Modeling of dose and linear energy transfer homogeneity in cell nuclei exposed to alpha particles under various setup conditions.

PURPOSE: Different alpha exposure setups are often used to study the relation between biological responses and LET. This study aimed to estimate the dose heterogeneity and uncertainty in four exposure setups using Geant4 and PARTRAC codes. The importance of the irradiation system characteristics was shown in the context of reporting experimental results, especially in radiobiological studies at the molecular level. MATERIALS AND METHODS: Geant4 was used to estimate the dose distributions in cells grown on a disk exposed to alpha particles penetrating from above and below. The latter setup was simulated without and with a collimator. PARTRAC was used for the validation of Geant4 simulations based on distributions of the number of alpha particles penetrating a round nucleus and the deposited energy. RESULTS: The LET distributions obtained for simulated setups excluding the collimator were wide and non-Gaussian. Using a collimator resulted in a Gaussian LET distribution, but strongly reduced dose rate and dose homogeneity. Comparison between PARTRAC and Geant4 calculations for the cell nucleus exposed to alpha radiation showed an excellent agreement. CONCLUSIONS: The interpretation of results from radiobiological experiments with alpha particles should always cover the characteristics of the experimental setup, which can be done precisely with computational methods.

Socioscientific Issues in Science Education: An opportunity to Incorporate Education about Risk and Risk Analysis?

Socioscientific issues (SSI) concern social issues, often lacking simple solutions, that relate to science and often also risk controversies. SSIs have become an established part of science education, aiming to teach students not only about content knowledge but also about the nature of science and to offer them practice in argumentation and decision making. We performed a scoping review of the literature on SSI in science education research, in order to investigate if the topics covered would lean themselves to education about risk, and if risk is raised in these works. Using Web of Science we identified 296 empirical publications and 91 theoretical or review publications about SSI teaching in science education. The empirical publications covered studies performed in primary to tertiary school, most commonly upper secondary school (32%). The most frequently taught SSI themes were nature conservation, biotechnology, and climate change. Despite that these, as most of the other identified themes, clearly are connected to risk analysis and risk management, few publications raised the concept of risk and the methods of risk analysis. In fact, almost half (empirical: 48%, theoretical: 49%) did not mention risk at all. We argue that SSIs present an opportunity for risk researchers to engage with educators to incorporate risk in school science education and to contribute in developing teaching materials suitable toward that aim.

Monte Carlo dosimetry using Fluka code and experimental dosimetry with Gafchromic EBT2 and XR-RV3 of self-built experimental setup for radiobiological studies with low-energy X-rays.

Purpose: The aim of this research was to simulate self-built experimental setup for radiobiological research using X-ray diffraction C-tech tube and PW 3830 generator (PANalytical, Netherlands) and to calculate absorbed dose and to compare it with experimental dose measurements. The maximum X-ray energy was 60 keV.Materials and methods: Petri dish was specially adapted to hold biological cells during the irradiation process. Rotation of Petri dish ensured radiation homogeneity and effectiveness of rotation process was confirmed using EBT2 Gafchromic film. Monte Carlo simulation using Fluka 2011 2c.4 was used to model the setup and to calculate dose absorbed by live cells. The EBT2 and XR-RV3 Gafchromic films were used to estimate relative experimental absorbed dose.Results: The radiation homogeneity provided values with maximum deviation equal to ±3.5% from the average value and the absorbed dose rate was 0.9 Gy/min using simulation process and 1 Gy/min or 0.8 Gy/min using experimental methods (XR-RV3 and EBT2 Gafchromic film, respectively). All dose rate values show metrological compatibility.Conclusions: Influence of specially constructed Petri dish on absorbed dose was determined using simulations that showed that low-energy photons, emitted as characteristic line from borosilicate glass forming component of Petri dish, were source of increase in dose absorbed by cells. This experimental setup will be used to conduct radiobiological research.HighlightsA low-energy X-ray system constructed for radiobiological studies was used.Dosimetry was based on a Monte Carlo simulation using Fluka 2011 code version 2c.4.A specially designed rotating Petri dish ensured the uniformity of the radiation distribution.Gafchromic EBT2 and XR-RV3 films were used to experimental dosimetry.Monte Carlo and experimental dosimetry showed metrological compatibility.

CALIBRATION OF LOW ENERGY X-RAY EXPERIMENTAL SETUP WITH STRONGLY FILTERED BEAM USING DATA FROM A SEMICONDUCTOR AND A THERMOLUMINESCENT DETECTORS.

The calibration of low energy X-ray experimental setup with strongly filtered beam dedicated to radiobiological research was performed using the absorbed dose calculated from the data collected by two types detectors. For this purpose a semiconductor (Amptek, USA) and a thermoluminescent (Institute of Nuclear Physics, Krakow, Poland) detectors were applied. The absorbed dose in water values estimated by both detectors are in good agreement.

