| 1. |
- Alinaghizadeh, Hassan, et al.
(författare)
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Cancer incidence in northern Sweden before and after the Chernobyl nuclear power plant accident
- 2014
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 53:3, s. 495-504
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Tidskriftsartikel (refereegranskat)abstract
- Sweden received about 5 % of the total release of Cs-137 from the Chernobyl nuclear power plant accident in 1986. The distribution of the fallout mainly affected northern Sweden, where some parts of the population could have received an estimated annual effective dose of 1-2 mSv per year. It is disputed whether an increased incidence of cancer can be detected in epidemiological studies after the Chernobyl nuclear power plant accident outside the former Union of Soviet Socialist Republics. In the present paper, a possible exposure-response pattern between deposition of Cs-137 and cancer incidence after the Chernobyl nuclear power plant accident was investigated in the nine northernmost counties of Sweden (2.2 million inhabitants in 1986). The activity of Cs-137 from the fallout maps at 1986 was used as a proxy for the received dose of ionizing radiation. Diagnoses of cancer (ICD-7 code 140-209) from 1980 to 2009 were received from the Swedish Cancer Registry (273,222 cases). Age-adjusted incidence rate ratios, stratified by gender, were calculated with Poisson regression in two closed cohorts of the population in the nine counties 1980 and 1986, respectively. The follow-up periods were 1980-1985 and 1986-2009, respectively. The average surface-weighted deposition of Cs-137 at three geographical levels; county (n = 9), municipality (n = 95) and parish level (n = 612) was applied for the two cohorts to study the pre- and the post-Chernobyl periods separately. To analyze time trends, the age-standardized total cancer incidence was calculated for the general Swedish population and the population in the nine counties. Joinpoint regression was used to compare the average annual percent change in the general population and the study population within each gender. No obvious exposure-response pattern was seen in the age-adjusted total cancer incidence rate ratios. A spurious association between fallout and cancer incidence was present, where areas with the lowest incidence of cancer before the accident coincidentally had the lowest fallout of Cs-137. Increasing the geographical resolution of exposure from nine county averages to 612 parish averages resulted in a two to three times higher value of variance in the regression model. There was a secular trend with an increase in age-standardized incidence of cancer in both genders from 1980 to 2009, but significant only in females. This trend was stronger and statistically significant for both genders in the general Swedish population compared to the nine counties. In conclusion, using both high quality cancer registry data and high resolution exposure maps of Cs-137 deposition, it was not possible to distinguish an effect of Cs-137 on cancer incidence after the Chernobyl nuclear power plant accident in Sweden.
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| 2. |
- Applegate, K. E., et al.
(författare)
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Individual response of humans to ionising radiation : governing factors and importance for radiological protection
- 2020
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 59:2, s. 185-209
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Forskningsöversikt (refereegranskat)abstract
- Tissue reactions and stochastic effects after exposure to ionising radiation are variable between individuals but the factors and mechanisms governing individual responses are not well understood. Individual responses can be measured at different levels of biological organization and using different endpoints following varying doses of radiation, including: cancers, non-cancer diseases and mortality in the whole organism; normal tissue reactions after exposures; and, cellular endpoints such as chromosomal damage and molecular alterations. There is no doubt that many factors influence the responses of people to radiation to different degrees. In addition to the obvious general factors of radiation quality, dose, dose rate and the tissue (sub)volume irradiated, recognized and potential determining factors include age, sex, life style (e.g., smoking, diet, possibly body mass index), environmental factors, genetics and epigenetics, stochastic distribution of cellular events, and systemic comorbidities such as diabetes or viral infections. Genetic factors are commonly thought to be a substantial contributor to individual response to radiation. Apart from a small number of rare monogenic diseases such as ataxia telangiectasia, the inheritance of an abnormally responsive phenotype among a population of healthy individuals does not follow a classical Mendelian inheritance pattern. Rather it is considered to be a multi-factorial, complex trait.
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| 3. |
- Bakshi, Mayur V., et al.
(författare)
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Long-term effects of acute low-dose ionizing radiation on the neonatal mouse heart : a proteomic study
- 2013
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 52:4, s. 451-461
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies establish that children and young adults are especially susceptible to radiation-induced cardiovascular disease (CVD). The biological mechanisms behind the elevated CVD risk following exposure at young age remain unknown. The present study aims to elucidate the long-term effects of ionizing radiation by studying the murine cardiac proteome after exposure to low and moderate radiation doses. NMRI mice received single doses of total body Co-60 gamma-irradiation on postnatal day 10 and were sacrificed 7 months later. Changes in cardiac protein expression were quantified using isotope-coded protein label and tandem mass spectrometry. We identified 32, 31, 66, and 34 significantly deregulated proteins after doses of 0.02, 0.1, 0.5, and 1.0 Gy, respectively. The four doses shared 9 deregulated proteins. Bioinformatics analysis showed that most of the deregulated proteins belonged to a limited set of biological categories, including metabolic processes, inflammatory response, and cytoskeletal structure. The transcription factor peroxisome proliferator-activated receptor alpha was predicted as a common upstream regulator of several deregulated proteins. This study indicates that both adaptive and maladaptive responses to the initial radiation damage persist well into adulthood. It will contribute to the understanding of the long-term consequences of radiation-induced injury and developmental alterations in the neonatal heart.
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| 4. |
- Bernhardsson, Christian, et al.
(författare)
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Household salt as a retrospective dosemeter using optically stimulated luminescence.
- 2009
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 48, s. 21-28
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to investigate the potential of a selection of household salts (NaCl) as a retrospective dosemeter for ionising radiation using optically stimulated luminescence (OSL). The OSL-response of five brands of salt to an absorbed dose in the range from 1 mGy to 9 Gy was investigated using a Risø TL/OSL-15 reader and a (60)Co beam, allowing low dose-rate irradiations. The salt was optically stimulated with blue light (lambda = 470 +/- 30 nm) at a constant stimulation power (CW-OSL) of 20 mW cm(-2). A linear dose response relationship was found in the dose range from 1 mGy to about 100 mGy and above that level, the relationship becomes moderately supra-linear, at least up to 9 Gy. Depending on the sensitivity and background signal, the minimum detectable absorbed dose (MDD) for the household salt when kept at sealed conditions varied from 0.2 to 1.0 mGy, for the household salts investigated. In addition to its widespread abundance and availability, the low MDD suggests that household salt should seriously be considered as an emergency dosemeter. However, the OSL-properties of NaCl under normal household usage need to be more properly investigated as well as the variation in sensitivity by the quality of the radiation. A further optimisation of the read-out sequence for various brands of commercially available salt may further improve the sensitivity, in terms of luminescence yield, and the signal reproducibility.
