Red Bone Marrow and Male Breast Doses for a Cohort of Atomic Veterans

Abstract

Both red bone marrow and male breast doses with associated uncertainty have been reconstructed for a 1,982-person subset of a cohort of 114, 270 military personnel (referred to as "atomic veterans") who participated in U.S. atmospheric nuclear weapons testing from 1945 to 1962. The methods used to calculate these doses and corresponding uncertainty have been reported in detail by Till et al. in an earlier publication. In this current article we report the final results of those calculations. These doses are being used in a case-cohort design epidemiological investigation of leukemia and male breast cancer. This cohort of atomic veterans is one component in a broader-scope study of approximately one million U.S. persons designed to investigate risk from chronic low-dose radiation exposure. Doses to the atomic veterans in this sub-cohort were relatively low, with approximately two-thirds receiving red bone marrow doses <5 mGy and only four individuals receiving a red bone marrow dose >50 mGy. The average red bone marrow dose for members of the sub-cohort was 5.9 mGy. Doses to male breast were approximately 20% higher than red bone marrow doses. The uncertainty in the estimated doses was relatively low, considering relevant personnel dosimetry was available for only about 25% of the subjects, and most of the doses were reconstructed from film badges worn by co-workers or from the individual's military record and military unit activities. The average coefficient of variation for the individual dose estimates was approximately 0.5, comparable to the uncertainty in doses estimated for the Japanese A-bomb survivors. Although the reconstructed red bone marrow doses were about 36% lower on average than the conservative doses previously estimated by the military for compensation, the overall correlation was quite good, suggesting that the estimates of doses from external exposure by the military for all ∼115,000 cohort members could be adjusted appropriately and used in further epidemiological analyses.

Estimation of Radiation Doses to U.S. Military Test Participants from Nuclear Testing: A Comparison of Historical Film-Badge Measurements, Dose Reconstruction and Retrospective Biodosimetry

“…The general dose reconstruction approach is described elsewhere (3), and detailed procedures for estimating external dose to the RBM have also been published (5). For each of the external dose scenarios considered by dose reconstruction, the RBM dose was estimated by applying an exposure (R) to an RBM conversion of 6.5 mGy/R (26 that assumes 2/3 of the radiation was incident rotationally and 1/3 isotopically).…”

“…For each of the external dose scenarios considered by dose reconstruction, the RBM dose was estimated by applying an exposure (R) to an RBM conversion of 6.5 mGy/R (26 that assumes 2/3 of the radiation was incident rotationally and 1/3 isotopically). This approach accounts for unknown exposure geometries, and individual variability, and is reflected in the estimate of uncertainty, which, according to Beck et al (5), can be characterized by a geometric standard deviation (GSD) of approximately 1.2.…”

“…The population studied was derived from a large cohort of over 115,000 U.S. military personnel who participated in at least one of the 230 atmospheric nuclear weapons tests from 1945 through 1962 (3,5). Available information on the military test participants included name, military service number, date of birth, gender, pay grade, rank or rating, unit membership and dates during participation, permanent unit, and dates of entry to and separation from military service.…”

“…Their methodology attempts to determine the scenario of exposure for each individual military test participant using all available information, and then calculates a dose and an estimated uncertainty without the high-sided bias often present in the compensation programs. Following up on that work, Beck et al (5) estimated bone marrow and male breast doses to ;2,000 exposed military test participants, representing a subset of a ;115,000 military participants being studied as part of the One-Million U.S. Workers and Veterans Study of Low-Dose Radiation Health Effects (4). The red bone marrow (RBM) doses for the subcohort described in (5) averaged approximately 6 mGy and the maximum calculated RBM dose for that study was 108 mGy.…”

Introduction to the special issue on the US Million Person Study of health effects from low-level exposure to radiation

“…178 (NCRP 2018b) emphasizing the dosimetry and uncertainty approaches for the MPS (Dauer et al 2018). An article delineating the specific dosimetry associated with individual veterans who participated in nuclear weapons testing emphasizes the importance of an in-depth understanding of exposure scenarios (Till et al 2014;Beck et al 2017;Till et al 2018a), while another addresses approaches associated with dose reconstruction for internal emitters (Leggett et al 2018a). Dosimetry for medical radiation workers also is particularly unique and was given Quantitative information on female and male lung cancer risks is provided among workers in the MPS and TB-fluoroscopy cohorts (Boice et al 2019c).…”