Low-level Radiation Exposure Research Articles

Why Low-level Radiation Exposure Should Not Be Feared.

The purpose of this paper is to address the public fear that is usually associated with low-level radiation exposure situations. Its ultimate objective is to provide persuasive assurances to informed but skeptical members of the public that exposure situations involving low-level radiation are not to be feared. Unfortunately, just acquiescing to an unsupportive public fear of low-level radiation is not without consequences. It is causing severe disruptions to the benefits that harnessed radiation can produce for the well-being of all humanity. In this pursuit, the paper provides the scientific and epistemological basis needed for regulatory reform by reviewing the history in quantifying, understanding, modeling, and controlling radiation exposure, including some of the evolving contributions of the United Nations Scientific Committee on the Effects of Atomic Radiation, the International Commission on Radiological Protection, and the myriad of international and intergovernmental organizations establishing radiation safety standards. It also explores the various interpretations of the linear no-threshold model and the insights gained from radiation pathologists, radiation epidemiologists, radiation biologists, and radiation protectionists. Given that the linear no-threshold model is so deeply imbedded in current radiation exposure guidance, despite the lack of a solid scientific base on the actually proven radiation effects at low-doses, the paper suggests near-term ways to improve regulatory implementation and better serve the public by excluding and/or exempting trivial low-dose situations from the regulatory scope. Several examples are given where the unsubstantiated public fear of low-level radiation has resulted in crippling the beneficial effects that controlled radiation offers to a modern society.

Ex-vivo dose response characterization of the recently identified EDA2R gene after low level radiation exposures and comparison with FDXR gene expression and the γH2AX focus assay

Objective Recently, promising radiation-induced EDA2R gene expression (GE) changes after low level radiation could be shown. Stimulated by that, in this study, we intended to independently validate these findings and to further characterize dose-response relationships in comparison to FDXR and the γH2AX-DNA double-strand break (DSB) focus assay, since both assays are already widely used for biodosimetry purposes. Materials and methods Peripheral blood samples from six healthy human donors were irradiated ex vivo (dose: ranging from 2.6 to 49.7 mGy). Subsequently, the fold-differences relative to the sham irradiated reference group were calculated. Radiation-induced changes in GE of FDXR and EDA2R were examined using the quantitative real-time polymerase-chain-reaction (qRT-PCR). DSB foci were quantified in 100 γH2AX + 53BP1 immunostained cells employing fluorescence microscopy. Examinations were performed at single time points enabling sufficient detection of both endpoints. Results A significant increase in EDA2R GE relative to the unexposed control was observed in the range of 2.6 mGy (1.6-fold, p = .045) to 5.4 mGy (2.2-fold, p = .0002), whereas the copy numbers increased linearly up to 13.1-fold at 49.7 mGy. On the contrary, FDXR upregulation (2.2-fold) became significant after a 22.6 mGy exposure (p ≤ .02) and increased linearly up to 4-fold at 49.7 mGy. A significant increase in radiation-induced foci (relative to unexposed, RIF-fd) was observed after 11.3 mGy (RIF-fd: 1.5 ± 0.5, p ≤ .03), while the foci increased linearly up to 3-fold at 49.7 mGy. From this, the FDXR and RIF-fd slopes have shown comparability, while the EDA2R slope was five times higher. Nevertheless, the coefficient of variation (CV) of EDA2R was about 30% higher than for RIF-fd. Conclusion Higher radiation-induced EDA2R GE changes and a lower radiation detection level compared to RIF-fd and FDXR GE changes examined under optimal conditions ex vivo on human samples appear promising. Yet, our results represent just the beginning of further studies to be conducted in animal models for further time- and dose-dependent evaluation and additional examinations on radiologically examined patients to evaluate the impact of confounder, such as age, sex, social behavior, or diseases.

Evaluation of the relationship between γ-H2AX biomarker levels and dose received after radiation exposure in abdominal-pelvic and chest CT scans.

