits of a methodology for these "theoretical corrections" are investigated in this work using isotopically enriched targets, which can produce very accurate results without the need for such corrections. Experimental cross-section measurements have been made for the 76Ge(n,2n)75Ge, 72Ge(n,α)69mZn and 72Ge(n,p)72Ga reactions, via the activation technique, with the 27Al(n,α)24Na reaction used as reference, employing both a natGe and isotopically enriched Ge targets. The 3H(d,n)4He (D-T) reaction was used for producing the quasi-monoenergetic neutron beam in the 5.5 MV Tandem Accelerator Laboratory of the National Centre for Scientific Research "Demokritos" in Athens, Greece, at an incident deuteron beam energy of 2.9 MeV. Using HPGe detectors, γ-ray spectroscopy was applied to determine the induced γ-ray activity of the residual nuclei.
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Affiliation(s)
- S Chasapoglou
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens, 15772, Greece.
| | - M Kokkoris
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens, 15772, Greece
| | - R Vlastou
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens, 15772, Greece
| | - M Diakaki
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens, 15772, Greece
| | - V Michalopoulou
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens, 15772, Greece; European Organization for Nuclear Research (CERN), Geneva, Switzerland
| | - A Kalamara
- Institute of Nuclear and Radiological Sciences, Technology, Energy & Safety, N.C.S.R. "Demokritos", Athens, Greece; Institute of Nanoscience and Nanotechnology, N.C.S.R. "Demokritos", Athens, Greece
| | - G Gkatis
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens, 15772, Greece; CEA/DES/IRESNE/DER/SPRC/LEPh, Cadarache, Saint Paul Lez Durance, France
| | - A Stamatopoulos
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens, 15772, Greece; Physics Division, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - M Axiotis
- Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, N.C.S.R. "Demokritos", Athens, Greece
| | - S Harissopulos
- Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, N.C.S.R. "Demokritos", Athens, Greece
| | - A Lagoyannis
- Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, N.C.S.R. "Demokritos", Athens, Greece
| | - M I Savva
- Institute of Nuclear and Radiological Sciences, Technology, Energy & Safety, N.C.S.R. "Demokritos", Athens, Greece
| | - T Vasilopoulou
- Institute of Nuclear and Radiological Sciences, Technology, Energy & Safety, N.C.S.R. "Demokritos", Athens, Greece
| | - C Lederer-Woods
- School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - N Patronis
- Department of Physics, University of Ioannina, Ioannina, Greece
| | - K Kaperoni
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens, 15772, Greece
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3
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Endesfelder D, Kulka U, Bucher M, Giesen U, Garty G, Beinke C, Port M, Gruel G, Gregoire E, Terzoudi G, Triantopoulou S, Ainsbury EA, Moquet J, Sun M, Prieto MJ, Moreno Domene M, Barquinero JF, Pujol-Canadell M, Vral A, Baeyens A, Wojcik A, Oestreicher U. International Comparison Exercise for Biological Dosimetry after Exposures with Neutrons Performed at Two Irradiation Facilities as Part of the BALANCE Project. Cytogenet Genome Res 2023; 163:163-177. [PMID: 37071978 PMCID: PMC10641373 DOI: 10.1159/000530728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 04/10/2023] [Indexed: 04/20/2023] Open
Abstract
In the case of a radiological or nuclear event, biological dosimetry can be an important tool to support clinical decision-making. During a nuclear event, individuals might be exposed to a mixed field of neutrons and photons. The composition of the field and the neutron energy spectrum influence the degree of damage to the chromosomes. During the transatlantic BALANCE project, an exposure similar to a Hiroshima-like device at a distance of 1.5 km from the epicenter was simulated, and biological dosimetry based on dicentric chromosomes was performed to evaluate the participants ability to discover unknown doses and to test the influence of differences in neutron spectra. In a first step, calibration curves were established by irradiating blood samples with 5 doses in the range of 0-4 Gy at two different facilities in Germany (Physikalisch-Technische Bundesanstalt [PTB]) and the USA (the Columbia IND Neutron Facility [CINF]). The samples were sent to eight participating laboratories from the RENEB network and dicentric chromosomes were scored by each participant. Next, blood samples were irradiated with 4 blind doses in each of the two facilities and sent to the participants to provide dose estimates based on the established calibration curves. Manual and semiautomatic scoring of dicentric chromosomes were evaluated for their applicability to neutron exposures. Moreover, the biological effectiveness of the neutrons from the two irradiation facilities was compared. The calibration curves from samples irradiated at CINF showed a 1.4 times higher biological effectiveness compared to samples irradiated at PTB. For manual scoring of dicentric chromosomes, the doses of the test samples were mostly successfully resolved based on the calibration curves established during the project. For semiautomatic scoring, the dose estimation for the test samples was less successful. Doses >2 Gy in the calibration curves revealed nonlinear associations between dose and dispersion index of the dicentric counts, especially for manual scoring. The differences in the biological effectiveness between the irradiation facilities suggested that the neutron energy spectrum can have a strong impact on the dicentric counts.
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Affiliation(s)
- David Endesfelder
- Department of Effects and Risks of Ionising and Non-Ionising Radiation, Federal Office for Radiation Protection (BfS), Oberschleißheim, Germany,
| | - Ulrike Kulka
- Department of Effects and Risks of Ionising and Non-Ionising Radiation, Federal Office for Radiation Protection (BfS), Oberschleißheim, Germany
| | - Martin Bucher
- Department of Effects and Risks of Ionising and Non-Ionising Radiation, Federal Office for Radiation Protection (BfS), Oberschleißheim, Germany
| | - Ulrich Giesen
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
| | - Guy Garty
- Radiological Research Accelerator Facility (RARAF), Columbia University, Irvington, New York, USA
| | | | - Matthias Port
- Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Gaetan Gruel
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-Santé, SERAMED, LRAcc, Fontenay-aux-Roses, France
| | - Eric Gregoire
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-Santé, SERAMED, LRAcc, Fontenay-aux-Roses, France
| | - Georgia Terzoudi
- Health Physics, Radiobiology & Cytogenetics Laboratory, National Centre for Scientific Research "Demokritos,", Athens, Greece
| | - Sotiria Triantopoulou
- Health Physics, Radiobiology & Cytogenetics Laboratory, National Centre for Scientific Research "Demokritos,", Athens, Greece
| | - Elizabeth A Ainsbury
- Radiation, Chemicals and Environmental Hazards Directorate, UK Health Security Agency, Chilton, Oxfordshire, UK
| | - Jayne Moquet
- Radiation, Chemicals and Environmental Hazards Directorate, UK Health Security Agency, Chilton, Oxfordshire, UK
| | - Mingzhu Sun
- Radiation, Chemicals and Environmental Hazards Directorate, UK Health Security Agency, Chilton, Oxfordshire, UK
| | - María Jesús Prieto
- Centro de Oncología Radioterápica, Laboratorio de Dosimetría Biológica, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Mercedes Moreno Domene
- Centro de Oncología Radioterápica, Laboratorio de Dosimetría Biológica, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Joan-Francesc Barquinero
- Departament de Biologia Animal, Unitat d'Antropologia Biològica, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Monica Pujol-Canadell
- Departament de Biologia Animal, Unitat d'Antropologia Biològica, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Anne Vral
- Faculty of Medicine and Health Sciences, Department of Human Structure and Repair, Radiobiology Research Unit, Ghent University, Gent, Belgium
| | - Ans Baeyens
- Faculty of Medicine and Health Sciences, Department of Human Structure and Repair, Radiobiology Research Unit, Ghent University, Gent, Belgium
| | - Andrzej Wojcik
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- Institute of Biology, Jan Kochanowski University, Kielce, Poland
| | - Ursula Oestreicher
- Department of Effects and Risks of Ionising and Non-Ionising Radiation, Federal Office for Radiation Protection (BfS), Oberschleißheim, Germany
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van Amelrooij E, van de Giesen N, Plomp J, Thijs M, Fico T. BLOSM: Boron-based large-scale observation of soil moisture: First laboratory results of a cost-efficient neutron detector. HardwareX 2022; 12:e00342. [PMID: 35942180 PMCID: PMC9356203 DOI: 10.1016/j.ohx.2022.e00342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A newly developed Boron-based Large-scale Observation of Soil Moisture (or BLOSM) system is currently being tested and implemented. The stationary system provides a cost-effective way to measure fast and thermalized neutrons by using low-cost, non-hazardous and accessible materials and equipment. BLOSM operates by measuring cosmic-ray induced neutrons and by comparing the amount of fast neutrons with the amount of thermal neutrons. Fast neutrons are moderated by hydrogen atoms in the air, organic materials, and especially and primarily by water in the soil, causing the ratio between fast and thermal to be a strong indicator of soil moisture content. The fast/thermal ratio is representative for soil moisture a scale of about 30 hectares, while standard soil moisture measurements are representative for less than a square meter. This is a well-established fact but present neutron detectors are very costly. Thanks to the low-cost of the probe, BLOSM can eventually be applied at a large scale and significantly increase the number of soil-water data points thereby enabling improvement of existing hydrology models as well as new applications such as monitoring fire hazards and agricultural droughts. Here, we present the build and first tests in the laboratory. We show that BLOSM can indeed measure fast and thermal neutrons, which opens the way to applications outside the laboratory.
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Affiliation(s)
- Edward van Amelrooij
- Department of Water Management, Faculty of Civil Engineering & Geosciences, Delft University of Technology, 2628 CN Delft, The Netherlands
| | - Nick van de Giesen
- Department of Water Management, Faculty of Civil Engineering & Geosciences, Delft University of Technology, 2628 CN Delft, The Netherlands
| | - Jeroen Plomp
- Reactor Institute Delft, Delft University of Technology, 2628 CN Delft, The Netherlands
| | - Michel Thijs
- Reactor Institute Delft, Delft University of Technology, 2628 CN Delft, The Netherlands
| | - Tomáš Fico
- MicroStep-MIS, spol. s r.o., 831 04 Bratislava, Slovakia
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5
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Mendes RMS, Silva MG, Rebello WF, Oliveira CL, Stenders RM, Medeiros MPC, Braga KL, Santos RFG, Thalhofer JL, Andrade ERD. Influence of radiotherapy room shielding on ambient dose equivalent due to photons H*(10)p and neutrons H*(10)n in the patient's plane. Appl Radiat Isot 2022; 181:110095. [PMID: 34999307 DOI: 10.1016/j.apradiso.2021.110095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 12/15/2021] [Accepted: 12/31/2021] [Indexed: 11/02/2022]
Abstract
This study discusses a computer simulation for the equivalent ambient dose due to photons, H*(10)p, and neutrons, H*(10)n, in the patient's plane undergoing radiation therapy. A standard radiotherapy room with an additional shielding made by one lead or steel tenth-value layer was considered. A Varian 2100/2300 C/D linear accelerator head operating at 18 MV was modeled. Jaw openings of 5 cm × 5 cm, 10 cm × 10 cm, 20 cm × 20 cm, and 30 cm × 30 cm, as well as the multileaf collimator under eight different angles of gantry inclination, were also modeled. The use of steel in the shield generates a slightly raised average value of H*(10)p (0.527%) compared to when using lead. This finding can be interpreted as that the use of lead or steel coating makes no difference to the additional shield calculations when only photons are considered. When considering the contribution to H*(10)n, there is a significant difference (11.7% increase) for using lead compared to steel shielding.
