ArticleLiterature Review

Low dose or low dose rate ionizing radiation-induced health effect in the human

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  • National Research Centre for Radiation Medicine of National Academy of Medical Sciences of Ukraine
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... However, whether such detrimental effects can be produced after exposure to low-dose IR is still controversial (10). Usually, a low dose of IR is a radiation dose of 100 mSv or less (≤100 mGy) (11). Epidemiological and clinical studies show that low-dose IR may induce cancer, cardiovascular diseases and long-term psychological consequences (11). ...
... Usually, a low dose of IR is a radiation dose of 100 mSv or less (≤100 mGy) (11). Epidemiological and clinical studies show that low-dose IR may induce cancer, cardiovascular diseases and long-term psychological consequences (11). For example, increased risk of leukemia and brain tumors have been reported in pediatric patients following doses of 30-50 mGy, as observed using CT scans (12). ...
... There are still questions, however, about the impact of even lower doses of exposure for which classical epidemiological studies are limited. In addition, when the health risks associated with exposure to low-dose IR were estimated in previous studies, there were many uncertainties (11,13). These uncertainties significantly affect almost every facet of society, especially medical care, energy production, occupational health and safety, manufacturing and industry, and all these factors emphasize the importance of low-dose IR research (10,13,14). ...
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Exposure to environmental ionizing radiation (IR) is ubiquitous, and large-dose exposure to IR is known to cause DNA damage and genotoxicity which is associated with an increased risk of cancer. Whether such detrimental effects are caused by exposure to low-dose IR is still debated. Therefore, rapid and early estimation of absorbed doses of IR in individuals, especially at low levels, using radiation response markers is a pivotal step for early triage during radiological incidents to provide adequate and timely clinical interventions. However, there is currently a crucial shortage of methods capable of determining the extent of low-dose IR exposure to human beings. The phosphorylation of histone H2AX on serine 139 (designated γ-H2AX), a classic biological dosimeter, can be used to evaluate the DNA damage response. We have developed an estimation assay for low-level exposure to IR based on the mass spectrometry quantification of γ-H2AX in blood. Human peripheral blood lymphocytes sensitive to low-dose IR, maintaining low temperature (4°C) and adding enzyme inhibitor are proven to be key steps, possibly insuring that a stable and marked γ-H2AX signal in blood cells exposed to low-dose IR could be detected. For the first time, DNA damage at low dose exposures to IR as low as 0.01 Gy were observed using the sensitive variation of γ-H2AX with high throughput mass spectrometry quantification in human peripheral blood, which is more accurate than the previously reported methods by virtue of isotope-dilution mass spectrometry, and can observe the time effect of DNA damage. These in vitro cellular dynamic monitoring experiments show that DNA damage occurred rapidly and then was repaired slowly over the passage of post-irradiation time even after exposure to very low IR doses. This assay was also used to assess different radiation exposures at the in vitro cellular level. These results demonstrate the potential utility of this assay in radiation biodosimetry and environmental risk assessment.
... The authors called into question the safety of LDIR for diagnostic purposes [169]. Another review by Tang and Loganovsky (2018) concluded that LDIR (<100 mGy) or low dose rate ionising radiation (<6 mSv/hr) may or may not induce cancer, depending on a variety of factors including demographics, lifestyle, and diagnostic accuracy [170]. However, LDIR may increase incidences of vascular diseases, cognitive and mental health disorders, eye diseases, and other pathologies, whilst reducing cancer mortality and mutations, and increasing longevity [170]. ...
... Another review by Tang and Loganovsky (2018) concluded that LDIR (<100 mGy) or low dose rate ionising radiation (<6 mSv/hr) may or may not induce cancer, depending on a variety of factors including demographics, lifestyle, and diagnostic accuracy [170]. However, LDIR may increase incidences of vascular diseases, cognitive and mental health disorders, eye diseases, and other pathologies, whilst reducing cancer mortality and mutations, and increasing longevity [170]. Despite more studies beginning to investigate radiosensitivity [171], it remains unclear what effect LDIR truly has on different organs or tissues. ...
... Arguably, the most important takeaway from this study is that, without radiation, Tg female mice have higher Aβ levels than Tg male mice; however, radiation reduced these levels in the female Tg mice, which correlated with decreased microglial activation as determined by CD68 receptor staining [169]. Recently, rat models of AD were also shown to have improved memory performance in response to a higher dose of ionising radiation of 2 Gy/day for 5 days, without increasing neuroinflammation or amyloid load [170]. LDIR has also been shown to promote an M2 morphology in LPS treated mice microglial (BV2) cells [171]. ...
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Microglia, the innate immune cells of the central nervous system, play a pivotal role in the modulation of neuroinflammation. Neuroinflammation has been implicated in many diseases of the CNS, including Alzheimer’s disease and Parkinson’s disease. It is well documented that microglial activation, initiated by a variety of stressors, can trigger a potentially destructive neuroinflammatory response via the release of pro-inflammatory molecules, and reactive oxygen and nitrogen species. However, the potential anti-inflammatory and neuroprotective effects that microglia are also thought to exhibit have been under-investigated. The application of ionising radiation at different doses and dose schedules may reveal novel methods for the control of microglial response to stressors, potentially highlighting avenues for treatment of neuroinflammation associated CNS disorders, such as Alzheimer’s disease and Parkinson’s disease. There remains a need to characterise the response of microglia to radiation, particularly low dose ionising radiation.
... The risk of atherosclerosis resulting from LDR exposure has not yet been accurately determined. However, a disease resulting from LDR exposure has been continuously reported, indicating the need for further research (Baker et al. 2011;Kreuzer 2017;Tang and Loganovsky 2018;Tapio et al. 2021). Thus, the purpose of this study was to investigate the effects of LDR-induced changes in cytokine expression on the progression of atherosclerosis. ...
... Although the system of radiological protection has been highly improved and permissible occupational radiation exposure of radiation workers dose limits have been used worldwide, LDR has become a global issue as its hazardous effects have been reported (Baker et al. 2011;Kreuzer 2017;Tang and Loganovsky 2018;Tapio et al. 2021). However, LDR exposure cause different biological effects and have organ specificity (Shin et al. 2020). ...
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Purpose Atherosclerosis is a lipid-driven chronic inflammatory disease that causes cardiovascular diseases (CVD). The association between radiation and atherosclerosis has already been demonstrated; however, the effects of low-dose radiation (LDR) exposure on atherosclerosis have not been reported. Our study aims to propose that LDR may cause atherosclerosis phenotypes by the upregulation of plasminogen activator inhibitor-1 (PAI-1) and downregulation of androgen receptor (AR), which are cytokines secreted from the liver. Methods Low-density lipoprotein (LDL) receptor deficient (Ldlr−/−) mice were irradiated at 50 mGy, 100 mGy, and 1000 mGy. LDR irradiated Ldlr−/− mice serum was analyzed by cytokine array and proteomics with silver staining. Oil Red O staining and BODIPY staining were performed to determine lipid accumulation in Human umbilical vein endothelial cells (HUVECs). Foam cell formation and monocyte recruitment were assessed through co-culture system with HUVECs and THP-1 cells. Results After irradiation with LDR (100 mGy) the mice showed atherosclerotic phenotypes and through analysis results, we selected regulated cytokines, PAI-1 and AR, and found that these were changed in the liver. LDR-regulated cytokines have the potential to be transported to endothelial cells and induce lipid accumulation, inflammation of monocytes, increased oxidized low-density lipoprotein (oxLDL) and foam cells formation, that were series of phenotypes lead to plaque formation in endothelial cells and induces atherosclerosis. As a further aspect of this study, testosterone undecanoate (TU) was found to pharmacologically inhibit a series of atherosclerotic phenotypes exhibited by LDR. This study suggests a role for PAI-1 and AR in regulating the development of atherosclerosis after LDR exposure. Targeting PAI-1 and AR could serve as an attractive strategy for the management of atherosclerosis following LDR exposure.
... DNA alterations caused by space radiation are not necessarily repaired [69] by the dedicated cellular machineries [52,54], which can perturb DNA replication and cause genomic instability [70], thereby leading to mutations of various possible types in somatic cells that may produce detrimental effects such as cellular deregulations, cell death and cancers (carcinogenesis) [71,72,73,74,75]. These may also be the cause of various health issues and pathologies [76,77,78], including nervous system alterations [79,80]. Such somatic cell DNA alterations would not be transmitted to the offspring. ...
... Of course, if genetic alterations caused by space radiation occur in germ line (sexual) cells, they are, only in this case -if not repaired -, transmitted to the offspring [83], potentially leading to congenital diseases and/or other abnormalities [76,77,84], if the associated mutations are not neutral. Studies on mouse models show that mutation rates increase in germ line cells when they are chronically exposed to ionizing radiations, especially in males, and that the effect becomes much greater for acute exposures and the same can likely be extended to humans [83,85]. ...
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We updated the agent based Monte Carlo code HERITAGE that simulates human evolution within restrictive environments such as interstellar, sub-light speed spacecraft in order to include the effects of population genetics. We incorporated a simplified -- yet representative -- model of the whole human genome with 46 chromosomes (23 pairs), containing 2110 building blocks that simulate genetic elements (loci). Each individual is endowed with his/her own diploid genome. Each locus can take 10 different allelic (mutated) forms that can be investigated. To mimic gamete production (sperm and eggs) in human individuals, we simulate the meiosis process including crossing-over and unilateral conversions of chromosomal sequences. Mutation of the genetic information from cosmic ray bombardments is also included. In this first paper of a series of two, we use the neutral hypothesis: mutations (genetic changes) have only neutral phenotypic effects (physical manifestations), implying no natural selection on variations. We will relax this assumption in the second paper. Under such hypothesis, we demonstrate how the genetic patrimony of multi-generational crews can be affected by genetic drift and mutations. It appears that centuries-long deep space travels have small but unavoidable effects on the genetic composition/diversity of the traveling populations that herald substantial genetic differentiation on longer time-scales if the annual equivalent dose of cosmic ray radiation is similar to the Earth radioactivity background at sea level. For larger doses, genomes in the final populations can deviate more strongly with significant genetic differentiation that arises within centuries.
... However, in the low dose range (<100 mGy), other phenomena than a linear response can occur. There is evidence that low doses of IR could have beneficial effects, such as hormesis and adaptive responses (19,20). Hormesis occurs when exposure to low IR doses produces a favorable effect, whereas high IR doses result in detrimental effects (21). ...
... Adaptive responses occur when a very low dose, or priming dose, stimulates cells which results in increased resistance to a second, larger dose of the same trigger at a later time point. This could include the activation of genes associated with DNA damage repair, stress scavenging, cell cycle control and apoptosis (19,20). DNA DSBs are the most crucial DNA lesions that are associated with increased cancer risk and IR exposure. ...
Article
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Stem cells contained within the dental mesenchymal stromal cell (MSC) population are crucial for tissue homeostasis. Assuring their genomic stability is therefore essential. Exposure of stem cells to ionizing radiation (IR) is potentially detrimental for normal tissue homeostasis. Although it has been established that exposure to high doses of ionizing radiation (IR) has severe adverse effects on MSCs, knowledge about the impact of low doses of IR is lacking. Here we investigated the effect of low doses of X-irradiation with medical imaging beam settings (<0.1 Gray; 900 mGray per hour), in vitro , on pediatric dental mesenchymal stromal cells containing dental pulp stem cells from deciduous teeth, dental follicle progenitor cells and stem cells from the apical papilla. DNA double strand break (DSB) formation and repair kinetics were monitored by immunocytochemistry of γH2AX and 53BP1 as well as cell cycle progression by flow cytometry and cellular senescence by senescence-associated β-galactosidase assay and ELISA. Increased DNA DSB repair foci, after exposure to low doses of X-rays, were measured as early as 30 min post-irradiation. The number of DSBs returned to baseline levels 24 h after irradiation. Cell cycle analysis revealed marginal effects of IR on cell cycle progression, although a slight G 2 /M phase arrest was seen in dental pulp stromal cells from deciduous teeth 72 h after irradiation. Despite this cell cycle arrest, no radiation-induced senescence was observed. In conclusion, low X-ray IR doses (< 0.1 Gray; 900 mGray per hour), were able to induce significant increases in the number of DNA DSBs repair foci, but cell cycle progression seems to be minimally affected. This highlights the need for more detailed and extensive studies on the effects of exposure to low IR doses on different mesenchymal stromal cells.
... The use of IR in medical diagnosis and cancer treatment has increased significantly. Consequently, nuclear waste from hospitals accounts for approximately 14% of the world's total annual radiation exposure [16]. Several studies have shown that long-term exposure to low-dose IR in catheterization laboratories increases the risk of cardiovascular diseases, indicating that it causes enhanced vascular aging and early atherosclerosis [17]. ...
... Effects References Medical radiation (radiographs, computed tomography scans) Cardiovascular disease, premature aging, inflammation, and neurodegenerative diseases [16,17,21] Natural background radiation Inflammation, immunosenescence, thyroid cancer, and childhood leukemia [41,42] [ 43,44] Nuclear disasters "Chernobyl AIDS," CNS damage, premature aging, atherosclerosis, and senile encephalopathy [28][29][30] [31,32] ...
