Effects of generational low dose-rate 137Cs internal exposure in descendant mice.

To quantitatively investigate the effects of chronic low-dose internal exposure to Cesium-137 on DNA damage, carcinogenicity, and offspring over multiple generations. The potential genetic risk in humans was predicted based on next-generation murine mutation rates to confirm the reasonableness of the current Cesium-137 dose limits for food. Cesium-137 (100 Bq/mL) was provided in drinking water to A/J mice, facilitating chronic, low-dose, low-dose-rate internal exposure through sibling mating over 25 generations (G25). The A/J mice were compared with a control strain with the same origin ancestry (no Cesium-137 water) for DNA double-strand breaks (DSBs), oxidative stress, chromosome aberrations, micronucleus test results, whole genome analysis, carcinogenicity, tumor growth rate, and immune competence. Compared to the control group, DNA DSBs and oxidative stress were significantly increased in the Cesium-137 group. However, no significant differences were observed between the groups regarding chromosome aberration, micronuclei, or the whole genome sequence mutation analysis. Although the carcinogenic rate did not differ between the groups, the rate of tumor growth was significantly suppressed in the Cesium-137 group. The anti-tumor cytokine trend in the Cesium-137 group likely contributed to this effect. No pathological or genetic effects were observed in the offspring of mice drinking water containing 100 Bq/mL Cesium-137 after G25. The contribution of low dose-rate radiation to carcinogenicity was not additive but growth-inhibitory. Although the negative data are not conclusive, these findings are deemed highly reliable.

Radioactive contamination in feral dogs in the Chernobyl exclusion zone: Population body-burden survey and implications for human radiation exposure.

This report describes a two-year effort to survey the internal 137Cs and external ß-emitter contamination present in the feral dog population near the Chernobyl nuclear power plant (ChNPP) site, and to understand the potential for human radiation exposure from this contamination. This work was performed as an integral part of the radiation safety and control procedures of an animal welfare oriented trap-neuter-release (TNR) program. The measurement program focused on external contamination surveys using handheld ß-sensitive probes, and internal contamination studies using a simple whole-body counter. Internal 137Cs burden was measured non-invasively during post-surgical observation and recovery. External ß contamination surveys performed during intake showed that 21/288 animals had significant, removable external contamination, though not enough to pose a large hazard for incidental contact. Measurements with the whole-body counter indicated internal 137Cs body burdens ranging from undetectable (minimum detection level ∼100 Bq/kg in 2017, ∼30 Bq/kg in 2018) to approximately 30,000 Bq/kg. A total of 33 animals had 137Cs body-burdens above 1 kBq/kg, though none posed an external exposure hazard. The large variation in the 137Cs concentration in these animals is not well-understood, could be due to prey selection, access to human food scraps, or extended residence in highly contaminated areas. The small minority of animals with external contamination may pose a contamination risk allowing exposures in excess of regulatory standards.

Health risks from radioactive particles on Cumbrian beaches near the Sellafield nuclear site.

A monitoring programme, in place since 2006, continues to recover radioactive particles (<2 mm diameter) and larger objects from the beaches of West Cumbria. The potential risks to members of the public using the beaches are mainly related to prolonged skin contact with or the inadvertent ingestion of small particles. Most particles are classified as either 'beta-rich' or 'alpha-rich' and are detected as a result of their caesium-137 or americium-241 content. Beta-rich particles generally also contain strontium-90, with90Sr:137Cs ratios of up to about 1:1, but typically <0.1:1. Alpha-rich particles contain plutonium isotopes, with Pu:241Amαratios usually around 0.5-0.6:1. 'Beta-rich' particles have the greatest potential to cause localised skin damage if held in stationary contact with the skin for prolonged periods. However, it is concluded that only particles of >106Bq of137Cs, with high90Sr:137Cs ratios, would pose a significant risk of causing acute skin ulceration. No particles of this level of activity have been found. Inadvertent ingestion of a particle will result in the absorption to blood of a small proportion of the radionuclide content of the particle. The subsequent retention of radionuclides in body organs and tissues presents a potential risk of the development of cancer. For 'beta-rich' particles with typical activities (mean 2 × 104Bq137Cs, Sr:Cs ratio of 0.1:1), the estimated committed effective doses are about 30µSv for adults and about 40µSv for 1 year old infants, with lower values for 'alpha-rich' particles of typical activities. The corresponding estimates of lifetime cancer incidence following ingestion for both particle types are of the order of 10-6for adults and up to 10-5for infants. These estimates are subject to substantial uncertainties but provide an indication of the low risks to members of the public.

