Radiation Risk Estimates Research Articles

Evaluation of the measurement accuracy and uncertainty of a solid-state detector under diagnostic x-ray beam conditions.

An accurate measurement of x-ray beams is expected to reduce the uncertainties associated with estimating radiation risk to patients in clinical settings. To perform assessment tasks based on the readings of a solid-state detector (SSD) using semiconductor technology, the characteristics of the detector should be elucidated. In this study, we evaluated the measurement accuracy of a new SSD under diagnostic x-ray beam conditions in terms of air kerma, tube voltage, and half-value layer (HVL). The performance of the SSD was then compared with those of reference instruments. The tube voltage was varied within the range of 50-120kV in steps of 10kV and the thickness and materials of additional filters were concurrently changed (several combinations were tested). In addition, the dose rate and energy dependence of the SSD were also investigated. These effects were analyzed based on statistical significance tests. Furthermore, the expanded uncertainties in the series of measurements were meticulously calculated. The results showed average relative differences of -3.26±1.33%, 0.44±1.01%, and -2.60±3.31% for air kerma, tube voltage, and HVL, respectively. Furthermore, air kerma did not exhibit any dependence on dose rate and energy, in contrast to tube voltage and HVL measurements. The measurement values of the SSD fall within the acceptable range of uncertainty, highlighting its measurement accuracy and reliability. Furthermore, based on the characteristics elucidated by this study, valuable insights are provided concerning the assurance of appropriate measurement values in clinical settings.

Radiation exposure during orthodontic treatment: risk to children and adolescents.

To estimate radiation risk to children and adolescents during orthodontic treatment by retrieving number and type of radiographs from the patient records. Radiographs, along with justifications for radiation exposure, were obtained retrospectively from the patient records of 1,790 children and adolescents referred to two Swedish orthodontic clinics. Data were grouped according to treatment stage: treatment planning, treatment, and follow-up. Estimated risk was calculated using the concept of effective dose. Each patient had received around seven radiographs for orthodontic purposes. The most common exposures during treatment planning were one panoramic, one lateral, and three intraoral periapical radiographs. A small number of patients received a tomographic examination (8.2%). Few justifications for treatment planning and follow-up, but more in the actual treatment stage, had been recorded. The most common examinations were to assess root resorption and the positions of unerupted teeth, or simply carry out an unspecified control. The estimated risk of developing fatal cancer was considered low. The radiation risk from orthodontic treatment was equivalent to about 5-10 days of natural background radiation. Children and adolescents sometimes undergo multiple radiographic examinations, but despite the low radiation burden, accumulated radiation exposure should be considered and justified in young patients.

Estimated Doses to the Heart, Lungs and Oesophagus and Risks From Typical UK Radiotherapy for Early Breast Cancer During 2015–2023

