Radiation exposure during sacral neuromodulation lead placement: Multi-institutional descriptive study.

OBJECTIVES: Fluoroscopy has significantly improved lead placement and decreased surgical time for implantable sacral neuromodulation (SNM). There is a paucity of data regarding radiation and safety of fluoroscopy during SNM procedures. Our study aims to characterize fluoroscopy time and dose used during SNM surgery across multiple institutions and assess for predictors of increased fluoroscopy time and radiation dose. METHODS: Electronic medical records were queried for SNM procedures (Stage 1 and full implant) from 2016 to 2021 at four academic institutions. Demographic, clinical, and intraoperative data were collected, including fluoroscopy time and radiation dose in milligray (mGy). The data were entered into a centralized REDCap database. Univariate and multivariate analysis were performed to assess for predictive factors using STATA/BE 17.0. RESULTS: A total of 664 procedures were performed across four institutions. Of these, 363 (54.6%) procedures had complete fluoroscopy details recorded. Mean surgical time was 58.8 min. Of all procedures, 79.6% were performed by Female Pelvic Medicine and Reconstructive Surgery specialists. There was significant variability in fluoroscopy time and dose based on surgical specialty and institution. Most surgeons (76.4%) were considered "low volume" implanters. In a multivariate analysis, bilateral finder needle testing, surgical indication, surgeon volume, and institution significantly predicted increased fluoroscopy time and radiation dose (p < 0.05). CONCLUSIONS: There is significant variability in fluoroscopy time and radiation dose utilized during SNM procedures, with differences across institutions, surgeons, and subspecialties. Increased radiation exposure can have harmful impacts on the surgical team and patient. These findings demonstrate the need for standardized fluoroscopy use during SNM procedures.

Medical imaging utilization and associated radiation exposure in children with down syndrome.

OBJECTIVE: To evaluate the frequency of medical imaging or estimated associated radiation exposure in children with Down syndrome. METHODS: This retrospective cohort study included 4,348,226 children enrolled in six U.S. integrated healthcare systems from 1996-2016, 3,095 of whom were diagnosed with Down syndrome. We calculated imaging rates per 100 person years and associated red bone marrow dose (mGy). Relative rates (RR) of imaging in children with versus without Down syndrome were estimated using overdispersed Poisson regression. RESULTS: Compared to other children, children with Down syndrome received imaging using ionizing radiation at 9.5 times (95% confidence interval[CI] = 8.2-10.9) the rate when age <1 year and 2.3 times (95% CI = 2.0-2.5) between ages 1-18 years. Imaging rates by modality in children <1 year with Down syndrome compared with other children were: computed tomography (6.6 vs. 2.0, RR = 3.1[95%CI = 1.8-5.1]), fluoroscopy (37.1 vs. 3.1, RR 11.9[95%CI 9.5-14.8]), angiography (7.6 vs. 0.2, RR = 35.8[95%CI = 20.6-62.2]), nuclear medicine (6.0 vs. 0.6, RR = 8.2[95% CI = 5.3-12.7]), radiography (419.7 vs. 36.9, RR = 11.3[95%CI = 10.0-12.9], magnetic resonance imaging(7.3 vs. 1.5, RR = 4.2[95% CI = 3.1-5.8]), and ultrasound (231.2 vs. 16.4, RR = 12.6[95% CI = 9.9-15.9]). Mean cumulative red bone marrow dose from imaging over a mean of 4.2 years was 2-fold higher in children with Down syndrome compared with other children (4.7 vs. 1.9mGy). CONCLUSIONS: Children with Down syndrome experienced more medical imaging and higher radiation exposure than other children, especially at young ages when they are more vulnerable to radiation. Clinicians should consider incorporating strategic management decisions when imaging this high-risk population.

Evaluating Radiation Exposure in Patients with Stable Chest Pain in the SCOT-HEART Trial.