Dose-Dependent Transmissibility of Chromosome Aberrations in Human Lymphocytes at First Mitosis. II. Biological Effectiveness of Heavy Charged Particles Versus Gamma Rays.

Chromosome aberrations (CAs) are large scale structural rearrangements to the genome that have been used as a proxy endpoint of mutagenic and carcinogenic potential. And yet, many types of CAs are incapable of causing either of these effects simply because they are lethal. Using 24-color multi-fluor combinatorial painting (mFISH), we examined CAs in normal human lymphocytes exposed to graded doses of 1 GeV/nucleon accelerated 56Fe ions and 662 keV 137Cs gamma rays. As expected, the high-linear energy transfer (LET) heavy ions were considerably more potent per unit dose at producing total yields of CAs compared to low-LET gamma rays. As also anticipated, the frequency distribution of aberrations per cell exposed to 56Fe ions was significantly overdispersed compared to the Poisson distribution, containing excess numbers of cells devoid of aberrations. We used the zero-inflated negative binomial (ZINB) distribution to model these data. Based on objective cytogenetic criteria that are subject to caveats we discuss, each cell was individually evaluated in terms of likely survival (i.e., its ability to transmit to daughter cell progeny). For 56Fe ion irradiations, the frequency of surviving cells harboring complex aberrations represented a significant portion of aberration-bearing cells, while for gamma irradiation no survivable cells containing complex aberrations were observed. When the dose responses for the two radiation types were compared, and the analysis was limited to surviving cells that contained aberrations, we were surprised to find the high-LET 56Fe ions only marginally more potent than the low-LET gamma rays for doses less than 1 Gy. In fact, based on dose-response modeling, they were predicted to be less effective than gamma rays at somewhat higher doses. The major implication of these findings is that measures of relative biological effectiveness that fail to account for coincident lethality will tend to overstate the impact of transmissible chromosomal damage from high-LET particle exposure.

Perfil sociodemográfico e situação de saúde dos pacientes expostos ao Césio 137 em Goiânia / Sociodemographic profile and health situation of patients exposed to Cesium 137 in Goiânia

Este trabalho teve por objetivo analisar os aspectos sociodemográficos e da situação de saúde dos indivíduos expostos ao Césio 137, que constam com cadastro ativo no Sistema de Informação ao Radioacidentado (SISRAD) do Centro de Assistência aos Radioacidentados (CARA). Métodos: Trata-se de um estudo descritivo, com análise transversal, realizado no período de outubro de 2019 a fevereiro de 2020 e que contempla dados registrados desde o ano de 1987. O público-alvo da pesquisa consistiu em indivíduos expostos de forma direta e indireta ao Césio 137 na cidade de Goiânia-Goiás, e que se encontram devidamente cadastrados no CARA. Levou-se em consideração aspectos sociodemográficos, a fim de construir o perfil dos pacientes. Realizado esse processo, procedeu-se à classificação e distribuição dos pacientes, através de critérios como a forma de contato e a dose de exposição. O levantamento de dados foi executado pela análise dos prontuários no SISRAD. Resultados e Conclusões: nos grupos mais jovens não foram identificados cânceres precoces ou malformações nos Grupos NGI e NGII, mas existem relatos que conflitam com as declarações de óbitos dos grupos GI e GII, o que trouxe dificuldades para uma análise estratificada e detalhada. As doenças psíquicas, apresentam maior prevalência, seguidas de causas associadas a hipertensão e a diabetes. Verificou-se a importância da análise de saúde dos radioacidentados como ferramenta de planejamento, preparação e avaliação dos grupos de risco