Article
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Population aging is occurring rapidly worldwide, challenging the global economy and healthcare services. Brain aging is a significant contributor to various age-related neurological and neuropsychological disorders, including Alzheimer's disease and Parkinson's disease. Several ex-trinsic factors, such as exposure to ionizing radiation, can accelerate senescence. Multiple human and animal studies have reported that exposure to ionizing radiation can have varied effects on organ aging and lead to the prolongation or shortening of life span depending on the radiation dose or dose rate. This paper reviews the effects of radiation on the aging of different types of brain cells, including neurons, microglia, astrocytes, and cerebral endothelial cells. Further, the relevant molecular mechanisms are discussed. Overall, this review highlights how radiation-induced senescence in different cell types may lead to brain aging, which could result in the development of various neurological and neuropsychological disorders. Therefore, treatment targeting radiation-induced oxidative stress and neuroinflammation may prevent radiation-induced brain aging and the neuro-logical and neuropsychological disorders it may cause.
... 22 Therefore, medical exposure to IR accounts for about 14% of the total annual exposure worldwide, which makes it the largest man-made source of IR exposure to the general population. 22, 23 The rapid increase in the use of IR for medical diagnostics and associated health concerns, have led to several retrospective epidemiological studies that investigated whether IR exposure due to medical diagnostics, such as CT scans, is associated with an increase in cancer incidence later in life. Pearce et al. 24 suggests that the use of CT scans in children could triple the risk of leukemia and brain cancers later in life. ...
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Objectives This review aimed to present studies that prospectively investigated biological effects in patients following diagnostic dentomaxillofacial radiology (DMFR). Methods Literature was systematically searched to retrieve all studies assessing radiobiological effects of using X-ray imaging in the dentomaxillofacial area, with reference to radiobiological outcomes for other imaging modalities and fields. Results There is a lot of variability in the reported radiobiological assessment methods and radiation dose measures, making comparisons of radiobiological studies challenging. Most radiological DMFR studies are focusing on genotoxicity and cytotoxicity, data for 2D dentomaxillofacial radiographs, albeit with some methodological weakness biasing the results. For CBCT, available evidence is limited and few studies include comparative data on both adults and children. Conclusions In the future, one will have to strive towards patient-specific measures by considering age, gender and other individual radiation sensitivity-related factors. Ultimately, future radioprotection strategies should build further on the concept of personalized medicine, with patient-specific optimization of the imaging protocol, based on radiobiological variables.
... This mainly involves increased oxidative stress as well as inflammation, playing a role in radiation-induced cardiovascular damage, which has been highlighted by multiple studies (Soucy et al., 2011;Coleman et al., 2015;Seawright et al., 2017; Table 1C). The relationship between dosage and response for some biological effects are therefore not linear and not proportional to dose (Betlazar et al., 2016(Betlazar et al., , 2020(Betlazar et al., , 2021Puukila et al., 2017;Tang and Loganovsky, 2018). Chronic low doses of radiation (<100 mGy) may not be detrimental and could even induce benefits to the central nervous system and possibly to the cardiovascular system. ...
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In recent years, there has been an increasing interest in space exploration, supported by the accelerated technological advancements in the field. This has led to a new potential environment that humans could be exposed to in the very near future, and therefore an increasing request to evaluate the impact this may have on our body, including health risks associated with this endeavor. A critical component in regulating the human pathophysiology is represented by the cardiovascular system, which may be heavily affected in these extreme environments of microgravity and radiation. This mini review aims to identify the impact of microgravity and radiation on the cardiovascular system. Being able to understand the effect that comes with deep space explorations, including that of microgravity and space radiation, may also allow us to get a deeper understanding of the heart and ultimately our own basic physiological processes. This information may unlock new factors to consider with space exploration whilst simultaneously increasing our knowledge of the cardiovascular system and potentially associated diseases.
... Not only have these reviews provoked controversy between evidence supporting an hormetic dose response versus the LNT risk model, but they have increasingly revived interest in exploring the evidence base for bio-positive effects of LDIR. A number of reviews have summarised the bio-positive effects of LDIR in epidemiological, animal model, and clinical studies [61][62][63]. These papers also discussed the underlying protective mechanisms of LDIR such as enhanced DNA repairs, increased protein folding and the upregulation of oxidative stress enzyme activities, resulting in induced cellular effects such as adaptive response, immunological activity and bystander effects. ...
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The concept of radiation-induced hormesis, whereby a low dose is beneficial and a high dose is detrimental, has been gaining attention in the fields of molecular biology, environmental toxicology and radiation biology. There is a growing body of literature that recognises the importance of hormetic dose response not only in the radiation field, but also with molecular agents. However, there is continuing debate on the magnitude and mechanism of radiation hormetic dose response, which could make further contributions, as a research tool, to science and perhaps eventually to public health due to potential therapeutic benefits for society. The biological phenomena of low dose ionising radiation (LDIR) includes bystander effects, adaptive response, hypersensitivity, radioresistance and genomic instability. In this review, the beneficial and the detrimental effects of LDIR-induced hormesis are explored, together with an overview of its underlying cellular and molecular mechanisms that may potentially provide an insight to the therapeutic implications to human health in the future.
... Transcriptomic analysis showed a similar response among the brain, eye, ovary, and testis, as well as the liver and intestine, after 2 months of Medaka exposure to cosmic radiation in the ISS (Murata et al. 2015). Non-linear correspondence between low-doses of IR and consequences (positive or negative) has been observed in phenomena including hypersensitivity and induced radio resistance (Marples and Joiner 1993;Joiner 1994;Joiner et al. 1996;Tang and Loganovsky 2018). On the other hand, downregulation of proteins occurs in organs in a dose-dependent manner, with an increasing number of differential proteins observed at higher doses ( Figure 4). ...
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Purpose: Chronic exposure to ionizing radiation (IR) at low doses (<100mGy) that arise from non-natural sources, including nuclear power plants, nuclear medicine, extensive air travel, space missions and maintenance of the nuclear arsenal has not been sufficiently studied to fully understand the risk to health. Relatively little knowledge exists regarding how species and healthy tissues respond at the protein level to low doses of IR and especially what the consequences are from chronic exposure. Profiling of protein expression as a result of comparative proteomic studies is a powerful tool for studying changes in proteins of metabolic and structural importance. Materials and methods: In this study, SDS gel electrophoresis, LC-MS/MS mass spectrometry-based approaches and bioinformatic data analytics were used to detect proteomic changes following chronic exposure to moderate/low doses of radiation (2.25 mGy/day, 21.01 mGy/day and 204.3 mGy/day during 190 days) in fully grown and normally developed Medaka fish (Oryzias latipes). Results: This semiquantitative method provides evidence of significant variations in the abundance of proteins involved in endocrine systems, including thyroid hormone signaling and lipid metabolism, which could be related to the gonadal regression phenotype observed in fish exposed to 21.04 mGy and 204.3 mGy/day. Interestingly, the global proteomic change in response to chronic exposure to IR was towards overexpression of proteins in muscle and skin, while the opposite effect was observed in internal organs. Conclusion: The present study provides information on the impacts of biologically relevant low doses of IR, which will be useful in future research for the identification of potential biomarkers of IR exposure and allow for a better assessment of radiation biosafety regulations.
... However, it is rather consensual in the scientific community the need to better understand the biophysics involved in processes of damage induction in cases of sudden exposure to low and moderate doses. Dose increments produced by sudden exposures can initiate responses capable of altering the DNA of somatic cells, being one of the key events in the process of carcinogenesis [1,2]. ...
Article
Effective provisions of preparedness and response are necessary to protect human life, health, property, and the environment in any nuclear and radiological emergency. Recently, the International Commission on Radiological Protection recognized the need to provide more quantitative guidance on environmental radiation protection to integrate these analyses. A required assessment is a correlation between dose and its effects in non-human biota. Plants are highly sensitive environmental monitors for the assessment of potentially genotoxic agents and avoid the controversial use of animal models. The Allium test is commonly used to assess genotoxicity for a wide variety of chemical and physical factors, as it allows for estimates of possible DNA damage in eukaryotes in general, including humans. In this work, onion (Allium cepa) seedlings were exposed to 20–200 mGy of \(\alpha\)-radiation. We studied the possibility of using cytogenetic analyses of irradiated onion cells to determine the biological dose. It was observed that the increase in the frequencies of chromosomal aberrations, mitotic abnormalities, and micronuclei occurred proportional to the radiation dose, but a reduction in cytological damage was observed from 100 mGy, suggesting the onset of cytotoxic activity. Our research shows the potential of Allium cepa as a sensitive support system for dosimetry, detection, and screening of cellular effects produced by low doses of environmental radiation.
... In situations in which the patient cannot move, the equipment is taken to the bed and the examinations are carried out without the adoption of adequate protection measures [9], putting everyone in the environment at risk. Clinical and epidemiological studies show deleterious effects on human health such as mutations, cancer, congenital abnormalities, cardio and cerebrovascular diseases, cataracts and others, even when exposed to low doses of ionizing radiation [10]. ...
... To determine the risk of cancer as a function of dose-rate is an important challenge for space radiobiology but also for radiobiology in general. Indeed, the potential cancer risks linked to mammography (about 2 mGy per s) and to CT scan exams (some tens mGy per min) raise the question of the dose-rate effect on cancer occurrence [59,60] (Table 2). ...
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After having been an instrument of the Cold War, space exploration has become a major technological, scientific and societal challenge for a number of countries. With new projects to return to the Moon and go to Mars, radiobiologists have been called upon to better assess the risks linked to exposure to radiation emitted from space (IRS), one of the major hazards for astronauts. To this aim, a major task is to identify the specificities of the different sources of IRS that concern astronauts. By considering the probabilities of the impact of IRS against spacecraft shielding, three conclusions can be drawn: (1) The impacts of heavy ions are rare and their contribution to radiation dose may be low during low Earth orbit; (2) secondary particles, including neutrons emitted at low energy from the spacecraft shielding, may be common in deep space and may preferentially target surface tissues such as the eyes and skin; (3) a “bath of radiation” composed of residual rays and fast neutrons inside the spacecraft may present a concern for deep tissues such as bones and the cardiovascular system. Hence, skin melanoma, cataracts, loss of bone mass, and aging of the cardiovascular system are possible, dependent on the dose, dose-rate, and individual factors. This suggests that both radiosusceptibility and radiodegeneration may be concerns related to space exploration. In addition, in the particular case of extreme solar events, radiosensitivity reactions—such as those observed in acute radiation syndrome—may occur and affect blood composition, gastrointestinal and neurologic systems. This review summarizes the specificities of space radiobiology and opens the debate as regards refinements of current radiation protection concepts that will be useful for the better estimation of risks.
... In situations in which the patient cannot move, the equipment is taken to the bed and the examinations are carried out without the adoption of adequate protection measures [9], putting everyone in the environment at risk. Clinical and epidemiological studies show deleterious effects on human health such as mutations, cancer, congenital abnormalities, cardio and cerebrovascular diseases, cataracts and others, even when exposed to low doses of ionizing radiation [10]. In hospital facilities whose space for hospitalization of patients is reduced, there may be an increase in the exposure of professionals in the sector, in addition to exposure to unqualified professionals and patients. ...
Article
onizing Radiation (IR) is widely used in different applications. The energy capable of moving electrons in some materials has been used in different human activities, including in the health sector. Technological advances and diversity in the use of IR are expressed in the treatment of tumors, in diagnostic imaging and in the monitoring of invasive procedures. The performance of procedures with application of IR requires structural adequacy and procedures to guarantee the radiological protection of the patient and the source operator. The present work sought to carry out a narrative review of the literature on ionizing radiation, with the inclusion of definitions and concepts and the presentation of theories and evidence that helped to emphasize the topic of interest. International initiatives have been pioneering in the investigation of security and dosimetry parameters, however, there are still technical and conceptual gaps that do not allow the full implementation of international standards. The radioprotection theme needs to be widely discussed so that professionals who are currently exposed, even without operating radioactive sources, have access to adequate care procedures and guarantees. Continuing educational actions represent an important strategy for reducing health problems, including cancer, and improving workers’ quality of life.
... Consequently, the statistical power of most lowdose studies was limited, existed some potential biases, with increasing possibility results of false positive and false negative. Although the health effects of low-dose ionizing radiation (< 100 mSv) are still controversial, human epidemiological and clinical studies have shown that the influencing factors of low-dose ionizing radiation and health effects are socio-demographic, genetics, radiation composition, and source, lifestyle, and other environments exposure [40]. Therefore, this study found that platelet levels of medical workers increased to the cumulative dose after adjusting to gender, age at baseline, service at the baseline, occupation, and medical level. ...