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| 5. |
- Bertucci, Antonella, et al.
(författare)
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Shielding of relativistic protons
- 2007
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 46:2, s. 107-111
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Tidskriftsartikel (refereegranskat)abstract
- Protons are the most abundant element in the galactic cosmic radiation, and the energy spectrum peaks around 1 GeV. Shielding of relativistic protons is therefore a key problem in the radiation protection strategy of crewmembers involved in long-term missions in deep space. Hydrogen ions were accelerated up to 1 GeV at the NASA Space Radiation Laboratory, Brookhaven National Laboratory, New York. The proton beam was also shielded with thick ( about 20 g/cm(2)) blocks of lucite (PMMA) or aluminium ( Al). We found that the dose rate was increased 40-60% by the shielding and decreased as a function of the distance along the axis. Simulations using the General Purpose Particle and Heavy-Ion Transport code System (PHITS) show that the dose increase is mostly caused by secondary protons emitted by the target. The modified radiation Weld after the shield has been characterized for its biological eVectiveness by measuring chromosomal aberrations in human peripheral blood lymphocytes exposed just behind the shield block, or to the direct beam, in the dose range 0.53 Gy. Notwithstanding the increased dose per incident proton, the fraction of aberrant cells at the same dose in the sample position was not significantly modified by the shield. The PHITS code simulations show that, albeit secondary protons are slower than incident nuclei, the LET spectrum is still contained in the low-LET range (
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| 6. |
- Blomgren, August, et al.
(författare)
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Home-made low-cost dosemeter for photon dose measurements in radiobiological experiments and for education in the field of radiation sciences
- 2024
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Ingår i: Radiation and Environmental Biophysics. - 0301-634X .- 1432-2099. ; 63, s. 395-404
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Tidskriftsartikel (refereegranskat)abstract
- Reliable dosimetry systems are crucial for radiobiological experiments either to quantify the biological consequences of ionizing radiation or to reproduce results by other laboratories. Also, they are essential for didactic purposes in the field of radiation research. Professional dosemeters are expensive and difficult to use in exposure facilities with closed exposure chambers. Consequently, a simple, inexpensive, battery-driven dosemeter was developed that can be easily built using readily available components. Measurements were performed to validate its readout with photons of different energy and dose rate and to demonstrate the applicability of the dosemeter. It turned out that the accuracy of the dose measurements using the developed dosemeter was better than 10%, which is satisfactory for radiobiological experiments. It is concluded that this dosemeter can be used both for determining the dose rates of an exposure facility and for educational purposes.
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| 7. |
- Brahme, Anders, et al.
(författare)
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A systems biology approach to radiation therapy optimization
- 2010
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 49:2, s. 111-124
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Tidskriftsartikel (refereegranskat)abstract
- During the last 20 years, the field of cellular and not least molecular radiation biology has been developed substantially and can today describe the response of heterogeneous tumors and organized normal tissues to radiation therapy quite well. An increased understanding of the sub-cellular and molecular response is leading to a more general systems biological approach to radiation therapy and treatment optimization. It is interesting that most of the characteristics of the tissue infrastructure, such as the vascular system and the degree of hypoxia, have to be considered to get an accurate description of tumor and normal tissue responses to ionizing radiation. In the limited space available, only a brief description of some of the most important concepts and processes is possible, starting from the key functional genomics pathways of the cell that are not only responsible for tumor development but also responsible for the response of the cells to radiation therapy. The key mechanisms for cellular damage and damage repair are described. It is further more discussed how these processes can be brought to inactivate the tumor without severely damaging surrounding normal tissues using suitable radiation modalities like intensity-modulated radiation therapy (IMRT) or light ions. The use of such methods may lead to a truly scientific approach to radiation therapy optimization, particularly when invivo predictive assays of radiation responsiveness becomes clinically available at a larger scale. Brief examples of the efficiency of IMRT are also given showing how sensitive normal tissues can be spared at the same time as highly curative doses are delivered to a tumor that is often radiation resistant and located near organs at risk. This new approach maximizes the probability to eradicate the tumor, while at the same time, adverse reactions in sensitive normal tissues are as far as possible minimized using IMRT with photons and light ions.
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| 8. |
- Brzozowska, Beata, et al.
(författare)
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Freeware tool for analysing numbers and sizes of cell colonies
- 2019
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 58:1, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- The clonogenic cell survival assay is a basic method to study the cytotoxic effect of radiation and chemical toxins. In large experimental setups, counting of colonies by eye is tiresome and prone to bias. Moreover, it is often interesting to quantify the size of individual colonies. Such analyses are largely facilitated by computerised image analysis systems. Although a number of such systems exist, they all focus on enumerating colonies and not on analysing the colony size. We have developed a new software package for both counting colonies and plotting their size distributions. The software called count and Plot HIstograms of Colony Size(countPHICS) consists of two parts: (1) a macro written for ImageJ which analyses computerised images of cell culture dishes or 6-well plates, counts colonies, estimates their size and saves the results in a text file; (2) a program written with QT Creator which reads the text file, plots histograms of colony size distribution and fits the best function. The full program is freely available at: http://www.fuw.edu.pl/similar to bbrzozow/FizMed/countPHICS.html. In conclusion, our new publically available software will facilitate colony counting and provide additional information on the colony growth rate, which is relevant especially for radiosensitisation studies.
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| 9. |
- Christiansson, Maria, et al.
(författare)
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Household salt for retrospective dose assessments using OSL: signal integrity and its dependence on containment, sample collection, and signal readout.
- 2014
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 53:3, s. 559-569
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to determine how a latent optically stimulated luminescence (OSL) signal in irradiated household salt is preserved under various ambient conditions, from the time of exposure to the time of signal readout. The following parameters were examined: optical fading in fluorescent light and under darkroom conditions (red light), thermal stability of the OSL signal during storage in a light-tight container, optical fading in representative container types, and sensitization effects of the OSL signal in exposed household salt. Furthermore, the influence of grain mixing within the saltshaker or salt container was studied by determining the dose gradient within typical salt packages. Finally, the signal integrity of salt irradiated under field conditions in a village in Belarus contaminated by Chernobyl fallout was investigated. The results show that the OSL signal in household salt is preserved in large cardboard box containers, but not in white plastic salt containers or in small portion bags used in, e.g., fast food restaurants. Furthermore, the continuous wave blue OSL signal in household salt does not fade significantly during storage up to 140 days. On the contrary, the signal appears to slowly increase during storage ("inverse fading"). Field tests of two different salt containers (with and without black tape to block light) located in Belarussian households confirmed that the signal is preserved in white plastic salt containers when they are covered with extra light-shielding material.