PurposeBreast cancer radiotherapy can increase the risks of heart disease, lung cancer and oesophageal cancer. At present, the best dosimetric predictors of these risks are mean doses to the whole heart, lungs and oesophagus, respectively. We aimed to estimate typical doses to these organs and resulting risks from UK breast cancer radiotherapy. MethodsA systematic review and meta-analysis was conducted of planned or delivered mean doses to the whole heart, lungs or oesophagus from UK breast cancer radiotherapy in studies published during 2015–2023. Average mean doses were summarised for combinations of laterality and clinical targets. Heart disease and lung cancer mortality risks were then estimated using established models. ResultsFor whole heart, thirteen studies reported 2893 doses. Average mean doses were higher in left than in right-sided radiotherapy and increased with extent of clinical targets. For left-sided radiotherapy, average mean heart doses were: 2.0 Gy (range 1.2–8.0 Gy) breast/chest wall, 2.7 Gy (range 0.6–5.6 Gy) breast/chest wall with either axilla or supraclavicular nodes and 2.9 Gy (range 1.3–4.7 Gy) breast/chest wall with nodes including internal mammary. For right-sided radiotherapy, average mean heart doses were: 1.0 Gy (range 0.3–1.0 Gy) breast/chest wall and 1.2 Gy (range 1.0–1.4 Gy) breast/chest wall with either axilla or supraclavicular nodes. There were no whole heart dose estimates from right internal mammary radiotherapy. For whole lung, six studies reported 2230 doses. Average mean lung doses increased with extent of targets irradiated: 2.6 Gy (range 1.4–3.0 Gy) breast/chest wall, 3.0 Gy (range 0.9–5.1 Gy) breast/chest wall with either axilla or supraclavicular nodes and 7.1 Gy (range 6.7–10.0 Gy) breast/chest wall with nodes including internal mammary. For whole oesophagus, two studies reported 76 doses. Average mean oesophagus doses increased with extent of targets irradiated: 1.4 Gy (range 1.0–2.0 Gy) breast/chest wall with either axilla or supraclavicular nodes and 5.8 Gy (range 1.9–10.0 Gy) breast/chest wall with nodes including internal mammary. ConclusionsThe typical doses to these organs may be combined with dose-response relationships to estimate radiation risks. Estimated 30-year absolute lung cancer mortality risks from modern UK breast cancer radiotherapy for patients irradiated when aged 50 years were 2–6% for long-term continuing smokers, and <1% for non-smokers. Estimated 30-year mortality risks for heart disease were <1%.

Misclassification of causes of death among a small all-autopsied group of former nuclear workers: Death certificates vs. autopsy reports.

The U.S. Transuranium and Uranium Registries performs autopsies on each of its deceased Registrants as a part of its mission to follow up occupationally-exposed individuals. This provides a unique opportunity to explore death certificate misclassification errors, and the factors that influence them, among this small population of former nuclear workers. Underlying causes of death from death certificates and autopsy reports were coded using the 10th revision of the International Classification of Diseases (ICD-10). These codes were then used to quantify misclassification rates among 268 individuals for whom both full autopsy reports and death certificates with legible underlying causes of death were available. When underlying causes of death were compared between death certificates and autopsy reports, death certificates correctly identified the underlying cause of death's ICD-10 disease chapter in 74.6% of cases. The remaining 25.4% of misclassified cases resulted in over-classification rates that ranged from 1.2% for external causes of mortality to 12.2% for circulatory disease, and under-classification rates that ranged from 7.7% for external causes of mortality to 47.4% for respiratory disease. Neoplasms had generally lower misclassification rates with 4.3% over-classification and 13.3% under-classification. A logistic regression revealed that the odds of a match were 2.8 times higher when clinical history was mentioned on the autopsy report than when it was not. Similarly, the odds of a match were 3.4 times higher when death certificates were completed using autopsy findings than when autopsy findings were not used. This analysis excluded cases where it could not be determined if autopsy findings were used to complete death certificates. The findings of this study are useful to investigate the impact of death certificate misclassification errors on radiation risk estimates and, therefore, improve the reliability of epidemiological studies.

Measurement of Environmental Gamma Radiation Dose Rates and Estimation of Radiation Risk near the Construction Site of the Nuclear Power Plant, Indoor and Outdoor Locations of the Research Reactor, and Coal-Fired Thermal Power Plant Area

Measurement of Environmental Gamma Radiation Dose Rates and Estimation of Radiation Risk near the Construction Site of the Nuclear Power Plant, Indoor and Outdoor Locations of the Research Reactor, and Coal-Fired Thermal Power Plant Area