This study aimed to analyze the sociodemographic aspects and the health situation of individuals exposed to Cesium 137, who have an active record in the Information System for Radio Accidents (SISRAD) of the Assistance Center for Radio Accidents (CARA). Methods: This is a descriptive study, with cross-sectional analysis, carried out from October 2019 to February 2020 and which includes data recorded since 1987. The target audience of the research consisted of individuals exposed directly and indirect exposure to Cesium 137 in the city of Goiânia-Goiás, and who are duly registered with the CARA. Sociodemographic aspects were taken into account in order to build the profile of patients. Once this process was completed, the patients were classified and distributed using criteria such as the form of contact and the dose of exposure. Data collection was carried out by analyzing the medical records in SISRAD. Results and Conclusions: In the younger groups, no early cancers or malformations were identified in Groups NGI and NGII, but there are reports that conflict with the death certificates of groups GI and GII, which brought difficulties for a stratified and detailed analysis. Mental illnesses are more prevalent, followed by causes associated with hypertension and diabetes. The importance of analyzing the health of radio-accidents as a tool for planning, preparing and evaluating risk groups was verified

Patient-specific radiological protection precautions following Cs collagen embedded Cs-131 implantation in the brain.

OBJECTIVE: Cesium-131 brachytherapy is an adjunct for brain tumor treatment, offering potential clinical and radiation protection advantages over other isotopes including iodine-125. We present evidence-based radiation safety recommendations from an initial experience with Cs-131 brachytherapy in the resection cavities of recurrent, previously irradiated brain metastases. METHODS: Twenty-two recurrent brain metastases in 18 patients were resected and treated with permanent Cs-131 brachytherapy implantation using commercially procured seed-impregnated collagen tiles (GammaTile, GT Medical Technologies). Exposure to intraoperative staff was monitored with NVLAP-accredited ring dosimeters. For patient release considerations, NCRP guidelines were used to develop an algorithm for modeling lifetime exposure to family and ancillary staff caring for patients based on measured dose rates. RESULTS: A median of 16 Cs-131 seeds were implanted (range 6-46) with median cumulative strength of 58.72U (20.64-150.42). Resulting dose rates were 1.19 mSv/h (0.28-3.3) on contact, 0.08 mSv/h (0.01-0.35) at 30 cm, and 0.01 mSv/h (0.001-0.03) at 100 cm from the patient. Modeled total caregiver exposure was 0.91 mSv (0.16-3.26), and occupational exposure was 0.06 mSv (0.02-0.23) accounting for patient self-shielding via skull and soft tissue attenuation. Real-time dose rate measurements were grouped into brackets to provide close contact precautions for caregivers ranging from 1-3 weeks for adults and longer for pregnant women and children, including cases with multiple implantations. CONCLUSIONS: Radiological protection precautions were developed based on patient-specific emissions and accounted for multiple implantations of Cs-131, to maintain exposure to staff and the public in accordance with relevant regulatory dose constraints.

Disabling the Fanconi Anemia Pathway in Stem Cells Leads to Radioresistance and Genomic Instability.

Fanconi anemia is an inherited genome instability syndrome characterized by interstrand cross-link hypersensitivity, congenital defects, bone marrow failure, and cancer predisposition. Although DNA repair mediated by Fanconi anemia genes has been extensively studied, how inactivation of these genes leads to specific cellular phenotypic consequences associated with Fanconi anemia is not well understood. Here we report that Fanconi anemia stem cells in the C. elegans germline and in murine embryos display marked nonhomologous end joining (NHEJ)-dependent radiation resistance, leading to survival of progeny cells carrying genetic lesions. In contrast, DNA cross-linking does not induce generational genomic instability in Fanconi anemia stem cells, as widely accepted, but rather drives NHEJ-dependent apoptosis in both species. These findings suggest that Fanconi anemia is a stem cell disease reflecting inappropriate NHEJ, which is mutagenic and carcinogenic as a result of DNA misrepair, while marrow failure represents hematopoietic stem cell apoptosis. SIGNIFICANCE: This study finds that Fanconi anemia stem cells preferentially activate error-prone NHEJ-dependent DNA repair to survive irradiation, thereby conferring generational genomic instability that is instrumental in carcinogenesis.