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Background Numerous studies have concentrated on high-dose radiation exposed accidentally or through therapy, and few involve low-dose occupational exposure, to investigate the correlation between low-dose ionizing radiation and changing hematological parameters among medical workers. Methods Using a prospective cohort study design, we collected health examination reports and personal dose monitoring data from medical workers and used Poisson regression and restricted cubic spline models to assess the correlation between changing hematological parameters and cumulative radiation dose and determine the dose-response relationship. Results We observed that changing platelet of 1265 medical workers followed up was statistically different among the cumulative dose groups ( P = 0.010). Although the linear trend tested was not statistically significant ( P trend = 0.258), the non-linear trend tested was statistically significant ( P non-linear = 0.007). Overall, there was a correlation between changing platelets and cumulative radiation dose (a change of β a 0.008 × 10 ⁹ /L during biennially after adjusting for gender, age at baseline, service at baseline, occupation, medical level, and smoking habits; 95% confidence interval [CI] = 0.003,0.014 × 10 ⁹ /L). Moreover, we also found positive first and then negative dose-response relationships between cumulative radiation dose and changing platelets by restricted cubic spline models, while there were negative patterns of the baseline service not less than 10 years (− 0.015 × 10 ⁹ /L, 95% CI = − 0.024, − 0.007 × 10 ⁹ /L) and radiation nurses(− 0.033 × 10 ⁹ /L, 95% CI = − 0.049, − 0.016 × 10 ⁹ /L). Conclusion We concluded that although the exposure dose was below the limit, medical workers exposed to low-dose ionizing radiation for a short period of time might have increased first and then decreased platelets, and there was a dose-response relationship between the cumulative radiation dose and platelets changing.
... This radiation-induced lifespan extension could to a great extent be associated with the decrease in cancer mortality rate observed in HLR areas for several common cancers including lung, pancreas, colon, brain, and bladder cancers. Such trends of lower cancer mortality rates in higher background radiation areas were also found in India (Nambi and Soman 1987), Iran and China (Tang and Loganovsky 2018), and are in line with the studies on US population conducted by Cohen (1995Cohen ( , 1997 and Hart (2010Hart ( , 2011. ...
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The current linear no-threshold paradigm assumes that any exposure to ionizing radiation carries some risk, thus every effort should be made to maintain the exposures as low as possible. We examined whether background radiation impacts human longevity and cancer mortality. Our data covered the entire US population of the 3139 US counties, encompassing over 320 million people. This is the first large-scale study which takes into account the two major sources of background radiation (terrestrial radiation and cosmic radiation), covering the entire US population. Here, we show that life expectancy, the most integrative index of population health, was approximately 2.5 years longer in people living in areas with a relatively high vs. low background radiation. (≥ 180 mrem/year and ≤ 100 mrem/year, respectively; p < 0.005; 95% confidence interval [CI]). This radiation-induced lifespan extension could to a great extent be associated with the decrease in cancer mortality rate observed for several common cancers (lung, pancreas and colon cancers for both genders, and brain and bladder cancers for males only; p < 0.05; 95% CI). Exposure to a high background radiation displays clear beneficial health effects in humans. These hormetic effects provide clear indications for re-considering the linear no-threshold paradigm, at least within the natural range of low-dose radiation.
... Artificial sources of radiation have a lower impact on living organisms. Some investment in gamma-emission has an emerging fallout radionuclides, particularly 137 Cs (BEIR, 2006;IAEA, 2010;Tang and Loganovsky, 2018;UNSCEAR, 2010). ...
Article
Spatial pattern of naturally occurring radionuclides (NOR): ²²⁶Ra, ²³²Th, ⁴⁰K, and artificial ¹³⁷Cs was studied using soil samples of the multipurpose geochemical survey of the city of Yerevan, capital of Armenia. High purity Ge detector-based gamma spectrometry system was used for the determination of radionuclides activity concentrations in urban soils. A combination of compositional data analysis, geochemical mapping and radiological assessment were applied to reveal potential factors of technologically enhanced natural radioactivity and excess lifetime cancer risk for Yerevan’s population due to NOR and artificial ¹³⁷Cs in the urban environment. Statistical methods with the geochemical mapping revealed the great contribution of soil-forming rocks to NOR distribution in urban soils. The spatial distribution of calculated radiological indices and dose rates levels follows the distribution patterns of NOR. The activity concentration of fallout radionuclide ¹³⁷Cs was within the range typical for the studied altitudes. Above baseline activity of ¹³⁷Cs was observed in the north-western and western part of the city that is in typical ranges of ¹³⁷Cs content in soil derived from global radioactive fallout. Urban soils of Yerevan were found radiologically safe, however, igneous rock derived soils are a sink of NOR and the main environmental source of continuous exposure to the residents. Values of excess lifetime cancer risk were higher than mean global value.
... Even if these investigations imply an exposition to low doses of ionizing radiations, these cannot be undervalued. Indeed, studies published already in 2013, but lately in 2018 and 2016 [4][5], reported how, even though there aren't any de nite data yet, low doses are likely to be involved in an increasing risk of cancer or other kinds of pathologies (e.g. cardiovascular problems and malformations). ...
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Background: Ionizing radiations, even at low doses, present side effects that are known as well as girls and toung women constitute the most sensible individuals from a radioprotectional point of view. On the other side full spine x-ray radiography is the gold standard in diagnose and follow-up of AIS, where individuals involved are typicaly girls and young women. For these reasons, a partuicular care permorming radiographics esamination in this scope, in mandatory. The aim of this work is to provide a simple and detailed protocol to perform full-spine X-ray examination in diagnosis and follow-up of AIS This paper is the result of our experience along 7y of work in application and study of the scoliosis in the first two decades of life, combining the orthopaedist’s requirements, the surgical requirements along with the care for the particularly significant relational feature, due to the specific category of most individuals undergoing this radiological examination. Methods: For the maximum usability and Clarity, we considered three main topics: a) single examination b) examination during orthotic treatment and c) pre-op control. For each one we explained number and type of X-ray view used and how we performed them with the assistance of detalide figures. Results: By comparing X-ray images before and after the application of our protocol, we saw a significant increase in the quality of the produced images as well as a positive feedback from patients and parents acceptance. Conclusions: An extended collaboration between the Orthopaedic Surgeons and the Radiographer, has led to a clear improvement in technical execution and in an exposure dose reduction. Furthermore a particular attention to the patient’s comfort, along with some technical stratagems, led to an improving effectiveness of the services supplied.
... In situations in which the patient cannot move, the equipment is taken to the bed and the examinations are carried out without the adoption of adequate protection measures [9], putting everyone in the environment at risk. Clinical and epidemiological studies show deleterious effects on human health such as mutations, cancer, congenital abnormalities, cardio and cerebrovascular diseases, cataracts and others, even when exposed to low doses of ionizing radiation [10]. In hospital facilities whose space for hospitalization of patients is reduced, there may be an increase in the exposure of professionals in the sector, in addition to exposure to unqualified professionals and patients. ...
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Ionizing Radiation (IR) is widely used in different applications. The energy capable of moving electrons in some materials has been used in different human activities, including in the health sector. Technological advances and diversity in the use of IR are expressed in the treatment of tumors, in diagnostic imaging and in the monitoring of invasive procedures. The performance of procedures with application of IR requires structural adequacy and procedures to guarantee the radiological protection of the patient and the source operator. The present work sought to carry out a narrative review of the literature on ionizing radiation, with the inclusion of definitions and concepts and the presentation of theories and evidence that helped to emphasize the topic of interest. International initiatives have been pioneering in the investigation of security and dosimetry parameters, however, there are still technical and conceptual gaps that do not allow the full implementation of international standards. The radioprotection theme needs to be widely discussed so that professionals who are currently exposed, even without operating radioactive sources, have access to adequate care procedures and guarantees. Continuing educational actions represent an important strategy for reducing health problems, including cancer, and improving workers’ quality of life.
... The association of ionizing radiation and cardiovascular diseases mortality has been previously observed. Epidemiological and clinical studies show that radiation exposure can induce cardiovascular and cerebrovascular mortality (Tang and Loganovsky, 2018). High doses of Ayuso-Álvarez et al. ...
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The role of metals and metalloids beyond arsenic, copper, lead and cadmium in cardiovascular disease is not entirely clear. The aim of this study was to assess the association between 18 metal or metalloid levels in topsoil (upper soil horizon) with all-cause and specific cardiovascular mortality endpoints in Spain. We designed an ecological spatial study, to assess cardiovascular mortality in 7941 Spanish mainland towns from 2010 to 2014. The estimation of metals and metalloids concentration in topsoil came from the Geochemical Atlas of Spain from 13,317 soil samples. We also summarized the joint variability of the metals using principal components analysis (PCA). These components (PCs) were included in a Besag, York, and Mollié model to assess their association with cardiovascular mortality from all causes, coronary heart disease, cerebrovascular, hypertension, and conduction disorders. Our results showed, both in men and women, that at the lowest component scores range, PC2 (mainly reflecting Al, Be, Tl and U) was positively associated with coronary heart disease and cerebrovascular mortality. At medium/highest scores range, PC4 (mainly reflecting Hg) was positively associated with cerebrovascular mortality. For PC3 (reflecting Se), the association with coronary heart disease mortality was positive only in men at the highest PC scores range. For PC1 (partly reflecting metals such as Pb, As, Cu or Cd), we observed a strongly suggestive positive association with all-cause cardiovascular diseases mortality. Our ecological results are consistent with the available evidence supporting a cardiovascular role of excessive exposure to Se, Hg, Pb, As, Cu and Cd, but also identify Al, Be, Tl and U as potentially novel cardiovascular factors. Additional research is needed to confirm the biological relevance of our findings.
... It has to be kept in mind; however, that low doses can be beneficial or harmful for human health [207,208]. ...
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Until recently, radiation effects have been considered to be mainly due to nuclear DNA damage and their management by repair mechanisms. However, molecular biology studies reveal that the outcomes of exposures to ionizing radiation (IR) highly depend on activation and regulation through other molecular components of organelles that determine cell survival and proliferation capacities. As typical epigenetic-regulated organelles and central power stations of cells, mitochondria play an important pivotal role in those responses. They direct cellular metabolism, energy supply and homeostasis as well as radiation-induced signaling, cell death, and immunological responses. This review is focused on how energy, dose and quality of IR affect mitochondria-dependent epigenetic and functional control at the cellular and tissue level. Low-dose radiation effects on mitochondria appear to be associated with epigenetic and non-targeted effects involved in genomic instability and adaptive responses, whereas high-dose radiation effects (>1 Gy) concern therapeutic effects of radiation and long-term outcomes involving mitochondria-mediated innate and adaptive immune responses. Both effects depend on radiation quality. For example, the increased efficacy of high linear energy transfer particle radiotherapy, e.g., C-ion radiotherapy, relies on the reduction of anastasis, enhanced mitochondria-mediated apoptosis and immunogenic (antitumor) responses.
... Although the pathophysiology of the brain effects of ionizing radiation is still unclear, some possible explanations have been proposed. They include, amongst others, inhibition of neurogenesis, mainly in the hippocampus, telomere length and gene expression changes, apoptosis, neuroinflammation, autoimmune processes, and glial mechanisms (75)(76)(77)(78)(79)(80)(81). ...
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Goal: To explore the possible impact of ionizing radiation in the pathophysiology of neuropsychiatric disorders amongst clean-up workers of the Chornobyl catastrophe (liquidators). Design, object, and methods: Retrospective-prospective study (1987-2015) of liquidators from the State Register of Ukraine (SRU) with radiation doses records and Clinical-Epidemiological Register (CER) of the State Institution ≪National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine≫ (NRCRM). Moreover, cohort and cross-sectional studies of the randomized sample of liquidators from the CER (exposed group, 198 subjects) were examined. Internal control group included the liquidators irradiated in doses <50.0 mSv (42 persons). All subjects were assessed by a detailed clinical examination and a battery of standardized neuropsychiatric scales, psychometric, and neuropsychological tests. Descriptive and variation statistics, non-parametric criteria, regression-correlation analysis, survival analysis by Kaplan & Meier, and risk analysis were used. Results: Exposed group vs. control group showed cognitive disorders in 99 (50.0%) vs. 20 (18.1%), (P = 0.04); affective disorders in 96 (48.3%) vs. 36 (32.7%) (P = 0.007), and stress-related disorders in 115 (58.4%) vs. 8 (7.3%) (P < 0.001). In the main group exposed to ≥50 mSv vs. internal control group (exposed to <50 mSv), affective disorders were present, respectively, in 89 (56.4%) vs. 7 (19.1%) (P < 0.001), and stress-related disorders in 98 (62.8%) vs. 17 (40.4%) (P = 0.009). Relative risks (RR) and 95% confidential intervals (95%CI) of Incidence of some neuropsychiatric disorders in liquidators of 1986-1987 related to internal control (doses <50 mSv) were as follows: organic psychosis (RR = 3.15; 95% CI: 2.6; 3.7); non-psychotic organic brain damage (RR = 1.99; 95% CI: 1.6; 2.5); acute (RR = 1.40, 95% CI: 1.3; 1.5), and chronic cerebrovascular disorders (RR = 1.23; 95% CI 1.0;1.5). Neuropsychiatric diseases show a strong, increasing, and approximately quadratic statistically significant (Pv < 0.001) relationship with individual dose, yielding an estimated excess relative risk ERR = 2.76 Sv −2 (95% CI 1.06-7.15). Loganovsky et al. Radiation Risk of Neuropsychiatric Disorders Conclusions: Liquidators have an excess of cognitive, affective, and stress-related disorders. The risk of diseases rises with radiation dose. Radiation risks are revealed for organic psychoses, non-psychotic organic brain damage, acute and chronic cerebrovascular pathology.