As one of the most informative diagnostic radiation instruments, computed tomography (CT) has seen considerable improvement since its implementation in the 1970s; however, the possibility of low-dose radiation risk after CT procedures is still challenging and little is known about the biological effects of CT exposure on patients. As a result, this research aimed to look at the biological and cytogenetic effects of low-dose abdominal-pelvic and chest CT scans on adults, focusing on the number of γ-H2AX foci formation. Blood tests were taken before and 10 min after CT exams on patients aged 25-55 who were undergoing abdominal-pelvic and chest CT exams with very low-ionizing radiation exposure (TLD doses of 15.67-63.45 mGy). Blood lymphocytes that had been isolated, fixed, and stained were dyed with γ-H2AX antibodies. Finally, the percentage of phosphorylation of histone H2AX as an indicator of double-strand breaks was determined using a cytometry technique. Our findings showed that after CT examination, the mean value of γ-H2AX foci in patients increased (P < 0.0001). A statistically significant correlation between dose radiation and the number of γ-H2AX foci was also found (P = 0.047, r = 0.4731). The current study also found a pattern of elevated γ-H2AX foci in patients over 40 years of age relative to younger patients. A Significant activation of γ-H2AX foci was found in lymphocytes of peripheral blood samples of patients after CT compared to before CT scan. This increase in γ-H2AX foci levels in blood cells may be a useful quantitative biomarker of low-level radiation exposure in humans.

Indoor Radon and Thoron Measurement using CR-39 and LR-115 detectors in dwellings of Beni Mellal-Khenifra area (Morocco)

Radon and thoron are radioactive gases that are found naturally in the environment. They can seep into homes through cracks in the foundation, walls, and floors. Once inside, they can build up to levels that are harmful to human health. A study of radon and thoron concentrations in 65 homes in the Beni Mellal province of Morocco found that the levels varied widely, from 16 to 304 Bq.m-3 for radon and from 1 to 25 Bq.m-3 for thoron. The concentrations were found to be influenced by a number of factors, including the type of home, ventilation conditions, and the geological materials in the area. The average estimated dose received by the public due to radon and thoron in the homes studied was 45 ± 0.28 mSv.y-1 and 0.20 ± 0.01 mSv.y-1, respectively. These doses are considered to be low-level radiation exposure, but they can increase the risk of cancer over time. These results suggest that it would be beneficial to prohibit the construction of houses near industrial areas and to use construction materials that are adapted to the criteria of dose limitation.

Study of certain congenital malformations due to low-level radiation exposures from high background radiation areas

The coastal regions of some states (Kerala, Tamil Nadu, Andhra Pradesh and Orissa) in India are known to have plenty of thorium-rich minerals, therefore possess high external gamma radiation fields, and are identified as Natural High Background Radiation Areas. There are concerns about congenital malformations due to the high background radiation prevailing in the region.Therefore, scientists find interest to study the possible biological effects of low-level exposures on the local populace who are living with generations under these extraordinary radiation fields. The present study is an attempt to find the correlation between the incidences of certain congenital malformations through a 1:3 matched case-control study. A total of 75 subjects (58 mental retardation cases and 17 Cleft lip/palate cases) along with 225 controls were selected for the investigations. Indoor and outdoor gamma dose rates were measured using a halogen-quenched GM tube-based survey meter, while the indoor inhalation dose rates were measured based on the radon and progeny measurements using the twin cup dosimeters equipped with LR-115 Type II solid-state nuclear track detectors. Conditional logistic regression analysis was used to find out the correlation between the radiation dose with congenital malformation. This study found an insignificant risk of cleft lip/palate (but not for mental retardation) from the exposures to natural high external gamma radiation fields in the study area. Therefore, the results of the investigation indicate no explicit risk of congenital malformations by the high background natural radiation prevailing in the region.

The second decade of the blue butterfly in Fukushima: Untangling the ecological field effects after the Fukushima nuclear accident.

Many field observations of the biological effects of the Fukushima nuclear accident have been reported in the first decade after the accident. A series of observational and experimental studies have demonstrated causal adverse effects on the pale grass blue butterfly even at the low-level radiation exposure in the "field," contrary to the dosimetric view that insects are generally tolerant of radiation exposure. However, it has been demonstrated that the pale grass blue butterfly is tolerant of high oral doses of anthropogenic radioactive cesium (137 Cs) under "laboratory" conditions. This field-laboratory paradox can be explained by ecological field effects; for example, radiation stress in the field causes physiological and biochemical changes in the host plant, which then trophically affects butterfly larvae. The second decade of butterfly-based Fukushima research will be devoted to demonstrating how such adverse field effects occur. Changes in the host plant's nutritional contents likely affect butterfly physiology. The host plant may also upregulate secondary metabolites that affect herbivorous insects. The plant may be affected by changes in endophytic soil microbes in radioactively contaminated areas. If demonstrated, these results will reveal that the delicate ecological balances among the butterfly, its host plant, and soil microbes have been affected by radioactive pollution in Fukushima, which has important implications for environmental policies and human health. Integr Environ Assess Manag 2022;18:1539-1550. © SETAC.