Adjustment for duration of employment in occupational epidemiology

PurposeIn occupational epidemiology, the healthy worker survivor effect can manifest as a time-dependent confounder because healthier workers can accrue greater amounts of exposure over longer periods of employment. For example, in occupational studies of radiation exposure that focus on cumulative annualized radiation dose, workers can accrue greater amounts of cumulative radiation exposure over longer periods of employment, while workers with longer periods of employment can transition into jobs with a reduced potential for annualized radiation exposure. The extent to which confounding arising from the healthy worker survivor effect impacts radiation risk estimates is unknown. MethodsWe assessed the impact of the healthy worker survivor effect on estimates of radiation risk among nuclear workers in a Million Person Study cohort. In simulation studies, we contrasted the ability of marginal structural Cox models with inverse probability weighting and Cox proportional hazards models to account for time-dependent confounding arising from the healthy worker survivor effect. ResultsMarginal structural Cox models and Cox proportional hazards models with flexible functional forms for duration of employment provided reliable results. ConclusionsIt is crucial to flexibly adjust for duration of employment to account for confounding arising from the healthy worker survivor effect in occupational epidemiology.

Updated Estimates of Radiation Risk for Cancer and Cardiovascular Disease: Implications for Cardiology Practice.

This review aims to furnish an updated assessment of the societal healthcare load, including cancer and cardiovascular disease resulting from diagnostic radiologic operations. The previously projected additional cancer risk of 0.9% in a United States 2004 study referred to radiological conditions in 1996 with an X-ray exposure of 0.50 millisievert (mSv) per capita annually. Radiological exposure (radiology + nuclear medicine) has escalated to 2.29 mSv (2016) per capita per year. Low-dose exposures were previously assumed to have a lower biological impact, since they allow the DNA repair system to mitigate molecular damage. However, epidemiological data matured and disproved this assumption, as shown by updated cancer risk assessments derived from the World Health Organization 2013 and the German Institute of Radioprotection 2014 data. The risk of cardiovascular disease aligns within the same order of magnitude as cancer risk and compounds it, as shown by a comprehensive meta-analysis of 93 studies. The collective societal burden arising from the augmented risks of cancer and cardiovascular disease attributable to diagnostic radiology and nuclear medicine is higher than previously thought.

The Use of Joint Models in Analysis of Aggregate Endpoints in RERF Cohort Studies.

In radiation risk estimation based on the Radiation Effects Research Foundation (RERF) cohort studies, one common analysis is Poisson regression on radiation dose and background and effect modifying variables of an aggregate endpoint such as all solid cancer incidence or all non-cancer mortality. As currently performed, these analyses require selection of a surrogate radiation organ dose, (e.g., colon dose), which could conceptually be problematic since the aggregate endpoint comprises events arising from a variety of organs. We use maximum likelihood theory to compare inference from the usual aggregate endpoint analysis to analyses based on joint analysis. These two approaches are also compared in a re-analysis of RERF Life Span Study all cancer mortality. We show that, except for a trivial difference, these two analytic approaches yield identical inference with respect to radiation dose response and background and effect modification when based on a single surrogate organ radiation dose. When repeating the analysis with organ-specific doses, an interesting issue of bias in intercept parameters arises when dose estimates are undefined for one sex when sex-specific outcomes are included in the aggregate endpoint, but a simple correction will avoid this issue. Lastly, while the joint analysis formulation allows use of organ-specific doses, the interpretation of such an analysis for inference regarding an aggregate endpoint can be problematic. To the extent that analysis of radiation risk for an aggregate endpoint is of interest, the joint-analysis formulation with a single surrogate dose is an appropriate analytic approach, whereas joint analysis with organ-specific doses may only be interpretable if endpoints are considered separately for estimating dose response. However, for neither approach is inference about dose response well defined.

Влияние фактора полиморбидности на прогноз пожизненных радиационных рисков смертности от злокачественных новообразований