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Affiliation(s)
- Raphael M S Mendes
- Nuclear Engineering Graduate Program, Military Institute of Engineering (IME), Rio de Janeiro, Brazil.
| | - Maria G Silva
- Nuclear Engineering Graduate Program, Military Institute of Engineering (IME), Rio de Janeiro, Brazil.
| | - Wilson F Rebello
- Rio de Janeiro State University, Faculty of Engineering and IBRAG, Rio de Janeiro, Brazil.
| | - Cláudio L Oliveira
- Nuclear Engineering Graduate Program, Military Institute of Engineering (IME), Rio de Janeiro, Brazil.
| | | | - Marcos P C Medeiros
- Nuclear Engineering Graduate Program, Military Institute of Engineering (IME), Rio de Janeiro, Brazil; Nuclear Engineering Graduate Program, Federal University of Rio de Janeiro (COPPE/UFRJ), Rio de Janeiro, Brazil.
| | - Kelmo L Braga
- Nuclear Engineering Graduate Program, Military Institute of Engineering (IME), Rio de Janeiro, Brazil; Nuclear Engineering Graduate Program, Federal University of Rio de Janeiro (COPPE/UFRJ), Rio de Janeiro, Brazil.
| | - Raphael F G Santos
- Nuclear Engineering Graduate Program, Federal University of Rio de Janeiro (COPPE/UFRJ), Rio de Janeiro, Brazil.
| | - Jardel L Thalhofer
- Nuclear Engineering Graduate Program, Federal University of Rio de Janeiro (COPPE/UFRJ), Rio de Janeiro, Brazil.
| | - Edson Ramos de Andrade
- Nuclear Engineering Graduate Program, Military Institute of Engineering (IME), Rio de Janeiro, Brazil; Nuclear Engineering Graduate Program, Federal University of Rio de Janeiro (COPPE/UFRJ), Rio de Janeiro, Brazil; Defense Engineering Graduate Program, Military Institute of Engineering (IME), Rio de Janeiro, Brazil; Graduate Program in Development and Environment (PRODEMA - UFPB), Federal University of Paraiba, João Pessoa, Brazil.
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6
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Kollitz E, Han H, Kim CH, Pinto M, Schwarz M, Riboldi M, Kamp F, Belka C, Newhauser WD, Dedes G, Parodi K. A patient-specific hybrid phantom for calculating radiation dose and equivalent dose to the whole body. Phys Med Biol 2021; 67. [PMID: 34969024 DOI: 10.1088/1361-6560/ac4738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/30/2021] [Indexed: 11/12/2022]
Abstract
OBJECTIVE As cancer survivorship increases, there is growing interest in minimizing the late effects of radiation therapy such as radiogenic second cancer, which may occur anywhere in the body. Assessing the risk of late effects requires knowledge of the dose distribution throughout the whole body, including regions far from the treatment field, beyond the typical anatomical extent of clinical CT scans. APPROACH A hybrid phantom was developed which consists of in-field patient CT images extracted from ground truth whole-body CT (WBCT) scans, out-of-field mesh phantoms scaled to basic patient measurements, and a blended transition region. Four of these hybrid phantoms were created, representing male and female patients receiving proton therapy treatment in pelvic and cranial sites. To assess the performance of the hybrid approach, we simulated treatments using the hybrid phantoms, the scaled and unscaled mesh phantoms, and the ground truth whole-body CTs. We calculated absorbed dose and equivalent dose in and outside of the treatment field, with a focus on neutrons induced in the patient by proton therapy. Proton and neutron dose was calculated using a general purpose Monte Carlo code. MAIN RESULTS The hybrid phantom provided equal or superior accuracy in calculated organ dose and equivalent dose values relative to those obtained using the mesh phantoms in 78% in all selected organs and calculated dose quantities. Comparatively the default mesh and scaled mesh were equal or superior to the other phantoms in 21% and 28% of cases respectively. SIGNIFICANCE The proposed methodology for hybrid synthesis provides a tool for whole-body organ dose estimation for individual patients without requiring CT scans of their entire body. Such a capability would be useful for personalized assessment of late effects and risk-optimization of treatment plans.
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Affiliation(s)
- Erika Kollitz
- Department of Medical Physics, Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Garching, Bayern, 85748, GERMANY
| | - Haegin Han
- Department of Nuclear Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seongdong-gu, Seoul, 04763, Korea (the Republic of)
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seongdong-gu, Seoul, 04763, Korea (the Republic of)
| | - Marco Pinto
- Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Garching, Bayern, 85748, GERMANY
| | - Marco Schwarz
- Provincia autonoma di Trento Azienda Provinciale per i Servizi Sanitari, Via Alcide Degasperi 79, Trento, Trentino-Alto Adige, 38123, ITALY
| | - Marco Riboldi
- Department of Medical Physics, Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Munchen, Bayern, 85748, GERMANY
| | - Florian Kamp
- Radiotherapy, Klinikum der Universitat Munchen, Marchioninistraße 15, Munich, 81377, GERMANY
| | - Claus Belka
- Department of Radiation Oncology, Klinikum der Universitat Munchen, Marchioninistraße 15, Munchen, Bayern, 81377, GERMANY
| | - Wayne David Newhauser
- Department of Physics & Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, Louisiana, 70803, UNITED STATES
| | - Georgios Dedes
- Department of Medical Physics, Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Munchen, Bayern, 85748, GERMANY
| | - Katia Parodi
- Experimental Physics Medical Physics, Ludwig-Maximilians-Universitat Munchen, Ludwig-Maximilians-Universität München, Department for Medical Physics (LS Parodi), Am Coulombwall 1, Munchen, Bayern, 85748, GERMANY
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7
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Wang Q, Lee Y, Pujol-Canadell M, Perrier JR, Smilenov L, Harken A, Garty G, Brenner DJ, Ponnaiya B, Turner HC. Cytogenetic Damage of Human Lymphocytes in Humanized Mice Exposed to Neutrons and X Rays 24 h After Exposure. Cytogenet Genome Res 2021; 161:352-361. [PMID: 34488220 PMCID: PMC8455411 DOI: 10.1159/000516529] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/02/2021] [Indexed: 11/19/2022] Open
Abstract
Detonation of an improvised nuclear device highlights the need to understand the risk of mixed radiation exposure as prompt radiation exposure could produce significant neutron and gamma exposures. Although the neutron component may be a relatively small percentage of the total absorbed dose, the large relative biological effectiveness (RBE) can induce larger biological DNA damage and cell killing. The objective of this study was to use a hematopoietically humanized mouse model to measure chromosomal DNA damage in human lymphocytes 24 h after in vivo exposure to neutrons (0.3 Gy) and X rays (1 Gy). The human dicentric and cytokinesis-block micronucleus assays were performed to measure chromosomal aberrations in human lymphocytes in vivo from the blood and spleen, respectively. The mBAND assay based on fluorescent in situ hybridization labeling was used to detect neutron-induced chromosome 1 inversions in the blood lymphocytes of the neutron-irradiated mice. Cytogenetics endpoints, dicentrics and micronuclei showed that there was no significant difference in yields between the 2 irradiation types at the doses tested, indicating that neutron-induced chromosomal DNA damage in vivo was more biologically effective (RBE ∼3.3) compared to X rays. The mBAND assay, which is considered a specific biomarker of high-LET neutron exposure, confirmed the presence of clustered DNA damage in the neutron-irradiated mice but not in the X-irradiated mice, 24 h after exposure.
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Affiliation(s)
- Qi Wang
- Center for Radiological Research, Columbia University Irving Medical Center, New York, (NY), USA
| | - Younghyun Lee
- Center for Radiological Research, Columbia University Irving Medical Center, New York, (NY), USA
| | - Monica Pujol-Canadell
- Center for Radiological Research, Columbia University Irving Medical Center, New York, (NY), USA
| | - Jay R. Perrier
- Center for Radiological Research, Columbia University Irving Medical Center, New York, (NY), USA
| | - Lubomir Smilenov
- Center for Radiological Research, Columbia University Irving Medical Center, New York, (NY), USA
| | - Andrew Harken
- Radiological Research Accelerator Facility, Columbia University, Irvington, (NY), USA
| | - Guy Garty
- Radiological Research Accelerator Facility, Columbia University, Irvington, (NY), USA
| | - David J. Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, New York, (NY), USA
| | - Brian Ponnaiya
- Radiological Research Accelerator Facility, Columbia University, Irvington, (NY), USA
| | - Helen C. Turner
- Center for Radiological Research, Columbia University Irving Medical Center, New York, (NY), USA
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8
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Alexandrov ID, Alexandrova MV. The dose-, LET-, and gene-dependent patterns of DNA changes underlying the point mutations in spermatozoa of Drosophila melanogaster. I. Autosomal gene black. Mutat Res 2021; 823:111755. [PMID: 34217017 DOI: 10.1016/j.mrfmmm.2021.111755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 04/23/2021] [Accepted: 05/24/2021] [Indexed: 11/26/2022]
Abstract
Sequence analysis of 7 spontaneous, 27 γ-ray- and 20 neutron/neutron+γ-ray-induced black (b) point mutants was carried out. All these mutants were isolated as non-mosaic transmissible recessive visibles in the progeny of irradiated males from the wild-type high-inbred laboratory D32 strain of Drosophila melanogaster. Among spontaneous mutants, there were two (28.5 %) mutants with copia insertion in intron 1 and exon 2, three (42.8 %) with replacement of b+D32 paternal sequence with maternal b1 sequence (gene conversion), one (14.3 %) with 142-bp-long insertion in exon 2, and one (14.3 %) with a short deletion and two single-base substitutions in exon 3. Among γ-ray-induced mutants, there were 1 (3.7 %) with copia insertion in intron 2, 6 (22.2 %) with gene conversion, and the remaining 20 (74.1 %) mutants had 37 different small-scale DNA changes. There were 20 (54.1 %) single- or double-base substitutions, 7 (18.9 %) frameshifts (indels), 9 (24.3 %) extended deletions or insertions, and 1(2.7 %) mutant with a short insertion instead of a short deletion. Remarkably, clusters of independent small-scale changes inside the gene or within one DNA helical turn were recovered. The spectrum of DNA changes in 20 neutron/ neutron+γ-ray-induced mutants was drastically different from that induced by γ-rays in that 18 (90.0 %) mutants had the b1sequence. In addition, 2 (10.0 %) with gene conversion had 600- or 19-bp-long deletion in exon 3 and 1 (5.0 %) mutant with a short insertion instead of a short deletion. Analysis of all 27 mutants with gene conversion events shows that 20 (74.1 %) had full b1 sequence whereas 7 others (25.9 %) contained a partial b1 sequence. These data are the first experimental evidence for gene conversion in the early stages of animal embryogenesis in the first diploid cleavage nucleus after male and female pronuclei have united. The gene conversion, frameshifts (indels), and deletions between short repeats were considered as products of a relevant DNA repair pathways described in the literature. As the first step, the gametic doubling doses for phenotypic black point mutations and for intragenic base substitution mutations in mature sperm cells irradiated by 40 Gy of γ-rays were estimated as 5.8 and 1.2 Gy, respectively, showing that doubling dose for mutations at the molecular level is about 5 times lower than that at the phenotypic level.