... Spatial perception of tortuosity and depth is thereby eliminated, making navigation more difficult and increasing the potential for procedural errors, prolonged procedural time, and increased radiation exposure. Exposure to fluoroscopy imposes potential long-term DNA damage and health effects, which limits the risks of perioperative radiation exposure, and therefore plays a major role during these procedures [7,8]. In order to achieve the lowest possible radiation exposure at which the endovascular procedure can be performed safely, current radiation guidelines are based on the 'as low as reasonably achievable' (ALARA) principle. ...
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Introduction: The evolution of endovascular surgery over the past thirty years has made it possible to treat increasingly complex vascular pathologies with an endovascular method. Although this generally speeds up the patient's recovery, the risks of health problems caused by long-term exposure to radioactive radiation increase. This warrants the demand for radiation-reducing tools to reduce radiation exposure during these procedures. Areas covered: For this systematic review Pubmed, Embase and Cochrane library databases were searched on December 28, 2021 to provide an overview of tools that are currently used or have the potential to contribute to reducing radiation exposure during endovascular aortic procedures. In addition, an overview is presented of radiation characteristics of clinical studies comparing a (potential) radiation-reducing device with conventional fluoroscopy use. Expert opinion: Radiation-reducing instruments such as fiber optic shape sensing or electromagnetic tracking devices offer the possibility to further reduce or even eliminate the use of radiation during endovascular procedures. In an era of increasing endovascular interventional complexity and awareness of the health risks of long-term radiation exposure, the use of these technologies could have a major impact on an ongoing challenge to move towards radiation-free endovascular surgery.
... Recently, new evidence suggests LDR's potential as immune amplifier sensitizing tumors to immune checkpoint blockade responsiveness 23 . Almost 30 million workers are professionally exposed to radiation; of these, interventional fluoroscopists, including cardiologists and radiologists, are among the most highly exposed 24 . A dose of approximately 5 mSv annually is attributed to a projected lifetime cancer risk of 1 in 100 in the following 30 years of work 25 . ...
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Co-exposure of High-fat-diet (HFD) behavior and environmental low-dose radiation (LDR) is common among majority occupational workers, but the synergism of this co-exposure in metabolic health is poorly understood. This study aimed to investigate the impact of gut microbiota and its metabolites on the regulation of HFD accompanied by LDR-associated with metabolic dysfunction and insulin resistance. Here, we reported that Parasutterella was markedly elevated in the gut microbiota of mice in co-exposure of HFD and LDR, accompanied by increased pyrrolidinecarboxylic acid (PA) level in both intestine and plasma. Transplantation of fecal microbiota from mice with co-exposure HFD and LDR with metabolic dysfunction resulted in increased disruption of metabolic dysfunction, insulin resistance and increased PYCR1 (Pyrroline-5-carboxylate reductase 1) expression. Mechanistically, intestinal barrier was damaged more serious in mice with co-exposure of HFD and LDR, leading high PA level in plasma, activating PYCR1 expression to inhibit insulin Akt/mTOR (AKT kinase-transforming protein/Serine threonine-protein kinase) signaling pathway to aggravate HFD-induced metabolic impairments. This study suggests a new avenue for interventions against western diet companied with low dose radiation exposure-driven metabolic impairments. Characterisation of gut microbiota shows that low-dose radiation enhances the metabolic defects induced by high-fat diet in mice, in a manner involving increased levels of pyrrolidinecarboxylic acid.
... As another readily accessible and noninvasive biofluid, the urine is also a primary source for radiation metabolomic biomarker studies. One research group detected the urine levels of metabolites in mice after internal exposure to radionuclides 137 Cs (Goudarzi et al. 2014a), 90 Sr (Goudarzi et al. 2015a), or external exposure to X-rays (Goudarzi et al. 2014b), which leading to a low dose-rate radiation defined as less than 0.1 mGy/min (Tang and Loganovsky 2018). Tiglylcarnitine (C5:1) and hexanoylcarnitine (C6) were decreased in urine after exposure to low dose-rate radiation. ...
Article
Purpose: With the development of radiation metabolomics, a large number of radiation-related metabolic biomarkers have been identified and validated. The L-carnitine and acylcarnitines have the potential to be the new promising candidate indicators of radiation exposure. This review summarizes the effect of carnitine shuttle system on the profile of acylcarnitines, and correlates the radiation effects on upstream regulators of carnitine shuttle system with the change characteristics of L-carnitine and acylcarnitines after irradiation across different animal models as well as a few humans. Conclusions: Studies report that acylcarnitines were ubiquitously elevated after irradiation, especially the free L-carnitine and short-chain acylcarnitines (C2-C5). However, the molecular mechanism underlying acylcarnitine alterations after irradiation is not fully investigated, and further studies are needed to explore the biological effect and its mechanism. The activity of the carnitine shuttle system plays a key role in the alteration of L-carnitine and acylcarnitines, and the upstream regulators of the system are known to be affected by irradiation. These evidences indicate that that there is a logistic role of carnitine shuttle system on radiation-induced L-carnitine and acylcarnitines alteration.
... In addition, the UNSCEAR report showed that epidemiological studies in several regions of the world (Ramsar, Yangjiang, Kerala and Guarapari) reported no correlation between radiation exposure and cancer rate or mortality in areas with high natural background radiation [3], indicating that the effect of low dose rates on health and the cancer risk after exposure to ionizing radiation is still unclear. Tang et al. also reported that the mechanisms of low-dose ionizing radiation (≤100 mSv) or low-dose-rate ionizing radiation (<6 mSv/h)-induced health effects are poorly understood [4]. Issues related to the health effects of low doses require further research in the future. ...
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The details of the dose-dependent response of serum proteins exposed to ionizing radiation, especially the oxidative modification response in amino acid sequences of albumin, the most abundant protein, are unknown. Thus, a proteomic analysis of the serum components from mice exposed to total body X-irradiation (TBI) ranging from 0.5 Gy to 3.0 Gy was conducted using LC-MS/MS. The analysis of oxidative modification sequences of albumin (mOMSA) in TBI mouse serum revealed significant moderate or strong correlations between the X-irradiation exposure dose and modification of 11 mOMSAs (especially the 97th, 267th and 499th lysine residues, 159th methionine residue and 287th tyrosine residues). In the case of X-irradiation of serum alone, significant correlations were also found in the 14 mOMSAs. In addition, a dose-dependent variation in six proteins (Angiotensinogen, Odorant-binding protein 1a, Serine protease inhibitor A3K, Serum paraoxonase/arylesterase 1, Prothrombin and Epidermal growth factor receptor) was detected in the serum of mice exposed to TBI. These findings suggest the possibility that the protein variation and serum albumin oxidative modification responses found in exposed individuals are important indicators for considering the effects of radiation on living organisms, along with DNA damage, and suggests their possible application as biomarkers of radiation dose estimation.
... In addition, PS is also a well-accepted risk factor in cancer initiation and progression as PS-induced inflammation and immune dysfunction could cause metabolism disorder and difficulties in maintaining homeostasis; increase susceptibility to cancer; and promote cancer initiation, progression, and metastasis [54][55][56][57][58][59]. Exposure to IR at low doses could also lead to various health consequences, such as genetic and epigenetic changes associated with a range of physiological disturbances [60][61][62]. As human activities under certain conditions such as crewed space exploration would unavoidably encounter exposure to PS and high-LET IR, and high-LET IR could cause differential biological effects compared to that caused by low-LET IR [63,64], it is of great concern to verify if any enhanced biological effects could be induced from concurrent exposure to both PS and high-LET IR at low doses. ...
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Humans are exposed to both psychological stress (PS) and radiation in some scenarios such as manned deep-space missions. It is of great concern to verify possible enhanced deleterious effects from such concurrent exposure. Pioneer studies showed that chronic restraint-induced PS (CRIPS) could attenuate Trp53 functions and increase gamma-ray-induced carcinogenesis in Trp53-heterozygous mice while CRIPS did not significantly modify the effects on X-ray-induced hematopoietic toxicity in Trp53 wild-type mice. As high-linear energy transfer (LET) radiation is the most important component of space radiation in causing biological effects, we further investigated the effects of CRIPS on high-LET iron-particle radiation (Fe)-induced hematopoietic toxicity in Trp53-heterozygous mice. The results showed that CRIPS alone could hardly induce significant alteration in hematological parameters (peripheral hemogram and micronucleated erythrocytes in bone marrow) while concurrent exposure caused elevated genotoxicity measured as micronucleus incidence in erythrocytes. Particularly, exposure to either CRISP or Fe-particle radiation at a low dose (0.1 Gy) did not induce a marked increase in the micronucleus incidence; however, concurrent exposure caused a significantly higher increase in the micronucleus incidence. These findings indicated that CRIPS could enhance the deleterious effects of high-LET radiation, particularly at a low dose, on the hematopoietic toxicity in Trp53-heterozygous mice.
... As another readily accessible and noninvasive biofluid, the urine is also a primary source for radiation metabolomic biomarker studies. One research group detected the urine levels of metabolites in mice after internal exposure to radionuclides 137 Cs (Goudarzi et al. 2014a), 90 Sr (Goudarzi et al. 2015a), or external exposure to X-rays (Goudarzi et al. 2014b), which leading to a low dose-rate radiation defined as less than 0.1 mGy/min (Tang and Loganovsky 2018). Tiglylcarnitine (C5:1) and hexanoylcarnitine (C6) were decreased in urine after exposure to low dose-rate radiation. ...
Article
The intestinal compensatory proliferative potential is a key influencing factor for susceptibility to radiation-induced intestinal injury. Studies indicated that the carnitine palmitoyltransferase 1 (CPT1) mediated fatty acid β-oxidation (FAO) plays a crucial role in promoting the survival and proliferation of tumor cells. Here, we aimed to explore the effect of 60Co gamma rays on CPT1 mediated FAO in the radiation-induced intestinal injury models, and investigate the role of CPT1 mediated FAO in the survival and proliferation of intestinal cells after irradiation. We detected the changed of FAO in the plasma and small intestine of Sprague Dawley (SD) rats at 24 h after 60Co gamma irradiation (0, 5 and 10 Gy), using target metabolomics, qRT-PCR, immunohistochemistry (IHC), western blot (WB) and related enzymatic activity kits. We then analyzed the FAO changes in radiation-induced intestinal injury models regardless of ex vivo (mice enteroids), or in vitro (normal human intestinal epithelial cell lines, HIEC-6). HIEC-6 cells were transduced with lentivirus vector GV392 and treated with puromycin for obtaining CPT1 stable knockout cell lines, named CPT1 KO. CPT1 enzymatic activities of HIEC-6 cells and mice enteroids were also inhibited by pharmaceutical inhibitor ST1326 and Etomoxir (ETO), to study the function of CPT1 in the survival and proliferation of HIEC-6 cells after 60Co gamma irradiation. We found that CPT1 mediated FAO was altered in the small intestine of the SD rats after irradiation, especially, the expression level and enzymatic activity of CPT1 were significantly increased. Similarly, the expression levels of CPT1 were also remarkably enhanced in mice enteroids and HIEC-6 cells after irradiation. CPT1 inhibition decreased the proliferation of the HIEC-6 cells and mice enteroids after irradiation partially by reducing the extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) pathways activation, CPT1 inhibition also reduced the proliferation of mice enteroids after irradiation partially by down-regulating the Wnt/β-catenin signaling activity. In conclusion, our study indicated that CPT1 plays a crucial role in promoting intestinal epithelial cell proliferation after irradiation.
... Exposure to fluoroscopy during endovascular procedures poses risks to both the patient and the treatment team [1][2][3]. In addition, three-dimensional structures are projected onto screens only as two-dimensional grayscale images, eliminating spatial perception of depth and tortuosity. ...
Article
Purpose: Report of a successful case of endovascular recanalization of an occluded superficial femoral artery (SFA) using Fiber Optic RealShape (FORS) technology. Case report: A 79-year-old male was referred for evaluation of multiple ischemic pretibial ulcers of the right lower extremity. Computed tomography-angiography (CTA) imaging confirmed significant stenosis of the right common femoral artery (CFA) and an occlusion of the SFA from its origin to the Hunter's canal. The patient was treated with a hybrid surgical procedure: an endarterectomy of the CFA and SFA origin was performed combined with an endovascular recanalization of the occluded SFA using FORS technology. During recanalization, the FORS guidewire slowly twisted subintimally around the occluded lumen of the SFA, maintaining the created corkscrew shape after pre-dilation with the percutaneous transluminal angioplasty (PTA) balloon and subsequent stenting. Conclusions: FORS technology can be successfully used during recanalization of an occluded SFA without the use of fluoroscopy. The corkscrew shape formed during recanalization in this case was retained during PTA balloon pre-dilation and stenting; this potentially improves hemodynamics and thereby reduces the risk of in-stent restenosis. However, expanding patient series and longer follow-up data are needed to increase the understanding of the feasibility and effectiveness of using FORS in the treatment of peripheral arterial occlusive disease.