Background In the Scottish Computed Tomography of the Heart (SCOT-HEART) trial in individuals with stable chest pain, a treatment strategy based on coronary CT angiography (CTA) led to improved outcomes. Purpose To assess 5-year cumulative radiation doses of participants undergoing investigation for suspected angina due to coronary artery disease with or without coronary CTA. Materials and Methods This secondary analysis of the SCOT-HEART trial included data from six of 12 recruiting sites and two of three imaging sites. Participants were recruited between November 18, 2010, and September 24, 2014, with follow-up through January 31, 2018. Study participants had been randomized (at a one-to-one ratio) to standard care with CT (n = 1466) or standard care alone (n = 1428). Imaging was performed on a 64-detector (n = 223) or 320-detector row scanner (n = 1466). Radiation dose from CT (dose-length product), SPECT (injected activity), and invasive coronary angiography (ICA; kerma-area product) was assessed for 5 years after enrollment. Effective dose was calculated using conversion factors appropriate for the imaging modality and body region imaged (using 0.026 mSv/mGy · cm for cardiac CT). Results Cumulative radiation dose was assessed in 2894 participants. Median effective dose was 3.0 mSv (IQR, 2.6-3.3 mSv) for coronary calcium scoring, 4.1 mSv (IQR, 2.6-6.1 mSv) for coronary CTA, 7.4 mSv (IQR, 6.2-8.5 mSv) for SPECT, and 4.1 mSv (IQR, 2.5-6.8 mSv) for ICA. After 5 years, total per-participant cumulative dose was higher in the CT group (median, 8.1 mSv; IQR, 5.5-12.4 mSv) compared with standard-care group (median, 0 mSv; IQR, 0-4.5 mSv; P < .001). In participants who underwent any imaging, cumulative radiation exposure was higher in the CT group (n = 1345; median, 8.6 mSv; IQR, 6.1-13.3 mSv) compared with standard-care group (n = 549; median, 6.4 mSv; IQR, 3.4-9.2 mSv; P < .001). Conclusion In the SCOT-HEART trial, the 5-year cumulative radiation dose from cardiac imaging was higher in the coronary CT angiography group compared with the standard-care group, largely because of the radiation exposure from CT. Clinical trial registration no. NCT01149590 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Dodd and Bosserdt in this issue.

Practical guidance to reduce radiation exposure in electrophysiology applying ultra low-dose protocols: a European Heart Rhythm Association review.

Interventional electrophysiology offers a great variety of treatment options to patients suffering from symptomatic cardiac arrhythmia. Catheter ablation of supraventricular and ventricular tachycardia has globally evolved a cornerstone in modern arrhythmia management. Complex interventional electrophysiological procedures engaging multiple ablation tools have been developed over the past decades. Fluoroscopy enabled interventional electrophysiologist throughout the years to gain profound knowledge on intracardiac anatomy and catheter movement inside the cardiac cavities and hence develop specific ablation approaches. However, the application of X-ray technologies imposes serious health risks to patients and operators. To reduce the use of fluoroscopy during interventional electrophysiological procedures to the possibly lowest degree and to establish an optimal protection of patients and operators in cases of fluoroscopy is the main goal of modern radiation management. The present manuscript gives an overview of possible strategies of fluoroscopy reduction and specific radiation protection strategies.

High-dose radiation exposure of cold-stored whole blood does not affect hemostatic function.

BACKGROUND: Whole blood (WB) transfusion is routinely used to resuscitate severely injured military trauma patients. Blood can be stored refrigerated while still maintaining reasonable function but is susceptible to environmental influences, including radiation exposure. Immune-compromised patients are transfused with irradiated blood to inactivate donor lymphocyte function (25 Gy per Association for the Advancement of Blood and Biotherapies [AARB] standard 5.7.3.2). However, there is limited information on function of WB exposed to high radiation doses. OBJECTIVE: This study aimed to determine if stored irradiated WB still retains function. This will be important if the stored blood supply is exposed to radiation in a combat situation or mass casualty incident when the need for blood will be high. METHODS: Whole blood collected from healthy donors was irradiated at 0, 25, or 75 Gy and stored at 4°C. Blood cell count, blood gas chemistry, thromboelastometry, platelet aggregation, and reactive oxygen species were measured before irradiation and at 1, 7, and 14 days of storage. Irradiated WB was compared with nonirradiated WB controls. RESULTS: Irradiated WB stored for up to 14 days was not significantly different than nonirradiated WB in most of the parameters measured. Stored blood showed expected changes associated with functional decline at longer storage times, but irradiation did not hasten the decline. There was a significant change in potassium and sodium ion concentrations after irradiation, but the functional relevance is not clear. CONCLUSION: High-dose irradiation had little effect on stored WB. Although there were changes in plasma sodium and potassium levels, there was little to no effect on hemostasis and blood cell viability. This suggests that stored blood subjected to a radiation event generating at least a dose of 75 Gy is still suitable for transfusion, which could be particularly important in the event of a mass casualty event where a large amount of blood is needed.

Cohort profile: The Australian Paediatric Exposure to Radiation Cohort (Aust-PERC).