Funding for radiation research: past, present and future.

For more than a century, ionizing radiation has been indispensable mainly in medicine and industry. Radiation research is a multidisciplinary field that investigates radiation effects. Radiation research was very active in the mid- to late 20th century, but has then faced challenges, during which time funding has fluctuated widely. Here we review historical changes in funding situations in the field of radiation research, particularly in Canada, European Union countries, Japan, South Korea, and the US. We also provide a brief overview of the current situations in education and training in this field. A better understanding of the biological consequences of radiation exposure is becoming more important with increasing public concerns on radiation risks and other radiation literacy. Continued funding for radiation research is needed, and education and training in this field are also important.

The RENEB operational basis: complement of established biodosimetric assays.

PURPOSE: To set up an operational basis of the Realizing the European Network of Biodosimetry (RENEB) network within which the application of seven established biodosimetric tools (the dicentric assay, the FISH assay, the micronucleus assay, the PCC assay, the gamma-H2AX assay, electron paramagnetic resonance and optically stimulated luminescence) will be compared and standardized among the participating laboratories. METHODOLOGY: Two intercomparisons were organized where blood samples and smartphone components were irradiated, coded and sent out to participating laboratories for dosimetric analysis. Moreover, an accident exercise was organized during which each RENEB partner had the chance to practice the procedure of activating the network and to handle large amounts of dosimetric results. RESULTS: All activities were carried out as planned. Overall, the precision of dose estimates improved between intercomparisons 1 and 2, clearly showing the value of running such regular activities. CONCLUSIONS: The RENEB network is fully operational and ready to act in case of a major radiation emergency. Moreover, the high capacity for analyzing radiation-induced damage in cells and personal electronic devices makes the network suitable for large-scale analyses of low doses effects, where high numbers of samples must be scored in order to detect weak effects.

Dose assessment intercomparisons within the RENEB network using G0-lymphocyte prematurely condensed chromosomes (PCC assay).

PURPOSE: Dose assessment intercomparisons within the RENEB network were performed for triage biodosimetry analyzing G0-lymphocyte PCC for harmonization, standardization and optimization of the PCC assay. MATERIALS AND METHODS: Comparative analysis among different partners for dose assessment included shipment of PCC-slides and captured images to construct dose-response curves for up to 6 Gy γ-rays. Accident simulation exercises were performed to assess the suitability of the PCC assay by detecting speed of analysis and minimum number of cells required for categorization of potentially exposed individuals. RESULTS: Calibration data based on Giemsa-stained fragments in excess of 46 PCC were obtained by different partners using galleries of PCC images for each dose-point. Mean values derived from all scores yielded a linear dose-response with approximately 4 excess-fragments/cell/Gy. To unify scoring criteria, exercises were carried out using coded PCC-slides and/or coded irradiated blood samples. Analysis of samples received 24 h post-exposure was successfully performed using Giemsa staining (1 excess-fragment/cell/Gy) or centromere/telomere FISH-staining for dicentrics. CONCLUSIONS: Dose assessments by RENEB partners using appropriate calibration curves were mostly in good agreement. The PCC assay is quick and reliable for whole- or partial-body triage biodosimetry by scoring excess-fragments or dicentrics in G0-lymphocytes. Particularly, analysis of Giemsa-stained excess PCC-fragments is simple, inexpensive and its automation could increase throughput and scoring objectivity of the PCC assay.

Premature chromosome condensation (PCC) assay for dose assessment in mass casualty accidents.

The study was undertaken to establish a dose calibration curve for a practical PCC ring assay and to apply it in a simulated mass casualty accident. The PCC assay was validated against the conventional dicentric assay. A linear relationship was established for PCC rings after (60)Co gamma irradiation with doses up to 20 Gy. In the simulated accident experiment, 62 blood samples were analyzed with both the PCC ring assay and the conventional dicentric assay, applying a triage approach. Samples received various uniform and non-uniform (10-40% partial-body) irradiations up to doses of 13 Gy. The results indicated that both assays yielded good dose estimates for the whole-body exposure scenario, although in the lower-dose range (0-6 Gy) dicentric scoring resulted in more accurate whole-body estimates, whereas PCC rings were better in the high-dose range (>6 Gy). Neither assay was successful in identifying partial-body exposures, most likely due to the low numbers of cells scored in the triage mode. In conclusion, the study confirmed that the PCC ring assay is suitable for use as a biodosimeter after whole-body exposure to high doses of radiation. However, there are limitations for its use in the triage of people exposed to high, partial-body doses.