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| 10. |
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| 11. |
- Fattibene, Paola, et al.
(författare)
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EPR dosimetry intercomparison using smart phone touch screen glass
- 2014
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Ingår i: Radiation and Environmental Biophysics. - : Springer-Verlag New York. - 0301-634X .- 1432-2099. ; 53:2, s. 311-320
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results of an interlaboratory comparison of retrospective dosimetry using the electron paramagnetic resonance method. The test material used in this exercise was glass coming from the touch screens of smart phones that might be used as fortuitous dosimeters in a large-scale radiological incident. There were 13 participants to whom samples were dispatched, and 11 laboratories reported results. The participants received five calibration samples (0, 0.8, 2, 4, and 10 Gy) and four blindly irradiated samples (0, 0.9, 1.3, and 3.3 Gy). Participants were divided into two groups: for group A (formed by three participants), samples came from a homogeneous batch of glass and were stored in similar setting; for group B (formed by eight participants), samples came from different smart phones and stored in different settings of light and temperature. The calibration curves determined by the participants of group A had a small error and a critical level in the 0.37-0.40-Gy dose range, whereas the curves determined by the participants of group B were more scattered and led to a critical level in the 1.3-3.2-Gy dose range for six participants out of eight. Group A were able to assess the dose within 20 % for the lowest doses (< 1.5 Gy) and within 5 % for the highest doses. For group B, only the highest blind dose could be evaluated in a reliable way because of the high critical values involved. The results from group A are encouraging, whereas the results from group B suggest that the influence of environmental conditions and the intervariability of samples coming from different smart phones need to be further investigated. An alongside conclusion is that the protocol was easily transferred to participants making a network of laboratories in case of a mass casualty event potentially feasible.
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| 12. |
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| 13. |
- Geber-Bergstrand, Therése, et al.
(författare)
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Optically stimulated luminescence (OSL) dosimetry in irradiated alumina substrates from mobile phone resistors
- 2018
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 57:1, s. 69-75
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Tidskriftsartikel (refereegranskat)abstract
- In this study the dosimetric properties of alumina (Al2O3) substrates found in resistors retrieved from mobile phones were investigated. Measurements of the decline of optically stimulated luminescence (OSL) generated following exposure of these substrates to ionising radiation showed that 16% of the signal could still be detected after 2 years (735 days). Further, the magnitude of the regenerative dose (calibration dose; Di) had no impact on the accuracy of dose estimates. Therefore, it is recommended that the Di be set as low as is practicable, so as to accelerate data retrieval. The critical dose, DCL, and dose limit of detection, DDL, taking into account the uncertainty in the dose–response relation as well as the uncertainty in the background signal, was estimated to be 7 and 13 mGy, respectively, 1 h after exposure. It is concluded that given the significant long-term component of fading, an absorbed dose of 0.5 Gy might still be detectable up to 6 years after the exposure. Thus, OSL from alumina substrates can be used for dosimetry for time periods far in excess of those previously thought.
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| 14. |
- Geber, Therese, et al.
(författare)
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Retrospective dosimetry using OSL of tooth enamel and dental repair materials irradiated under wet and dry conditions.
- 2012
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 51:4, s. 443-449
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Tidskriftsartikel (refereegranskat)abstract
- Following a radiological or nuclear emergency event, there is a need for quick and reliable dose estimations of potentially exposed people. In situations where dosimeters are not readily available, the dose estimations must be carried out using alternative methods. In the present study, the optically stimulated luminescence (OSL) properties of tooth enamel and different dental repair materials have been examined. Specimens of the materials were exposed to gamma and beta radiation in different types of liquid environments to mimic the actual irradiation situation in the mouth. Measurements were taken using a Risø TL/OSL reader, and irradiations were made using a (90)Sr/(90)Y source and a linear accelerator (6 MV photons). Results show that the OSL signal from tooth enamel decreases substantially when the enamel is kept in a wet environment. Thus, tooth enamel is not reliable for retrospective dose assessment without further studies of the phenomenon. Dental repair materials, on the other hand, do not exhibit the same effect when exposed to liquids. In addition, dose-response and fading measurements of the dental repair materials show promising results, making these materials highly interesting for retrospective dosimetry. The minimum detectable dose for the dental repair materials has been estimated to be 20-185 mGy.
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| 15. |
- Georgiadou, Elisavet, et al.
(författare)
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Bomb-pulse (14)C analysis combined with (13)C and (15)N measurements in blood serum from residents of Malmö, Sweden.
- 2013
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 52:2, s. 175-187
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Forskningsöversikt (refereegranskat)abstract
- The (14)C content of 60 human blood serum samples from residents of Malmö (Sweden) in 1978, obtained from a biobank, has been measured to estimate the accuracy of (14)C bomb-pulse dating. The difference between the date estimated using the Calibomb software and sampling date varied between -3 ± 0.4 and +0.2 ± 0.5 years. The average age deviation of all samples was -1.5 ± 0.7 years, with the delay between production and consumption of foodstuffs being probably the dominating cause. The potential influence of food habits on the (14)C date has been evaluated using stable isotope δ(13)C and δ(15)N analysis and information about the dietary habits of the investigated individuals. Although the group consisting of lacto-ovo vegetarians and vegans (pooled group) was not completely separated from the omnivores in a stable isotopic trophic level diagram, this analysis proved to add valuable information on probable dietary habits. The age deviation of the sampling date from the respective Calibomb date was found strongly correlated with the δ(13)C values, probably due to influence from marine diet components. For the omnivore individuals, there were indications of seasonal effects on δ(13)C and the age deviation. No significant correlation was found between the age deviation and the δ(15)N values of any dietary group. No influence of sex or year of birth was found on neither the (14)C nor the δ(13)C and δ(15)N values of the serum samples. The data were also divided into two groups (omnivores and pooled group), based on the level of δ(15)N in the samples. The consumption of high δ(15)N-valued fish and birds can be responsible for this clustering.
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| 16. |
- Hjerpe, Thomas, et al.
(författare)
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Accounting for the depth distribution of (137)Cs in on-line mobile gamma spectrometry through primary and forward-scattered photons.