Chronic Background Radiation Correlates With Sperm Swimming Endurance in Bank Voles From Chernobyl

Sperm quantity and quality are key features explaining intra- and interspecific variation in male reproductive success. Spermatogenesis is sensitive to ionizing radiation and laboratory studies investigating acute effects of ionizing radiation have indeed found negative effects of radiation on sperm quantity and quality. In nature, levels of natural background radiation vary dramatically, and chronic effects of low-level background radiation exposure on spermatogenesis are poorly understood. The Chernobyl region offers a unique research opportunity for investigating effects of chronic low-level ionizing radiation on reproductive properties of wild organisms. We captured male bank voles (Myodes glareolus) from 24 locations in the Chernobyl exclusion zone in 2011 and 2015 and collected information on sperm morphology and kinetics. The dataset is limited in size and there overall was a relatively weak correlation between background radiation and sperm quality. Still, some correlations are worth discussing. First, mid-piece segments of spermatozoa tended to be smaller in bank vole males from areas with elevated background radiation levels. Second, we demonstrated a significant positive relationship between background radiation dose rates and the proportion of static spermatozoa among males within and among study locations after 10 as well as 60 min of incubation. Our results provide novel evidence of damaging effects of low dose ionizing radiation on sperm performance in wild rodent populations, and highlight that this topic requires further study across the natural gradients of background radiation that exist in nature.

Overview of epidemiological studies of nuclear workers: opportunities, expectations, and limitations ∗ ∗ Based upon an invited presentation in Special Session 9 of the IRPA15 Virtual Congress, January–February 2021.

Epidemiological studies of those exposed occupationally to ionising radiation offer an important opportunity to directly check the assumptions underlying the international system of radiological protection against low-level radiation exposures. Recent nuclear worker studies, notably the International Nuclear Workers Study (INWORKS) and studies of the Mayak workforce in Russia, provide powerful investigations of a wide range of cumulative photon doses received at a low dose-rate over protracted periods, and broadly confirm radiation-related excess risks of leukaemia and solid cancers at around the levels predicted by standard risk models derived mainly from the experience of the Japanese atomic-bomb survivors acutely exposed principally to gamma radiation. However, the slope of the dose-response for solid cancers expressed in terms of the excess relative risk per unit dose, ERR/Gy, differs between INWORKS and Mayak, such that when compared with the slope derived from the atomic-bomb survivors, INWORKS does not provide obvious support for the use in radiological protection of a dose and dose-rate effectiveness factor greater than one whereas the Mayak workforce apparently does. This difference could be a chance effect, but it could also point to potential problems with these worker studies. Of particular concern is the adequacy of recorded doses received in the early years of operations at older nuclear installations, such as the potential for ‘missed’ photon doses. A further issue is how baseline cancer rates may influence radiation-related excess risks. There is scope for a considerable increase in the statistical power of worker studies, with longer follow-up capturing more deaths and incident cases of cancer, and further workforces being included in collaborative studies, but the difficulties posed by dosimetry questions should not be ignored and need to be the subject of detailed scrutiny.

SAFETY ASSESSMENTS FOR SUPPORTING THE APPLICATION OF NUCLEAR TECHNOLOGY IN INDONESIA AND A COMPREHENSIVE STUDY ON HIGH NATURAL RADIOACTIVITY AREA