Deviation from Mendelian transmission of autosomal SNPs can be used to estimate germline mutations in humans exposed to ionizing radiation.

We aimed to estimate the rate of germline mutations in the offspring of individuals accidentally exposed to Cesium-137 ionizing radiation. The study included two distinct groups: one of cases, consisting of males and females accidentally exposed to low doses of ionizing radiation of Cs137, and a control group of non-exposed participants. The cases included 37 people representing 11 families and 15 children conceived after the accident. Exposed families incurred radiation absorbed doses in the range of 0.2 to 0.5 Gray. The control group included 15 families and 15 children also conceived after 1987 in Goiânia with no history of radiation exposure. DNA samples from peripheral blood were analyzed with the Affymetrix GeneChip® CytoScanHD™ to estimate point mutations in autosomal SNPs. A set of scripts previously developed was used to detect de novo mutations by comparing parent and offspring genotypes at the level of each SNP marker. Overall numbers of observed Mendelian deviations were statistically significant between the exposed and control groups. Our retrospective transgenerational DNA analysis showed a 44.0% increase in the burden of SNP mutations in the offspring of cases when compared to controls, based on the average of MFMD for the two groups. Parent-of-origin and type of nucleotide substitution were also inferred. This proved useful in a retrospective estimation of the rate of de novo germline mutations in a human population accidentally exposed to low doses of radiation from Cesium-137. Our results suggested that observed burden of germline mutations identified in offspring was a potentially useful biomarker of effect to estimate parental exposure to low doses of IR and could become an important marker suitable for biomonitoring human population exposed to environmental mutagens.

Evaluation of ionizing radiation as a risk factor for the incidence of breast cancer: long-term analysis after the cesium-137 accident in Goiânia, Brazil. An ecological study.

BACKGROUND: The largest radiological accident to occur in any urban area happened in Goiânia, Brazil, in 1987. OBJECTIVE: To evaluate the association between breast cancer incidence and ionizing radiation levels. DESIGN AND SETTING: Ecological study among residents of the city of Goiânia, Brazil. METHODS: The central region of Goiânia, with seven major sources of contamination from cesium-137, was defined as the study area. The addresses of women diagnosed with breast cancer were identified between 2001 and 2010. The data were geographically referenced and, using census data, the annual averages of crude incidence rates were estimated. The existence of clusters of new cases was ascertained by means of the Moran index. Correlations of radiometric measurements with the incidence were assessed using unconditional linear regression. RESULTS: A total of 4,105 new cases were identified, of which 2,233 were in the study area, and of these, 1,286 (57.59%) were georeferenced. The gross rates of total and referenced cases were 102.91 and 71.86/100,000 women, respectively. These were close to the average for Brazilian state capitals, which is 79.37/100,000 women. The cluster analysis showed slight correlations in three small sets of census tracts, but these were far from the sources of contamination. The scatter plot of points and the R2 value close to zero indicated that there was no association between the variables. CONCLUSION: This study reinforces the hypothesis that the ionizing radiation levels to which women living in Goiânia are now exposed to are not associated with the onset of new cases of breast cancer.

Evaluation of ionizing radiation as a risk factor for the incidence of breast cancer: long-term analysis after the cesium-137 accident in Goiânia, Brazil. An ecological study

ABSTRACT BACKGROUND: The largest radiological accident to occur in any urban area happened in Goiânia, Brazil, in 1987. OBJECTIVE: To evaluate the association between breast cancer incidence and ionizing radiation levels. DESIGN AND SETTING: Ecological study among residents of the city of Goiânia, Brazil. METHODS: The central region of Goiânia, with seven major sources of contamination from cesium-137, was defined as the study area. The addresses of women diagnosed with breast cancer were identified between 2001 and 2010. The data were geographically referenced and, using census data, the annual averages of crude incidence rates were estimated. The existence of clusters of new cases was ascertained by means of the Moran index. Correlations of radiometric measurements with the incidence were assessed using unconditional linear regression. RESULTS: A total of 4,105 new cases were identified, of which 2,233 were in the study area, and of these, 1,286 (57.59%) were georeferenced. The gross rates of total and referenced cases were 102.91 and 71.86/100,000 women, respectively. These were close to the average for Brazilian state capitals, which is 79.37/100,000 women. The cluster analysis showed slight correlations in three small sets of census tracts, but these were far from the sources of contamination. The scatter plot of points and the R2 value close to zero indicated that there was no association between the variables. CONCLUSION: This study reinforces the hypothesis that the ionizing radiation levels to which women living in Goiânia are now exposed to are not associated with the onset of new cases of breast cancer.