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Affiliation(s)
- I D Alexandrov
- Dzhelepov Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Moscow Region, Russia.
| | - M V Alexandrova
- Dzhelepov Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Moscow Region, Russia
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9
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Yeom YS, Griffin K, Han H, Choi C, Shin B, Nguyen TT, Kim CH, Lee C. Dose conversion coefficients for neutron external exposures with five postures: walking, sitting, bending, kneeling, and squatting. Radiat Environ Biophys 2021; 60:317-328. [PMID: 33704559 PMCID: PMC9923510 DOI: 10.1007/s00411-021-00900-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 02/20/2021] [Indexed: 06/12/2023]
Abstract
In a previous study, posture-dependent dose coefficients (DCs) for photon external exposures were calculated using the adult male and female mesh-type reference computational phantoms (MRCPs) of the International Commission on Radiological Protection (ICRP) that had been transformed into five non-standing postures (i.e. walking, sitting, bending, kneeling, and squatting). As an extension, the present study was conducted to establish another DC dataset for external exposures to neutrons by performing Monte Carlo radiation transport simulations with the adult male and female MRCPs in the five non-standing postures. The resulting dataset included the DCs for absorbed doses (i.e., organ/tissue-averaged absorbed doses) delivered to 29 individual organs/tissues, and for effective doses for neutron energies ranging from 10-9 to 104 MeV in six irradiation geometries: antero-posterior (AP), posteroanterior (PA), left-lateral (LLAT), right-lateral (RLAT), rotational (ROT), and isotropic (ISO) geometries. The comparison of DCs for the non-standing MRCPs with those of the standing MRCPs showed significant differences. In the lateral irradiation geometries, for example, the standing MRCPs overestimate the breast DCs of the squatting MRCPs by up to a factor of 4 due to the different arm positions but underestimate the gonad DCs by up to about 17 times due to the different leg positions. The impact of different postures on effective doses was generally less than that on organ doses but still significant; for example, the standing MRCPs overestimate the effective doses of the bending MRCPs only by 20% in the AP geometry at neutron energies less than 50 MeV, but underestimate those of the kneeling MRCPs by up to 40% in the lateral geometries at energies less than 0.1 MeV.
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Affiliation(s)
- Yeon Soo Yeom
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | - Keith Griffin
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
| | - Haegin Han
- Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea
| | - Chansoo Choi
- Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea
| | - Bangho Shin
- Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea
| | - Thang Tat Nguyen
- School of Nuclear Engineering and Environmental Physics, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hai Ba Trung District, Hanoi, Vietnam
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea.
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, USA
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10
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Litvak ML, Mitrofanov IG, Sanin AB, Bakhtin B, Golovin DV, Zeitlin C. Observations of neutron radiation environment during Odyssey cruise to Mars. Life Sci Space Res (Amst) 2021; 29:53-62. [PMID: 33888288 DOI: 10.1016/j.lssr.2021.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 03/10/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
In April 2001, Mars Odyssey spacecraft with the High Energy Neutron Detector (HEND) onboard was launched to Mars. HEND/Odyssey was switched on measurement mode for most of transit to Mars to monitor variations of spacecraft background and solar activity. Although HEND/Odyssey was originally designed to measure Martian neutron albedo and to search for Martian subsurface water/water ice, its measurements during cruise phase to Mars are applicable to evaluate spacecraft ambient radiation background. The biological impact of the neutron component of this radiation background should be understood, as it must be taken into account in planning future human missions to Mars. We have modeled the spacecraft neutron spectral density and compared it with HEND measurements to estimate neutron dose equivalent rates during Odyssey cruise phase, which occurred during the maximum period of solar cycle 23. We find that the Odyssey ambient neutron environment during May - September 2001 yields 10.6 ± 2.0 μSv per day in the energy range from 0 to 15 MeV, and about 29 μSv per day when extrapolated to the 0-1000 MeV energy range during solar quiet time (intervals without Solar Particle Events, SPEs). We have also extrapolated HEND/Odyssey measurements to different periods of solar cycle and find that during solar minimum (maximum of GCR flux), the neutron dose equivalent rate during cruise to Mars could be as high as 52 μSv per day with the same shielding. These values are in good agreement with results reported for a similar measurement made with an instrument aboard the Mars Science Laboratory during its cruise to Mars in 2011-2012.
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Affiliation(s)
- M L Litvak
- Space Research Institute, RAS, Moscow, 117997, Russia.
| | | | - A B Sanin
- Space Research Institute, RAS, Moscow, 117997, Russia
| | - B Bakhtin
- Space Research Institute, RAS, Moscow, 117997, Russia
| | - D V Golovin
- Space Research Institute, RAS, Moscow, 117997, Russia
| | - C Zeitlin
- Leidos, Inc., Houston, TX 77058, USA
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11
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El Abd A, Taman M, Zhao Y. A new method for measurement of moisture transport in porous media based on forward and backward scattering of epithermal neutrons. Appl Radiat Isot 2021; 173:109730. [PMID: 33894468 DOI: 10.1016/j.apradiso.2021.109730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/17/2021] [Accepted: 04/08/2021] [Indexed: 11/26/2022]
Abstract
We present a new method for determining the spatial distribution and transport of water in porous media. It is based on the detection of both forward and backward scattered neutrons from the wet regions of the samples under investigation. The experimental set-up is based on a Pu-Be neutron source and He-3 neutron detector assemblies. The results obtained showed that back scattered neutrons are more sensitive than the forward scattered neutrons to determine water content. Moreover, both forward and back scattered neutrons are more sensitive than either back or forward neutrons for determining water content. The method was used to measure moisture transport in sand columns and brick samples. Forward and backward scattered neutrons from different wet regions along the water flow path (x) are recorded as the sample absorbs water. Water saturates the regions of the samples tested near the inlet of water faster than the others. The water front positions were found to follow the square root behavior of the absorption time, and capillary penetration coefficients were determined for the samples investigated. The developed method can be used to investigate water absorption at various flow rates in porous samples of various sizes.
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Affiliation(s)
- A El Abd
- Reactor Physics Department, Nuclear Research Center, Egyptian Atomic Energy Authority, P.O. Box:13759, Inchass, Cairo, Egypt.
| | - M Taman
- Department of Structural Engineering, Faculty of Engineering, Tanta University, 31511, Tanta, Egypt
| | - Yixin Zhao
- Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing, 100083, China; State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, PR China; School of Energy & Mining Engineering, China University of Mining and Technology, Beijing, 100083, PR China
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12
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Malekkhaiat Häffner S, Parra-Ortiz E, Skoda MWA, Saerbeck T, Browning KL, Malmsten M. Composition effects on photooxidative membrane destabilization by TiO 2 nanoparticles. J Colloid Interface Sci 2021; 584:19-33. [PMID: 33039680 DOI: 10.1016/j.jcis.2020.09.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 11/30/2022]
Abstract
Membrane interactions and photooxidative membrane destabilization of titanium dioxide (TiO2) nanoparticles were investigated, focusing on the effects of membrane composition, notably phospholipid headgroup charge and presence of cholesterol. For this, we employed a battery of state-of-the-art methods for studies of bilayers formed by zwitterionic palmitoyloleoylphosphatidylcholine (POPC) containing also polyunsaturated palmitoylarachidonoylphosphocholine (PAPC), as well as its mixtures with anionic palmitoyloleoylphosphatidylglycerol (POPG) and cholesterol. It was found that the TiO2 nanoparticles display close to zero charge at pH 7.4, resulting in aggregation. At pH 3.4, in contrast, the 6 nm TiO2 nanoparticles are well dispersed due to a strongly positive ζ-potential. Mirroring this pH dependence, TiO2 nanoparticles were observed to bind to negatively charged lipid bilayers at pH 3.4, but much less so at pH 7.4. While nanoparticle binding has some destabilizing effect alone, illumination with ultraviolet (UV) light accentuates membrane destabilization, a result of oxidative stress caused by generated reactive oxygen species (ROS). Neutron reflectivity (NR), quartz crystal microbalance (QCM), and small-angle X-ray scattering (SAXS) results all demonstrate that membrane composition strongly influences membrane interactions and photooxidative destabilization of lipid bilayers. In particular, the presence of anionic POPG makes the bilayers more sensitive to oxidative destabilization, whereas a stabilizing effect was observed in the presence of cholesterol. Also, structural aspects of peroxidation were found to depend strongly on membrane composition, notably the presence of anionic phospholipids. The results show that membrane interactions and UV-induced ROS generation act in concert and need to be considered together to understand effects of lipid membrane composition on UV-triggered oxidative destabilization by TiO2 nanoparticles, e.g., in the context of oxidative damage of bacteria and cells.
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Affiliation(s)
| | - E Parra-Ortiz
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - M W A Skoda
- ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
| | - T Saerbeck
- Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France
| | - K L Browning
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - M Malmsten
- Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark; Department of Physical Chemistry 1, University of Lund, SE-22100 Lund, Sweden
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13
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Abstract
There is a need to find a replacement for the 252Cf sources currently used in Standards-based performance testing of neutron instrumentation. This is a result of its relatively short half-life, concerns about future availability and recent increases in cost. A potential replacement source, 244Cm is evaluated in this study where two commercially available sources have been acquired and their neutron emission spectra measured using a pair of spectrometers. Both instruments showed the 244Cm spontaneous neutron spectrum to be fully consistent with a MCNP6®-calculated spectrum using published Watt fission parameters for 244Cm. In addition, the emission rate of the weaker 244Cm source was established through a direct count rate comparison against a calibrated and similarly encapsulated 252Cf source. The 244Cm source emission rate was found to be in excellent agreement with value stated on the manufacturer's source certificate. It is concluded that 244Cm would be an ideal replacement for 252Cf based on its longer half-life (18.1 y) and its essentially identical neutron emission spectrum. In addition, 244Cm sources are commercially available at reasonable cost.
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Affiliation(s)
- Radoslav Radev
- Lawrence Livermore National Laboratory, PO Box 808, L-186, Livermore, CA, 94550, USA.
| | - Thomas D McLean
- Los Alamos National Laboratory, PO Box 1663, MS J-573, Los Alamos, NM, 87545, USA.
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14
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Portocarrero Bonifaz A, Bosch Moliné O, Olivares Schneider J, La Rosa La Rosa B, Rojas Hancco J, Guevara Rojas V, Palacios Fernández D, Pereyra Anaya P, López Herrera ME. Simple and low cost alternative method for detecting photo neutrons produced in some radiotherapy treatments using SSNTDs. Appl Radiat Isot 2020; 161:109169. [PMID: 32321701 DOI: 10.1016/j.apradiso.2020.109169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/07/2020] [Accepted: 03/28/2020] [Indexed: 10/24/2022]
Abstract
A simple and low cost alternative which is able to identify thermal and fast neutrons in a clinical environment of radiotherapy is presented. CR-39 and LR-115 Solid State Nuclear Track Detectors (SSNTDs) were used, estimating their viability. In order to register alpha tracks due to thermal neutrons, natural boric acid tablets were placed in close contact to the detector, whereas in order to detect epithermal neutrons, some were additionally covered in a thin cadmium layer. Different configurations were assembled, changing the position of the converter with respect to the detector and the incident neutron fluence, which was evaluated in different positions of a radiotherapy table. The contribution due to environmental 222Rn and its daughters to the track density registered by the detector during the measurements was found to be negligible. It is concluded that the designed experimental set up constitutes a trustworthy and affordable method to carry out neutron measurements with the recommended configurations provided for the CR-39 detector, and not with LR-115.