SAFETY ASSESSMENTS FOR SUPPORTING THE APPLICATION OF NUCLEAR TECHNOLOGY IN INDONESIA AND A COMPREHENSIVE STUDY ON HIGH NATURAL RADIOACTIVITY AREA. Historically BATAN was established to investigate the negative impacts of nuclear explosions previously conducted in the Pacific area. However, this governmental institute is presently tasked to carry out research and development as well as services in the field of radiation safety and metrology. Therefore, this study aim to determine the activities carried out by BATAN in assessing the safety of workers and the environment. For instance, a standard source of dosimetry laboratory (SSDL) is used in calibration services to successfully support radiotherapy, with the highest achievement in the Designated Institute (DI) for Ionizing Radiation. The health research covers the application of gamma rays to create malaria vaccine, diagnose metabolic diseases with nuclear medicine techniques, and microdosimetry through radiodiagnostic assessment. This study also determined the effective dose and epidemiological study of radioecology and radiation biology in Mamuju (HBRA), which provides a unique opportunity to examine the health effects of chronic low-level radiation exposure to humans. Furthermore, the authors collaborated with Hirosaki University to obtain valuable information on the essential need to assess the health and physical status as well as cytogenetic and deoxynucleotide acid (DNA) damages in the lymphocytes of local populations. Dosimetry study was conducted by direct measurement in the field area by analyzing external radiation exposure of indoor and outdoor gamma dose rate. The internal radiation assessment was conducted by taking urine and inhaled air (radon) from the residents. Studies through the cytogenetic response supported by γ-H2AX, G0, and G2 micronucleus assays and TP53 showed no impacts on the natural radiation with significant differences compared to the control. Marine radioecology studies and radionuclides monitoring throughout the Indonesian archipelago showed no negative impacts as well. Nuclear emergency practice needs to be routinely conducted in the Center for strengthening safety and security cultures.

Radiation exposure associated with percutaneous fluoroscopically guided lag screw fixation for sacroiliac luxation in dogs.

To determine radiation exposure to surgical personnel and to evaluate the accuracy of a modified percutaneous lag screw fixation technique for sacroiliac luxation (SIL) under fluoroscopic guidance in dogs. Cadaveric experimental study. Seventeen beagle cadavers with iatrogenic SIL. Seventeen beagles with iatrogenic SIL underwent reduction and stabilization with 3.5-mm screws. Hypodermic needles (14 gauge) and fluoroscopy were used to orient two Kirschner wires for temporary stabilization and to guide drilling of glide and pilot holes using cannulated drill bits. Duration of surgery and radiation exposure were recorded. Postoperative computed tomographic evaluation of screw position and angulation was performed. Average time for fixation was 15.85 minutes (range, 6.37-33.5). Cumulative radiation doses of 0.4 mrem for the dominant arm of the assistant and 0 mrem for the primary surgeon were recorded. The mean dorsoventral and craniocaudal screw angles were 0.68° ± 3.4° (range - 5.4° to 9.5°) and 1.9° ± 3.2° (range - 4.3° to 9.1°), respectively. Sixteen of the 17 dogs had 100% sacral screw purchase, with the remaining case achieving 93.4% purchase. Fluoroscopy-assisted percutaneous placement of 3.5-mm cortical screws in lag fashion performed with 14-gauge needles in conjunction with Kirschner wires and cannulated drill bits yielded repeatable accurate screw placement with low levels of ionizing radiation exposure to the surgical team. The described technique may be a viable method for minimally invasive osteosynthesis fixation of SIL with low levels of radiation exposure to the surgical team. These results provide evidence to support further evaluation of radiation exposure in clinical cases and can aid in study design and sample size determination.

SOLLID - a single centre study to develop methods to investigate the effects of low radiation doses within nuclear medicine, to enable multicentre epidemiological investigations.

There is continuing debate concerning the risks of secondary malignancies from low levels of radiation exposure. The current model used for radiation protection is predicated on the assumption that even very low levels of exposure may entail risk. This has profound implications for medical procedures involving ionising radiation as radiation doses must be carefully monitored, and for diagnostic procedures are minimised as far as possible. This incurs considerable expense. The SOLLID study (ClinicalTrials.gov Identifier: NCT03580161) aims to develop the methodology to enable a large-scale epidemiological investigation of the effect of radiopharmaceutical administrations to patients undergoing diagnostic nuclear medicine procedures. Patients will undergo a series of scans in addition to that acquired as standard of care to enable the radiation doses delivered to healthy organs to be accurately calculated. Detailed analysis will be performed to determine the uncertainty in the radiation dose calculations as a function of the number and type of scans acquired. It is intended that this will inform a subsequent long-term multicentre epidemiological study that would address the question definitively. Secondary aims of the study are to evaluate the range of absorbed doses that are delivered from diagnostic nuclear medicine procedures and to use current risk models to ascertain the relative risks from these administrations.

Spectral CT quantification stability and accuracy for pediatric patients: A phantom study.