Although the carcinogenic effects of high-dose radiation are well-established, the risks at low doses, such as from diagnostic X-rays, are less well understood. Children are susceptible to radiation induced cancers, and in the last decade, several cohort studies have reported increased cancer risks following computed tomography (CT) scans in childhood. However, cohort studies can be limited by insufficient follow-up, indication bias, reverse causation, or by lack of organ doses from CT scans or other exposures. Aust-PERC is a retrospective cohort designed to study the effects of low-dose medical radiation exposure, primarily from CT scans, in young Australians. The cohort was ascertained using deidentified billing records from patients who were aged 0-19 years while enrolled in Medicare (Australia's universal healthcare system) between 1985 and 2005. All procedures billed to Medicare in this age/time window that involved low-dose radiation were identified, and persons without such procedures were flagged as unexposed. The Aust-PERC cohort has been linked, using confidential personal identifiers, to the Australian Cancer Database and the National Death Index, on two occasions (to Dec. 2007 and Dec. 2012) by the responsible government agency (Australian Institute of Health and Welfare). Deidentified Medicare service records of all radiological procedures including CT scans, nuclear medicine (NM) scans and fluoroscopy and plain X-ray procedures have been available to derive estimated radiation doses in the cohort. Records of other medical and surgical procedures, together with demographic and socioeconomic variables are being used in analyses to assess biases arising from reverse causation and confounding. After excluding patients with errant records, 11 802 846 persons remained in the baseline cohort, with an average follow-up time of 22.3 years to December 2012. There were 275 489 patients exposed to diagnostic nuclear medicine scans and 688 363 patients exposed to CT scans before age 20 and before cancer diagnosis. Between 1 January 1985 and 31 December 2012, there were 105 124 deaths and 103 505 incident cancers. Dose-response analyses based on the relevant organ doses are underway for individual cancers, and we plan to extend the follow-up for another 8 years to Dec 2020. Analyses using this very large Aust-PERC cohort, with extended follow-up, will help to resolve international uncertainties about the causal role of diagnostic medical radiation as a cause of cancer.

Radiation exposure and clinical outcome in patients undergoing percutaneous intradiscal ozone therapy for disc herniation: Fluoroscopic versus conventional CT guidance.

PURPOSE: To compare technical success, clinical success, complications and radiation dose for percutaneous intradiscal ozone therapy in patients with lumbar disc herniation using fluoroscopic guidance versus conventional computed tomography (CT) guidance. MATERIALS AND METHODS: Between March 2018and March 2021, 124consecutive percutaneous intradiscal ozone therapies wereperformedon111 patients with low back pain (LBP) and/or sciatic pain due to lumbar disc herniation, using fluoroscopic or conventional CT guidance, respectively in 53 and 58 herniated lumbar discs, with at least 1-month follow up. Dose area product (DAP) and dose length product (DLP) were recorded respectively for fluoroscopy and CT, and converted to effective dose (ED). RESULTS: Fluoroscopic and CT groups were similar in terms of patient age (p-value 0.39), patient weight (p-value 0.49) and pre-procedure Oswestry Disability Index (ODI, p-value 0.94). Technical success was achieved in all cases. Clinical success was obtained in 83.02% (44/53) patients in fluoroscopic group and 79.31% (46/58) in CT group. Mean DAP was 11.63Gy*cm2 (range 5.42-21.61). Mean DLP was 632.49mGy-cm (range 151.51-1699). ED was significantly lower in the fluoroscopic group compared toCT group (0.34 vs. 5.53mSv, p = 0.0119). No major complication was registered. Minor complications were observed in 4 cases (2 in fluoroscopic group; 2 in CT group). CONCLUSIONS: Compared to conventional CT guidance, fluoroscopic guidance for percutaneous intradiscal ozone therapy in patients with lumbar disc herniation shows similar technical and clinical success rates, with lower radiation dose. This technique helps sparing dose exposure to patients.

The neuroprotective effects of icariin on ageing, various neurological, neuropsychiatric disorders, and brain injury induced by radiation exposure.

Epimedium brevicornum Maxim, a Traditional Chinese Medicine, has been used for the treatment of impotence, sinew and bone disorders, "painful impediment caused by wind-dampness," numbness, spasms, hypertension, coronary heart disease, menopausal syndrome, bronchitis, and neurasthenia for many years in China. Recent animal experimental studies indicate that icariin, a major bioactive component of epimedium may effectively treat Alzheimer's disease, cerebral ischemia, depression, Parkinson's disease, multiple sclerosis, as well as delay ageing. Our recent study also suggested that epimedium extract could exhibit radio-neuro-protective effects and prevent ionizing radiation-induced impairment of neurogenesis. This paper reviewed the pharmacodynamics of icariin in treating different neurodegenerative and neuropsychiatric diseases, ageing, and radiation-induced brain damage. The relevant molecular mechanisms and its anti-neuroinflammatory, anti-apoptotic, anti-oxidant, as well as pro-neurogenesis roles were also discussed.

