The author provides a literature review examining the clinical risks of cosmic radiation exposure and incidence of cancer in aircrews including pilots, flight attendants, and flight engineers or navigators. The review focuses on ionizing radiation exposure in aircrews as an occupational working group. The author will discuss the types of cancer associated with cosmic ionizing radiation exposure and the prevalence of certain cancer types noted in this population. Monitoring of ionizing radiation of aircrews in the United States is not required in 2024, which makes assessing exposure a challenge. The author also discusses associated risk factors and prevention strategies in aircrews. United States aircrews are an occupational group with known elevated exposure to ionizing radiation from natural cosmic sources, which has been linked to health risks, particularly for cancer. This occupational group is not monitored in 2024 and would benefit from occupational exams for medical surveillance and hazard awareness.

Completely randomized experimental design statistical modeling techniques were employed to analyze exposure rate measurements for evaluating hypothetical natural background post uranium mill operations at Coles Hill, Virginia uranium milling processes. The proposed Coles Hill Uranium Mine is situated upstream of the Banister River. This River is nearly homogenous throughout the reach length used in analysis and feeds into the mouth of Kerr Reservoir, Lake Gaston, which serves as the main drinking water source for cities in the Hampton Roads area including Norfolk, Virginia Beach, and Chesapeake. A critical scan value (=DCGLscan) was developed to flag anomalies of surface contamination during simulated post remediation final status surveys. The natural background was critical for meeting the Multi-Agency Radiation Survey and Site Investigation Manual guidance for post remediation final status surveys. The overarching null hypothesis suggested that the selected mean natural background is equal to the survey unit's mean natural background. Using SAS Procedures Shapiro-Wilk Test, ANOVA, and CR, it was decided the exposure rate data was normal, had no extreme outliers, and no collinearity between the number of samples (=treatment) and the areas (=block). Using the q-hyper (hypergeometric) distribution, the soil sampling density was decided for a final status survey unit. The most likely worst-case catastrophic failure analysis, 500-year event, such as the1969 Hurricane Camille of 69 centimeters of rain in Nelson County, Virginia was included in the model. The model showed impact was minimal at most to the Banister River's drinking water and likely less than the Virginia's Drinking Water Standards for gross alpha, 226Ra and 228Ra, and total uranium.

Uranium is naturally occurring in groundwater used for drinking; however, health risks from naturally occurring concentrations are uncertain. Uranium can cause both radiological and chemical toxicity following ingestion. Bladder and kidneys receive a dose when uranium is excreted into the urine. Investigate the association between uranium in drinking water and bladder cancer risk in a case-control study. A population-based bladder cancer case-control study was conducted in 11 counties of southeastern Michigan. A total of 411 cases and 566 controls provided drinking water and toenail samples and answered questions about lifestyle and residential history. Uranium was measured in drinking water and toenails, and its association with bladder cancer was assessed via unconditional logistic regression models. Median uranium concentration in water was 0.12 μg L -1 , with a maximum of 4.99 μg L -1 , and median uranium concentration in toenails was 0.0031 μg g -1 . In adjusted regression models, there was a suggestion of a protective effect among those exposed to the upper quartile of uranium in drinking water (HR = 0.64, 95% CI: 0.43, 0.96) and toenails (HR 0.66; 95% CI 0.45, 0.96) compared to those in the lowest quartile. Our objective is to investigate additional adjustment of drinking water source at home residence at time of recruitment to address potential selection bias and confounding attenuated results toward the null for drinking water uranium (HR = 0.68, 95% CI: 0.44, 1.05) and toenail uranium (HR = 0.80, 95% CI: 0.53, 1.20). This case-control study showed no increased risk of bladder cancer associated with uranium found in drinking water or toenails.