- 2002
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 41:3, s. 225-230
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Tidskriftsartikel (refereegranskat)abstract
- Stationary and mobile field gamma spectrometry is a useful tool for rapid estimation of environmental radioactivity inventories on and in the ground. A weak point however, is that the depth distribution of the activity in the ground must be known in order to calculate the true activity per unit area or unit mass from an observed photon fluence rate. A promising method for converting incoming spectral data into both true activity content and depth distribution in real time is the peak-to-valley method, which is based on an analysis of the ratio between count rates from primary and forward-scattered photons. In this study the peak-to-valley method was adapted to car-borne mobile gamma spectrometry, where the depth distribution of (137)Cs is fitted to a Lorenz function. Results from field experiments with a large HPGe detector, utilising point sources at different depths, are presented. It was found that the method can be useful for mobile measurements with a measuring time of 5-10 min for activity concentrations of about 100 kBq.m(-2) or higher, resulting in an uncertainty in the estimate of the true activity of about 50%.
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| 17. |
- Koshurnikova, NA, et al.
(författare)
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Studies on the Ozyorsk population: health effects
- 2002
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Ingår i: Radiation and environmental biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 41:1, s. 37-39
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Tidskriftsartikel (refereegranskat)
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| 18. |
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| 19. |
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| 20. |
- Kreuzer, M., et al.
(författare)
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Multidisciplinary European Low Dose Initiative (MELODI) : strategic research agenda for low dose radiation risk research
- 2018
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 57:1, s. 5-15
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Forskningsöversikt (refereegranskat)abstract
- MELODI (Multidisciplinary European Low Dose Initiative) is a European radiation protection research platform with focus on research on health risks after exposure to low-dose ionising radiation. It was founded in 2010 and currently includes 44 members from 18 countries. A major activity of MELODI is the continuous development of a long-term European Strategic Research Agenda (SRA) on low-dose risk for radiation protection. The SRA is intended to identify priorities for national and European radiation protection research programs as a basis for the preparation of competitive calls at the European level. Among those key priorities is the improvement of health risk estimates for exposures close to the dose limits for workers and to reference levels for the population in emergency situations. Another activity of MELODI is to ensure the availability of European key infrastructures for research activities, and the long-term maintenance of competences in radiation research via an integrated European approach for training and education. The MELODI SRA identifies three key research topics in low dose or low dose-rate radiation risk research: (1) dose and dose rate dependence of cancer risk, (2) radiation-induced non-cancer effects and (3) individual radiation sensitivity. The research required to improve the evidence base for each of the three key topics relates to three research lines: (1) research to improve understanding of the mechanisms contributing to radiogenic diseases, (2) epidemiological research to improve health risk evaluation of radiation exposure and (3) research to address the effects and risks associated with internal exposures, differing radiation qualities and inhomogeneous exposures. The full SRA and associated documents can be downloaded from the MELODI website (http://www.melodi-online.eu/sra.html).
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| 21. |
- Langen, Britta, et al.
(författare)
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The IRI-DICE hypothesis: ionizing radiation-induced DSBs may have a functional role for non-deterministic responses at low doses
- 2020
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 59, s. 349-355
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Tidskriftsartikel (refereegranskat)abstract
- Low-dose ionizing radiation (IR) responses remain an unresolved issue in radiation biology and risk assessment. Accurate knowledge of low-dose responses is important for estimation of normal tissue risk in cancer radiotherapy or health risks from occupational or hazard exposure. Cellular responses to low-dose IR appear diverse and stochastic in nature and to date no model has been proposed to explain the underlying mechanisms. Here, we propose a hypothesis on IR-induced double-strand break (DSB)-induced cis effects (IRI-DICE) and introduce DNA sequence functionality as a submicron-scale target site with functional outcome on gene expression: DSB induction in a certain genetic target site such as promotor, regulatory element, or gene core would lead to changes in transcript expression, which may range from suppression to overexpression depending on which functional element was damaged. The DNA damage recognition and repair machinery depicts threshold behavior requiring a certain number of DSBs for induction. Stochastically distributed persistent disruption of gene expression may explain-in part-the diverse nature of low-dose responses until the repair machinery is initiated at increased absorbed dose. Radiation quality and complexity of DSB lesions are also discussed. Currently, there are no technologies available to irradiate specific genetic sites to test the IRI-DICE hypothesis directly. However, supportive evidence may be achieved by developing a computational model that combines radiation transport codes with a genomic DNA model that includes sequence functionality and transcription to simulate expression changes in an irradiated cell population. To the best of our knowledge, IRI-DICE is the first hypothesis that includes sequence functionality of different genetic elements in the radiation response and provides a model for the diversity of radiation responses in the (very) low dose regimen.
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- López Riego, Milagrosa, 1992-, et al.
(författare)
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The DNA damage response to radiological imaging : from ROS and γH2AX foci induction to gene expression responses in vivo
- 2023
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Ingår i: Radiation and Environmental Biophysics. - 0301-634X .- 1432-2099. ; 62:3, s. 371-393
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Tidskriftsartikel (refereegranskat)abstract
- Candidate ionising radiation exposure biomarkers must be validated in humans exposed in vivo. Blood from patients undergoingpositron emission tomography–computed tomography scan (PET-CT) and skeletal scintigraphy (scintigraphy) was drawnbefore (0 h) and after (2 h) the procedure for correlation analyses of the response of selected biomarkers with radiation doseand other available patient information. FDXR, CDKN1A, BBC3, GADD45A, XPC, and MDM2 expression was determinedby qRT-PCR, DNA damage (γH2AX) by flow cytometry, and reactive oxygen species (ROS) levels by flow cytometry usingthe 2′, 7′—dichlorofluorescein diacetate test in peripheral blood mononuclear cells (PBMC). For ROS experiments, 0- and2-h samples were additionally exposed to UVA to determine whether diagnostic irradiation conditioned the response tofurther oxidative insult. With some exceptions, radiological imaging induced weak γH2AX foci, ROS and gene expressionfold changes, the latter with good coherence across genes within a patient. Diagnostic imaging did not influence oxidativestress in PBMC successively exposed to UVA. Correlation analyses with patient characteristics led to low correlation coefficientvalues. γH2AX fold change, which correlated positively with gene expression, presented a weak positive correlationwith injected activity, indicating a radiation-induced subtle increase in DNA damage and subsequent activation of the DNAdamage response pathway. The exposure discrimination potential of these biomarkers in the absence of control samples asfrequently demanded in radiological emergencies, was assessed using raw data. These results suggest that the variability ofthe response in heterogeneous populations might complicate identifying individuals exposed to low radiation doses.