... 5 Furthermore, fluoroscopy exposure during these procedures also possesses potential health risks, such as DNA damage and long-term health effects, to both the patient and the treatment team. [7][8][9] Guidelines including The Trans-Atlantic Inter-Society Consensus for the Management of PAC generally recommend for revascularisation options (open, endovascular or hybrid procedures) based on the anatomical location and extent of the arterial lesions. 4 5 10 Endovascular revascularisation is generally preferred over open procedures due to the reduced perioperative morbidity and shorter hospital stays. 1 11 However, endovascular strategies for stenotic lesions located in anatomically 'hostile' arterial segments or 'no stent areas,' such as arterial flexion points (surrounding joints), remain a subject for debate. ...
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Introduction Peripheral arterial disease (PAD) is an atherosclerotic disease leading to stenosis and/or occlusion of the arterial circulation of the lower extremities. The currently available revascularisation methods have an acceptable initial success rate, but the long-term patency is limited, while surgical revascularisation is associated with a relatively high perioperative risk. This urges the need for development of less invasive and more effective treatment modalities. This protocol article describes a study investigating a new non-invasive technique that uses robot assisted high-intensity focused ultrasound (HIFU) to treat atherosclerosis in the femoral artery. Methods and analysis A pilot study is currently performed in 15 symptomatic patients with PAD with a significant stenosis in the common femoral and/or proximal superficial femoral artery. All patients will be treated with the dual-mode ultrasound array system to deliver imaging-guided HIFU to the atherosclerotic plaque. Safety and feasibility are the primary objectives assessed by the technical feasibility of this therapy and the 30-day major complication rate as primary endpoints. Secondary endpoints are angiographic and clinical success and quality of life. Ethics and dissemination Ethical approval for this study was obtained in 2019 from the Medical Ethics Committee of the University Medical Center Utrecht, the Netherlands. Data will be presented at national and international conferences and published in a peer-reviewed journal. Trial registration number NL7564.
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Background: Although the risk of radiographic imaging is negligible compared to its benefits, the overall risk to the population is significant due to a large number of these examinations. Therefore, this study was designed to estimate entrance surface air kerma (ESAK) and provide diagnostic reference level (DRL) in routine radiological examinations. Methods: In this study 783 patients were involved who had a mean age of 41±14 years. The study included five routine radiological examinations; lumbar vertebrae, pelvis, abdomen, chest, and skull from 11 radiology devices located in Yazd province. The ESAK was estimated for each examination, and then the DRL values as the third quartile of the distribution of the ESAK median values were calculated. The effective dose and risk of exposure-induced death (REID) were also estimated using PCXMC (a personal computer-based Monte Carlo) software. Results: The DRL values for the investigated examinations were obtained as: abdomen (anterior-posterior [AP]): 3.57, chest (AP): 1.23, chest (lateral [LAT]): 1.12, chest (posterior- anterior [PA]): 0.48, lumbar vertebrae (AP): 4.16, lumbar vertebrae (LAT): 8.81, lumbar vertebrae (oblique [OB]): 10.33, pelvis (AP): 2.77, pelvis (LAT): 2.82, skull (AP): 2.34, skull (LAT): 1.39, and skull (PA): 2.03 mGy. The lumbar vertebrae (OB) radiology examination had the highest effective dose (1.03 ± 0.76 mSv). In addition, the highest REID value in lumbar examination was associated to stomach cancer (7.03±6.11 deaths per million). Conclusion: Based on the results, although the DRL values were not higher than those of the international organizations' levels, they can be reduced by adequate training of radiographers. Keywords: Radiology, Diagnostic reference level, Effective dose, Cancer risk, Exposure- induced
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Exposure to silica nanoparticles (SNPs) causes lung fibrosis and threatens human health. However, it is unknown if low-dose radiation (LDR) exposure exacerbates SNP-induced lung dysfunction. Thus, the aim of our study was to determine the combined effect of SNPs and LDR on lung fibrosis and elucidate the potential mechanisms involved. We used SNP-induced A549 cells and mouse models and detected gut microbiota alteration by 16S rDNA amplicon sequencing. Additionally, lung fibrosis-related parameters were also detected using hematoxylin and eosin (H&E) staining, immunofluorescence (IF) staining, qRT-PCR, and western blot analysis. The histopathological and IF staining assays illustrated that co-exposure of mice to SNPs and LDR had a significant deleterious effect on both lung function and lung fibrosis, in comparison to exposure to SNPs or LDR alone. Furthermore, the abundance of Bacteroidetes significantly increased while that of Firmicutes significantly decreased following co-exposure to SNPs and LDR. Mechanistically, the Notch cascade was activated in chronically SNP-exposed mice with lung fibrosis and A549 cells. Additionally, the Notch pathway-associated proteins showed increased expression levels in the lungs following SNP exposure both in vivo and in vitro. Notably, SNP-induced dysbiosis of the gut microbiota promoted lung epithelial damage by triggering the Notch pathway, resulting in SNP-induced lung fibrosis. However, oral administration of probiotics protected the mice from SNP-induced lung injury. Our results strongly indicate that the activation of the gut microbiota-dependent Notch pathway in response to co-exposure to SNPs and LDR results in lung epithelial injury in vivo. Probiotics supplementation is a potential way to protect against SNP- and LDR-induced lung fibrosis.
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This study has developed a relationship that categorized radiation protection and allows for a proper, clear, and concise review of the different classifications in terms of principles of protection, dose criteria, categories, fundamental tools, exposure situations, applications and control measures. With the groundwork laid, advances of the linear no-threshold (LNT) model which has attracted attention in the field of radiobiology and epidemiology were examined in detail. Various plausible dose-response relationship scenarios were x-rayed under low-dose extrapolation. Intensive review of factors opposing the LNT model involving radiophobia (including misdiagnosis, alternative surgery/imaging, suppression of ionizing radiation (IR) research); radiobiology (including DNA damage repair, apoptosis/necrosis, senescence protection) and cost issues (including-high operating cost of LNT, incorrect prioritization, exaggeration of LNT impact, risk-to-benefit analysis) were performed. On the other hand, factors supporting the use of LNT were equally examined, they include regulatory bodies’ endorsement, insufficient statistical significance, partial DNA repair, variability of irradiated bodies, different latency periods for cancer, dynamic nature of threshold and conflicting interests. After considering the gaps in the scientific investigations that either support or counter the scientific paradigm on the use of LNT model, further research and advocacy is recommended that will ultimately lead to the acceptance of an alternative paradigm by the international regulators.
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Background: Exposure to ionizing radiation could affect the brain and eyes leading to cognitive and vision impairment, behavior disorders and performance decrement during professional irradiation at medical radiology, includinginterventional radiological procedures, long-term space flights, and radiation accidents. Objective: The objective was to analyze the current experimental, epidemiological, and clinical data on the radiation cerebro-ophthalmic effects. Materials and methods: In our analytical review peer-reviewed publications via the bibliographic and scientometric bases PubMed / MEDLINE, Scopus, Web of Science, and selected papers from the library catalog of NRCRM - theleading institution in the field of studying the medical effects of ionizing radiation - were used. Results: The probable radiation-induced cerebro-ophthalmic effects in human adults comprise radiation cataracts,radiation glaucoma, radiation-induced optic neuropathy, retinopathies, angiopathies as well as specific neurocognitive deficit in the various neuropsychiatric pathology including cerebrovascular pathology and neurodegenerativediseases. Specific attention is paid to the likely stochastic nature of many of those effects. Those prenatally and inchildhood exposed are a particular target group with a higher risk for possible radiation effects and neurodegenerative diseases. Conclusions: The experimental, clinical, epidemiological, anatomical and pathophysiological rationale for visualsystem and central nervous system (CNS) radiosensitivity is given. The necessity for further international studieswith adequate dosimetric support and the follow-up medical and biophysical monitoring of high radiation riskcohorts is justified. The first part of the study currently being published presents the results of the study of theeffects of irradiation in the participants of emergency works at the Chornobyl Nuclear Power Plant (ChNPP).
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Space is an isolated, confined environment for humans. These conditions can have numerous effects on astronaut mental health and safety. Psychological and social issues affect space crew due to the isolation, confinement, and prolonged separation from family and friends. This area of research is particularly crucial given the space sector's plans for Martian colonies and space tourism, as well as to aid astronauts when under high stress. Therefore, this paper reviews the effects of isolation/confinement on psychological and cognitive health; impact of radiation and microgravity on cognitive health; and implications of disturbances to the circadian rhythm and sleep in space. Possible solutions to relevant mentioned cognitive and mental health challenges are also discussed.
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The strategy used for the treatment of given brain cancer is critical in determining the post effects and survival. An oncological diagnosis of tumour evaluates a range of parameters such as shape, size, volume, location and neurological complexity that define the symptomatic severity. The evaluation determines the suitable treatment approach chosen from a range of options such as surgery, chemotherapy, hormone therapy, radiation therapy and other targeted therapies. Often, a combination of such therapies is applied to achieve superior results. Radiotherapy serves as a better treatment strategy because of a higher survival rate. It offers the flexibility of synergy with other treatment strategies and fewer side effects on organs at risk. This Review presents a radiobiological perspective in the treatment of brain tumour. The cause, symptoms, diagnosis, treatment, post-treatment effects and the framework involved in its elimination are summarized.
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Background: Ionizing radiation (IR) can affect the brain and the visual organ even at low doses, while provoking cognitive, emotional, behavioral, and visual disorders. We proposed to consider the brain and the visual organ as potential targets for the influence of IR with the definition of cerebro-ophthalmic relationships as the «eye-brain axis». Objective: The present work is a narrative review of current experimental, epidemiological and clinical data on radiation cerebro-ophthalmic effects in children, individuals exposed in utero, astronauts and interventional radiologists. Materials and methods: The review was performed according to PRISMA guidelines by searching the abstract and scientometric databases PubMed/MEDLINE, Scopus, Web of Science, Embase, PsycINFO, Google Scholar, published from 1998 to 2021, as well as the results of manual search of peer-reviewed publications. Results: Epidemiological data on the effects of low doses of IR on neurodevelopment are quite contradictory, while data on clinical, neuropsychological and neurophysiological on cognitive and cerebral disorders, especially in the left, dominant hemisphere of the brain, are nore consistent. Cataracts (congenital - after in utero irradiation) and retinal angiopathy are more common in prenatally-exposed people and children. Astronauts, who carry out longterm space missions outside the protection of the Earth's magnetosphere, will be exposed to galactic cosmic radiation (heavy ions, protons), which leads to cerebro-ophthalmic disorders, primarily cognitive and behavioral disorders and cataracts. Interventional radiologists are a special risk group for cerebro-ophthalmic pathology - cognitivedeficits, mainly due to dysfunction of the dominant and more radiosensitive left hemisphere of the brain, andcataracts, as well as early atherosclerosis and accelerated aging. Conclusions: Results of current studies indicate the high radiosensitivity of the brain and eye in different contingents of irradiated persons. Further research is needed to clarify the nature of cerebro-ophthalmic disorders in different exposure scenarios, to determine the molecular biological mechanisms of these disorders, reliable dosimetric support and taking into account the influence of non-radiation risk factors.
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While previous studies have focused on the health effects of occupational exposure of radiations on medical radiation workers, few have analyzed the dose-response relationship between low radiation doses and changes in blood parameters. Even fewer studies have been conducted on industrial worker populations. Using a prospective cohort study design, this study collected health examination reports and personal dose monitoring data from 705 industrial irradiation workers who underwent regular physical examinations at Dongguan Sixth People’s Hospital. The dose-response effects of low-dose ionizing radiation on blood parameters were assessed using a generalized linear model and restricted cubic spline model. Red blood cell counts decreased then increased, before decreasing again with increasing ionizing radiation. This was in contrast to the curve of the total platelet count after irradiation. Additionally, a radiation dose of 2.904 mSv was the turning point for the nonlinear curve of hemoglobin count changes. In conclusion, long-term, low-dose ionizing radiation affects blood cell levels in industrial irradiation workers. There is a nonlinear dose-response relationship between red blood cell, platelet, and hemoglobin counts and the cumulative radiation dose. These findings should alert radiation workers to seek preventive medical treatment before the occurrence of any serious hematopoietic disease.