Radiation exposure in the intra-arterial nimodipine therapy of subarachnoid hemorrhage related cerebral vasospasm.

The selective intra-arterial nimodipine application for the treatment of cerebral vasospasm (CVS) in patients after spontaneous subarachnoid hemorrhage (sSAH) is widely employed. The purpose of this study is to examine the radiation exposure and to determine local diagnostic reference levels (DRLs) of intra-arterial nimodipine therapy. In a retrospective study design, DRLs and achievable dose (AD) were assessed for all patients undergoing (I) selective intra-arterial nimodipine application or (II) additional mechanical angioplasty for CVS treatment. Interventional procedures were differentiated according to the type of procedure and the number of probed vessels. Altogether 494 neurointerventional procedures of 121 patients with CVS due to sSAH could be included. The radiation exposure indices were distributed as follows: (I) DRL 74.3 Gy·cm2, AD 59.8 Gy·cm2; (II) DRL 128.3 Gy·cm2, AD 94.5 Gy·cm2. Kruskal-Wallis test confirmed significant dose difference considering the number of probed vessels (p< 0.001). The mean cumulative dose per patient was 254.9 Gy·cm2(interquartile range 88.6-315.6 Gy·cm2). The DRLs of intra-arterial nimodipine therapy are substantially lower compared with DRLs proposed for other therapeutic interventions, such as thrombectomy or aneurysm coiling. However, repeated therapy sessions are often required, bearing the potential risk of a cumulatively higher radiation exposure.

Bioassays in workers exposed to long time random intakes.

Workers who are occupationally exposed to radioactive aerosols are usually subjected to periodic controls of internal contamination by performing bioassays (whole body or partial body monitoring and measurement of excreta samples). The intakes are also estimated by using Static Air Samples (SAS). These measurements are used to estimate the radioactive intakes of the workers. A typical assumption is the workers are chronically (constant) exposed for long periods of time. However, the intakes are random and there are also periods without any exposure (weekends, holidays, etc.). The method presented here considers both facts. Simulations help to choose the most appropriate method of evaluation to minimize the statistical uncertainties in the intake. It has been applied to evaluate workers exposed to UO2 aerosols for a long time (30 years or more for most of them) in the same working area (sintering). Results of measurements of uranium in urine and daily intakes (from SAS) of these workers have been used. For this evaluation, the new Occupational Intakes of Radionuclides (OIR) biokinetic models of the International Commission on Radiological Protection (ICRP) for uranium have been solved. For some workers the evaluation gives a significative deviation between the intake estimated from urine samples and the intake estimated using the SAS values, supporting the idea that the physiological standard parameters of the reference worker are not always applicable. The computations have been implemented in the BIOKMOD code.

High-dose radiation exposure and hypothyroidism: aetiology, prevention and replacement therapy.

Without any doubt, high dose radiation exposure can induce hypothyroidism. However, there are open questions related to the mechanisms of its induction, corresponding dose thresholds and possible countermeasures. Therefore, this review addresses the aetiology, prevention and therapy of radiation induced hypothyroidism. External beam radiotherapy with several 10 Gy to the head and neck region and radioiodine therapy with several 100 Gy thyroid absorbed dose can destroy the thyroid gland and can induce autoantibodies against thyroid tissue. According to recent literature, clinical hypothyroidism is observed at threshold doses of ∼10 Gy after external beam radiotherapy and of ∼50 Gy after radioiodine therapy, children being more sensitive than adults. In children and adolescents exposed by the Chernobyl accident with mean thyroid absorbed doses of 500-800 mGy, subclinical hypothyroidism has been detected in 3%-6% of the cases with significant correlation to thyroid absorbed doses above 2.5 Gy. In case of nuclear emergencies, iodine thyroid blocking (ITB) is the method of choice to keep thyroid absorbed doses low. Large doses of stable iodine affect two different steps of internalization of radioiodine (transport and organification); perchlorate affecting the transport only may be an alternative to iodine. Administered before radioiodine incorporation, the effect of 100 mg iodide or more is still about 90% after 1 days, 80% after 2 days, and 50% or less after 3 days. If administered (too) late after exposure to radioiodine, the theoretically expected protective effect of ITB is about 50% after 6 h, 25% after 12 h, and about 6% after 24 h. In case of repeated or continuous exposure, repeated administration of 50 mg of iodide daily is indicated. If radiation-induced hypothyroidism cannot be avoided, thyroid hormone replacement therapy with individualized dosing and regular monitoring in order to maintain thyroid-stimulating hormone levels within the normal range ensures normal life expectancy.