The forecast of lifetime radiation risks in exposed cohorts is currently carried out without considering the heterogeneity of cohort members in terms of their degree of polymorbidity. Polymorbidity is characterized by a reduction in the life expectancy of a person in the presence of several chronic diseases. Therefore, considering the polymorbidity factor can significantly affect the estimate of lifetime radiation risk. The purpose of this study is to investigate the effect of the polymorbidity factor of patients on the estimates of lifetime radiation risks of mortality from malignant neoplasms, as well as to compare the impact of polymorbidity factors and uncertainty of radiation doses on these estimates. To calculate the lifetime attributable radiation risk (LAR) per 1 mSv, the radiation risk models recommended by Publication 103 of the International Commission on Radiological Protection were used. The calculations are based on official medical and statistical data of 2021 for the Russian population. The effect of polymorbidity on human lifespan and on LAR estimates was considered using the classic Charlson Comorbidity Index (CCI). To assess the effect of the uncertainty of radiation doses on the LAR value, an example of a lognormal dose distribution with a standard geometric deviation of 2.2 (i.e., with a 90% uncertainty factor of 3.6) was chosen, which is typical for the population living in the areas of the Kaluga and Bryansk regions of Russia contaminated as a result of the Chernobyl accident. Simulation modeling was used to assess the effect of radiation dose uncertainty. It is shown that the variability of estimates of the lifetime radiation risk of mortality from malignant neoplasms due to the polymorbidity factor is comparable to the variability of this radiation risk due to the uncertainty of doses with an 90% uncertainty factor of 3.6. Thus, when calculating radiation risks in persons exposed to radiation, it is necessary to consider the presence or absence of chronic diseases, since this significantly affects the final assessments of radiation risks. Underestimation or overestimation of risk can be from 1.5 times or more.

Patient-specific Effective Dose Estimation from Dose-Length Product in Lung Computed Tomography Using Monte Carlo Simulation.

Computed tomography (CT) imaging has a large portion in the dose of patients from radiological procedures; therefore, accurate calculation of radiation risk estimation in this modality is inevitable. In this study, a method for determining the patient-specific effective dose using the dose-length product (DLP) index in lung CT scan using Monte Carlo (MC) simulation is introduced. EGSnrc/BEAMnrc MC code was used to simulate a CT scanner. The DOSxyznrc simulation code was used to simulate a specific voxelized phantom from the patient's lungs and irradiate it according to X-ray parameter of routing lung CT scan, and dose delivered to thorax organs was calculated. Three types of phantoms were simulated according to three different body habits (slim, standard, and fat patients) in two groups of men and women. A factor was used to convert the relative dose per particle in MC code to the absolute dose. The dose was calculated in all lung organs, and the effective dose was calculated for all three groups of patient body habits. DLP index and volume CT dose index (CTDIvol) were extracted from the patient's dose report in the CT scanner. The DLP to effective dose conversion factor (k-factor) for patients with different body habitus was calculated. Lung radiation dose in slim, standard, and fat patients in men was 0.164, 0.103, and 0.078 mGy/mAs and in women was 0.164, 0.105, and 0.079 mGy/mAs, respectively. The k-factor in the group of slim patients, especially in women, was higher than in other groups. CT scan dose indexes for slim patients are reported to be underestimated in studies. The dose report in CT scan systems should be modified in proportion to the patient's body habitus, to accurately estimate the radiation risk.

Оценка радиационных рисков на индивидуальном уровне при многократном прохождении компьютерной томографии на современных компьютерных томографах

Technological developments, as well as software upgrades to existing computerized tomography (CT) scanners, require a continuous review of the methods for estimating radiation risk from CT procedures. According to the International Commission on Radiological Protection (ICRP), such assessments should be based on absorbed doses in organs and tissues exposed to radiation. This work is devoted to the study of the influence of various characteristics of the CT (manufacturer, type of scanner, etc.) on the evaluation of radiation risks on the example of multiple exposures in standard CT procedures. As an example, the value of lifetime attribute risk (LAR) and lifetime attributable risk fraction (LARF) for 5 CT scans during the life of a woman aged 20, 25, 30, 45 and 50 years is estimated. The lifetime attributable risk of possible cancer induction was estimated according to the ICRP mathematical model (Publication 103) and using the medical and demographic characteristics of the Russian population, as well as scan protocol data for typical CT scanners of selected models. The results were obtained with the use of old and updated conversion factors for the DLP (Dose Length Product – a measure of the absorbed radiation dose for the whole CT examination) parameter to organ doses from a particular procedure. The lifetime attributable risk of possible cancer induction calculated using organ doses derived from old conversion factors was compared with the risk calculated with data for modern CT scanners with updated conversion factors. The LAR was evaluated over time for one CT examination, two, three, four and five different procedures during the patient's lifetime. It was found that to date such factor as software updates in the field of optimisation of scanning protocols or the CT scanner manufacturer still do not has a significant impact on the radiation risks associated with specific diagnostic procedures. The methods developed by the authors for calculating absorbed doses and radiation risks can be used in planning CT examinations and optimising patient dose loads on any modern CT scanners.