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Cellular senescence refers to the permanent arrest of cell cycle caused by intrinsic and/or extrinsic stressors including oncogene activation, irradiation, DNA damage, oxidative stress, and certain cytokines (including senescence associated secretory phenotype). Cellular senescence is an important factor in aging. Accumulation of senescent cells has been implicated in the causation of various age-related organ disorders, tissue dysfunction, and chronic diseases. It is widely accepted that the biological effects triggered by low-dose radiation (LDR) are different from those caused by high-dose radiation. Experimental evidence suggests that LDR may promote growth and development, enhance longevity, induce embryo production, and delay the progression of chronic diseases. The underlying mechanisms of these effects include modulation of immune response, stimulation of hematopoietic system, antioxidative effect, reduced DNA damage and improved ability for DNA damage repair. In this review, we discuss the possible mechanisms by which LDR prevents senescence and aging from the perspectives of inhibiting cellular senescence and promoting the removal of senescent cells. We review a wide broad of evidence about the beneficial impact of LDR in senescence and aging models (including cardiovascular diseases, neurological diseases, arthritis and osteoporosis, chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis) to highlight the potential value of LDR in preventing aging and age-related diseases. However, there is no consensus on the effect of LDR on human health, and several important aspects require further investigation.
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It is well established that cohorts of individuals exposed to ionizing radiation demonstrate increased risks of cardio- and cerebrovascular diseases. However, mechanisms of these radiation-induced diseases developing in individuals exposed to ionizing radiation remain unclear. To identify biomarkers of the atherosclerotic vessel damage in workers chronically exposed to ionizing radiation, this study considered 49 workers of the Russian nuclear production facility-the Mayak Production Association (mean age of 68.73 ± 6.92 years)-and 38 unexposed individuals (mean age of 68.84 ± 6.20 y) who had never been exposed to ionizing radiation (control). All workers were chronically exposed to combined radiation (external gamma rays and internal alpha particles). The mean cumulative liver absorbed dose from external gamma-ray exposure was 0.18 ± 0.12 Gy; the mean cumulative liver absorbed dose from internal alpha-particles was 0.14 ± 0.21 Gy. Levels of biomarkers in blood serum of the study participants were measured using the ELISA method. Elevated levels of apolipoprotein B, superoxide dismutase, monocyte chemoattractant protein 1, vascular cell adhesion protein 1, and a decreased level of endothelin-1 were observed in blood serum of Mayak PA workers chronically exposed to combined radiation compared to control individuals. A significant positive correlation was demonstrated between the vascular cell adhesion protein 1 level and cumulative liver absorbed doses from external gamma radiation and internal alpha radiation. Findings of the study suggest that molecular changes in blood of individuals occupationally exposed to ionizing radiation (combined internal exposure to alpha particles and external exposure to gamma rays) may indicate dyslipidemia, oxidative stress, inflammation, and endothelial dysfunction involved in atherosclerosis development.
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Radiation-induced changes in the immune system develop quite early after the onset of radiation exposure and persist over a long time after it's removal. In case of chronic radiation exposure at dose rate lower than 0.1 Gy/year, the threshold of annual dose to suppress red bone marrow hemato- and immunopoiesis reaches 0.3-0.5 Gy. It was shown that adaptation mechanisms are triggered under the chronic impact of ionizing radiation in the hematopoietic system. In our study we quantitatively and qualitatively analyzed relationships between individual arms of the immune system which is important for understanding features of homeostasis and the adaptation capacity of immune system in chronically irradiated subjects at later time points. The main group included 376 persons exposed to chronic irradiation due to 1949-1960 industrial pollution with radioactive waste residing in Techa River basin. Average radiation dose for the red bone marrow in this group was 1.08±0.04 (0.08-4.46) Gy. The comparison group included 162 unexposed persons. The mean age of people in the main and comparison group was 70.3±0.3 (58-88) and 69.3±0.5 (58-90) years, respectively. The Kendall correlation analysis identified 82 statistically significant correlations (correlation coefficient higher than 0.3, p 0.05) between individual immune parameters versus 65 similar correlations found in the comparison group. The majority of identified correlation links in both groups ranged from 0.3 to 0.5 (main group – 57 correlations, comparison group – 41 correlations). There were found 16 and 14 correlations in the main and comparison group, respectively, with a coefficient ranged from 0.5 to 0.7. The correlation coefficient value higher than 0.7 was noted for 9 correlations in the main group and for 10 – in the comparison group. The χ-square analysis revealed no significant differences between total number of correlations and number of correlations of varying strength both in the main and comparison groups. The obtained data are consistent with previous studies and confirm that delayed changes in the immune system of subjects exposed to chronic low-rate irradiation were mild and evidenced about developed feedforward and feedback compensatory mechanisms.
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Our study adopted a big data analysis approach to determine whether there was a significant relationship between environmental radiation dose rates or age and cancer incidence rates in the Republic of Korea. The data for this analysis included environmental radiation dose rates, number of cancer patients, and age distributions of the residents from 2009 to 2016 in the administrative districts where environmental radiation monitoring posts were located. For this analysis, the environmental radiation dose rates were obtained from 171 monitoring posts located in 113 elementary administrative districts in the Republic of Korea. The number of cancer patients and the age distributions were obtained from the Central Cancer Information Center of the National Cancer Center of Korea and the Ministry of the Interior and Safety, respectively. Our findings indicated that there was no statistically significant relationship between the environmental radiation dose rate and the cancer incidence rate. However, age had a considerable influence on the cancer incidence rate of the monitored regions.
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Adverse health outcomes of ionizing radiation given chronically at low dose rates are highly debated, a controversy also relevant for other stressors. Increased knowledge is needed for a more comprehensive understanding of the damaging potential of ionizing radiation from all dose rates and doses. There is a lack of relevant low dose rate data that is partly ascribed to the rarity of exposure facilities allowing chronic low dose rate exposures. Using the FIGARO facility, we assessed early (one day post-radiation) and late (recovery time of 100–200 days) hepatic genome-wide transcriptional profiles in male mice of two strains (CBA/CaOlaHsd and C57BL/6NHsd) exposed chronically to a low dose rate (2.5 mGy/h; 1200h, LDR), a mid-dose rate (10 mGy/h; 300h, MDR) and acutely to a high dose rate (100 mGy/h; 30h, HDR) of gamma irradiation, given to an equivalent total dose of 3 Gy. Dose-rate and strain-specific transcriptional responses were identified. Differently modulated transcriptional responses across all dose rate exposure groups were evident by the representation of functional biological pathways. Evidence of changed epigenetic regulation (global DNA methylation) was not detected. A period of recovery markedly reduced the number of differentially expressed genes. Using enrichment analysis to identify the functional significance of the modulated genes, perturbed signaling pathways associated with both cancer and non-cancer effects were observed, such as lipid metabolism and inflammation. These pathways were seen after chronic low dose rate and were not restricted to the acute high dose rate exposure. The transcriptional response induced by chronic low dose rate ionizing radiation suggests contribution to conditions such as cardiovascular diseases. We contribute with novel genome wide transcriptional data highlighting dose-rate-specific radiation responses and emphasize the importance of considering both dose rate, duration of exposure, and variability in susceptibility when assessing risks from ionizing radiation.
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The effects of low-dose radiation (LDR, ≤0.1 Gy) on living organisms have been the hot areas of radiation biology but do not reach a definitive conclusion yet. So far, few studies have adequately accounted for the male reproductive system responses to LDR, particularly the regulation of testosterone content. Hence, this study was designed to evaluate the effects of LDR on Leydig cells and testicular tissue, especially the ability to synthesize testosterone. We found that less than 0.2-Gy 60 Co gamma rays did not cause significant changes in the hemogram index and the body weight; also, pathological examination did not find obvious structural alterations in testis, epididymis, and other radiation-sensitive organs. Consistently, the results from in vitro showed that only more than 0.5-Gy gamma rays could induce remarkable DNA damage, cycle arrest, and apoptosis. Notably, LDR disturbed the contents of testosterone in mice serums and culture supernatants of TM3 cells and dose dependently increased the expression of 3β-HSD. After cotreatment with trilostane (Tril), the inhibitor of 3β-HSD, increased testosterone could be partially reversed. Besides, DNA damage repair-related enzymes, including DNMT1, DNMT3B, and Sirt1, were increased in irradiated TM3 cells, accompanying by evident demethylation in the gene body of 3β-HSD. In conclusion, our results strongly suggest that LDR could induce obvious perturbation in the synthesis of testosterone without causing organic damage, during which DNA demethylation modification of 3β-HSD might play a crucial role and would be a potential target to prevent LDR-induced male reproductive damage.
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Long-term low-dose ionizing radiation (LLIR) widely exists in human life and has been confirmed to have potential pathogenic effects on cancer and cardiovascular diseases. However, it is technically and ethically unfeasible to explore LLIR-induced phenotypic changes in the human cohort, leading to slow progress in revealing the pathogenesis of LLIR. In this work, we recruited 32 radiation workers and 18 healthy non-radiation workers from the same city with the same eating habits for radiation damage evaluation and metabolomics profiling. It was found that clear metabolic phenotypic differences existed between LLIR and non-LLIR exposed participants. Moreover, LLIR exposed workers can be further divided into two types of metabolic phenotypes, corresponding to high and low damage types respectively. 3-hydroxypropanoate and glycolaldehyde were identified as sensitive indicators to radiation damage, which specific response to the chromosomal aberration of workers and may be potential monitoring markers for LLIR protection. Taurine metabolism-related pathways were identified as the main differential metabolic pathway under LLIR inducing, which had been confirmed to have a response to acute or chronic radiation exposure. We expect our study can be helpful to LLIR damage monitoring and symptomatic intervention in the future.
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There remains considerable uncertainty in obtaining risk estimates of adverse health outcomes of chronic low-dose radiation. In the absence of reliable direct data, extrapolation through the linear no-threshold (LNT) hypothesis forms the cardinal tenet of all risk assessments for low doses (≤ 100 mGy) and for the radiation protection principle of As Low As Reasonably Achievable (ALARA). However, as recent evidence demonstrates, LNT assumptions do not appropriately reflect the biology of the cell at the low-dose end of the dose-response curve. In this regard, human populations living in high-level natural radiation areas (HLNRA) of the world can provide valuable insights into the biological and cellular effects of chronic radiation to facilitate improved precision of the dose-response relationship at low doses. Here, data obtained over decades of epidemiological and radiobiological studies on HLNRA populations is summarized. These studies do not show any evidence of unfavourable health effects or adverse cellular effects that can be correlated with high-level natural radiation. Contrary to the assumptions of LNT, no excess cancer risks or untoward pregnancy outcomes have been found to be associated with cumulative radiation dose or in-utero exposures. Molecular biology-driven studies demonstrate that chronic low-dose activates several cellular defence mechanisms that help cells to sense, recover, survive, and adapt to radiation stress. These mechanisms include stress-response signaling, DNA repair, immune alterations and most importantly, the radiation-induced adaptive response. The HLNRA data is consistent with the new evolving paradigms of low-dose radiobiology and can help develop the theoretical framework of an alternate dose-response model. A rational integration of radiobiology with epidemiology data is imperative to reduce uncertainties in predicting the potential health risks of chronic low doses of radiation.
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Plenty of reports focus on effects of low dose radiation (LDR) on peripheral blood lymphocytes in radiation workers. However, red blood cells (RBCs) are few reported in radiation workers. Many researches only investigate the hemogram of radiation staffs without detecting other components of RBCs. To investigate the potential impact of LDR on RBCs, we detected the level of RBCs, hemoglobin, 2, 3-Disphosphoglycerate (2, 3-DPG) and GSH and analyzed influence factors on these indexes in 106 medical radiation workers. As results, RBC count was affected by sex, age, type of work, length of service (only for female) and annual effective dose (only for male). Hemoglobin status was affected by sex, type of work and annual effective dose (only for male). Sex, age and type of work had no effects on concentration of 2, 3-DPG and GSH. Length of service affected 2, 3-DPG concentration, and GSH levelwas affected by annual effective dose. In conclusion, chronic occupational LDR exposure may has effect on RBC count, hemoglobin status, concentration of 2, 3-DPG and GSH in radiation workers in some extent. However, it is still unknown how this kind of influence to affect the health of radiation workers. Thus, it is worth exploring further.
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The radiation shielding properties of ball clays produced with various percentages of 5, 10, 15, and 20 w.t% of micro and nano ZnO were experimentally evaluated in this paper. The effects of micro and nano ZnO on the attenuation competence of the prepared ball clays were compared. At all energies, we discovered that the ball clay with nano ZnO has a higher linear attenuation coefficient (LAC) than ZnO with microparticles. This finding suggests that nano-sized ZnO-ball clay samples absorbed more photons than microsized ZnO ball clay samples. The half-value layer (HVL) for the ball clay prepared with micro and nano ZnO was reported. At all the energies tested, we discovered that the ball clay with nano ZnO has a slightly lower HVL than the ball clay with micro ZnO. The HVL at 0.06 MeV is found to be 0.934 cm for the ball clay containing 5 w.t% micro ZnO and 0.866 cm for the ball clay containing 5 w.t% nano ZnO. We concluded from the HVL results that if the space in which the shield will be used is limited, the ball clay with nano ZnO is more useful because a thinner specimen with nano ZnO can attenuate half ofthe incoming photons. Scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy were used to investigate the properties of ZnO/ball clay.