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| 26. |
- Madas, Balázs G., et al.
(författare)
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The 2020 MELODI workshop on the effects of spatial and temporal variation in dose delivery
- 2022
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 61:4, s. 479-483
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Tidskriftsartikel (refereegranskat)abstract
- A key activity of MELODI is to organise annual European meetings where scientific results and future directions and strategies of relevant research are discussed. The annual meetings, previously organised solely under the auspices of MELODI are, since 2016, jointly organised by the European platforms and referred to as European Radiation Protection Weeks (ERPW). In addition to ERPW meetings, MELODI organises and finances annual workshops dedicated to specific topics. Outputs and recommendations from the meetings are published as review articles. The 2020 workshop focussed on one of the cross cutting topics: the effects of spatial and temporal variation in dose delivery on disease risk. The current issue of REBS includes five review articles from the workshop on the effects of spatial and temporal variation in dose delivery and this editorial is a short summary of their content..
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| 27. |
- Mancusi, Davide, 1980, et al.
(författare)
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Calculation of Energy-Deposition Distributions and Microdosimetric Estimation of the Biological Effect of a 9C Beam
- 2009
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Ingår i: Radiation and Environmental Biophysics. - 1432-2099 .- 0301-634X. ; 48:2, s. 135-143
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Tidskriftsartikel (refereegranskat)abstract
- Among the alternative beams being recently considered for external cancer radiotherapy, C-9 has received some attention because it is expected that its biological effectiveness could be boosted by the beta-delayed emission of two alpha particles and a proton that takes place at the ion-stopping site. Experiments have been performed to characterise this exotic beam physically and models have been developed to estimate quantitatively its biological effect. Here, the particle and heavy-ion transport code system (PHITS ) is used to calculate energy-deposition and linear energy transfer distributions for a C-9 beam in water and the results are compared with published data. Although PHITS fails to reproduce some of the features of the distributions, it suggests that the decay of C-9 contributes negligibly to the energy-deposition distributions, thus contradicting the previous interpretation of the measured data. We have also performed a microdosimetric calculation to estimate the biological effect of the decay, which was found to be negligible; previous microdosimetric Monte-Carlo calculations were found to be incorrect. An analytical argument, of geometrical nature, confirms this conclusion and gives a theoretical upper bound on the additional biological effectiveness of the decay. However, no explanation can be offered at present for the observed difference in the biological effectiveness between C-9 and C-12; the reproducibility of this surprising result will be verified in coming experiments.
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| 28. |
- Mannerling, Ann-Christine, et al.
(författare)
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Effects of 50-Hz magnetic field exposure on superoxide radical anion formation and HSP70 induction in human K562 cells
- 2010
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 49:4, s. 731-741
-
Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies suggest a correlation between exposure to low-level extremely low-frequency (ELF) magnetic fields (MF) and certain cancers and neurodegenerative diseases. Experimental studies have not provided any mechanism for such effects, although at flux density levels significantly higher than the ones encountered in epidemiological studies, radical homoeostasis and levels of stress response proteins can be affected. Here, we report on the influence of MF exposure (50-Hz sine wave; 1 h; 0.025-0.10 mT; vertical or horizontal MF exposure direction) on different cellular parameters (proliferation, cell cycle distribution, superoxide radical anion, and HSP70 protein levels) in the human leukaemia cell line K562. The positive control heat treatment (42A degrees C, 1 h) did not affect either cell proliferation or superoxide radical anion production but caused accumulation of cells in the G2 phase and increased the stress protein HSP70. MF exposure (0.10 mT, 1 h) did not affect either cell cycle kinetics or proliferation. Both vertical and horizontal MF exposures for 1 h caused significantly and transiently increased HSP70 levels (> twofold), at several flux densities, compared to sham controls and also compared to heat treatment. This exposure also increased (30-40%) the levels of the superoxide radical anion, comparable to the positive control PMA. Addition of free radical scavengers (melatonin or 1,10-phenantroline) inhibited the MF-induced increase in HSP70. In conclusion, an early response to ELF MF in K562 cells seems to be an increased amount of oxygen radicals, leading to HSP70 induction. Furthermore, the results suggest that there is a flux density threshold where 50-Hz MF exerts its effects on K562 cells, at or below 0.025 mT, and also that it is the MF, and not the induced electric field, which is the active parameter.
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| 29. |
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| 30. |
- Olofsson, Dante, et al.
(författare)
-
Biological effectiveness of very high gamma dose rate and its implication for radiological protection
- 2020
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 59, s. 451-460
-
Tidskriftsartikel (refereegranskat)abstract
- Many experimental studies are carried out to compare biological effectiveness of high dose rate (HDR) with that of low dose rate (LDR). The rational for this is the uncertainty regarding the value of the dose rate effectiveness factor (DREF) used in radiological protection. While a LDR is defined as 0.1 mGy/min or lower, anything above that is seen as HDR. In cell and animal experiments, a dose rate around 1 Gy/min is usually used as representative for HDR. However, atomic bomb survivors, the reference cohort for radiological protection, were exposed to tens of Gy/min. The important question is whether gamma radiation delivered at very high dose rate (VHDR-several Gy/min) is more effective in inducing DNA damage than that delivered at HDR. The aim of this investigation was to compare the biological effectiveness of gamma radiation delivered at VHDR (8.25 Gy/min) with that of HDR (0.38 Gy/min or 0.79 Gy/min). Experiments were carried out with human peripheral mononuclear cells (PBMC) and the human osteosarcoma cell line U2OS. Endpoints related to DNA damage response were analysed. The results show that in PBMC, VHDR is more effective than HDR in inducing gene expression and micronuclei. In U2OS cells, the repair of 53BP1 foci was delayed after VHDR indicating a higher level of damage complexity, but no VHDR effect was observed at the level of micronuclei and clonogenic cell survival. We suggest that the DREF value may be underestimated when the biological effectiveness of HDR and LDR is compared.
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| 31. |
- Olsson, Gunilla, et al.