Time-integrated radiation risk metrics and interpopulation variability of survival

Task Group 115 of the International Commission on Radiological Protection is focusing on mission-related exposures to space radiation and concomitant health risks for space crew members including, among others, risk of cancer development. Uncertainties in cumulative radiation risk estimates come from the stochastic nature of the considered health outcome (i.e., cancer), uncertainties of statistical inference and model parameters, unknown secular trends used for projections of population statistics and unknown variability of survival properties between individuals or population groups. The variability of survival is usually ignored when dealing with large groups, which can be assumed well represented by the statistical data for the contemporary general population, either in a specific country or world averaged. Space crew members differ in many aspects from individuals represented by the general population, including, for example, their lifestyle and health status, nutrition, medical care, training and education. The individuality of response to radiation and lifespan is explored in this modelling study. Task Group 115 is currently evaluating applicability and robustness of various risk metrics for quantification of radiation-attributed risks of cancer for space crew members. This paper demonstrates the impact of interpopulation variability of survival curves on values and uncertainty of the estimates of the time-integrated radiation risk of cancer.

Natural radioactivity Measurements of Dur-Kurigalzu's Ziggurat, Baghdad Governorate-Iraq using HPGe detector

Measurement of 238U, 233Th and 40K concentrations in soil samples collected from Ziggurat of Dur-Kurigalzu west region of Baghdad, have been evaluated, using high purity germanium detector. The activity concentrations of 238U, 233Th and 40K varied from 16.040 to 26.620 , 14.510 to 31.480 , and 153.820 to 266.320 with average values of 20.604±2.9 , 24.534±3.3 , 212.22±25.1 , respectively. The importance of these measurements lies in the estimation of radiation risk, radium equivalent, absorbed dose, annual effective dose, risk indices, gamma index, and cancer risk. The average value of the absorbed dose ranged from 33.187 outdoors to 63.111 indoors. The mean annual effective dose value was estimated to be 0.043 outdoors and 0.310 indoors from the study area. The total calculated lifetime risk of cancer ranged from 0.991×10-3 to 1.485×10-3, while the indoor lifetime cancer risk exceeded the recommended limit in samples 6, 8, 9, and 10. The areas examined in this study showed radioactive contamination less than the internationally permissible limits for the sites inhabited by the population.

Comparison of radon exhalation rate measurements on reference device in open and closed loop by AlphaGUARD in flow-through mode.

Radon-222 (Rn-222) exhalation rate is vital for estimating radiation risk from many kinds of materials. AlphaGUARD measures the radon concentration based on the ionization chamber principle, which is currently recognized as a reference instrument to measure radon. In China, measurements of radon exhalation rate are performed by AlphaGUARD operated in flow-through mode on a reference device to verify measurement accuracy. These measurements are performed in both open and closed loop. AlphaGUARD can fast rapidly the variation of the radon concentration in the chamber, which is tightly pressed against the surface of the medium to accumulate the exhaled radon. When the model is used to obtain the radon exhalation rate, the radon exhalation rates obtained by nonlinear data fitting on the measured radon concentrations are similar to the reference value of the device. The difference of radon exhalation rate values of six measurements is small.