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A new sample stage for characterizing radioactive materials by X-ray powder diffraction was developed at the ATALANTE facility (CEA Marcoule, France) using a conventional (non-nuclearized) Bruker D8 goniometer mounted in Bragg–Brentano geometry. The setup consists of a removable, fully hermetic sample stage, with a 200 µm-thick beryllium window, that can be plugged onto a glove-box, allowing the sample to be introduced in an hermetic medium that also encapsulates the glove-box atmosphere throughout the analysis process. The whole setup is thus hermetically unplugged from the glove-box and positioned on the centre of the goniometer. No preliminary decontamination and/or decontainment of the sample is necessary. The device was developed to avoid an expensive and time-consuming nuclearization of the diffractometer while also keeping it easily accessible for maintenance. Ultimately, keeping the diffractometer out of a glove-box also limits the volume of the final nuclear wastes, and thus the removable sample stage is the only `active' part. X-ray diffraction results of two NIST standards LaB 6 and α-Al 2 O 3 as well as five actinide dioxides ThO 2 , UO 2 , NpO 2 , PuO 2 and AmO 2 are presented to show the efficiency of the setup.
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Animal experimental studies indicate that acute or chronic low-dose ionizing radiation (LDIR) (≤100 mSv) or low-dose-rate ionizing radiation (LDRIR) (<6 mSv/h) exposures may be harmful. It induces genetic and epigenetic changes and is associated with a range of physiological disturbances that includes altered immune system, abnormal brain development with resultant cognitive impairment, cataractogenesis, abnormal embryonic development, circulatory diseases, weight gain, premature menopause in female animals, tumorigenesis and shortened lifespan. Paternal or prenatal LDIR/LDRIR exposure is associated with reduced fertility and number of live fetuses, and transgenerational genomic aberrations. On the other hand, in some experimental studies, LDIR/LDRIR exposure has also been reported to bring about beneficial effects such as reduction in tumorigenesis, prolonged lifespan and enhanced fertility. The differences in reported effects of LDIR/LDRIR exposure are dependent on animal genetic background (susceptibility), age (prenatal or postnatal days), sex, nature of radiation exposure (i.e. acute, fractionated or chronic radiation exposure), type of radiation, combination of radiation with other toxic agents (such as smoking, pesticides or other chemical toxins) or animal experimental designs. In this review paper, we aimed to update radiation researchers and radiologists on the current progress achieved in understanding the LDIR/LDRIR-induced bionegative and biopositive effects reported in the various animal models. The roles played by a variety of molecules that are implicated in LDIR/LDRIR-induced health effects will be elaborated. The review will help in future investigations of LDIR/LDRIR-induced health effects by providing clues for designing improved animal research models in order to clarify the current controversial/contradictory findings from existing studies.
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This study aimed at comparing neuropsychological test scores in 83 cardiologists and nurses (exposed group, EG) working in the cardiac catheterization laboratory, and 83 control participants (non exposed group, nEG), to explore possible cognitive impairments. The neuropsychological assessment was carried out by means of a battery called “Esame Neuropsicologico Breve.” EG participants showed significantly lower scores on the delayed recall, visual short-term memory, and semantic lexical access ability than the nEG ones. No dose response could be detected. EG participants showed lower memory and verbal fluency performances, as compared with nEG. These reduced skills suggest alterations of some left hemisphere structures that are more exposed to IR in interventional cardiology staff. On the basis of these findings, therefore, head protection would be a mandatory good practice to reduce effects of head exposure to ionizing radiation among invasive cardiology personnel (and among other exposed professionals). ( JINS , 2015, 21 , 1–7)
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Exposure to medium or high doses of ionizing radiation is a known risk factor for cancer in children. The extent to which low dose radiation from natural sources contributes to the risk of childhood cancer remains unclear. In a nationwide census-based cohort study, we investigated whether the incidence of childhood cancer was associated with background radiation from terrestrial gamma and cosmic rays. Children aged <16 years in the Swiss National Censuses in 1990 and 2000 were included. The follow-up period lasted until 2008 and incident cancer cases were identified from the Swiss Childhood Cancer Registry. A radiation model was used to predict dose rates from terrestrial and cosmic radiation at locations of residence. Cox regression models were used to assess associations between cancer risk and dose rates and cumulative dose since birth. Among 2,093,660 children included at census, 1,782 incident cases of cancer were identified including 530 with leukemia, 328 with lymphoma, and 423 with a tumor of the central nervous system (CNS). Hazard ratios for each mSv increase in cumulative dose of external radiation were 1.03 (95% CI: 1.01, 1.05) for any cancer, 1.04 (1.00, 1.08) for leukemia, 1.01 (0.96, 1.05) for lymphoma, and 1.04 (1.00, 1.08) for CNS tumors. Adjustment for a range of potential confounders had little effect on the results. Our study suggests that background radiation may contribute to the risk of cancer in children including leukemia and CNS tumors.
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Incidence and mortality from cerebrovascular disease (CVD) [International Classification of Diseases 9th revision (ICD-9) codes: 430-438] was studied in a cohort of 22,377 workers first employed at the Mayak Production Association (Mayak PA) in 1948-1982 and followed up to the end of 2008. The cohort size was increased by 19% and follow-up extended by 3 years over the previous analysis. Radiation doses were estimated using an updated dosimetry system: Mayak Worker Dosimetry System 2008 (MWDS-2008). For the first time, in an analysis of this cohort, quantitative smoking data were used. Workers of the study cohort were exposed occupationally to prolonged external gamma rays and internal alpha particles. The mean (±standard deviation) total dose from external gamma rays was 0.54 ± 0.76 Gy (95% percentile 2.21 Gy) for males and 0.44 ± 0.65 Gy (95% percentile 1.87 Gy) for females. The mean plutonium body burden in the 31% of workers monitored for internal exposure was 1.32 ± 4.87 kBq (95% percentile 4.71 kBq) for males and 2.21 ± 13.24 kBq (95% percentile 4.56 kBq) for females. The mean total absorbed alpha-particles dose to the liver from incorporated plutonium was 0.23 ± 0.77 Gy (95% percentile 0.89 Gy) in males and 0.44 ± 2.11 Gy (95% percentile 1.25 Gy) in females. After adjusting for nonradiation factors (gender, age, calendar period, employment period, facility, smoking, alcohol consumption), there were significantly increasing trends in CVD incidence associated with total absorbed dose from external gamma rays and total absorbed dose to the liver from internal alpha-particle radiation exposure. Excess relative risks per Gy (ERR/Gy) were 0.46 (95% CI 0.37, 0.57) and 0.28 (95% CI 0.16, 0.42), respectively, based on a linear dose-response model. Adjustments for additional factors (hypertension, body mass index, duration of employment, smoking index and total absorbed dose to the liver from internal exposure during the analysis of external exposure and vice versa) had little effect on the results. The categorical analyses showed that CVD incidence was significantly higher among workers with total absorbed external gamma-ray doses greater than 0.1 Gy compared to those exposed to lower doses and that CVD incidence was also significantly higher among workers with total absorbed internal alpha-particle doses to the liver from incorporated plutonium greater than 0.01 Gy compared to those exposed to lower doses. The results of the categorical analyses of CVD incidence were in good agreement with a linear dose response for external gamma-ray doses but for internal alpha-particle doses the picture was less clear. For the first time an excess risk of CVD mortality was seen in workers whose livers were exposed to internal alpha-particle doses greater than 0.1 Gy compared to those workers who were exposed to doses of less than 0.01 Gy. A significant increasing trend for CVD mortality with internal alpha-particle dose was revealed in the subcohort of workers exposed at doses <1.0 Gy after having adjusted for nonradiation factors, ERR/Gy = 0.84 (95% CI, 0.09, 1.92). These updated results provide good evidence for a linear trend in risk of CVD incidence with external gamma-ray dose. The trend for CVD incidence with internal alpha-particle dose is less clear due to the impact of issues concerning the use of dose estimates based on below the limit of detection bioassay measurements.
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This report from HPA Radiation Protection Division reflects understanding and evaluation of the current scientific evidence as presented and referenced in this document. ABSTRACT Mortality and cancer incidence have been studied in a cohort of about 175,000 persons on the National Registry for Radiation Workers (NRRW) who were followed until the end of 2001. This analysis is based on a larger cohort and nine years' further follow-up compared with the 2 nd NRRW analysis, and includes cancer registration data for the first time. As in previous NRRW analyses, total mortality and mortality from major causes were less than would be expected based on rates for England and Wales; the Standardised Mortality Ratio (SMR) for all causes was 81, whilst the SMR for all malignant neoplasms was 84. This "healthy worker effect" was still present after adjustment for social class. The only cause for which mortality was statistically significantly greater than expected from national rates was pleural cancer, probably reflecting exposure to asbestos. Within the cohort, there was borderline evidence of an increasing trend in total mortality with increasing external radiation dose. Much of the evidence for this trend related to cancer. Mortality and incidence from both leukaemia excluding chronic lymphatic leukaemia and the grouping of all malignant neoplasms other than leukaemia increased to a statistically significant extent with increasing dose. The corresponding central estimates of the trend in risk with dose were similar to those for the survivors of the atomic bombings of Hiroshima and Nagasaki, whilst the 90% confidence intervals for the NRRW trends excluded values more than about 2-3 times greater than the A-bomb risk estimates as well as values of zero or less. Whilst there was some evidence of an increasing trend with dose in mortality from all circulatory diseases combined, the irregular pattern in risk with dose and similarities with the corresponding pattern for lung cancer suggest that this finding may, at least in part, be due to confounding by smoking.
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Purposes: To review research progress on the molecular mechanisms of low dose ionizing radiation (LDIR)-induced hormesis, adaptive responses, radioresistance, bystander effects, and genomic instability in order to provide clues for therapeutic approaches to enhance biopositive effects (defined as radiation-induced beneficial effects to the organism), and control bionegative effects (defined as radiation-induced harmful effects to the organism) and related human diseases. Conclusions: Experimental studies have indicated that Ataxia telangiectasia-mutated (ATM), extracellular signal-related kinase (ERK), mitogen-activated protein kinase (MAPK), phospho-c-Jun NH(2)-terminal kinase (JNK) and protein 53 (P53)-related signal transduction pathways may be involved in LDIR-induced hormesis; MAPK, P53 may be important for adaptive response; ATM, cyclooxygenase-2 (COX-2), ERK, JNK, reactive oxygen species (ROS), P53 for radioresistance; COX-2, ERK, MAPK, ROS, tumor necrosis factor receptor alpha (TNFα) for LDIR-induced bystander effect; whereas ATM, ERK, MAPK, P53, ROS, TNFα-related signal transduction pathways are involved in LDIR-induced genomic instability. These results suggest that different manifestations of LDIR-induced cellular responses may have different signal transduction pathways. On the other hand, LDIR-induced different responses may also share the same signal transduction pathways. For instance, P53 has been involved in LDIR-induced hormesis, adaptive response, radioresistance and genomic instability. Current data therefore suggest that caution should be taken when designing therapeutic approaches using LDIR to induce beneficial effects in humans.
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The theoretical systematization and new solution of the current scientific problem of mental and behavioral disorders related to alcohol abuse in Chernobyl accident clean-up workers have been realized in the study. This involved the clinical and epidemiological pattern of the alcohol dependence syndrome (ADS) development following the Chernobyl accident. The secondariness of alcohol abuse and ADS among clean-up workers following to external exposure to ionizing radiation in doses of 0.0003–2.87 Gy on the background of mental, somatic and neurological abnormalities was shown. ADS was diagnosed in 26.8% of the clean-up workers while the ADS group risk includes 17.2% of them. Thus 44% of the clean-up workers faced with mental and behavioral disorders because of alcohol consumption. Declaration of interest: the authors declare no competing financial interests V.m. postrelko, k.n. loganovsky, A.i. chorny state institution "national research center for radiation medicine of national Academy of medical sciences of ukraine"
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Dear Editors, The long-term unfavorable impact of the Chernobyl disaster on mental health is internationally recognized (UN Chernobyl Forum 2006, Bromet and Havenaar 2007, Bromet et al. 2011). Effects on a developing brain and organic brain damage in the Chernobyl accident clean-up workers (liquidators), both with cognitive dysfunction are considered among priorities to be explored. There is also an increasing pool of evidences concerning radiation risks of cerebrovascular disorders following exposure to low doses of ionizing radiation (Shimizu et al. 1999; Ivanov et al. 2001, 2006; Buzunov et al. 2001, 2011; Preston et al. 2003; Azizova et al. 2011). A prospective 3-point neuropsychiatric study of prenatally exposed persons: (1) WHO Pilot project "Brain Damage in utero", IPHECA (1992–1995, Nyagu et al. 1996); (2) French-German Initiative for Chernobyl (1998–2004, Nyagu et al. 2004); and (3) Study of National Academy of Medical Sciences of Ukraine (since 2010, Loganovsky and Bazyka et al.) is conducted by researchers from the Research Center of Radiation Medicine (RCRM) in Ukraine. An excess of cognitive dysfunctions was found among Chernobyl accident survivors exposed to low doses of ionizing radiation in utero. The cerebral and molecular-biological basis of these disorders is still unknown and should be elucidated. Dose-related neuropsychiatric, neurophysiological, neuropsychological, and neuroimaging abnormalities following exposure to >0.3 Gy and neurophysiological and neuroimaging radiation markers at doses >1 Gy were revealed by RCRM in Ukraine. Radiation associated cerebrovascular effects were reported at >0.15 Gy (Ivanov et al. 2006). These health defects may be the consequence of accelerated aging due to radiation exposure which could be associated with cell senescence and telomere shortening (Bazyka et al. 2011, 2012). There exists an urgent need in finding out the cerebral and molecular basis of the cognitive impairment in Caucasian population exposed to low-dose irradiation.
