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Potential benefit of retrospective use of neutron monitors in improving ionising radiation exposure assessment on international flights: issues raised by neutron passive dosimeter measurements and EPCARD simulations during sudden changes in solar activity. Arh Hig Rada Toksikol 2020; 71:152-157. [PMID: 32975102 PMCID: PMC7968484 DOI: 10.2478/aiht-2020-71-3403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 06/01/2020] [Indexed: 11/20/2022] Open
Abstract
Since air transport became more accessible, more and more people have been exposed to ionising radiation of cosmic origin. Measuring the neutron dose equivalent is a good approximation of total ambient dose equivalent, as neutrons carry about 50 % of the dose at flight altitudes. The aim of our study was to compare our measurements of the neutron component of secondary cosmic radiation dose, taken with passive dosimeters, with the data obtained from a simulation generated by EPCARD software, which is common in assessing flight crew exposure to ionising radiation. We observed deviations (both above and below) from the expected proportion of the neutron component (between 40 and 80 %), which pointed to certain issues with actual passive dosimeter measurement and the EPCARD simulation. The main limitation of the dosimeter are large uncertainties in high energy neutron response, which may result in underestimation of neutron dose equivalent. The main drawback of the software simulation is monthly averaging of solar potential in calculations, which can neglect sporadic high energy events. Since airlines worldwide almost exclusively use software (due to costs and convenience) to estimate the dose received by their crew, it is advisable to retrospectively recalculate the dose taking into account neutron monitor readings when solar activity changes.
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Bakshi A, Pal R, Dawn S, Dhabekar B, Datta D. Measurement of environmental radiation and analysis of microdosimetric spectra of cosmic rays during the 35th expedition to Indian station Bharati, Antarctica. RADIAT MEAS 2019. [DOI: 10.1016/j.radmeas.2019.106122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Poje M, Vuković B, Radolić V, Miklavčić I, Planinić J. Neutron radiation measurements on several international flights. HEALTH PHYSICS 2015; 108:344-350. [PMID: 25627946 DOI: 10.1097/hp.0000000000000192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The earth is continually exposed to cosmic radiation of both solar and galactic origin. High-energy particles interact with the constituents in the atmosphere producing secondary particles that create radiation fields at aircraft altitudes. These secondary particles consist mainly of photons, protons, neutrons, charged and uncharged pions, and muons. The neutron component dominates the hadron cascade at lower altitudes as a result of its longer mean free path. Since air transportation has become more available to a greater number of people, this has led to an increase in the number of persons exposed to ionizing radiation of cosmic origin. This concerns pilots and cabin crews as well as frequent flyers. A neutron component of cosmic radiation was measured using an LR 115/CR-39 track detector associated with a 10B converter foil. The measurement of the neutron dose is a good approximation of the total dose since neutrons carry about 50% of the total ambient dose equivalent at aircraft altitudes. Also, the results of the measurements were compared with the data obtained by EPCARD software simulation. The measured neutron dose rate had a span from 0.36 to 8.83 μSv h(-1) (dose enhancement due to high solar activity in the flight period).
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Affiliation(s)
- Marina Poje
- *Department of Physics, University of Osijek, Osijek, P.O. Box 125, Croatia
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Seth I, Schwartz JL, Stewart RD, Emery R, Joiner MC, Tucker JD. Neutron exposures in human cells: bystander effect and relative biological effectiveness. PLoS One 2014; 9:e98947. [PMID: 24896095 PMCID: PMC4045982 DOI: 10.1371/journal.pone.0098947] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/09/2014] [Indexed: 11/19/2022] Open
Abstract
Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy), and irradiated-cell conditioned media (ICCM) was transferred to unirradiated cells. The cytokinesis-block micronucleus assay was used to quantify genetic damage in radiation-naïve cells exposed to ICCM from cultures that received 0 (control), 0.5, 1, 1.5, 2, 3 or 4 Gy neutrons. Cells grown in ICCM from irradiated cells showed no significant increase in the frequencies of micronuclei or nucleoplasmic bridges compared to cells grown in ICCM from sham irradiated cells for either cell line. However, the neutron beam has a photon dose-contamination of 5%, which may modulate a neutron-induced bystander effect. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. No significant increase in the frequencies of micronuclei or bridges was observed at these doses of photons for either cell line when cultured in ICCM. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (p<0.0001). These data indicate that neutrons do not induce a bystander effect in these cells. Finally, neutrons had a relative biological effectiveness of 2.0 ± 0.13 for micronuclei and 5.8 ± 2.9 for bridges compared to cobalt-60. These results may be relevant to radiation therapy with fast neutrons and for regulatory agencies setting standards for neutron radiation protection and safety.