Molecular and cellular basis of the dose-rate-dependent adverse effects of radiation exposure in animal models. Part II: Hematopoietic system, lung and liver.

While epidemiological data have greatly contributed to the estimation of the dose and dose-rate effectiveness factor (DDREF) for human populations, studies using animal models have made significant contributions to provide quantitative data with mechanistic insights. The current article aims at compiling the animal studies, specific to rodents, with reference to the dose-rate effects of cancer development. This review focuses specifically on the results that explain the biological mechanisms underlying dose-rate effects and their potential involvement in radiation-induced carcinogenic processes. Since the adverse outcome pathway (AOP) concept together with the key events holds promise for improving the estimation of radiation risk at low doses and low dose-rates, the review intends to scrutinize dose-rate dependency of the key events in animal models and to consider novel key events involved in the dose-rate effects, which enables identification of important underlying mechanisms for linking animal experimental and human epidemiological studies in a unified manner.

Методика оценки радиационного риска медицинского облучения при прохождении компьютерной томографии с учётом неопределённостей модели риска

The paper presents analysis of different factors affecting the uncertainty model for estimating ra-diation risk from computed tomography (CT). Uncertainties in radiation doses estimates caused by measurement (instrumental) errors or used dose estimation methods, the size of the scanned area and the type of CT scanner. The uncertainty of radiation dose due to measurement errors or dose estimation methods, the size of the scanned area and type of a CT scan may cause the uncertainties as well. Data used for calculating equivalent doses in individual organs and tissues and for calculating lifetime radiation risk of cancer development due to routine CT testing were updated. Conversion factors for DLP, a measure of radiation dose a patient received during CT exams of thoracic, abdomen and head organs, were determined and used for conversion of the CT doses to equivalent doses for individual organs and tissues exposed to radiation. Data for 15 state-of-the-art CT scanners with varying scanning geometry were updated. Uncertainties in life-time radiation risk were determined by estimating 95% confidence intervals for mean dose-proportionality ratios. Standard deviations related to specific dose distribution, scanning geometry and other factors that impact on uncertainty of radiation risk estimates were calculated. The standard deviations associated with the specifics of the dose distribution, scanning geometry and other factors affecting the uncertainties of radiation risk assessments were calculated. In the course of simulation modelling, organs and tissues were identified that are most exposed to radiation during CT of the chest, abdomen and head.

Статистические связи с дозой облучения и оценка радиационных рисков неонкологических заболеваний эндокринной системы ликвидаторов чернобыльской аварии с учётом возможных ошибок в постановке и регистрации диагнозов

The paper provides research on statistical relationship between endocrine diseases registered in the Chernobyl liquidators and radiation dose they received. Data of clinical and epidemiological observations accumulated at the National Radiation Epidemiological Register (NRER) for the period from 1986 to 2020 were used for analysis. The cohort contained 41,979 liquidators with 107,713 established diagnoses included in the ICD-10 Е00-E90 blocks. Statistical relationship between radiation doses and endocrine diseases was investigated with the use of statistical methods. Statistical Data Mining methods free of apriori guesses for probable doses and diagnoses distribution, models of dose-effect (disease) relationship were used for analysis of statistical relationship between radiation dose and the diagnoses structure. Statistically significant relationship between radiation doses and diagnoses were found in the blocks E01 (iodine deficiency), E04 (goiter), E06 (thyroiditis), E11 (type II diabetes mellitus). Relationships between radiation dose and diagnosis were also found in the E01.2 block (endemic goiter, caused due to iodine deficiency) and in E04.0 block (non-toxic diffuse goiter). Existence of identified statistical relationship is supported with the estimates of excess relative risk (ERR) and the relative risk (RR). The threshold relationship between RR and radiation dose with threshold of 0.3 Gy shows that radiation effect on human endocrine system is a deterministic effect (tissue reactions). Quantitative risks estimates for endocrine diseases in the liquidators are stable in relation to the diagnostic specificity index up to 90%. The general statistic Data Mining method to search relationship between a disease diagnosis and radiation dose is useful for the diseases identification in order to estimate radiation risk with conventual radiation epidemiology approaches.