BackgroundSpectral computed tomography (spectral CT) provides access to clinically relevant measures of endogenous and exogenous materials in patients. For pediatric patients, current spectral CT applications include lesion characterization, quantitative vascular imaging, assessments of tumor response to treatment, and more.ObjectiveThe aim of this study is a comprehensive investigation of the accuracy and stability of spectral quantifications from a spectral detector‐based CT system with respect to different patient sizes and radiation dose levels relevant for the pediatric population.Materials and methodsA spectral CT phantom with tissue‐mimicking materials and iodine concentrations relevant for pediatric imaging was scanned on a spectral detector CT system using a standard pediatric abdominal protocol at 100%, 67%, 33% and 10% of the nominal radiation dose level. Different pediatric patient sizes were simulated using supplemental 3D‐printed extension rings. Virtual mono‐energetic, iodine density, effective atomic number, and electron density results were analyzed for stability with respect to radiation dose and patient size.ResultsCompared to conventional CT imaging, a pronounced improvement in the stability of attenuation measurements across patient size was observed when using virtual mono‐energetic images. Iodine densities were within 0.1 mg/ml, effective atomic numbers were within 0.26 atomic numbers and electron density quantifications were within ±1.0% of their respective nominal values. Relative to the nominal dose clinical protocol, differences in attenuation of all tissue‐mimicking materials were maintained below 1.6 HU for a 33% dose reduction, below 2.7 HU for a 67% dose reduction and below 3.7 HU for a 90% dose reduction, for all virtual mono‐energetic energies equal to or greater than 50 keV. Iodine, and effective atomic number quantifications were stable to within 0.1 mg/ml and 0.06 atomic numbers, respectively, across all measured dose levels.ConclusionSpectral CT provides accurate and stable material quantification with respect to radiation dose reduction (up to 90%) and differing pediatric patient size. The observed consistency is an important step towards quantitative pediatric imaging at low radiation exposure levels.

Cancer risk of CT scan in COVID-19: Resolving the dilemma.

Cancer risk of CT scan in COVID-19: Resolving the dilemma.

Radiation Nation: Three Mile Island and the Political Transformation of the 1970s by Natasha Zaretsky

Reviewed by: Radiation Nation: Three Mile Island and the Political Transformation of the 1970s by Natasha Zaretsky Dolores L. Augustine (bio) Radiation Nation: Three Mile Island and the Political Transformation of the 1970s By Natasha Zaretsky. New York: Columbia University Press, 2018. Pp. 285. Natasha Zaretsky’s approach to the 1979 nuclear power plant accident at Three Mile Island, Pennsylvania, is deeply rooted in cultural history, yet also draws on political economy. The big question looming over Radiation Nation, as well as her earlier work, No Direction Home, is “how the New Left revolutions of the 1960s and 1970s transformed American culture and society but failed to halt the nation’s rightward political march” (p. xix). She makes an original contribution to the literature, centered on gender and family. She contends that the upsurge of local protest over this disaster led to a profound realignment of American conservative politics, drawing [End Page 981] on various strands of leftist movements in the 1960s and 1970s such as environmentalism and feminism, while also tapping into religious beliefs and the anti-abortion movement. Zaretsky’s central thesis is that this catastrophic failure of technology brought about what she calls “biotic nationalism,” rooted in the body, specifically an “aggrieved nationalism” based on the idea that “the nation has callously turned its back on the bodies of its own citizens” (p. xvii). White, working-class Americans saw themselves as the nation’s most loyal citizens, she argues, and felt that their government had treated them as disposable in the Vietnam War. According to the author, in 1979, this sense of betrayal initially centered on the callous disregard of how men’s bodies were treated in that conflict. In the wake of Three Mile Island, the female body and its reproductive capacity took center stage. Orders to evacuate pregnant women and preschoolers living within a 5-mile range of the nuclear power plant only added to residents’ anxiety and distrust in the government. Women argued that the release of radioactively contaminated water and gases from the nuclear power plant turned them, the unborn children in their wombs, their children, and their descendants into “guinea pigs” (p. 100). The scientific background was an ongoing debate about the somatic effects of low-level radiation exposure (notably cancer), as well as older concerns about radioactivity’s genetic impact (associated with eugenics). According to the author, it was the associated image of the wounded nation and the wounded fetus that created such a powerful narrative, making abortion a central issue for the burgeoning conservative movement. However, this preoccupation with the body did not carry over into concerns over gun ownership, healthcare, or food insecurity among American conservatives. The Three Mile Island crisis strengthened anti-statist conservatism in the United States, unlike in West Germany, where anti-nuclear power activism ushered in the rise of the leftist Green Party. The U.S. Nuclear Regulatory Commission came to be considered a “hostile, distant authority, callous toward residents’ physical suffering and psychological distress” (p. 142). In the final chapter the author moves on to the Second Cold War and the nuclear freeze movement of the 1980s. She points to parallels with the Three Mile Island protests: the importance of the “imperiled body” as a theme in the movement, concern about genetic damage, the significance of women and maternalist arguments, and appeals to Middle America. The concept of “Nuclear Winter”—a devastation of the planet caused by nuclear war and leading to mass extinction, also of the human race—placed reproduction and the “unborn” at the heart of the anti-nuclear narrative. She is critical of what she sees as the nuclear freeze movement’s failure to embrace the ideals of the New Left, asserting that freeze activists “unwittingly aligned themselves with the new nationalism of the 1980s” (p. 171). Thus, in her reading, the nuclear freeze movement failed to block the rightward [End Page 982] turn in American politics due to the lack of political commitment and apolitical anti-nuke stance. It is worth remembering, however, that some scholars believe that overcoming political divides was key to ending the Cold War. Those who wish to learn more about the Three Mile Island accident...