Spatiotemporal association of low birth weight with Cs-137 deposition at the prefecture level in Japan after the Fukushima nuclear power plant accidents: an analytical-ecologic epidemiological study.

BACKGROUND: Perinatal mortality increased in contaminated prefectures after the Fukushima Daichi Nuclear Power Plant (FDNPP) accidents in Japan in 2011. Elevated counts of surgeries for cryptorchidism and congenital heart malformations were observed throughout Japan from 2012 onward. The thyroid cancer detection rate (2011 to 2016) was associated with the dose-rate at the municipality level in the Fukushima prefecture. Since the birth weight is a simple and objective indicator for gestational development and pregnancy outcome, the question arises whether the annual birth weight distribution was distorted in a dose-rate-dependent manner across Japan after Fukushima. METHODS: The Japanese Ministry of Health, Labour, and Welfare provides prefecture-specific annual counts for 26.158 million live births from 1995 to 2018, of which 2.366 million births (9.04%) with weights < 2500 g. Prefecture-specific spatiotemporal trends of the low birth weight proportions were analyzed. Logistic regression allowing for level-shifts from 2012 onward was employed to test whether those level-shifts were proportional to the prefecture-specific dose-rates derived from Cs-137 deposition in the 47 Japanese prefectures. RESULTS: The overall trend of the low birth weight prevalence (LBWp) in Japan discloses a jump in 2012 with a jump odds ratio (OR) 1.020, 95%-confidence interval (1.003,1.037), p-value 0.0246. A logistic regression of LBWp on the additional dose-rate after the FDNPP accidents adjusted for prefecture-specific spatiotemporal base-line trends yields an OR per µSv/h of 1.098 (1.058, 1.139), p-value < 0.0001. Further adjusting the logistic regression for the annual population size and physician density of the prefectures, as well as for the counts of the dead, the missing, and the evacuees due to earthquake and tsunami (as surrogate measures for medical infrastructure and stress) yields an OR per µSv/h of 1.109 (1.032, 1.191), p-value 0.0046. CONCLUSIONS: This study shows increased low birth weight prevalence related to the Cs-137 deposition and the corresponding additional dose-rate in Japan from 2012 onward. Previous evidence suggesting compromised gestational development and pregnancy outcome under elevated environmental ionizing radiation exposure is corroborated.

Biological effectiveness of very high gamma dose rate and its implication for radiological protection.

Many experimental studies are carried out to compare biological effectiveness of high dose rate (HDR) with that of low dose rate (LDR). The rational for this is the uncertainty regarding the value of the dose rate effectiveness factor (DREF) used in radiological protection. While a LDR is defined as 0.1 mGy/min or lower, anything above that is seen as HDR. In cell and animal experiments, a dose rate around 1 Gy/min is usually used as representative for HDR. However, atomic bomb survivors, the reference cohort for radiological protection, were exposed to tens of Gy/min. The important question is whether gamma radiation delivered at very high dose rate (VHDR-several Gy/min) is more effective in inducing DNA damage than that delivered at HDR. The aim of this investigation was to compare the biological effectiveness of gamma radiation delivered at VHDR (8.25 Gy/min) with that of HDR (0.38 Gy/min or 0.79 Gy/min). Experiments were carried out with human peripheral mononuclear cells (PBMC) and the human osteosarcoma cell line U2OS. Endpoints related to DNA damage response were analysed. The results show that in PBMC, VHDR is more effective than HDR in inducing gene expression and micronuclei. In U2OS cells, the repair of 53BP1 foci was delayed after VHDR indicating a higher level of damage complexity, but no VHDR effect was observed at the level of micronuclei and clonogenic cell survival. We suggest that the DREF value may be underestimated when the biological effectiveness of HDR and LDR is compared.