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Affiliation(s)
| | - Oriol Bosch Moliné
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | - Jose Olivares Schneider
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | - Brian La Rosa La Rosa
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | - Jhonny Rojas Hancco
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | - Vanessa Guevara Rojas
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
| | | | - Patrizia Pereyra Anaya
- Sección Física, Departamento de Ciencias, Pontificia Universidad Católica Del Perú, Lima, Peru
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15
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Lund CM, Famulari G, Montgomery L, Kildea J. A microdosimetric analysis of the interactions of mono-energetic neutrons with human tissue. Phys Med 2020; 73:29-42. [PMID: 32283505 DOI: 10.1016/j.ejmp.2020.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/05/2020] [Accepted: 04/02/2020] [Indexed: 10/24/2022] Open
Abstract
Nuclear reactions induced during high-energy radiotherapy produce secondary neutrons that, due to their carcinogenic potential, constitute an important risk for the development of iatrogenic cancer. Experimental and epidemiological findings indicate a marked energy dependence of neutron relative biological effectiveness (RBE) for carcinogenesis, but little is reported on its physical basis. While the exact mechanism of radiation carcinogenesis is yet to be fully elucidated, numerical microdosimetry can be used to predict the biological consequences of a given irradiation based on its microscopic pattern of energy depositions. Building on recent studies, this work investigated the physics underlying neutron RBE by using the microdosimetric quantity dose-mean lineal energy (y‾D) as a proxy. A simulation pipeline was constructed to explicitly calculate the y‾D of radiation fields that consisted of (i) the open source Monte Carlo toolkit Geant4, (ii) its radiobiological extension Geant4-DNA, and (iii) a weighted track-sampling algorithm. This approach was used to study mono-energetic neutrons with initial kinetic energies between 1 eV and 10 MeV at multiple depths in a tissue-equivalent phantom. Spherical sampling volumes with diameters between 2 nm and 1 μm were considered. To obtain a measure of RBE, the neutron y‾D values were divided by those of 250 keV X-rays that were calculated in the same way. Qualitative agreement was found with published radiation protection factors and simulation data, allowing for the dependencies of neutron RBE on depth and energy to be discussed in the context of the neutron interaction cross sections and secondary particle distributions in human tissue.
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Affiliation(s)
- C M Lund
- Medical Physics Unit, McGill University, Montreal, QC H4A3J1, Canada.
| | - G Famulari
- Medical Physics Unit, McGill University, Montreal, QC H4A3J1, Canada
| | - L Montgomery
- Medical Physics Unit, McGill University, Montreal, QC H4A3J1, Canada
| | - J Kildea
- Medical Physics Unit, McGill University, Montreal, QC H4A3J1, Canada
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16
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Abstract
This chapter introduces this topic for the whole volume. It is not a review, rather it presents the basics, the key considerations and forward references to the other chapters. This starts by setting the scene of principles and overall strategy, moves onto planning an experiment including its feasibility and then outlines practicalities with options for the experiment. The crystal structure that results will lead to publication and associated with it, Protein Data Bank deposition.
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17
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Izadi Vasafi G, Firoozabadi MM. 10B Concentration, Phantom Size and Tumor Location Dependent Dose Enhancement and Neutron Spectra in Boron Neutron Capture Therapy. J Biomed Phys Eng 2019; 9:653-660. [PMID: 32039096 PMCID: PMC6943846 DOI: 10.31661/jbpe.v0i0.799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 07/23/2017] [Indexed: 12/02/2022]
Abstract
Background: The amount of average dose enhancement in tumor loaded with 10B may vary due to various factors in boron neutron capture therapy Objective: This study aims to evaluate dose enhancement in tumor loaded with 10B under influence of various factors and investigate the dependence of this dose enhancement on neutron spectra changes Material and Methods: In this simulation study, using 252Cf as a neutron source, the average in-tumor dose enhancement factor (DEF) and neutron energy spectra were calculated for various 10B concentrations, phantom with different sizes and for different tumor locations, through MCNPX code. Results: Obtained results showed that the values of average DEF rise with increasing 10B concentration, phantom diameter (˂ 30 cm) and tumor distance from the source, but this increment is not linear Conclusion: It was concluded that inequality in average dose enhancement rates, in tumor loaded with 10B under influence of various factors in boron neutron capture therapy, is due to non-identical changes of both the thermal neutron flux with increasing same number of 10B atoms and same thickness of scattering material, and the thermal to fast neutron flux ratio with increasing equal distances of tumor from the source
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Affiliation(s)
- Gh Izadi Vasafi
- PhD, Department of Physics, Faculty of Sciences, University of Birjand, Birjand, Iran
| | - M M Firoozabadi
- PhD, Department of Physics, Faculty of Sciences, University of Birjand, Birjand, Iran
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18
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J J B, S M J M. Poor Understanding of Radiation Profiles in Deep Space Causes Inaccurate Findings and Misleading Conclusions. J Biomed Phys Eng 2019; 9:587-588. [PMID: 31750273 PMCID: PMC6820022 DOI: 10.31661/jbpe.v0i0.1021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/20/2018] [Indexed: 11/16/2022]
Abstract
The radiation environment in deep space, where astronauts are behind the shelter provided by the Earth's magnetosphere, is a major health concern. Galactic cosmic rays (GCR) and solar particle events (SPE) are two basic sources of space radiation in the solar system. The health risks of exposure to high levels of space radiation can be observed either as acute and delayed effects. Zhang et al. in their recently published paper entitled "γ-H2AX responds to DNA damage induced by long-term exposure to combined low-dose-rate neutron and γ-ray radiation" have addressed the effects of different cumulative radiation doses on peripheral blood cell, subsets of T cells of peripheral blood lymphocytes and DNA damage repair. These researchers exposed animals to low dose rate 60Co-rays at 0.0167 Gy h-1for 2 h/d and 252Cf neutrons at 0.028 mGy h-1for 20 h/d for 15, 30, or 60 consecutive days. They reported that the mRNA of H2AX increased significantly, and showed a positive correlation with dose. Despite strengths, this paper has several shortcomings such as poor definition of low dose radiation as well as space and reactor radiation environments. Another shortcoming of this paper comes from this point that blood cell studies do not represent the biological effects of ionizing radiation on the total body. Moreover, the effects of the human immune system and DNA repair mechanisms are not included in the study. The role of pre-exposures and induction of adaptive response phenomena in decreasing the risk of radiation in deep space missions are also ignored.
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Affiliation(s)
- Bevelacqua J J
- PhD,Bevelacqua Resources, 343 Adair Drive, Richland, WA 99352, USA
| | - Mortazavi S M J
- PhD,Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
- PhD, Diagnostic Imaging Department, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
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19
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Lad J, Rusin A, Seymour C, Mothersill C. An investigation into neutron-induced bystander effects: How low can you go? Environ Res 2019; 175:84-99. [PMID: 31108356 DOI: 10.1016/j.envres.2019.04.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/28/2019] [Accepted: 04/29/2019] [Indexed: 06/09/2023]
Abstract
Neutron radiation is very harmful to both individual organisms and the environment. A n understanding of all aspects of both direct and indirect effects of radiation is necessary to accurately assess the risk of neutron radiation exposure. This review seeks to review current evidence in the literature for radiation-induced bystander effects and related effects attributable to neutron radiation. It also attempts to determine if the suggested evidence in the literature is sufficient to justify claims that neutron-based radiation can cause radiation-induced bystander effects. Lastly, the present paper suggests potential directions for future research concerning neutron radiation-induced bystander effects. Data was collected from studies investigating radiation-induced bystander effects and was used to mathematically generate pooled datasets and putative trends; this was done to potentially elucidate both the appearance of a conventional trend for radiation-induced bystander effects in studies using different types of radiation. Furthermore, literature review was used to compare studies utilizing similar tissue models to determine if neutron effects follow similar trends as those produced by electromagnetic radiation. We conclude that the current understanding of neutron-attributable radiation-induced bystander effects is incomplete. Various factors such as high gamma contamination during the irradiations, unestablished thresholds for gamma effects, different cell lines, energies, and different dose rates affected our ability to confirm a relationship between neutron irradiation and RIBE, particularly in low-dose regions below 100 mGy. It was determined through meta-analysis of the data that effects attributable to neutrons do seem to exist at higher doses, while gamma effects seem likely predominant at lower dose regions. Therefore, whether neutrons can induce bystander effects at lower doses remains unclear. Further research is required to confirm these findings and various recommendations are made to assist in this effort. With these recommendations, we hope that research conducted in the future will be better equipped to explore the indirect effects of neutron radiation as they pertain to biological and ecological phenomena.
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Affiliation(s)
- Jigar Lad
- Department of Physics and Astronomy, McMaster University, Hamilton, Canada.
| | - Andrej Rusin
- Department of Biology, McMaster University, Hamilton, Canada
| | - Colin Seymour
- Department of Biology, McMaster University, Hamilton, Canada
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20
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Torres-Cortés CO, Hernández-Adame L, Baltazar-Raigosa A, Vega-Carrillo HR, Rodríguez-López JL, Pérez-Arrieta ML. Synthesis and thermoluminescent response to γ-rays and neutrons of MgB 4O 7:Dy and MgB 4O 7:Dy,Na. Appl Radiat Isot 2019; 147:159-164. [PMID: 30878777 DOI: 10.1016/j.apradiso.2019.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 11/27/2022]
Abstract
MgB4O7 doped with rare earths and alkaline elements has been reported as a good TLD because of its high sensitivity, effective atomic number close to that of biological tissue and low fading. In this work, thermoluminescent matrices were synthesized of MgB4O7:Dy and MgB4O7:Dy, Na to evaluate their thermoluminescent response (TL) when exposed to γ-rays and neutrons. The amount of Dy was studied in a concentration range of 0.01-1.5 mol% of total doping, while for Na the concentration of 0.5 mol% was established to determine the TL response as a function of doping. The synthesis of the powders was carried out by the method of wet reaction assisted by heat treatment and the samples were characterized by techniques of scanning electron microscopy and X-ray diffraction to determine the size of grain and crystallographic phase. For the dosimetric study, thermoluminescent phosphors were irradiated with a source of 137Cs at an estimated dose 6.8 ± 0.4 mGy to evaluate their response to γ-rays exposure, while for neutrons a source of 241AmBe was used (estimated dose of 3.1 ± 0.1 mGy). The thermoluminescent responses are similar for all materials exposed to γ-rays as for neutrons, the differences are shown to 280 °C, where a peak of high temperature is observed in materials exposed to neutrons.