Radiation epidemiology and health effects following low-level radiation exposure

Radiation epidemiology is the study of human disease following radiation exposure to populations. Epidemiologic studies of radiation-exposed populations have been conducted for nearly 100 years, starting with the radium dial painters in the 1920s and most recently with large-scale studies of radiation workers. As radiation epidemiology has become increasingly sophisticated it is used for setting radiation protection standards as well as to guide the compensation programmes in place for nuclear weapons workers, nuclear weapons test participants, and other occupationally exposed workers in the United States and elsewhere. It is known with high assurance that radiation effects at levels above 100–150 mGy can be detected as evidenced in multiple population studies conducted around the world. The challenge for radiation epidemiology is evaluating the effects at low doses, below about 100 mGy of low-linear energy transfer radiation, and assessing the risks following low dose-rate exposures over years. The weakness of radiation epidemiology in directly studying low dose and low dose-rate exposures is that the signal, i.e. the excess numbers of cancers associated with low-level radiation exposure, is so very small that it cannot be seen against the very high background occurrence of cancer in the population, i.e. a lifetime risk of incidence reaching up to about 38% (i.e. 1 in 3 persons will develop a cancer in their lifetime). Thus, extrapolation models are used for the management of risk at low doses and low dose rates, but having adequate information from low dose and low dose-rate studies would be highly desirable. An overview of recently conducted radiation epidemiologic studies which evaluate risk following low-level radiation exposures is presented. Future improvements in risk assessment for radiation protection may come from increasingly informative epidemiologic studies, combined with mechanistic radiobiologic understanding of adverse outcome pathways, with both incorporated into biologically based models.

Assessment of thermal protective performance of firefighter’s clothing by a sweating manikin in low-level radiation

PurposeThe purpose of this paper is to assess the thermal protective performance of firefighter’s clothing by a sweating manikin in low-level radiation.Design/methodology/approachA new method and a novel objective index based on measurements of the sweating thermal manikin are proposed to measure the thermal protection performance of firefighter’s clothing under low-level radiation exposure of 3.0 kW/m2. Finally, the effect of thermal insulation on thermal protective performance of firefighter’s clothing was analyzed.FindingsThe results reveal that the new index which used the changing rate of core temperature of the clothed manikin is a vital indicator of the thermal protection performance. Furthermore, the results demonstrated that there is a linear correlation between thermal protection performance of firefighter’s clothing and the thermal insulation.Originality/valueA new method and a novel objective index are proposed to quantify the thermal protective performance of firefighter’s clothing in low-level radiation.

Long-Term Consequences of the Chernobyl Radioactive Fallout: An Exploration of the Aggregate Data.