(författare)
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Transient delay of radiation-induced apoptosis by phorbol acetate
- 2016
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 55:1, s. 95-102
-
Tidskriftsartikel (refereegranskat)abstract
- The mechanisms of interference of a model tumour promoter 12-O-tetra-decanoylphorbol-13-acetate (TPA) with radiation-induced apoptosis in human peripheral lymphocytes have been investigated. The cells were treated with TPA under various conditions and thereafter exposed to a single lethal dose of gamma radiation. Morphological and biochemical changes characteristic of apoptosis were followed up to 72 h of post-irradiation time. Acute exposure to low concentration of TPA resulted in delay in the onset of radiation-induced apoptosis (determined as morphological changes and rate of mitochondrial demise) by 24-48 h as compared to the irradiated, sham TPA-treated cells. The time course of this delay correlated well with confinement of the p53 protein to the cytoplasm and increase in bcl-2 levels at the nuclear periphery of irradiated cells. Our results indicate that confinement of p53 in the cytoplasm is one of the potential mechanisms by which TPA interferes with the process of radiation-induced apoptosis in human lymphocytes.
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| 32. |
- Pachnerova Brabcová, Katerina, 1978, et al.
(författare)
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Clustered DNA damage on subcellular level: effect of scavengers
- 2014
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 53:4, s. 705-712
-
Tidskriftsartikel (refereegranskat)abstract
- Clustered DNA damages are induced by ionizing radiation, particularly of high linear energy transfer (LET). Compared to isolated DNA damage sites, their biological effects can be more severe. We investigated a clustered DNA damage induced by high LET radiation (C 290 MeV u(-1) and Fe 500 MeV u(-1)) in pBR322 plasmid DNA. The plasmid is dissolved in pure water or in aqueous solution of one of the three scavengers (coumarin-3-carboxylic acid, dimethylsulfoxide, and glycylglycine). The yield of double strand breaks (DSB) induced in the DNA plasmid-scavenger system by heavy ion radiation was found to decrease with increasing scavenging capacity due to reaction with hydroxyl radical, linearly with high correlation coefficients. The yield of non-DSB clusters was found to occur twice as much as the DSB. Their decrease with increasing scavenging capacity had lower linear correlation coefficients. This indicates that the yield of non-DSB clusters depends on more factors, which are likely connected to the chemical properties of individual scavengers.
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| 33. |
- Puchalska, Monika, 1977, et al.
(författare)
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NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS
- 2014
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 53:4, s. 719-727
-
Tidskriftsartikel (refereegranskat)abstract
- The health effects of cosmic radiation on astronauts need to be precisely quantified and controlled. This task is important not only in perspective of the increasing human presence at the International Space Station (ISS), but also for the preparation of safe human missions beyond low earth orbit. From a radiation protection point of view, the baseline quantity for radiation risk assessment in space is the effective dose equivalent. The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA). This was achieved using the anthropomorphic torso phantom RANDO(A (R)) equipped with more than 6,000 passive thermoluminescent detectors and plastic nuclear track detectors, which have been exposed to cosmic radiation inside the European Space Agency MATROSHKA facility both outside and inside the ISS. In order to calculate the effective dose equivalent, a numerical model of the RANDO(A (R)) phantom, based on computer tomography scans of the actual phantom, was developed. It was found that the effective dose equivalent rate during an EVA approaches 700 mu Sv/d, while during an IVA about 20 % lower values were observed. It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %. A personal dosemeter can therefore deliver quite good exposure records during IVA, but may overestimate the effective dose equivalent received during an EVA considerably.
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| 34. |
- Romm, H., et al.
(författare)
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Web-based scoring of the dicentric assay, a collaborative biodosimetric scoring strategy for population triage in large scale radiation accidents
- 2014
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 53:2, s. 241-254
-
Tidskriftsartikel (refereegranskat)abstract
- In the case of a large scale radiation accident high throughput methods of biological dosimetry for population triage are needed to identify individuals requiring clinical treatment. The dicentric assay performed in web-based scoring mode may be a very suitable technique. Within the MULTIBIODOSE EU FP7 project a network is being established of 8 laboratories with expertise in dose estimations based on the dicentric assay. Here, the manual dicentric assay was tested in a web-based scoring mode. More than 23,000 high resolution images of metaphase spreads (only first mitosis) were captured by four laboratories and established as image galleries on the internet (cloud). The galleries included images of a complete dose effect curve (0-5.0 Gy) and three types of irradiation scenarios simulating acute whole body, partial body and protracted exposure. The blood samples had been irradiated in vitro with gamma rays at the University of Ghent, Belgium. Two laboratories provided image galleries from Fluorescence plus Giemsa stained slides (3 h colcemid) and the image galleries from the other two laboratories contained images from Giemsa stained preparations (24 h colcemid). Each of the 8 participating laboratories analysed 3 dose points of the dose effect curve (scoring 100 cells for each point) and 3 unknown dose points (50 cells) for each of the 3 simulated irradiation scenarios. At first all analyses were performed in a QuickScan Mode without scoring individual chromosomes, followed by conventional scoring (only complete cells, 46 centromeres). The calibration curves obtained using these two scoring methods were very similar, with no significant difference in the linear-quadratic curve coefficients. Analysis of variance showed a significant effect of dose on the yield of dicentrics, but no significant effect of the laboratories, different methods of slide preparation or different incubation times used for colcemid. The results obtained to date within the MULTIBIODOSE project by a network of 8 collaborating laboratories throughout Europe are very promising. The dicentric assay in the web based scoring mode as a high throughput scoring strategy is a useful application for biodosimetry in the case of a large scale radiation accident.
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| 35. |
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| 36. |
- Rühm, W., et al.
(författare)
-
Vancouver call for action to strengthen expertise in radiological protection worldwide
- 2023
-
Ingår i: Radiation and Environmental Biophysics. - 0301-634X .- 1432-2099. ; 62:2, s. 175-180
-
Forskningsöversikt (refereegranskat)abstract
- Ionising radiation has been used for over a century for peaceful purposes, revolutionising health care and promoting well-being through its application in industry, science, and medicine. For almost as long, the International Commission on Radiological Protection (ICRP) has promoted understanding of health and environmental risks of ionising radiation and developed a protection system that enables the safe use of ionising radiation in justified and beneficial practices, providing protection from all sources of radiation. However, we are concerned that a shortage of investment in training, education, research, and infrastructure seen in many sectors and countries may compromise society’s ability to properly manage radiation risks, leading to unjustified exposure to or unwarranted fear of radiation, impacting the physical, mental, and social well-being of our peoples. This could unduly limit the potential for research and development in new radiation technologies (healthcare, energy, and the environment) for beneficial purposes. ICRP therefore calls for action to strengthen expertise in radiological protection worldwide through: (1) National governments and funding agencies strengthening resources for radiological protection research allocated by governments and international organisations, (2) National research laboratories and other institutions launching and sustaining long-term research programmes, (3) Universities developing undergraduate and graduate university programmes and making students aware of job opportunities in radiation-related fields, (4) Using plain language when interacting with the public and decision makers about radiological protection, and (5) Fostering general awareness of proper uses of radiation and radiological protection through education and training of information multipliers. The draft call was discussed with international organisations in formal relations with ICRP in October 2022 at the European Radiation Protection Week in Estoril, Portugal, and the final call announced at the 6th International Symposium on the System of Radiological Protection of ICRP in November 2022 in Vancouver, Canada.