The Hiroshima A-Bomb Black Rain and the Lifespan Study; A Resolution of the Enigma.

The Japanese Lifespan Study (LSS) of the A-Bomb survivors is the principal basis of the current legal radiological framework. Evidence provided for the first time here shows that internal exposure to radiologically significant quantities of Uranium-234 contained in sub-micron particle rainout from the un-fissioned weapon warhead, the Black Rain, is a missing exposure in the LSS analysis. It is argued that this is responsible for a background excess cancer risk in all the LSS dose groups. This, together with epidemiological evidence based on unexposed controls falsifies the LSS cancer vs. dose regression coefficients for internal exposure.

Assessment of internal radiation exposure to Antarctic biota due to selected natural radionuclides in terrestrial and marine environment.

The present article introduces data on natural radioactivity (40K, 230,232Th, 234,238U) in the Antarctic marine and terrestrial environment. Various biota samples were analysed due to internal exposure to 40K, 230,232Th, 234,238U. Activity concentration of 40K was the highest in both marine and terrestrial samples. Mean values of 40K activity concentration are 1340 Bq/kg and 370 Bq/kg for the marine and terrestrial samples respectively. 234U/238U ratios analysis revealed that sea waters and sea spray are the main source of the uranium in the terrestrial samples. Average 230,232Th, 234,238U activity concentrations in the Antarctic biota do not exceed 6 Bq/kg. Weighted internal dose rates are relatively low; they range from approximately 0.1 to 0.6 µGy/h. Statistically significant differences in radionuclide accumulation were discovered between the mosses and lichens. It may point to various mechanisms of the nutrient absorption from the environment by these organisms.

Gender Differences in the Pursuit of Cardiac Electrophysiology Training in North America.

BACKGROUND: Despite the increase in the number of female physicians across most specialties within cardiology, <10% of clinical cardiac electrophysiology (EP) fellows are women. OBJECTIVES: This study sought to determine the factors that influence fellows-in-training (FITs) to pursue EP as a career choice and whether this differs by gender. METHODS: The authors conducted an online multiple-choice survey through the American College of Cardiology to assess the decision factors that influence FITs in the United States and Canada to pursue cardiovascular subspecialties. RESULTS: A total of 933 (30.5%) FITs completed the survey; 129 anticipated specializing in EP, 259 in interventional cardiology (IC), and 545 in a different field or were unsure. A total of 1 in 7 (14%) FITs indicated an interest in EP. Of this group, more men chose EP than women (84% vs 16%; P < 0.001). The most important factor that influenced FITs to pursue EP was a strong interest in the field. Women were more likely to be influenced by having a female role model (P = 0.001) compared with men. After excluding FITs interested in IC, women who deselected EP were more likely than men to be influenced by greater interest in another field (P = 0.004), radiation concerns (P = 0.001), lack of female role models (P = 0.001), a perceived "old boys' club" culture (P = 0.001) and discrimination/harassment concerns (P = 0.001). CONCLUSIONS: Women are more likely than men to be negatively influenced by many factors when it comes to pursuing EP as a career choice. Addressing those factors will help decrease the gender disparity in the field.

Antioxidant Supplements versus Health Benefits of Brief/Intermittent Exposure to Potentially Toxic Physical or Chemical Agents.

Although antioxidants can act locally to react with an oxidant, oral administration of "antioxidants" is quite useless in treating oxidative stress in tissues. Furthermore, it does not make sense to consider a vitamin as an antioxidant, but vitamin B3 leads to the in vivo formation of compounds that are essential for reducing this stress. A rigorous treatment of the subject indicates that to deal with oxidative stress, the most direct approach is to enhance the innate antioxidant mechanisms. The question is whether this is possible through daily activities. Diets can contain the necessary components for these mechanisms or may induce the expression of the genes involved in them. Another possibility is that pro-oxidant molecules in food increase the sensitivity and power of the detoxification pathways. This option is based on well-known DNA repair mechanisms after exposure to radiation (even from the Sun), or strong evidence of induction of antioxidant capacity after exposure to powerful pro-oxidants such as H2O2. More experimental work is required to test whether some molecules in food can increase the expression of antioxidant enzymes and/or improve antioxidant mechanisms. Identifying effective molecules to achieve such antioxidant power is critical to the food and nutraceutical industries. The potential of diet-based interventions to combat oxidative stress must be viewed from a new perspective.