A matched-pair analysis of clinical outcomes after intracavitary cesium-131 brachytherapy versus stereotactic radiosurgery for resected brain metastases.

OBJECTIVE: Adjuvant radiation therapy (RT), such as cesium-131 (Cs-131) brachytherapy or stereotactic radiosurgery (SRS), reduces local recurrence (LR) of brain metastases (BM). However, SRS is less efficacious for large cavities, and the delay between surgery and SRS may permit tumor repopulation. Cs-131 has demonstrated improved local control, with reduced radiation necrosis (RN) compared to SRS. This study represents the first comparison of outcomes between Cs-131 brachytherapy and SRS for resected BM. METHODS: Patients with BM treated with Cs-131 and SRS following gross-total resection were retrospectively identified. Thirty patients who underwent Cs-131 brachytherapy were compared to 60 controls who received SRS. Controls were selected from a larger cohort to match the patients treated with Cs-131 in a 2:1 ratio according to tumor size, histology, performance status, and recursive partitioning analysis class. Overall survival (OS), LR, regional recurrence, distant recurrence (DR), and RN were compared. RESULTS: With a median follow-up of 17.5 months for Cs-131-treated and 13.0 months for SRS-treated patients, the LR rate was significantly lower with brachytherapy; 10% for the Cs-131 cohort compared to 28.3% for SRS patients (OR 0.281, 95% CI 0.082-0.949; p = 0.049). Rates of regional recurrence, DR, and OS did not differ significantly between the two cohorts. Kaplan-Meier analysis with log-rank testing showed a significantly higher likelihood of freedom from LR (p = 0.027) as well as DR (p = 0.018) after Cs-131 compared to SRS treatment (p = 0.027), but no difference in likelihood of OS (p = 0.093). Six (10.0%) patients who underwent SRS experienced RN compared to 1 (3.3%) patient who received Cs-131 (p = 0.417). CONCLUSIONS: Postresection patients with BM treated with Cs-131 brachytherapy were more likely to achieve local control compared to SRS-treated patients. This study provides preliminary evidence of the potential of Cs-131 to reduce LR following gross-total resection of single BM, with minimal toxicity, and suggests the need for a prospective study to address this question.

Solid cancer risk dependence on the Pasquill-Gifford atmospheric stability classes in a radiological event.

In a radiological event, the lack of preliminary information about the site of explosion and the difficulty in predicting the accurate path and distribution of radioactive plumes makes it difficult to predict expected health effects of exposed individuals. So far, in such a health evaluation, radiation-induced stochastic health effects such as cancer are not included. The Pasquill-Gifford atmospheric classes generally allow connecting atmospheric stability with dispersion of radioactive contaminants to the environment. In this work, an environmental release of radioactive Cs-137 was simulated and the resulting relative risk for solid cancer incidence among the affected population calculated. The HotSpot health physics code was used to simulate the radioactive atmospheric dispersion and calculate the Total Effective Dose Equivalent (TEDE), which was then used to estimate the relative risk of cancer incidence. The main results from this work suggest that the relative cancer risk and atmospheric stability classes are linked by differences in the TEDE. Such a finding may support triage, because it adds additional information on the potentially affected population at the early stages of an emergency response.

Effects of chronic low-dose radiation on cataract prevalence and characterization in wild boar (Sus scrofa) from Fukushima, Japan.

This study evaluated cataracts in wild boar exposed to chronic low-dose radiation. We examined wild boar from within and outside the Fukushima Exclusion Zone for nuclear, cortical, and posterior subcapsular (PSC) cataracts in vivo and photographically. Plausible upper-bound, lifetime radiation dose for each boar was estimated from radioactivity levels in each animal's home range combined with tissue concentrations of 134+137Cesium. Fifteen exposed and twenty control boar were evaluated. There were no significant differences in overall prevalence or score for cortical or PSC cataracts between exposed and control animals. Nuclear (centrally located) cataracts were significantly more prevalent in exposed boar (p < 0.05) and had statistically higher median scores. Plausible upper-bound, lifetime radiation dose ranged from 1 to 1,600 mGy in exposed animals, with no correlation between dose and cortical or PSC score. While radiation dose and nuclear score were positively associated, the impact of age could not be completely separated from the relationship. Additionally, the clinical significance of even the highest scoring nuclear cataract was negligible. Based on the population sampled, wild boar in the Fukushima Exclusion Zone do not have a significantly higher prevalence or risk of cortical or PSC cataracts compared to control animals.