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Affiliation(s)
- Isheeta Seth
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
| | - Jeffrey L. Schwartz
- Department of Radiation Oncology, School of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Robert D. Stewart
- Department of Radiation Oncology, School of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Robert Emery
- Department of Radiation Oncology, School of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Michael C. Joiner
- Department of Radiation Oncology, Wayne State University, Detroit, Michigan, United States of America
| | - James D. Tucker
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
- * E-mail:
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Zeeb H, Hammer GP, Blettner M. Epidemiological investigations of aircrew: an occupational group with low-level cosmic radiation exposure. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2012; 32:N15-N19. [PMID: 22395103 DOI: 10.1088/0952-4746/32/1/n15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Aircrew and passengers are exposed to low-level cosmic ionising radiation. Annual effective doses for flight crew have been estimated to be in the order of 2-5 mSv and can attain 75 mSv at career end. Epidemiological studies in this occupational group have been conducted over the last 15-20 years, usually with a focus on radiation-associated cancer. These studies are summarised in this note. Overall cancer risk was not elevated in most studies and subpopulations analysed, while malignant melanoma, other skin cancers and breast cancer in female aircrew have shown elevated incidence, with lesser risk elevations in terms of mortality. In some studies, including the large German cohort, brain cancer risk appears elevated. Cardiovascular mortality risks were generally very low. Dose information for pilots was usually derived from calculation procedures based on routine licence information, types of aircraft and routes/hours flown, but not on direct measurements. However, dose estimates have shown high validity when compared with measured values. No clear-cut dose-response patterns pointing to a higher risk for those with higher cumulative doses were found. Studies on other health outcomes have shown mixed results. Overall, aircrew are a highly selected group with many specific characteristics and exposures that might also influence cancers or other health outcomes. Radiation-associated health effects have not been clearly established in the studies available so far.
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Affiliation(s)
- Hajo Zeeb
- Bremen Institute for Prevention Research and Social Medicine, Bremen, Germany.
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Poje M, Vuković B, Radolić V, Miklavčić I, Faj D, Varga Pajtler M, Planinić J. Mapping of cosmic radiation dose in Croatia. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2012; 103:30-33. [PMID: 22036155 DOI: 10.1016/j.jenvrad.2011.08.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 07/01/2011] [Accepted: 08/26/2011] [Indexed: 05/31/2023]
Abstract
The Earth is continually bombarded by high-energy particles coming from the outer space and the sun. These particles, termed cosmic radiation, interact with nuclei of atmospheric constituents and decrease in intensity with depth in the atmosphere. Measurements of photon and gamma radiation, performed with a Radiameter at 1 m above the ground, indicated dose rates of 50-100 nSv/h. The neutron dose rate was measured with the CR-39 track etch detector calibrated by the CERN-EU high-energy Reference Field (CERF) facility. Correlation between neutron dose rates and altitudes at 36 sites was examined in order to obtain a significant positive correlation coefficient; the resulting linear regression enabled estimation of a neutron dose at particular altitude. The measured neutron dose rate in Osijek (altitude of 89 m, latitude of 45.31° N) was 110 nSv/h.