Radionuclides and Radiation Exposure in Tantalite Mining, Ethiopia.

Tantalite and columbite ores have been reported as containing associated primordial radionuclides, such as uranium and thorium. Ethiopia is one of the world suppliers of tantalite ore through exploitation of Kenticha mine and tantalite production by a large number of artisanal miners. For the purpose of implementing the international standards for radiation protection of workers and members of the public, a preliminary assessment of radionuclides and radiation doses associated to tantalite mining was performed. Results confirmed and quantified the co-occurrence of uranium and thorium and their progeny in tantalite ore. Radiation doses at some workplaces may exceed the effective dose limit recommended by the international radiation safety standards for nonradiation workers and members of the public. Investments to be made in order to expand and modernize tantalite production in Ethiopia shall take into account the radiation hazards and implement a radiation protection program to prevent enhanced occupational radiation exposures and protect the public and the environment.

More Than Effects in Skin: Ultraviolet Radiation-Induced Changes in Immune Cells in Human Blood.

Cells of the skin and circulation are in constant two-way communication. Following exposure of humans to sunlight or to phototherapy, there are alterations in the number, phenotype and function of circulating blood cells. In this review, only data obtained from human studies are considered, with changes induced by UV radiation (UVR) exposure described for phagocytic leukocytes and peripheral blood mononuclear cells plus their component T and B cells, natural killer cells and dendritic cells. These immune modulations illustrate the potential of UVR to have therapeutic effects beyond the skin, and that sunlight exposure is an important environmental influence on human health.

Antenatal Exposure to UV-B Radiation and Preeclampsia: A Retrospective Cohort Study.

Background Risk of preeclampsia varies by month of delivery. We tested whether this seasonal patterning may be mediated through maternal vitamin D concentration using antenatal exposure to UV-B radiation as an instrumental variable. Methods and Results Scottish maternity records were linked to antenatal UV-B exposure derived from satellites between 2000 and 2010. Logistic regression analyses were used to explore the association between UV-B and preeclampsia, adjusting for the potential confounding effects of month of conception, child's sex, gestation, parity, and mean monthly temperature. Of the 522 896 eligible singleton deliveries, 8689 (1.66%) mothers developed preeclampsia. Total antenatal UV-B exposure ranged from 43.18 to 101.11 kJ/m2 and was associated with reduced risk of preeclampsia with evidence of a dose-response relationship (highest quintile of exposure: adjusted odds ratio, 0.57; 95% CI, 0.44-0.72; P<0.001). Associations were demonstrated for UV-B exposure in all 3 trimesters. Conclusions The seasonal patterning of preeclampsia may be mediated through low maternal vitamin D concentration in winter resulting from low UV-B radiation. Interventional studies are required to determine whether vitamin D supplements or UV-B-emitting light boxes can reduce the seasonal patterning of preeclampsia.

Cohort profile: four early uranium processing facilities in the US and Canada.

PURPOSE: Pooling of individual-level data for workers involved in uranium refining and processing (excluding enrichment) may provide valuable insights into risks from occupational uranium and external ionizing radiation exposures. METHODS: Data were pooled for workers from four uranium processing facilities (Fernald, Mallinckrodt and Middlesex from the U.S.; and Port Hope, Canada). Employment began as early as the 1930s and follow-up was as late as 2017. Workers were exposed to high concentrations of uranium, radium, and their decay products, as well as gamma radiation and ambient radon decay products. Exposure and outcome data were harmonized using similar definitions and dose reconstruction methods. Standardized mortality ratios (SMR) were estimated. RESULTS: In total, 560 deaths from lung cancer, 503 non-malignant respiratory diseases, 67 renal diseases, 1,596 ischemic heart diseases, and 101 dementia and Alzheimer's disease (AD) were detected in the pooled cohort of over 12,400 workers (∼1,300 females). Mean cumulative doses were 45 millisievert for whole-body external ionizing radiation exposure and 172 milligray for lung dose from radon decay products. Only SMR for dementia and AD among males was statistically significant (SMR=1.29; 95% confidence interval: 1.04, 1.54). CONCLUSIONS: This is the largest study to date to examine long-term health risks of uranium processing workers.