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Affiliation(s)
- Carina Oliva Torres-Cortés
- Programa de Doctorado en Ingeniería y Tecnología Aplicada, Unidad Academica de Ingeniería Eléctrica de la Universidad Autónoma de Zacatecas, Av. Ramón López Velarde No. 801, Col. Centro, 98000, Zacatecas, Zac, Mexico
| | - Luis Hernández-Adame
- CONACyT-Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Instituto Politécnico Nacional No. 195, Playa Palo de Santa Rita Sur, 23090, La Paz, B.C.S, Mexico
| | - Antonio Baltazar-Raigosa
- Programa de Doctorado en Ingeniería y Tecnología Aplicada, Unidad Academica de Ingeniería Eléctrica de la Universidad Autónoma de Zacatecas, Av. Ramón López Velarde No. 801, Col. Centro, 98000, Zacatecas, Zac, Mexico
| | - Hector Rene Vega-Carrillo
- Programa de Doctorado en Ingeniería y Tecnología Aplicada, Unidad Academica de Ingeniería Eléctrica de la Universidad Autónoma de Zacatecas, Av. Ramón López Velarde No. 801, Col. Centro, 98000, Zacatecas, Zac, Mexico; Unidad Académica de Estudios Nucleares de la Universidad Autónoma de Zacatecas, C. Ciprés No. 10, Fracc. La Peñuela, 98060, Zacatecas, Zac, Mexico.
| | - José Luis Rodríguez-López
- Advanced Materials Department, Instituto Potosino de Investigación Científica y Tecnológica, A.C., Camino a la Presa San José, 2055, Lomas 4(a) Seccion, 78216, San Luís Potosí, Mexico
| | - María L Pérez-Arrieta
- Unidad Académica de Física de la Universidad Autónoma de Zacatecas, C. Solidaridad, Col. Hidráulica, 98068, Zacatecas, Zac, Mexico
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21
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Haddad K, Anjak O, Yousef B. Neutron and high energy photon fluence estimation in CLINAC using gold activation foils. Rep Pract Oncol Radiother 2018; 24:41-46. [PMID: 30337847 DOI: 10.1016/j.rpor.2018.08.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/05/2018] [Accepted: 08/31/2018] [Indexed: 10/28/2022] Open
Abstract
Aim The thermal neutron, epithermal neutron and high-energy photon fluence were measured in this work around the Varian 21EX 23 MV CLINAC, which is operated in Albairouni hospital in Damascus, Syria. Background Photoneutron measurements around medical CLINAC aim to protect both patients and staff from unwanted radiation. Materials and methods Neutron and photon activation techniques were applied using gold foils. Results It was found that high-energy photons fluence has practically a constant value in the field size. The thermal and epithermal neutron fluence along ox and oy axes has the same order of magnitude. Conclusion Gold foils have been used successfully to measure neutron flux and high-energy photons simultaneously using activation techniques.
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Affiliation(s)
- Kh Haddad
- Protection & Safety Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria
| | - O Anjak
- Protection & Safety Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria
| | - B Yousef
- Protection & Safety Department, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria
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Manjunatha HC, Seenappa L, B M C, Sridhar KN, Hanumantharayappa C. Gamma, X-ray and neutron shielding parameters for the Al-based glassy alloys. Appl Radiat Isot 2018; 139:187-194. [PMID: 29803140 DOI: 10.1016/j.apradiso.2018.05.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 11/29/2022]
Abstract
The X-ray and gamma radiation shielding parameters (mass attenuation coefficient, mean free path, half value layer, tenth value layer, effective atomic numbers, electron density, exposure buildup factors, relative dose, dose rate and specific gamma ray constant) have been studied for the Al-based glassy alloys Al86Y7Ni5Co1Fe0.5Pd0.5, Al85Y8Ni5Co1Fe0.5Pd0.5, Al84Y9Ni4Co1.5Fe0.5Pd1, Al80Y13Ni5Co1Fe0.5Pd0.5, Al70Y23Ni5Co1Fe0.5Pd0.5 and Al60Y33Ni5Co1Fe0.5Pd0.5. For the same alloys, the neutron shielding parameters (coherent neutron scattering length, incoherent neutron scattering lengths, coherent neutron scattering cross section, incoherent neutron scattering cross sections, total neutron scattering cross section and neutron absorption cross sections) have also been explored. Al60Y33Ni5Co1Fe0.5Pd0.5 was found to be a good shielding material for the X-ray/gamma radiation, while Al86Y7Ni5Co1Fe0.5Pd0.5 is a good shielding material for neutrons.
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Affiliation(s)
- H C Manjunatha
- Department of Physics, Government College for Women, Kolar 563101, Karnataka, India.
| | - L Seenappa
- Department of Physics, Government College for Women, Kolar 563101, Karnataka, India; Research and Development Centre, Bharathiar University, Coimbatore 641046, TamilNadu, India
| | - Chandrika B M
- Research and Development Centre, Bharathiar University, Coimbatore 641046, TamilNadu, India; Shravana, #592, Ist Cross, PC Extension, Kolar 563101, Karnataka, India
| | - K N Sridhar
- Department of Physics, Government First Grade College, Kolar 563101, Karnataka, India
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Tran V, Little MP. Dose and dose rate extrapolation factors for malignant and non-malignant health endpoints after exposure to gamma and neutron radiation. Radiat Environ Biophys 2017; 56:299-328. [PMID: 28939964 DOI: 10.1007/s00411-017-0707-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 08/06/2017] [Indexed: 06/07/2023]
Abstract
Murine experiments were conducted at the JANUS reactor in Argonne National Laboratory from 1970 to 1992 to study the effect of acute and protracted radiation dose from gamma rays and fission neutron whole body exposure. The present study reports the reanalysis of the JANUS data on 36,718 mice, of which 16,973 mice were irradiated with neutrons, 13,638 were irradiated with gamma rays, and 6107 were controls. Mice were mostly Mus musculus, but one experiment used Peromyscus leucopus. For both types of radiation exposure, a Cox proportional hazards model was used, using age as timescale, and stratifying on sex and experiment. The optimal model was one with linear and quadratic terms in cumulative lagged dose, with adjustments to both linear and quadratic dose terms for low-dose rate irradiation (<5 mGy/h) and with adjustments to the dose for age at exposure and sex. After gamma ray exposure there is significant non-linearity (generally with upward curvature) for all tumours, lymphoreticular, respiratory, connective tissue and gastrointestinal tumours, also for all non-tumour, other non-tumour, non-malignant pulmonary and non-malignant renal diseases (p < 0.001). Associated with this the low-dose extrapolation factor, measuring the overestimation in low-dose risk resulting from linear extrapolation is significantly elevated for lymphoreticular tumours 1.16 (95% CI 1.06, 1.31), elevated also for a number of non-malignant endpoints, specifically all non-tumour diseases, 1.63 (95% CI 1.43, 2.00), non-malignant pulmonary disease, 1.70 (95% CI 1.17, 2.76) and other non-tumour diseases, 1.47 (95% CI 1.29, 1.82). However, for a rather larger group of malignant endpoints the low-dose extrapolation factor is significantly less than 1 (implying downward curvature), with central estimates generally ranging from 0.2 to 0.8, in particular for tumours of the respiratory system, vasculature, ovary, kidney/urinary bladder and testis. For neutron exposure most endpoints, malignant and non-malignant, show downward curvature in the dose response, and for most endpoints this is statistically significant (p < 0.05). Associated with this, the low-dose extrapolation factor associated with neutron exposure is generally statistically significantly less than 1 for most malignant and non-malignant endpoints, with central estimates mostly in the range 0.1-0.9. In contrast to the situation at higher dose rates, there are statistically non-significant decreases of risk per unit dose at gamma dose rates of less than or equal to 5 mGy/h for most malignant endpoints, and generally non-significant increases in risk per unit dose at gamma dose rates ≤5 mGy/h for most non-malignant endpoints. Associated with this, the dose-rate extrapolation factor, the ratio of high dose-rate to low dose-rate (≤5 mGy/h) gamma dose response slopes, for many tumour sites is in the range 1.2-2.3, albeit not statistically significantly elevated from 1, while for most non-malignant endpoints the gamma dose-rate extrapolation factor is less than 1, with most estimates in the range 0.2-0.8. After neutron exposure there are non-significant indications of lower risk per unit dose at dose rates ≤5 mGy/h compared to higher dose rates for most malignant endpoints, and for all tumours (p = 0.001), and respiratory tumours (p = 0.007) this reduction is conventionally statistically significant; for most non-malignant outcomes risks per unit dose non-significantly increase at lower dose rates. Associated with this, the neutron dose-rate extrapolation factor is less than 1 for most malignant and non-malignant endpoints, in many cases statistically significantly so, with central estimates mostly in the range 0.0-0.2.
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Affiliation(s)
- Van Tran
- Radiation Epidemiology Branch, National Cancer Institute, Medical Center Drive 9609, MSC 9778, Rockville, MD, 20892-9778, USA
| | - Mark P Little
- Radiation Epidemiology Branch, National Cancer Institute, Medical Center Drive 9609, MSC 9778, Rockville, MD, 20892-9778, USA.
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24
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Zanini A, Ciancio V, Laurenza M, Storini M, Esposito A, Terrazas JC, Morfino P, Liberatore A, Di Giovan G. Environmental radiation dosimetry at Argentine Antarctic Marambio Base (64° 13' S, 56° 43' W): preliminary results. J Environ Radioact 2017; 175-176:149-157. [PMID: 28544977 DOI: 10.1016/j.jenvrad.2017.04.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/11/2017] [Indexed: 06/07/2023]
Abstract
The preliminary results obtained in the first environmental radiation dosimetry campaign performed in the Antarctic region are presented. This experiment is carried out in the framework of CORA (COsmic Rays in Antarctica) Project, a collaboration between Argentine and Italian institutions. After a feasibility study performed in the Antarctic summer 2013, a new campaign has been carried out, started in March 2015, to measure various components of cosmic ray induced secondary atmospheric radiation at the Argentine Marambio Base (Antarctica; 196 m a.s.l., 64°13' S, 56°43' W). Due to a very few dosimetric data available in literature at high southern latitudes, accurate measurements are performed by using a set of different active and passive detectors. Special attention is dedicated to measure the neutron ambient dose equivalent in different energy ranges, by using an active detector, the Atomtex Rem Counter, for neutron energy between 0.025 eV-14 MeV and a set of passive bubble dosimeters, sensitive to thermal neutrons and neutrons in the energy range 100 keV-20 MeV. The results obtained in the first six months of measurements for X and γ radiation and for low and intermediate energy neutrons (En ≤ 20 MeV) are presented in this paper and show that at high latitude, also at sea level and at distance from the South Magnetic Pole, the ambient dose equivalent is significant, in particular for the high contribution of neutron component. This involves that at higher altitude (i.e. Antarctic Plateau, over 3000 m a.s.l.) the yearly ambient dose equivalent could be higher than the limit of 1 mSv recommended for general public by the International Commission on Radiological Protection (ICRP).