Institutional radiation safety committees review research studies with radiation exposure. However, ensuring that the potential patient benefit and knowledge gained merit the radiation risks involved often necessitates revisions that inadvertently delay protocol activations. This quality-improvement study analyzed protocols, identified factors associated with approval time by a radiation safety committee, and developed guidelines to expedite reviews without compromising quality. Clinical protocols submitted to the University of Pennsylvania's Radiation Research Safety Committee (RRSC) for review between 2017 and 2021 were studied. Protocol characteristics, review outcome, stipulations, and approval times were summarized. Statistical analysis (Spearman's rho) was used to investigate stipulations and approval time; rank-sum analysis (Kruskal-Wallis or Wilcoxon) was used to determine whether approval time differed by protocol characteristics. One hundred ten (110) protocols were analyzed. Approximately two-thirds of protocols used approved radiopharmaceuticals to aid investigational therapy trials. Twenty-three percent (23%) of protocols received RRSC approval, and 73% had approval withheld with stipulations, which included requests for edits or additional information. Submissions had a median of three stipulations. Median and mean RRSC approval times were 62 and 80.1 d, and 41% of protocols received RRSC approval after IRB approval. RRSC approval time was positively correlated with stipulations (Spearman's rho = 0. 632, p < 0.001). RRSC approval time was longer for studies using investigational new drugs (median 80 d) than approved radiopharmaceuticals (median 57 d, p = 0.05). The review process is lengthy and may benefit from changes, including publishing standardized radiation safety language and commonly required documents and encouraging timely response to stipulations.

Nuclear industry workers exposed to uranium aerosols may risk kidney damage and radiation-induced cancer. This warrants the need for well-established dose and risk assessments, which can be greatly improved by using material-specific absorption parameters in the ICRP Human Respiratory Tract Model. The present study focuses on the evaluation of the slow dissolution rate (ss, d−1), a parameter that is difficult to quantify with in vitro dissolution studies, especially for more insoluble uranium compounds. A long-term follow-up of urinary excretion after the cessation of chronic inhalation exposure can provide a better estimate of the slow-rate dissolution. In this study, two workers, previously working for >20 y at a nuclear fuel fabrication plant, provided urine samples regularly for up to 6 y. One individual had worked at the pelletizing workshop with the known presence of uranium dioxide (UO2) and triuranium octoxide (U3O8). The second individual worked at the conversion workshop where multiple compounds, including uranium hexafluoride (UF6), uranium dioxide (UO2), ammonium uranyl carbonate, and AUC [UO2CO3·2(NH4)2CO3], are present. Data on uranium concentration in urine during working years were also available for both workers. The daily excretion of uranium by urine was characterized by applying non-linear least square regression fitting to the urinary data. Material-specific parameters, such as the activity median aerodynamic diameter (AMAD), the respiratory tract absorption parameters, rapid fraction (fr,), rapid dissolution rate (sr, d−1), and slow dissolution rate (ss, d−1) and alimentary tract transfer factor (fA) acquired from previous work along with default absorption types, were applied to urine data, and the goodness of fit was evaluated. Thereafter intake estimates and dose calculations were performed. For the ex-pelletizing worker, a one-compartment model with a clearance half-time of 662 ± 100 d (ss = 0.0010 d−1) best represented the urinary data. For the ex-conversion worker, a two-compartment model with a major [93% of the initial urinary excretion (A0)] fast compartment with a clearance half-time of 1.3 ± 0.4 d (sr = 0.5 d−1) and a minor (7% of A0) slow compartment with a half-time of 394 ± 241 d (ss = 0.002 d−1) provided the best fit. The results from the data-fitting of urinary data to biokinetic models for the ex-conversion worker demonstrated that in vitro derived experimental parameters (AMAD = 20 μm, fr = 0.32, sr = 27 d−1, ss = 0.0008 d−1, f A = 0.005) from our previous work best represented the urinary data. This resulted in an estimated intake rate of 0.66 Bq d−1. The results from the data-fitting of urinary data to biokinetic models for the ex-pelletizing worker indicated that the experimental parameters (AMAD = 10 μm and 20 μm, fr = 0.008, sr = 12 d−1, fA = 0.00019) from our previous dissolution studies with the slow rate parameter step-wise optimized to urine-data (ss = 0.0008 d−1) gave the best fit. This resulted in an estimated intake rate of 5 Bq d−1. Experimental parameters derived from in vitro dissolution studies provided the best fit for the subject retired from work at the conversion workshop, where inhalation exposure to a mix of soluble (e.g., AUC, UF6) and relatively insoluble aerosol (e.g., UO2) can be assumed. For the subject retired from work at the pelletizing workshop, which involved exposure to relatively insoluble aerosols (UO2 and U3O8), a considerably higher ss than obtained in dissolution studies provided a better representation of the urinary data and was comparable to reported ss values for UO2 and U3O8 in other studies. This implies that in vitro dissolution studies of insoluble material can be uncertain. When evaluating the results from the retrospective fitting of urine data, it is evident that the urine samples acquired after cessation of exposure provide less fluctuation. Long-term follow-up of uranium excretion after cessation of exposure is a good alternative for determining absorption parameters and can be considered the most viable way for determining the slow rate for more insoluble material.