Estimation of Radon Concentration around Public Spaces and Residential Homes with Altitude within Cities of Delta State, Nigeria

This study evaluates the radon concentrations in public places and private residences with different altitudes in selected locations in Delta State. These measurements were carried out using a professional radon monitoring instrument (Alpha GUARD PQ2000 PRO) and a geographical positioning system (GPS-Garmin GPS Map 76S). The recorded mean radon concentration varied from 11.70 ± 5.20 Bq/m3 to 23.90 ±16.60 Bq/m3, which is within the WHO acceptable range (100 Bq/m3). The basement had greater radon concentrations than the upper floors in most situations, although there were few exceptions. The average values of the estimated radiation risk parameters, which include equilibrium equivalent radon concentration, the potential alpha energy concentration, radon exhalation rates, and excess lifetime cancer risk due to exposure to radon radiation from their progeny are 4.7 Bq/m3 to 9.5Bq/m3, 1.20 × 10-3mWL to 2.60 × 10-3mWL, 0.04 × 10-3WML/y to 0.09× 10-3 WML/y, 3.7Bq/m2/h to 7.52Bq/m2/h and 2.10 × 10-3 to 3.30 × 10-3 respectively. The calculated radiation risk factors were all found to be within the recommended limits based on the data obtained. The research region is deemed safe and poses no threat to people.

Manhattan Project genetic studies: Flawed research discredits LNT recommendations

This paper reexamines the technical report (∼ one page) of Uphoff and Stern (1949) in Science that was highly relied upon by the US National Academy of Sciences (NAS) Biological Effects of Atomic Radiation (BEAR) I Genetics Panel to support a linearity dose response for radiation risk assessment. The present paper demonstrates that research of Uphoff and Stern (1949) to evaluate whether total dose or dose rate best estimated radiation risks included two variables, thereby precluding the ability to accurately derive a reliable conclusion about this topic. Furthermore, the acute dose selected by Uphoff and Stern was given at a strikingly low dose rate that may have precluded the capacity to adequately test the total dose/dose rate hypothesis, even with a proper study design which also this research did not possess. The issue of total dose and dose rate was much later successfully addressed by Russell et al. (1958) using a murine model, yielding a dose-rate rather than a total dose conclusion. The failure to subject the experimental details of the Uphoff and Stern (1949) study to peer-review and publication in the open literature precluded a rigorous and necessary evaluation, profoundly and improperly impacting the adoption of the linear dose response model.

Updated findings from the International Nuclear Workers Study (INWORKS)

BACKGROUND Despite being a recognized carcinogen, public exposure to ionizing radiation has increased in recent decades. An update to the International Nuclear Workers Study (INWORKS) is being undertaken to strengthen direct assessments of the risks from low dose, low dose rate exposure to penetrating forms of ionizing radiation. Follow-up has been extended by 10 or more years in each partner country. METHODS We are conducting a pooled analysis of cohort mortality studies of nuclear industry workers in the United Kingdom, France, and the United States of America. Individual annual estimates of whole-body dose due to external exposure to penetrating radiation are derived from personal occupational exposure monitoring data. Vital status has been ascertained through 2012, 2014, and 2016 for workers in the United Kingdom, France, and the United States of America, respectively. RESULTS The updated pooled study includes 309,932 workers and 10.7 million person-years of observation. Over the period of follow-up, there have been 103,553 deaths observed, of which 31,009 are deaths due to cancer. CONCLUSIONS This presentation will describe the motivation for an update of the INWORKS study, the major aims of the project, and the progress that we have made to-date. We will report on a major update of this highly-influential study; the person-time in INWORKS increases by a factor of 1.3 and the number of cancer deaths increases by a factor of 1.6. The updated INWORKS analyses will provide some of the most informative direct estimates of low dose radiation risks reported to-date.