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Affiliation(s)
- M Poje
- Department of Physics, University of Osijek, P.O. Box 125, Gajev trg 6, 31000 Osijek, Croatia
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Voyant C, Roustit R, Tatje J, Biffi K, Leschi D, Briançon J, Marcovici CL. Therapeutic potential of atmospheric neutrons. Rep Pract Oncol Radiother 2011; 16:21-31. [PMID: 24669300 PMCID: PMC3920293 DOI: 10.1016/j.rpor.2010.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 10/05/2010] [Accepted: 11/03/2010] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Glioblastoma multiform (GBM) is the most common and most aggressive type of primary brain tumour in humans. It has a very poor prognosis despite multi-modality treatments consisting of open craniotomy with surgical resection, followed by chemotherapy and/or radiotherapy. Recently, a new treatment has been proposed - Boron Neutron Capture Therapy (BNCT) - which exploits the interaction between Boron-10 atoms (introduced by vector molecules) and low energy neutrons produced by giant accelerators or nuclear reactors. METHODS The objective of the present study is to compute the deposited dose using a natural source of neutrons (atmospheric neutrons). For this purpose, Monte Carlo computer simulations were carried out to estimate the dosimetric effects of a natural source of neutrons in the matter, to establish if atmospheric neutrons interact with vector molecules containing Boron-10. RESULTS The doses produced (an average of 1 μGy in a 1 g tumour) are not sufficient for therapeutic treatment of in situ tumours. However, the non-localised yet specific dosimetric properties of 10B vector molecules could prove interesting for the treatment of micro-metastases or as (neo)adjuvant treatment. On a cellular scale, the deposited dose is approximately 0.5 Gy/neutron impact. CONCLUSION It has been shown that BNCT may be used with a natural source of neutrons, and may potentially be useful for the treatment of micro-metastases. The atmospheric neutron flux is much lower than that utilized during standard NBCT. However the purpose of the proposed study is not to replace the ordinary NBCT but to test if naturally occurring atmospheric neutrons, considered to be an ionizing pollution at the Earth's surface, can be used in the treatment of a disease such as cancer. To finalize this study, it is necessary to quantify the biological effects of the physically deposited dose, taking into account the characteristics of the incident particles (alpha particle and Lithium atom) and radio-induced effects (by-stander and low dose effect). One of the aims of the presented paper is to propose to experimental teams (which would be interested in studying the phenomena) a simple way to calculate the dose deposition (allometric fit of free path, transmission factor of brain).
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Affiliation(s)
- Cyril Voyant
- University of Corsica, CNRS UMR SPE 6134, Campus Grimaldi, 20250 Corte, France
- Castelluccio Hospital, Radiotherapy Unit, BP 85, 20177 Ajaccio, France
| | - Rudy Roustit
- Castelluccio Hospital, Radiotherapy Unit, BP 85, 20177 Ajaccio, France
| | - Jennifer Tatje
- Castelluccio Hospital, Radiotherapy Unit, BP 85, 20177 Ajaccio, France
| | - Katia Biffi
- Castelluccio Hospital, Radiotherapy Unit, BP 85, 20177 Ajaccio, France
| | - Delphine Leschi
- Castelluccio Hospital, Radiotherapy Unit, BP 85, 20177 Ajaccio, France
| | - Jérome Briançon
- Castelluccio Hospital, Radiotherapy Unit, BP 85, 20177 Ajaccio, France
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Vuković B, Poje M, Varga M, Radolić V, Miklavcić I, Faj D, Stanić D, Planinić J. Measurements of neutron radiation in aircraft. Appl Radiat Isot 2010; 68:2398-402. [PMID: 20620072 DOI: 10.1016/j.apradiso.2010.06.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Revised: 06/14/2010] [Accepted: 06/17/2010] [Indexed: 10/19/2022]
Abstract
Radiation environment is a complex mixture of charged particles of the solar and galactic origin, as well as of secondary particles created in an interaction of galactic cosmic particles with the nuclei of the Earth's atmosphere. A radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. In order to measure a neutron component of the cosmic radiation, we investigated a few combinations of a track etch detector (CR-39, LR-115) with a plastic converter or boron foil. Detector calibration was performed on neutrons coming from the nuclear reactor, as well as in the CERN-EU high-energy Reference Field (CERF) facility. From November 2007 to September 2008, the neutron dose equivalent was measured by the track detectors during five aircraft flights, in the north geographical latitude from 21° to 58°; the respective average dose rate, determined by using the D-4 detector (CR-39/B), was Ḣ(n)=5.9 μSv/h. The photon dose rate, measured by the electronic dosimeter RAD-60 SE, had the average value of Ḣ(f)=1.4 μSv/h.
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Affiliation(s)
- B Vuković
- Department of Physics, University of Osijek, Osijek, P.O. Box 125, Croatia
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