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Affiliation(s)
- Alba Zanini
- INFN Sez. Torino, Via P. Giuria 1, 10125 Torino, Italy.
| | - Vicente Ciancio
- Università National de La Plata, Avenida 7776, 1900 La Plata, Argentina
| | - Monica Laurenza
- IAPS-INAF, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | - Marisa Storini
- IAPS-INAF, Via del Fosso del Cavaliere 100, 00133 Roma, Italy
| | | | | | - Paolo Morfino
- Efesto S.a.r.l, 55 Avenue Marceau, 75116 Paris 1, France
| | - Alessandro Liberatore
- Università degli studi di Torino, Dipartimento di Fisica, Via P. Giuria, 10125 Torino, Italy
| | - Gustavo Di Giovan
- Università National de La Plata, Avenida 7776, 1900 La Plata, Argentina
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Auditore L, Amato E, Baldari S. Theoretical estimation of 64Cu production with neutrons emitted during 18F production with a 30MeV medical cyclotron. Appl Radiat Isot 2017; 122:229-234. [PMID: 28209500 DOI: 10.1016/j.apradiso.2017.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/13/2017] [Accepted: 02/02/2017] [Indexed: 10/20/2022]
Abstract
PURPOSE This work presents the theoretical estimation of a combined production of 18F and 64Cu isotopes for PET applications. 64Cu production is induced in a secondary target by neutrons emitted during a routine 18F production with a 30MeV cyclotron: protons are used to produce 18F by means of the 18O(p,n)18F reaction on a [18O]-H2O target (primary target) and the emitted neutrons are used to produce 64Cu by means of the 64Zn(n,p)64Cu reaction on enriched zinc target (secondary target). METHODS Monte Carlo simulations were carried out using Monte Carlo N Particle eXtended (MCNPX) code to evaluate flux and energy spectra of neutrons produced in the primary (Be+[18O]-H2O) target by protons and the attenuation of neutron flux in the secondary target. 64Cu yield was estimated using an analytical approach based on both TENDL-2015 data library and experimental data selected from EXFOR database. RESULTS Theoretical evaluations indicate that about 3.8 MBq/μA of 64Cu can be obtained as a secondary, 'side' production with a 30MeV cyclotron, for 2h of irradiation of a proper designed zinc target. Irradiating for 2h with a proton current of 120 μA, a yield of about 457 MBq is expected. Moreover, the most relevant contaminants result to be 63,65Zn, which can be chemically separated from 64Cu contrarily to what happens with proton irradiation of an enriched 64Ni target, which provides 64Cu mixed to other copper isotopes as contaminants. CONCLUSIONS The theoretical study discussed in this paper evaluates the potential of the combined production of 18F and 64Cu for medical purposes, irradiating a properly designed target with 30MeV protons. Interesting yields of 64Cu are obtainable and the estimation of contaminants in the irradiated zinc target is discussed.
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Affiliation(s)
- Lucrezia Auditore
- Nuclear Medicine Unit, University Hospital "G. Martino", Messina, Italy; INFN - Istituto Nazionale di Fisica Nucleare, Messina, Italy.
| | - Ernesto Amato
- INFN - Istituto Nazionale di Fisica Nucleare, Messina, Italy; Section of Radiological Sciences, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
| | - Sergio Baldari
- Nuclear Medicine Unit, University Hospital "G. Martino", Messina, Italy; Section of Radiological Sciences, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
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Abstract
SAS is a powerful technique to investigate oligomeric state and domain organization of macromolecules, e.g. proteins and nucleic acids, under physiological, functional and even time resolved conditions. However, reconstructing three dimensional structures from SAS data is inherently ambiguous, as no information about orientation and phase is available. In addition experimental artifacts such as radiation damage, concentration effects and incorrect background subtraction can hinder the interpretation of even lead to wrong results. In this chapter, explanations on how to analyze data and how to assess and minimize the influence of experimental artifacts on the data. Furthermore, guidelines on how to present the resulting data and models to demonstrate the data supports the conclusion being made and that it is not biased by artifacts, will be given.
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27
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Hernández-Adame PL, Medina-Castro D, Rodriguez-Ibarra JL, Salas-Luevano MA, Vega-Carrillo HR. Design of an explosive detection system using Monte Carlo method. Appl Radiat Isot 2016; 117:27-31. [PMID: 27102306 DOI: 10.1016/j.apradiso.2016.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 04/03/2016] [Accepted: 04/11/2016] [Indexed: 10/21/2022]
Abstract
Regardless the motivation terrorism is the most important risk for the national security in many countries. Attacks with explosives are the most common method used by terrorists. Therefore several procedures to detect explosives are utilized; among these methods are the use of neutrons and photons. In this study the Monte Carlo method an explosive detection system using a 241AmBe neutron source was designed. In the design light water, paraffin, polyethylene, and graphite were used as moderators. In the work the explosive RDX was used and the induced gamma rays due to neutron capture in the explosive was estimated using NaI(Tl) and HPGe detectors. When light water is used as moderator and HPGe as the detector the system has the best performance allowing distinguishing between the explosive and urea. For the final design the Ambient dose equivalent for neutrons and photons were estimated along the radial and axial axis.
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Affiliation(s)
- Pablo Luis Hernández-Adame
- Unidad Académica de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Ciprés, 10, 98068 Zacatecas, Zac., Mexico.
| | - Diego Medina-Castro
- Unidad Académica de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Ciprés, 10, 98068 Zacatecas, Zac., Mexico
| | | | - Miguel Angel Salas-Luevano
- Unidad Académica de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Ciprés, 10, 98068 Zacatecas, Zac., Mexico
| | - Hector Rene Vega-Carrillo
- Unidad Académica de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Ciprés, 10, 98068 Zacatecas, Zac., Mexico
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28
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Abstract
Plasma experiments conducted on the PF-1000 device generate the release of neutrons and ionizing radiation that are the source of immediate exposure to personnel. Neutron activation of materials in the research device and the surroundings is a source of ongoing radiation exposure to the same personnel. Having reported on personnel exposure from ionizing radiation and neutron activation, we now aim to characterize exposure from direct neutron emission generated by the device, and describe the process of ensuring measurement accuracy.
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Affiliation(s)
- Kamil Szewczak
- Central Laboratory for Radiological Protection, Konwaliowa 7, 03-194 Warsaw, Poland
| | - Slawomir Jednorog
- Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw, Poland
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29
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Tavakoli MB, Mohammadi MM, Reiazi R, Jabbari K. Evaluation on Geant4 Hadronic Models for Pion Minus, Pion Plus and Neutron Particles as Major Antiproton Annihilation Products. J Med Signals Sens 2015; 5:105-9. [PMID: 26120569 PMCID: PMC4460664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 02/18/2015] [Indexed: 11/29/2022]
Abstract
Geant4 is an open source simulation toolkit based on C++, which its advantages progressively lead to applications in research domains especially modeling the biological effects of ionizing radiation at the sub-cellular scale. However, it was shown that Geant4 does not give a reasonable result in the prediction of antiproton dose especially in Bragg peak. One of the reasons could be lack of reliable physic model to predict the final states of annihilation products like pions. Considering the fact that most of the antiproton deposited dose is resulted from high-LET nuclear fragments following pion interaction in surrounding nucleons, we reproduced depth dose curves of most probable energy range of pions and neutron particle using Geant4. We consider this work one of the steps to understand the origin of the error and finally verification of Geant4 for antiproton tracking. Geant4 toolkit version 9.4.6.p01 and Fluka version 2006.3 were used to reproduce the depth dose curves of 220 MeV pions (both negative and positive) and 70 MeV neutrons. The geometry applied in the simulations consist a 20 × 20 × 20 cm(3) water tank, similar to that used in CERN for antiproton relative dose measurements. Different physic lists including Quark-Gluon String Precompound (QGSP)_Binary Cascade (BIC)_HP, the recommended setting for hadron therapy, were used. In the case of pions, Geant4 resulted in at least 5% dose discrepancy between different physic lists at depth close to the entrance point. Even up to 15% discrepancy was found in some cases like QBBC compared to QGSP_BIC_HP. A significant difference was observed in dose profiles of different Geant4 physic list at small depths for a beam of pions. In the case of neutrons, large dose discrepancy was observed when LHEP or LHEP_EMV lists were applied. The magnitude of this dose discrepancy could be even 50% greater than the dose calculated by LHEP (or LHEP_EMV) at larger depths. We found that effect different Geant4 physic list in reproducing depth dose profile of the beam of pions was not negligible. Because the discrepancies were pronounced in smaller depth and also regarding the contribution of pions in deposited dose of a beam of antiproton, further investigation on choosing most suitable and accurate physic list for this purpose should be done. Furthermore, this study showed careful attention must be paid to choose the appropriate Geant4 physic list for neutron tracking depending to the applications criteria. We failed to find any agreement between results from Geant4 and Fluka to reproduce depth dose profile of pion with the energy range used in this study.
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Affiliation(s)
| | | | - Reza Reiazi
- Department of Medical Physics, Isfahan University of Medical Sciences, Isfahan, Iran,Address for correspondence: Dr. Reza Reiazi, Department of Medical Physics, Isfahan University of Medical Sciences, Hezar Jarib Avenue, Isfahan, Iran. E-mail:
| | - Keyvan Jabbari
- Department of Medical Physics, Isfahan University of Medical Sciences, Isfahan, Iran
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Dawidowska A, Ferszt MP, Konefał A. The determination of a dose deposited in reference medium due to (p,n) reaction occurring during proton therapy. Rep Pract Oncol Radiother 2014; 19:S3-S8. [PMID: 28443192 DOI: 10.1016/j.rpor.2014.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 11/15/2013] [Accepted: 02/27/2014] [Indexed: 10/25/2022] Open
Abstract
AIM The aim of the investigation was to determine the undesirable dose coming from neutrons produced in reactions (p,n) in irradiated tissues represented by water. BACKGROUND Production of neutrons in the system of beam collimators and in irradiated tissues is the undesirable phenomenon related to the application of protons in radiotherapy. It makes that proton beams are contaminated by neutrons and patients receive the undesirable neutron dose. MATERIALS AND METHODS The investigation was based on the Monte Carlo simulations (GEANT4 code). The calculations were performed for five energies of protons: 50 MeV, 55 MeV, 60 MeV, 65 MeV and 75 MeV. The neutron doses were calculated on the basis of the neutron fluence and neutron energy spectra derived from simulations and by means of the neutron fluence-dose conversion coefficients taken from the ICRP dosimetry protocol no. 74 for the antero-posterior irradiation geometry. RESULTS The obtained neutron doses are much less than the proton ones. They do not exceed 0.1%, 0.4%, 0.5%, 0.6% and 0.7% of the total dose at a given depth for the primary protons with energy of 50 MeV, 55 MeV, 60 MeV, 65 MeV and 70 MeV, respectively. CONCLUSIONS The neutron production takes place mainly along the central axis of the beam. The maximum neutron dose appears at about a half of the depth of the maximum proton dose (Bragg peak), i.e. in the volume of a healthy tissue. The doses of neutrons produced in the irradiated medium (water) are about two orders of magnitude less than the proton doses for the considered range of energy of protons.