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| 37. |
- Sato, T., et al.
(författare)
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Dose estimation for astronauts using dose conversion coefficients calculated with the PHITS code and the ICRP/ICRU adult reference computational phantoms
- 2011
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 50:1, s. 115-123
-
Tidskriftsartikel (refereegranskat)abstract
- Absorbed-dose and dose-equivalent rates for astronauts were estimated by multiplying fluence-to-dose conversion coefficients in the units of Gy.cm(2) and Sv.cm(2), respectively, and cosmic-ray fluxes around spacecrafts in the unit of cm(-2) s(-1). The dose conversion coefficients employed in the calculation were evaluated using the general-purpose particle and heavy ion transport code system PHITS coupled to the male and female adult reference computational phantoms, which were released as a common ICRP/ICRU publication. The cosmic-ray fluxes inside and near to spacecrafts were also calculated by PHITS, using simplified geometries. The accuracy of the obtained absorbed-dose and dose-equivalent rates was verified by various experimental data measured both inside and outside spacecrafts. The calculations quantitatively show that the effective doses for astronauts are significantly greater than their corresponding effective dose equivalents, because of the numerical incompatibility between the radiation quality factors and the radiation weighting factors. These results demonstrate the usefulness of dose conversion coefficients in space dosimetry.
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| 38. |
- Shakeri Manesh, Sara, et al.
(författare)
-
Mutations and chromosomal aberrations in hMTH1-transfected and non-transfected TK6 cells after exposure to low dose rates of gamma radiation
- 2014
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 53:2, s. 417-425
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to analyse the dose rate effect of gamma radiation at the level of mutations, chromosomal aberrations, and cell growth in TK6 cells with normal as well as reduced levels of hMTH1 protein. TK6 cells were exposed to gamma radiation at dose rates ranging from 1.4 to 30.0 mGy/h (chronic exposure) as well as 24 Gy/h (acute exposure). Cell growth, frequency of thymidine kinase mutants, and of chromosomal aberrations in painted chromosomes 2, 8, and 14 were analysed. A decline in cell growth and an increase in unstable-type chromosomal aberrations with increasing dose rate were observed in both cell lines. A dose rate effect was not seen on mutations or stable-type chromosomal aberrations in any of the two cell lines. Reduction in the hMTH1 protein does not influence the sensitivity of TK6 cells to gamma radiation. This result fits well with data of others generated with the same cell line.
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| 39. |
- Sihver, Lembit, 1962, et al.
(författare)
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Simulations of the MATROSHKA experiment at the international space station using PHITS
- 2010
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 49:3, s. 351-357
-
Tidskriftsartikel (refereegranskat)abstract
- Concerns about the biological effects of space radiation are increasing rapidly due to the perspective of long-duration manned missions, both in relation to the International Space Station (ISS) and to manned interplanetary missions to Moon and Mars in the future. As a preparation for these long-duration space missions, it is important to ensure an excellent capability to evaluate the impact of space radiation on human health, in order to secure the safety of the astronauts/cosmonauts and minimize their risks. It is therefore necessary to measure the radiation load on the personnel both inside and outside the space vehicles and certify that organ- and tissue-equivalent doses can be simulated as accurate as possible. In this paper, simulations are presented using the three-dimensional Monte Carlo Particle and Heavy-Ion Transport code System (PHITS) (Iwase et al. in J Nucl Sci Tech 39(11):1142-1151, 2002) of long-term dose measurements performed with the European Space Agency-supported MATROSHKA (MTR) experiment (Reitz and Berger in Radiat Prot Dosim 120:442-445, 2006). MATROSHKA is an anthropomorphic phantom containing over 6,000 radiation detectors, mimicking a human head and torso. The MTR experiment, led by the German Aerospace Center (DLR), was launched in January 2004 and has measured the absorbed doses from space radiation both inside and outside the ISS. Comparisons of simulations with measurements outside the ISS are presented. The results indicate that PHITS is a suitable tool for estimation of doses received from cosmic radiation and for study of the shielding of spacecraft against cosmic radiation.
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| 40. |
- Sihver, Lembit, 1962, et al.
(författare)
-
Voxel model of individual cells and its implementation in microdosimetric calculations using GEANT4
- 2014
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 53:3, s. 571-579
-
Tidskriftsartikel (refereegranskat)abstract
- Accurate dosimetric calculations at cellular and sub-cellular levels are crucial to obtain an increased understanding of the interactions of ionizing radiation with a cell and its nucleus and cytoplasm. Ion microbeams provide a superior opportunity to irradiate small biological samples, e.g., DNA, cells, and to compare their response to computer simulations. However, the phantoms used to simulate small biological samples at cellular levels are often simplified as simple volumes filled with water. As a first step to improve the situation in comparing measurements of cell response to ionizing radiation with model calculations, a realistic voxel model of a KB cell was constructed and used together with an already constructed geometry and tracking 4 (GEANT4) model of the horizontal microbeam line of the Centre d'Etudes Nucl,aires de Bordeaux-Gradignan (CENBG) 3.5 MV Van de Graaf accelerator at the CENBG, France. The microbeam model was then implemented into GEANT4 for simulations of the average number of particles hitting an irradiated cell when a specified number of particles are produced in the beam line. The result shows that when irradiating the developed voxel model of a KB cell with 200 alpha particles, with a nominal energy of 3 MeV in the beam line and 2.34 MeV at the cell entrance, 100 particles hit the cell on average. The mean specific energy is 0.209 +/- A 0.019 Gy in the nucleus and 0.044 +/- A 0.001 Gy in the cytoplasm. These results are in agreement with previously published data, which indicates that this model could act as a reference model for dosimetric calculations of radiobiological experiments, and that the proposed method could be applied to build a cell model database.
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| 41. |
- Staaf, Elina, 1984-, et al.