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Background: Little is known about leukaemia risk following chronic radiation exposures at low dose rates. The Techa River Cohort of individuals residing in riverside villages between 1950 and 1961 when releases from the Mayak plutonium production complex contaminated the river allows quantification of leukaemia risks associated with chronic low-dose-rate internal and external exposures. Methods: Excess relative risk models described the dose–response relationship between radiation dose on the basis of updated dose estimates and the incidence of haematological malignancies ascertained between 1953 and 2007 among 28 223 cohort members, adjusted for attained age, sex, and other factors. Results: Almost half of the 72 leukaemia cases (excluding chronic lymphocytic leukaemia (CLL)) were estimated to be associated with radiation exposure. These data are consistent with a linear dose response with no evidence of modification. The excess relative risk estimate was 0.22 per 100 mGy. There was no evidence of significant dose effect for CLL or other haematopoietic malignancies. Conclusion: These analyses demonstrate that radiation exposures, similar to those received by populations exposed as a consequence of nuclear accidents, are associated with long-term dose-related increases in leukaemia risks. Using updated dose estimates, the leukaemia risk per unit dose is about half of that based on previous dosimetry.
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The etiology of radiation-induced cardiovascular disease (CVD) after chronic exposure to low doses of ionizing radiation is only marginally understood. We have previously shown that a chronic low-dose rate exposure (4.1 mGy/h) causes human umbilical vein endothelial cells (HUVECs) to prematurely senesce. We now show that a dose rate of 2.4 mGy/h is also able to trigger premature senescence in HUVECs, primarily indicated by a loss of growth potential and the appearance of the senescence-associated markers ß-galactosidase (SA-ß-gal) and p21. In contrast, a lower dose rate of 1.4 mGy/h was not sufficient to inhibit cellular growth or increase SA-ß-gal-staining despite an increased expression of p21. We used reverse phase protein arrays and triplex Isotope Coded Protein Labeling with LC-ESI-MS/MS to study the proteomic changes associated with chronic radiation-induced senescence. Both technologies identified inactivation of the PI3K/Akt/mTOR pathway accompanying premature senescence. In addition, expression of proteins involved in cytoskeletal structure and EIF2 signaling was reduced. Age-related diseases such as CVD have been previously associated with increased endothelial cell senescence. We postulate that a similar endothelial aging may contribute to the increased rate of CVD seen in populations chronically exposed to low-dose-rate radiation.
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The information for the present discussion on the uncertainties associated with estimation of radiation risks and probability of disease causation was assembled for the recently published NCRP Report No. 171 on this topic. This memorandum provides a timely overview of the topic, given that quantitative uncertainty analysis is the state of the art in health risk assessment and given its potential importance to developments in radiation protection. Over the past decade the increasing volume of epidemiology data and the supporting radiobiology findings have aided in the reduction of uncertainty in the risk estimates derived. However, it is equally apparent that there remain significant uncertainties related to dose assessment, low dose and low dose-rate extrapolation approaches (e.g. the selection of an appropriate dose and dose-rate effectiveness factor), the biological effectiveness where considerations of the health effects of high-LET and lower-energy low-LET radiations are required and the transfer of risks from a population for which health effects data are available to one for which such data are not available. The impact of radiation on human health has focused in recent years on cancer, although there has been a decided increase in the data for noncancer effects together with more reliable estimates of the risk following radiation exposure, even at relatively low doses (notably for cataracts and cardiovascular disease). New approaches for the estimation of hereditary risk have been developed with the use of human data whenever feasible, although the current estimates of heritable radiation effects still are based on mouse data because of an absence of effects in human studies. Uncertainties associated with estimation of these different types of health effects are discussed in a qualitative and semi-quantitative manner as appropriate. The way forward would seem to require additional epidemiological studies, especially studies of low dose and low dose-rate occupational and perhaps environmental exposures and for exposures to x rays and high-LET radiations used in medicine. The development of models for more reliably combining the epidemiology data with experimental laboratory animal and cellular data can enhance the overall risk assessment approach by providing biologically refined data to strengthen the estimation of effects at low doses as opposed to the sole use of mathematical models of epidemiological data that are primarily driven by medium/high doses. NASA's approach to radiation protection for astronauts, although a unique occupational group, indicates the possible applicability of estimates of risk and their uncertainty in a broader context for developing recommendations on: (1) dose limits for occupational exposure and exposure of members of the public; (2) criteria to limit exposures of workers and members of the public to radon and its short-lived decay products; and (3) the dosimetric quantity (effective dose) used in radiation protection.
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To assess cancer risks in a population that received prolonged low dose-rate gamma-irradiation for about 10 years as a result of occupying buildings containing 60Co-contaminated steel in Taiwan. The cancer risks were compared with those populations with the same temporal and geographic characteristics in Taiwan by standardized incidence ratios (SIR), adjusted for age and gender. The association of cancer risks with excess cumulative exposure was further evaluated for their relative risks by the Poisson multiple regression analysis. A total of 7271 people were registered as the exposed population, with 101,560 person-years at risk. The average excess cumulative exposure was approximately 47.8 mSv (range < 1 - 2,363 mSv). A total of 141 exposed subjects with various cancers were observed, while 95 developed leukemia or solid cancers after more than 2 or 10 years initial residence in contaminated buildings respectively. The SIR were significantly higher for all leukemia except chronic lymphocytic leukemia (n = 6, SIR = 3.6, 95% confidence interval [CI] 1.2 - 7.4) in men, and marginally significant for thyroid cancers (n = 6, SIR = 2.6, 95% CI 1.0 - 5.7) in women. On the other hand, all cancers combined, all solid cancers combined were shown to exhibit significant exposure-dependent increased risks in individuals with the initial exposure before the age of 30, but not beyond this age. The results suggest that prolonged low dose-rate radiation exposure appeared to increase risks of developing certain cancers in specific subgroups of this population in Taiwan.
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Three aspects of hormesis with low doses of ionizing radiation are presented: the good, the bad, and the ugly. The good is acceptance by France, Japan, and China of the thousands of studies showing stimulation and/or benefit, with no harm, from low dose irradiation. This includes thousands of people who live in good health with high background radiation. The bad is the nonacceptance of radiation hormesis by the U. S. and most other governments; their linear no threshold (LNT) concept promulgates fear of all radiation and produces laws which have no basis in mammalian physiology. The LNT concept leads to poor health, unreasonable medicine and oppressed industries. The ugly is decades of deception by medical and radiation committees which refuse to consider valid evidence of radiation hormesis in cancer, other diseases, and health. Specific examples are provided for the good, the bad, and the ugly in radiation hormesis.
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The aim of this study was to estimate the prevalence of lens opacities among physicians occupationally exposed to radiation - overall and by occupational factors - and to assess the feasibility of a large-scale study for risk assessment. Based on a nationwide registry of 1312 physicians, mostly radiologists with occupational exposure to ionizing radiation, 120 subjects were invited to participate, of which 59 (49%) consented. The inclusion criteria included (i) age 45-70 years, (ii) cumulative recorded radiation dose >10 mSv, and (iii) duration of work with dose monitoring >15 years. The participants completed a questionnaire regarding occupational history and other risk factors for lens opacities. A full ophthalmological examination was performed. Lenticular changes were graded using the Lens Opacities Classification System, version II (LOCS II), and the Nidek EAS-1000 Scheimpflug slit-imaging videophotography system. Lens opacities were detected in 42% [95% confidence interval (95% CI) 29-55] of the 57 physicians without prior cataract surgery. Nuclear opacities were found in 14% (95% CI 6-26), cortical in 7% (95% CI 2-19), and posterior subcapsular in 5% (95% CI 1-15) of the subjects. The prevalence of lens opacities increased with age, smoking, and cumulative recorded radiation dose. After controlling for age, gender, and smoking, the excess odds ratio for any lens opacity was 0.13 (95% CI -0.02-0.28) per 10 mSv of cumulative radiation dose. Our preliminary results show cortical and posterior subcapsular lens opacities among physicians exposed to occupational radiation, consistent with recent studies on low dose radiation exposure. A full study with an unexposed reference group for risk estimation is warranted.
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The prevailing belief for some decades has been that human radiation-related cataract occurs only after relatively high doses; for instance, the ICRP estimates that brief exposures of at least 0.5-2 Sv are required to cause detectable lens opacities and 5 Sv for vision-impairing cataracts. For protracted exposures, the ICRP estimates the corresponding dose thresholds as 5 Sv and 8 Sv, respectively. However, several studies, especially in the last decade, indicate that radiation-associated opacities occur at much lower doses. Several studies suggest that medical or environmental radiation exposure to the lens confers risk of opacities at doses well under 1 Sv. Among Japanese A-bomb survivors, risks for cataracts necessitating lens surgery were seen at doses under 1 Gy. The confidence interval on the A-bomb dose threshold for cataract surgery prevalence indicated that the data are compatible with a dose threshold ranging from none up to only 0.8 Gy, similar to the dose threshold for minor opacities seen among Chernobyl clean-up workers with primarily protracted exposures. Findings from various studies indicate that radiation risk estimates are probably not due to confounding by other cataract risk factors and that risk is seen after both childhood and adult exposures. The recent data are instigating reassessments of guidelines by various radiation protection bodies regarding permissible levels of radiation to the eye. Among the future epidemiological research directions, the most important research need is for adequate studies of vision-impairing cataract after protracted radiation exposure.
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The results of investigations on the cognitive outcomes of adolescents exposed prenatally to radiation from Chernobyl are inconsistent. In 2005 through 2006, we assessed individuals exposed prenatally (N = 84) and controls (N = 94) using a broad neuropsychological test battery. Neuropsychological performance was significantly weaker in the 84 adolescents exposed prenatally compared to the 94 controls on measures of verbal working memory, verbal memory, and executive functioning when controlling for possible confounders. Our findings add new and important support to the hypothesis that the Chernobyl accident had a specific effect on the neuropsychological functioning of those exposed prenatally.
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Exposure to high levels of ionizing radiation (IR) (>0.5Gy), negatively affect health. but, less is known about the effects of low dose IR (LDIR) but recent, evidence suggests that it may have profound effects on cellular functions. We are commonly exposed to LDIR over natural background levels from numerous sources: people may be exposed to low dose IR for medical diagnosis and therapy, air travel, illegal IR waste dumpsites or by occupational exposures in the nuclear and medical sectors. Stem cells reside for long periods of time in our bodies, and this increases the possibility that they may be accumulate genotoxic damage derived from extrinsic LDIR or intrinsic sources (such as DNA replication). In this review we provide an overview of LDIR effects on biology of stem cell compartments. The principal findings and issues reported in the scientific literature are discussed in order to present the current understanding of the LDIR exposure risk, and assess whether it may impact human health. We first consider the general biological consequences of LDIR exposure. Following this, we discuss the effects of LDIR on stem cells as discovered through in vitro and in vivo studies. This article is protected by copyright. All rights reserved.
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The tumor control effects of total body irradiation (TBI) for tumor bearing mice and human tumor were investigated fundamentally and clinically. TBI is usually used in tissue transplantation experiment in order to prevent rejective response for transplanted tissues by immunological reaction. This kind of suppressive effect of immunological response by TBI is considered as to be caused even if very small dose of TBI. However, there are only a few data concerning the effect of low dose of TBI, and TBI of low dose level is concluded to bring about the same effect as in high dose level by back extrapolation from the data of high dose level. In present paper, firstly the effects of TBI for tumor control in murine squamous carcinoma are reported, and secondly the results of clinical trial in malignant lymphoma are demonstrated. In fundamental studies, TBI of low doses (10–15 cGy) suggests potentiating effect in cell killing in combination of TBI of 10 cGy and local irradiation given at 12 hours after TBI, though TBI of 10 cGy is not able to detect any cell killing effect. TBI of 10 cGy or 15 cGy also stands for suppressive effect of distant metastasis (lung metastasis). In clinical studies, malignant lymphoma (non-Hodgikin’s lymphoma) is selected as the first disease of clinical trial, and the results is seemed to be prospective method to overcome cancers with radiotherapy, though the trial is not phase III clinical trial. © 1997, Japanese Society for Therapeutic Radiology and Oncology. All rights reserved.