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Affiliation(s)
- Anna Dawidowska
- Department of Nuclear Physics and Its Applications, Institute of Physics, University of Silesia, Katowice, Poland
| | - Monika Paluch Ferszt
- Department of Nuclear Physics and Its Applications, Institute of Physics, University of Silesia, Katowice, Poland
| | - Adam Konefał
- Department of Nuclear Physics and Its Applications, Institute of Physics, University of Silesia, Katowice, Poland
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Khatchadourian R, Davis S, Evans M, Licea A, Seuntjens J, Kildea J. Sci-Sat AM: Brachy - 04: Neutron production around a radiation therapy linac bunker - monte carlo simulations and physical measurements. Med Phys 2012; 39:4645. [PMID: 28516634 DOI: 10.1118/1.4740211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Photoneutrons are a major component of the equivalent dose in the maze and near the door of linac bunkers. Physical measurements and Monte Carlo (MC) calculations of neutron dose are key for validating bunker design with respect to health regulations. We attempted to use bubble detectors and a 3 He neutron spectrometer to measure neutron equivalent dose and neutron spectra in the maze and near the door of one of our bunkers. We also ran MC simulations with MCNP5 to measure the neutron fluence in the same region. Using a point source of neutrons, a Clinac 1800 linac operating at 10 MV was simulated and the fluence measured at various locations of interest. We describe the challenges faced when measuring dose with bubble detectors in the maze and the complexity of photoneutron spectrometry with linacs operating in pulsed mode. Finally, we report on the development of a userfriendly GUI for shielding calculations based on the NCRP 151 formalism.
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Affiliation(s)
| | - S Davis
- McGill University Health Center, Montreal, QC
| | - M Evans
- McGill University, Montreal, QC.,McGill University Health Center, Montreal, QC
| | - A Licea
- Canadian Nuclear Safety Commission - CNSC, Ottawa, ON
| | - J Seuntjens
- McGill University, Montreal, QC.,McGill University Health Center, Montreal, QC
| | - J Kildea
- McGill University Health Center, Montreal, QC
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32
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Spink R, Burmeister J, Bossenberger T, Snyder M. SU-E-T-573: Quality and Deliverability of Intensity Modulated Neutron Radiotherapy (IMNRT) Plans. Med Phys 2012; 39:3837. [PMID: 28517080 DOI: 10.1118/1.4735662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Intensity Modulated Neutron Radiotherapy (IMNRT) has been commissioned for clinical use. The number of allowable segments in IMNRT plans is limited by MLC speed. Quality and deliverability of static IMNRT treatment plans using the TG-119 test suite were evaluated to establish guidelines for the number of segments per plan. METHODS Treatment plans were created and optimized to specified constraints for all cases in the TG-119 test suite using the Varian Eclipse TPS. A 4MV photon beam with similar penetration characteristics as the fast neutron beam was used as a surrogate for this optimization. Final dose calculations were performed using an in-house TPS commissioned for neutron dose calculations. Following optimization, MLC segments were created for three ranges of total plan complexity - very limited (15-23 segments), limited (24- 31 segments), and unlimited. Calculated DVHs were then compared for compliance with TG-119 dose constraints. The estimated time of delivery for plans in each range was calculated based on known delivery parameters. RESULTS The prostate case passes all constraints for each complexity level. All other plans fail to meet at least one constraint for one or more of the complexity levels. For all cases combined, the very limited, limited, and unlimited complexity levels meet 16, 17, and 19 of 23 total dose constraints, respectively. The mean estimated delivery time for the very limited, limited, and unlimited plans is 34 minutes (range: 27-39), 40 minutes (range: 34-45), and 68 minutes (range: 53-81) respectively, neglecting any delay due to therapists entering the treatment room. CONCLUSION IMNRT plan quality is limited by current MLC capabilities. IMNRT plans should be limited to 25 segments to ensure a reasonable treatment time of 45 minutes. Even with this small number of segments, we were able to meet most dose constraints set forth in TG-119.
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Affiliation(s)
- R Spink
- Karmanos Cancer Center, Detroit, MI.,Wayne State University School of Medicine, Detroit, MI
| | - J Burmeister
- Karmanos Cancer Center, Detroit, MI.,Wayne State University School of Medicine, Detroit, MI
| | - T Bossenberger
- Karmanos Cancer Center, Detroit, MI.,Wayne State University School of Medicine, Detroit, MI
| | - M Snyder
- Karmanos Cancer Center, Detroit, MI.,Wayne State University School of Medicine, Detroit, MI
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33
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Sánchez-Nieto B, Expósito MR, Terrón JA, Paiusco M, Cagni E, Ghetti C, Filice S, Grishchuk D, Mateos JC, Roselló J, Planes D, Nã Ñez L, Sánchez-Doblado F. SU-E-T-466: TCP and NTCP: Is That All? Med Phys 2012; 39:3812. [PMID: 28517456 DOI: 10.1118/1.4735555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Concerns about the secondary cancer risks associated to the peripheral neutron and photon contamination in photon modern radiotherapy (RT) techniques (e.g., Intensity Modulated RT -IMRT- or Intensity Modulated Arc Therapy -IMAT) have been widely raised. Benefits in terms of better tumor coverage have to be balanced against the drawbacks of poorer organ at risk sparing and secondary cancer risk in order to make the decision on the optimum treatment technique. The aim of this study was to develop a tool which estimates treatment success taking into consideration the neutron secondary cancer probability. METHODS A methodology and benchmark dataset for radiotherapy real time assessment of patient neutron dose and application to a novel digital detector (DD) has been carried out (submitted to PMB, 2011). Our DD provides real time neutron equivalent dose distribution in relevant organs along the patient. This information, together with TCP and NTCP estimated from the DVH of target and organs at risks, respectively, have been built into a general biological model which allows us to evaluate the success of the treatments (Sánchez-Nieto et al., ESTRO meeting 2012). This model has been applied to make estimation of treatment success in a variety of treatment techniques (3DCRT, forward and inverse IMRT, RapidArc, Volumetric Modulated Arc Therapy and Helical Tomotherapy) to low and high energy. RESULTS MU-demanding techniques at high energies were able to deliver treatment plans with the highest complicated-free tumour control. Nevertheless, neutron peripheral dose must be taken into consideration as the associated risk could be of the same order of magnitude than the usually considered NTCPs. CONCLUSIONS The methodology developed to provide an online organ neutron peripheral dose can be successfully combined with biological models to make predictions on treatment success taking into consideration secondary cancer risks.
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Affiliation(s)
- B Sánchez-Nieto
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - M R Expósito
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - J A Terrón
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - M Paiusco
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - E Cagni
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - C Ghetti
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - S Filice
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - D Grishchuk
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - J C Mateos
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - J Roselló
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - D Planes
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - L Nã Ñez
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
| | - F Sánchez-Doblado
- Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla, Spain.,Hospital Universitario Virgen Macarena, Sevilla, Spain.,Arcispedale S. Maria Nuova, Reggio Emilia, Italy.,Azienda Ospedaliero-Universitaria, Parma, Italy.,Russian Research Center for Radiology and Surgical Technology, Saint Petersburg, Russia.,Hospital Duques del Infantado, Sevilla, Spain.,ERESA, Valencia, Spain.,Departamento de Fisiología, Universidad de Valencia, Spain.,Servicio de Radiofísica, Hospital Puerta de Hierro, Majadahonda, Spain
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34
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Abstract
PURPOSE To examine the various processes involved and to assess their effects on the accuracy in proton therapy. METHODS Proton therapy involved several processes: (1) Beam commissioning. (2) CT scan of patient. (3) Contouring. (4) Treatment planning. (5) Output factor measurements for each field. (6) Patient setup verification with image guidance. (7) Dose delivery. (8) Neutron dose and proton RBE at the distal edge. Within each step, there are several sub-processes that each may contribute to the uncertainty in the treatment. By analyzing each of the subprocesseswithin each process, based on measurements or published data, we estimated a % uncertainty to each sub-process and/or a distance uncertainty (in millimeter) on the proton range. A total uncertainty in proton therapy is estimated. RESULTS The uncertainties assessed for the various processes are : (1) ±1.5%; (4) ±3.0%, and 1-3mm; (5) ±2.0%; (6) ±2 mm; (7) ±2.0%, ±2mm. The uncertainties in (2) CT, (3) contouring and neutron dose in (8) strongly depend on the location and type of the tumor. On the other hand, the proton RBE at the distal edge in (9) is still debatable and may affect the dose uncertainty from 0-20% depending on which value we want to accept. Thus the overall uncertainty in proton therapy is at least ±4.5% and ±4 mm (by adding the various uncertainties in quadrature), without consideration of processes (2), (3) and (8), and the RBE effect. CONCLUSIONS Due to the complexity in proton therapy and the various factors that may affect the accuracy in proton therapy, it is far more complicated to assess the accuracy in proton therapy. Our preliminary study showed that the accuracy in proton therapy is at least ± 4.5% in dose delivered to a tumor with an uncertainty of ±4mm to the distal edge of the SOBP.
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Affiliation(s)
- C Cheng
- Indiana University- School of Medicine, Bloomington, IN.,Indiana University Health Proton Therapy Center, Bloomington, IN
| | - L Zhao
- Indiana University- School of Medicine, Bloomington, IN.,Indiana University Health Proton Therapy Center, Bloomington, IN
| | - Q Zhao
- Indiana University- School of Medicine, Bloomington, IN.,Indiana University Health Proton Therapy Center, Bloomington, IN
| | - V Moskvin
- Indiana University- School of Medicine, Bloomington, IN.,Indiana University Health Proton Therapy Center, Bloomington, IN
| | - J Buchsbaum
- Indiana University- School of Medicine, Bloomington, IN.,Indiana University Health Proton Therapy Center, Bloomington, IN
| | - I Das
- Indiana University- School of Medicine, Bloomington, IN.,Indiana University Health Proton Therapy Center, Bloomington, IN
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35
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Biltekin F, Özyigit G, Celik D, Yeginer M, Akyol F, Cengiz M, Yildiz F. SU-E-T-208: The Secondary Malignancy Risk Estimation Due to the Neutron Contamination in 3D-CRT and IMRT Treatment Techniques by Using Bubble Detectors. Med Phys 2012; 39:3751. [PMID: 28517335 DOI: 10.1118/1.4735269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In this study, the neutron measurements were performed in free in air and RW3 solid water phantom to estimate the secondary malignancy risk for three dimensional conformal radiotherapy (3D-CRT) and intensity modulated radiotherapy (IMRT) techniques in prostate cancer treatment. METHODS Neutron dose were measured in 18 MV Elekta Synergy Platform and Varian Clinac linear accelerators by using bubble detector for personal neutron dosimetry (BD-PND). To determine the neutron equivalent dose in different depths and different distance from the edge of treatment field RW3 solid water phantom was used and organs location was defined in Alderson Rando phantom with respect to target (prostate) position in the treatment field. By using these data, we determined the neutron equivalent dose and effective dose for the standard prostate cancer patient treated with 3D-CRT and IMRT with 18 MV photon energy. The total dose was 70 Gy in 3D-CRT and 76 Gy in IMRT treatment in the current study. For both of these treatment techniques, we estimated the risk of secondary malignancies due to the neutron contamination by using the International Commission on Radiological Protection (ICRP) report 103. RESULTS The equivalent dose and effective dose due the neutron contamination were considerably high in 18 MV IMRT technique. The secondary malignancy risk estimation for 3D-CRT and IMRT were found to be 0.44% and 1.15% for Elekta Synergy Platform linear accelerator, 0.92% and 2.38% for the Varian Clinac DHX High Performance linear accelerator, respectively. CONCLUSIONS Therefore, one should take care of the secondary malignancy risk in case of using 18 MV in IMRT applications.