Medical Therapy of Patients Contaminated with Radioactive Cesium or Iodine.

Follow-up studies after the Chernobyl and Fukushima accidents have shown that 137Cs and 131I made up the major amount of harmful contaminants in the atmospheric dispersion and fallout. Other potential sources for such radionuclide exposure may be terrorist attacks, e.g., via contamination of drinking water reservoirs. A primary purpose of radionuclide mobilization is to minimize the radiation dose. Rapid initiation of treatment of poisoned patients is imperative after a contaminating event. Internal contamination with radioactive material can expose patients to prolonged radiation, thus leading to short- and long-term clinical consequences. After the patient's emergency conditions are addressed, the treating physicians and assisting experts should assess the amount of radioactive material that has been internalized. This evaluation should include estimation of the radiation dose that is delivered and the specific radionuclides inside the body. These complex assessments warrant the reliance on a multidisciplinary approach that incorporates regional experts in radiation medicine and emergencies. Regional hospitals should have elaborated strategies for the handling of radiation emergencies. If radioactive cesium is a significant pollutant, Prussian blue is the approved antidote for internal detoxification. Upon risks of radioiodine exposure, prophylactic or immediate treatment with potassium iodide tablets is recommended. Chelators developed from calcium salts have been studied for gastrointestinal trapping and enhanced mobilization after strontium exposure.

Comparison of urine and blood as a convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium.

Blood and urine were compared to clarify which is a better sample for estimating the concentration of radioactive cesium in muscles of live cattle. The most probable concentration of 137 Cs in muscles was 21.0 times that in blood, and the error of this estimation was 28%. The concentration of 137 Cs in blood was estimated accurately using urine samples. The estimation error did not increase so much (33%), even when the concentration of 137 Cs in muscles was estimated using urine samples. On the other hand, the maximum volume of blood that can be collected with one syringe is 50 ml, whereas it is easy to collect 1,000 ml of urine. It took at least 360 min to confirm that a cow meets the legal standard by inspecting 50 ml of blood. However, with 1,000 ml of urine, a 20 min measurement time was sufficient for this purpose. This difference in the required measurement time is critically important for practical use. In addition, urine can be collected by farmers themselves, whereas the blood collection requires a veterinarian. Therefore, urine is a more convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium.

Long-Term Patient-Reported Rectal Bleeding and Bowel-Related Quality of Life After Cs-131 Prostate Brachytherapy.

PURPOSE: There is limited long-term data on outcome and side effects of Cs-131 prostate brachytherapy and minimal patient-reported data on rectal bleeding with any isotope. We aimed to describe the incidence, prevalence, and predictors of late patient-reported rectal bleeding after Cs-131 brachytherapy. METHODS AND MATERIALS: We reviewed a prospectively collected database of 620 men treated with Cs-131 prostate brachytherapy. Of 620 patients, 390 (62.9%) received brachytherapy as monotherapy; the remainder received combination therapy with external beam radiation therapy (EBRT). Patients were administered Expanded Prostate Cancer Index Composite questionnaires preoperatively and postoperatively at each follow-up visit. The primary outcome was late rectal bleeding, defined as rectal bleeding reported at the 6-month follow-up or later. Clinically significant rectal bleeding was defined as occurring more than "rarely," and clinically significant bother from rectal bleeding was defined as considering bleeding more than a "very small problem." Univariate and multivariate Cox regression were performed to identify factors predictive for rectal bleeding. RESULTS: With a median follow-up time of 48 months, the cumulative incidence of clinically significant late rectal bleeding was 12.4%, with 15.2% reporting clinically significant bother from bleeding. At the time of last follow-up, the prevalence of clinically significant rectal bleeding and bother were 4.0% and 4.7%, respectively. On univariate analysis, acute clinically significant rectal bleeding, defined as occurring within the first 6 months (P = .001) and combination therapy with EBRT (P = .001) predicted for clinically significant late rectal bleeding. On multivariate analysis, both EBRT (P = .001; hazard ratio, 2.50; 95% confidence interval, 1.58-3.94) and acute rectal bleeding (P < .001; hazard ratio, 3.11; 95% confidence interval, 1.75-5.53) remained significant predictors for late rectal bleeding. CONCLUSIONS: Prostate brachytherapy with Cs-131 is well tolerated in the long term. Although the incidence of clinically significant patient-reported late rectal bleeding was 12.4%, the prevalence at last follow-up was only 4.0%, suggesting that this problem tends to resolve.