(författare)
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Micronuclei in human peripheral blood lymphocytes exposed to mixed beams of X-rays and alpha particles
- 2012
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 51:3, s. 283-293
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to analyse the cytogenetic effect of exposing human peripheral blood lymphocytes (PBL) to a mixed beam of alpha particles and X-rays. Whole blood collected from one donor was exposed to different doses of alpha particles ((241)Am), X-rays and a combination of both. All exposures were carried out at 37 °C. Three independent experiments were performed. Micronuclei (MN) in binucleated PBL were scored as the endpoint. Moreover, the size of MN was measured. The results show that exposure of PBL to a mixed beam of high and low linear energy transfer radiation led to significantly higher than expected frequencies of MN. The measurement of MN size did not reveal any differences between the effect of alpha particles and mixed beam. In conclusion, a combined exposure of PBL to alpha particles and X-rays leads to a synergistic effect as measured by the frequency of MN. From the analysis of MN distributions, we conclude that the increase was due to an impaired repair of X-ray-induced DNA damage.
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| 42. |
- Stark, K., et al.
(författare)
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External radiation doses from 137Cs to frog phantoms in a wetland area : In situ measurements and dose model calculations
- 2008
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 47:4, s. 481-489
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Tidskriftsartikel (refereegranskat)abstract
- For assessment of external radiation doses to frogs in a wetland area contaminated with 137Cs, frog phantoms were constructed from polymethyl methacrylate (PMMA). The frog phantoms contained thermoluminescence (TL) chips and were used in situ at two study sites to measure doses. To test if higher doses are received by the sensitive skin of frogs, extra-thin TL chips were applied close to the surface of the frog phantoms. In addition, the measured doses were compared with those calculated on the basis of soil sample data from the wetland multiplied with dose-conversion coefficients from the US Department of Energy's RESRAD-BIOTA code and from the ERICA assessment tool. Measured doses were generally lower than those calculated to ellipsoids used to model frogs. Higher doses were measured at the frog phantoms' surfaces in comparison to inner parts at one of the two sites indicating that the frogs' thin skin could receive a higher radiation dose than expected. In the efforts to assure protection of non-human biota, in situ measurements with phantoms provide valuable dose information and input to dose models in site-specific risk assessments of areas contaminated with radionuclides. © 2008 Springer-Verlag.
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| 43. |
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| 44. |
- Stenström, Kristina, et al.
(författare)
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The use of hair as an indicator of occupational (14)C contamination.
- 2010
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 49:1, s. 97-107
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a study in which the specific activity of (14)C in hair has been investigated as an easily determined bio-indicator of the integrated (14)C exposure (over several months). The study includes 28 Swedish workers handling (14)C-labelled compounds, or working in a (14)C-enriched environment. Hair samples from personnel at a Swedish nuclear power plant showed very low levels of (14)C contamination, if any. In contrast, personnel at the investigated research departments showed (14)C levels in hair of up to 60% above the natural specific activity of (14)C. Much higher levels, up to 80 times the natural specific activity of (14)C, were found in hair from individuals working at a pharmaceutical research laboratory. This contamination was, however, not solely an internal contamination. There were indications that most of the (14)C in the hair originated from airborne (14)C-compounds, which were adsorbed onto the hair. The difficulties in removing this external (14)C contamination prior to analysis are discussed, as are the possibilities of using accelerator mass spectrometry to analyse various types of samples for retrospective dose assessment.
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| 45. |
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| 46. |
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| 47. |
- Waldner, Lovisa, et al.
(författare)
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NaCl pellets for prospective dosimetry using optically stimulated luminescence : Signal integrity and long-term versus short-term exposure
- 2020
-
Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 59:4, s. 693-702
-
Tidskriftsartikel (refereegranskat)abstract
- Optically stimulated luminescence (OSL) signal properties of pellets from three types of NaCl (two household salts and one analytical grade salt) were investigated for their use in prospective dosimetry. Special attention was given to the OSL signal behaviour with time. The readout protocol was optimised in terms of preheat temperature, and the OSL signal yield of the NaCl pellet with time as well as the fading of the OSL signal with time was investigated. The effects of acute and chronic irradiations were compared. Irradiations and readout were performed using a Risø TL/OSL reader (TL/OSL-DA-15, DTU Nutech, Denmark). The optimal preheat temperature was determined to be 100 ºC, yielding OSL signals similar to a 1 h pause before OSL signal readout. There was no OSL signal fading observed as a function of time, but a decrease in the OSL signal yield of the NaCl pellets with time resulted in an apparent inverse fading when converting the OSL signal to an absorbed dose. For chronic radiation exposures of up to five weeks, the sensitivity of the NaCl pellets was found to be stable. The results of this study show that the use of NaCl pellets for prospective dosimetry is a promising, cost-effective, and accessible complement to commercially available alternatives for accurate absorbed dose determinations.
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| 48. |
- Wilson, WE, et al.
(författare)
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A Monte Carlo code for positive ion track simulation
- 1999
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Ingår i: Radiation and environmental biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 38:2, s. 97-104
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Tidskriftsartikel (refereegranskat)
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| 49. |
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| 50. |
- Wojcik, Andrzej, et al.
(författare)
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Educating about radiation risks in high schools : towards improved public understanding of the complexity of low-dose radiation health effects
- 2019
-
Ingår i: Radiation and Environmental Biophysics. - : SPRINGER. - 0301-634X .- 1432-2099. ; 58:1, s. 13-20
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Tidskriftsartikel (refereegranskat)abstract
- The levels of stochastic health effects following exposure to low doses of ionising radiation are not well known. A consequence of the uncertainty is that any radiation exposure is met with deep concernboth by the public and by scientists who disagree about how the partly conflicting results from low-dose studies should be interpreted. The concern is not limited to ionising radiation but is inherent to other areas of modern technologies such as biotechnology or electromagnetic fields. The everyday presence of advanced technologies confronts people with the necessity to take decisions and there is an ongoing debate regarding both the nature and magnitude of potential risks and how education efforts may empower peoples ' decision-making. In the field of radiation research there are different opinions regarding the optimal education methods, spanning from the idea that peoples' fears will be eliminated by introducing dose thresholds below which the risk is assumed to be zero, to suggestions of concentrating research efforts in an attempt to eliminate all uncertainties regarding the effects of low doses. The aim of this paper was to present our approach which is based on developing an education program at the secondary school level where students learn to understand the role of science in society. Teaching about radiation risk as a socio-scientific issue is not based on presenting facts but on showing risks in a broader perspective aiming at developing students' competency in making decisions based on informed assessment. We hope to stimulate and encourage other researchers to pursue similar approaches.
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