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36
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Subramani V, Singh M, Sharma S, Bisht R, Gopishankar N, Rath G. SU-E-T-268: Evaluation of Photoneutron Contamination in Elekta Synergy-S High-Energy Linear Accelerator and Indigenous Novel Solution: The AIIMS Experience. Med Phys 2012; 39:3765. [PMID: 28517258 DOI: 10.1118/1.4735335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The photoneutron contamination problem was encountered due to laminated barrier wall and short maze. The purpose of this study was to report our experience in evaluating the photoneutron contamination during radiation safety survey and solution. METHODS The photoneutron contamination measurement was carried out in Elekta Synergy-S high-energylinear accelerator for 15MV beam. A NE Neutron survey meter and for photon, Victoreen and RADOS survey meters were used. The laminated barrier wall composed of 37cm steel with 30cm concrete both side and short maze length of 5 meter. During safety survey, higher photoneutron levels for 15MV X-rays at treatment room door found. The effect of photoneutron contamination as function of neutron shielding materials of wood, polyethylene and boron and thickness, distance, locations and directions to the control console at distance upto 7 meter were investigated for 4 gantry angles at locations of treatment room entry doors namely door1(A), door2(B), console(C), conduit (D) and above-ceiling(G) for 15MV. RESULTS The initial safety survey showed that neutron level of 47mR/h and photon leakage of 3.2mR/hr at the treatment entry room door1. The neutron values could bring down to the level of acceptance at the treatment entry door2, but the photon values are not acceptable. Therefore, 30cm concrete wall block was made at the location of door2 and another bend was taken. Finally, treatment entrance room door was made using 3cm polyethylene neutron shielding materials in order to achieve the both neutron contamination and photon leakage within the acceptable levels. CONCLUSIONS The neutron sliding-door is operated manually in finger-push by technologist for day-to-day usage. This simple solution is cost effective and increases the patient throughput. This study underlines that one needs to take appropriate safety measures prior to facility design whenever the space constraints situations arises for high energy linear accelerator.
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Affiliation(s)
- V Subramani
- All India Institute of Medical Sciences (AIIMS), New Delhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, New Delhi.,All India Institute of Medical Sciences, New Delhi, New Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi
| | - M Singh
- All India Institute of Medical Sciences (AIIMS), New Delhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, New Delhi.,All India Institute of Medical Sciences, New Delhi, New Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi
| | - S Sharma
- All India Institute of Medical Sciences (AIIMS), New Delhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, New Delhi.,All India Institute of Medical Sciences, New Delhi, New Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi
| | - R Bisht
- All India Institute of Medical Sciences (AIIMS), New Delhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, New Delhi.,All India Institute of Medical Sciences, New Delhi, New Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi
| | - N Gopishankar
- All India Institute of Medical Sciences (AIIMS), New Delhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, New Delhi.,All India Institute of Medical Sciences, New Delhi, New Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi
| | - G Rath
- All India Institute of Medical Sciences (AIIMS), New Delhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi.,All India Institute of Medical Sciences, New Delhi.,All India Institute of Medical Sciences, New Delhi, New Delhi.,All India Institute of Medical Sciences, NewDelhi, Delhi
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37
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Riley K, Cascio E. SU-E-T-158: Neutron Damage of Power Electronics Used during Image Guidance in Proton Therapy. Med Phys 2012; 39:3739. [PMID: 28517804 DOI: 10.1118/1.4735216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE A series of measurements were performed in a clinical proton therapy beam to assess the sensitivity of silicon-based electronics in commercial x-ray generators to single event burnout from the secondary neutron background in proton therapy treatments. METHODS Failure rates were nondestructively measured in various metal oxide semiconductor field-effect transistors (MOSFETs) as a function of applied voltage using a dedicated test circuit board. Neutrons were produced by 230 MeV protons stopping in a brass beam target and high beam current was used to accelerate testing. Neutron fluences were measured by activation analysis of carbon and aluminum in both the test setup and in situ at the generator. Failure rates were determined by scaling results based on beam monitor output to the relevant neutron fluence rate. RESULTS Current pulses from the test board clearly indicated the onset of single event burnout without destroying the MOSFET. The neutron fluence measured on the test board was 4.3 ± 0.8×106 n cm-2 MU-1 and this is consistent with previous measurements. The MOSFET failure rate decreased rapidly with a reduction in the applied voltage and is 20-30 times lower in higher-rated components at the same voltage. Under nominal operating conditions the estimated failure rate is tens of failures per year for a generator 6m from the treatment position. CONCLUSION The sensitivity of x-ray generator power electronics to neutron-induced single-event burnout is significant and can affect the implementation of image-guided techniques for proton therapy. Strategies and system designs to mitigate this phenomenon are being investigated to help enable x-ray generators withstand the proton therapy environment. This research was supported by the NIH/NCI under grant number 6-PO1 CA 21239.
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Affiliation(s)
- K Riley
- Massachusetts General Hospital, Boston, MA
| | - E Cascio
- Massachusetts General Hospital, Boston, MA
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38
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Kim FH, Penumadu D, Hussey DS. Water Distribution Variation in Partially Saturated Granular Materials Using Neutron Imaging. J Geotech Geoenviron Eng 2012; 138:10.1061/(asce)gt.1943-5606.0000583. [PMID: 34916772 PMCID: PMC8672734 DOI: 10.1061/(asce)gt.1943-5606.0000583] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 06/16/2011] [Indexed: 05/27/2023]
Abstract
The use of neutron imaging is demonstrated for visualizing and quantifying water distribution in partially saturated granular porous media. Because of the unique difference in the total neutron cross sections of water, sand, and air, a significant contrast for the three phases is observed in a neutron transmission image, and a quantitative analysis provides detailed information on the arrangement and distribution of particles, voids, and water. The experiments in this study are performed at the Neutron Imaging Facility (NIF) at the National Institute of Standard and Technology (NIST). An amorphous silicon flat panel detector was used in this research with a spatial resolution of approximately 250 μm (127 μm/pixel). The effect of particle morphology on water distribution in compacted granular columns is investigated by using round and angular silica sand. Silica sand specimens with different bulk gravimetric water contents (0%, 6%, 9%, and 12%) are studied for evaluating the water phase-distribution spatially for compacted sand specimens in an aluminum cylinder.
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Affiliation(s)
- Felix H Kim
- Graduate Student, Dept. of Civil and Environmental Engineering, Univ. of Tennessee, Knoxville, TN 37996
| | - Dayakar Penumadu
- Fred Peebles Professor and Head, JIAM Chair of Excellence, Dept. of Civil and Environmental Engineering, Univ. of Tennessee, Knoxville, TN 37996
| | - Daniel S Hussey
- Physicist, National Institute of Standards and Technology, Gaithersburg, MD 20899
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39
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Howell RM, Kry SF, Burgett E, Hertel NE, Followill D. Erratum: "Secondary neutron spectra from modern Varian, Siemens, and Elekta linacs with multileaf collimators" [Med. Phys. 36(9), 4027-4038 (2009)]. Med Phys 2011; 38:6789. [PMID: 28525097 DOI: 10.1118/1.3658654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 10/18/2011] [Indexed: 11/07/2022] Open
Affiliation(s)
- Rebecca M Howell
- Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Stephen F Kry
- Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Eric Burgett
- Department of Nuclear and Radiological Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Nolan E Hertel
- Department of Nuclear and Radiological Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - David Followill
- Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
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40
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Sharma AC, Turkington TG, Tourassi GD, Floyd CE. Near-Field High-Energy Spectroscopic Gamma Imaging Using a Rotation Modulation Collimator. Nucl Instrum Methods Phys Res B 2008; 266:4938-47. [PMID: 26523076 PMCID: PMC4624206 DOI: 10.1016/j.nimb.2008.07.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Certain trace elements are vital to the body and elemental imbalances can be indicators of certain diseases including cancer and liver diseases. Neutron Stimulated Emission Computed Tomography (NSECT) is being developed as spectroscopic imaging technique to non-invasively and non-destructively measure and image elemental concentrations within the body. A region of interest is illuminated via a high-energy beam of neutrons that scatter inelastically with elemental nuclei within the body. The excited nuclei then relax by emitting characteristic gamma rays. Acquiring the gamma spectrum in a tomographic manner allows not only the identification of elements, but also the formation of images representing spatial distributions of specific elements. We are developing a high-energy position-sensitive gamma camera that allows full illumination of the entire region of interest. Because current scintillation crystal based position-sensitive gamma cameras operate in too low of an energy range, we are adapting high-energy gamma imaging techniques used in space-based imaging. A High Purity Germanium (HPGe) detector provides high-resolution energy spectra while a rotating modulation collimator (RMC) placed in front of the detector modulates the incoming signal to provide spatial information. The purpose of this manuscript is to describe the near-field RMC geometry, which varies greatly from the infinite-focus space-based applications, and how it modulates the incident gamma flux. A simple geometric model is presented and then used to reconstruct two-dimensional planar images of both simulated point sources and extended sources.
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Affiliation(s)
- Amy C. Sharma
- Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, NC 27705
- Department of Radiology, Duke University Medical Center, Durham, NC 27705
| | | | - Georgia D. Tourassi
- Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, NC 27705
- Department of Radiology, Duke University Medical Center, Durham, NC 27705
| | - Carey E. Floyd
- Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, NC 27705
- Department of Radiology, Duke University Medical Center, Durham, NC 27705
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41
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Abstract
Previous research has demonstrated that adding a very small gamma-ray dose to a small alpha radiation dose can completely suppress lung cancer induction by alpha radiation (a gamma-ray hormetic effect). Here we investigated the possibility of gamma-ray hormesis during low-dose neutron irradiation, since a small contribution to the total radiation dose from neutrons involves gamma rays. Using binucleated cells with micronuclei (micronucleated cells) among in vitro monoenergetic-neutron-irradiated human lymphocytes as a measure of residual damage, we investigated the influence of the small gamma-ray contribution to the dose on suppressing residual damage. We used residual damage data from previous experiments that involved neutrons with five different energies (0.22-, 0.44-, 1.5-, 5.9-, and 13.7-million electron volts [MeV]). Corresponding gamma-ray contributions to the dose were approximately 1%, 1%, 2%, 6%, and 6%, respectively. Total absorbed radiation doses were 0, 10, 50, and 100 mGy for each neutron source. We demonstrate for the first time a protective effect (reduced residual damage) of the small gamma-ray contribution to the neutron dose. Using similar data for exposure to gamma rays only, we also demonstrate a protective effect of 10 mGy (but not 50 or 100 mGy) related to reducing the frequency of micronucleated cells to below the spontaneous level.
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Affiliation(s)
| | - Bobby R. Scott
- Lovelace Respiratory Research Institute, Albuquerque, NM
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42
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Abstract
Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities NCRP Report No. 151, 2005, 246 pp. (Hardcover $100). National Council on Radiation Protection and Measurements, 7910 Woodmont Avenue, Suite 400, Bethesda, MD 20814-3095. ISBN-10 0-0929600-87-8; http://www.NCRPonline.org.
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