Modeling the Optimum Prussian Blue Treatment for Acute Radiation Syndrome Following 137Cs Ingestion.

Accidents or radiological attacks may lead to ingestion of Cs by large numbers of the public. This work models the efficacy of Prussian blue, the medical countermeasure for internal contamination with Cs, to prevent acute radiation syndrome as a function of the duration of treatment and the time that treatment starts after uptake. Risk of acute radiation syndrome is modeled using the International Commission on Radiological Protection's acute radiation hazard model. Dose rates to target organs from Cs ingestion were based on the data published by the US Environmental Protection Agency and the retention of Cs in the reference man. Modeling found that treatment is most effective if begun within 15 d of ingestion, and the course length should be at least 75 d to mitigate cancer risk and 290 d to mitigate fatalities due to acute radiation syndrome. Both of these course lengths are much longer than the minimum Prussian blue treatment regimen of 30 d. Extending the treatment time for contaminated individuals would increase demand for Prussian blue following an accident or attack and in turn, would require a larger stockpile of Prussian blue to meet demand. Not enough data is available to determine if this longer treatment time would lead to adverse medical outcomes due to the toxicity of the treatment itself.

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

Policy Points Policymakers should invest more on researching the long-term health effects of low-ionizing radiation exposure, as we are far from reaching a consensus on a topic that is of enormous importance for public health and safety. Public policies such as those limiting the import of contaminated food from areas hit by a radioactive disaster or those regulating the resident population's access to such areas should follow a precautionary approach. Neoplasm diagnosis and medical care should be designed in order to take into account the possible role of long-term, low-dose radiation exposure. Health care policies should provide effective screening and prevention strategies with a specific focus on the regions that were hit most severely by the Chernobyl nuclear fallout. Health care expenditure should be targeted, taking into account the geographical dispersion of the fallout in order to attenuate its possible effect on neoplasm incidence. CONTEXT: This study investigates the association between the radioactive 137 Cesium fallout originated by the 1986 Chernobyl nuclear accident and dispersed over Western Europe, as a result of a combination of radioactive cloud passage days and rainy days over a 10-day period, and long-term health patterns and related costs. Since the half-life of 137 Cesium is 30.17 years, part of the radioactivity in the affected regions is still present today, and it is usually still detected in the food chain, although at lower concentration levels. METHODS: We match longitudinal data on neoplasm incidence over the time span 2000-2013 in a number of European regions not immediately adjacent to Chernobyl with the randomly distributed levels of cesium deposition after the nuclear disaster in order to assess whether we can detect an association with the long-term health effects on the European population through a random effects model. FINDINGS: Considering 3 levels of fallout deposition-low, medium, and high-hospital discharges after treatment for neoplasms are, respectively, 0.36, 0.44, and 0.98 discharges over 100 inhabitants higher compared to regions with no fallout, with the population average being around 1.7 hospital discharges by neoplasms over 100 inhabitants. We checked the robustness of our findings to a number of tests including a placebo simulation and different model specifications. CONCLUSIONS: Radioactive fallout is positively associated with a higher incidence of hospital discharges after treatment for neoplasms almost 30 years after its release, with larger effects in regions where the radioactivity was more intense. Our estimates are comparable to the findings of the largest-scale study on the long-term health effects of continuous low levels of radiation exposure among workers in the nuclear industry and suggest that more research is needed on this topic, given its enormous importance for public health and safety.