This study investigates the association between the radioactive 137 Cesium fallout originated by the 1986 Chernobyl nuclear accident and dispersed over Western Europe, as a result of a combination of radioactive cloud passage days and rainy days over a 10-day period, and long-term health patterns and related costs. Since the half-life of 137 Cesium is 30.17 years, part of the radioactivity in the affected regions is still present today, and it is usually still detected in the food chain, although at lower concentration levels. We match longitudinal data on neoplasm incidence over the time span 2000-2013 in a number of European regions not immediately adjacent to Chernobyl with the randomly distributed levels of cesium deposition after the nuclear disaster in order to assess whether we can detect an association with the long-term health effects on the European population through a random effects model. Considering 3 levels of fallout deposition-low, medium, and high-hospital discharges after treatment for neoplasms are, respectively, 0.36, 0.44, and 0.98 discharges over 100 inhabitants higher compared to regions with no fallout, with the population average being around 1.7 hospital discharges by neoplasms over 100 inhabitants. We checked the robustness of our findings to a number of tests including a placebo simulation and different model specifications. Radioactive fallout is positively associated with a higher incidence of hospital discharges after treatment for neoplasms almost 30 years after its release, with larger effects in regions where the radioactivity was more intense. Our estimates are comparable to the findings of the largest-scale study on the long-term health effects of continuous low levels of radiation exposure among workers in the nuclear industry and suggest that more research is needed on this topic, given its enormous importance for public health and safety.

LINE-1 hypomethylation is associated with radiation-induced genomic instability in industrial radiographers.

Global DNA hypomethylation is proposed as a potential biomarker for cancer risk associated with genomic instability, which is an important factor in radiation-induced cancer. However, the associations among radiation exposure, changes in DNA methylation, and carcinogenesis are unclear. The aims of this study were (1) to examine whether low-level occupational radiation exposure induces genomic DNA hypomethylation; and (2) to determine the relationships between radiation exposure, genomic DNA hypomethylation and radiation-induced genomic instability (RIGI) in industrial radiographers. Genomic DNA methylation levels were measured in blood DNA from 40 radiographers and 28 controls using the LINE-1 pyrosequencing assay and the luminometric methylation assay. Further, the micronucleus-centromere assay was performed to measure aneuploidy of chromosomes 1 and 4 as a marker of delayed RIGI. Genomic DNA methylation levels were significantly lower in radiographers than those in controls. LINE-1 hypomethylation was not significantly correlated with recent 1-year, recent 3-year, or total cumulative radiation doses in radiographers; however, LINE-1 hypomethylation significantly correlated with the cumulative radiation dose without recent 3-year exposure data (D3dose, r = -0.39, P < 0.05). In addition, LINE-1 hypomethylation was a significant contributor to aneuploidy frequency by D3dose (F (2, 34) = 13.85, P < 0.001), in which a total of 45% of the variance in aneuploidy frequency was explained. Our results provide suggestive evidence regarding the delayed effects of low-dose occupational radiation exposure in radiographers and its association with LINE-1 hypomethylation; however, additional studies using more subjects are needed to fully understand the relationship between genomic DNA hypomethylation and RIGI. Environ. Mol. Mutagen. 60: 174-184, 2019. © 2018 Wiley Periodicals, Inc.

Clinical Significance of Low-Level Radiation Exposure in Mammalian Radiobiology Investigated by Radon (Rn&lt;sup&gt;222&lt;/sup&gt;) Dissolved Water Intake in a Dog

To establish the clinical significance of low-level radiation exposure, this study was conducted under the artificial radioactive circumstances, such as internal exposure of alpha-ray with radon (Rn222) dissolved water (RDW) intake, and its production method is uncomplicated and presented as public property by the third party. Here, we report that this method provides the wide range of availabilities in radioactivity. This 1-year experimental study investigated the effect of RDW on a dog as a mammal model, resulted in no biochemical harmfulness. To acquire the accuracy of this consequence, the accumulation of more data in mammal models is indespensable with consistent radioactive backgrounds.

Chronic long-term risk of low-level radiation exposure: Bridging the lay/expert divide

ABSTRACTThe failure of experts and lay people to understand each other has been fueling conflict around the environmental clean-up of the many sites in the United States that are contaminated by the nuclear weapons program. This mutual distrust was exacerbated by the culture of secrecy surrounding the atomic weapons program during World War II, and later by the innate culture of bureaucracy in the federal agencies that have sprung up since then. A prime example of this problem can be found in the regulation of chronic long-term risk from low-level radiation exposure affecting communities in Missouri’s North St. Louis County. This case study illuminates this divide, and illustrates opportunities to close it.