WAM-A - Million Person Study Dosimetry Woodrow Wilson A 10:00 - 12:00
|
| Chair(s): Isaf Al-Nabulsi, David Bierman
|
| |
WAM-A.1
10:00 Comprehensive Dosimetry for the Million Person Study Epidemiology LT Dauer*, Memorial Sloan Kettering Cancer Center
; R Leggett, Oak Ridge National Laboratory CRPK; C Samuels, Oak Ridge National Laboratory CRPK; M Bellamy, Memorial Sloan Kettering Cancer Center; M Mumma, Vanderbilt/IEI; JD Boice, Jr., NCRP
Abstract: An essential key to high-quality epidemiology is high-quality dosimetry. The Million Person Study of Low-Level and Low-Dose-Rate Health Effects (MPS) utilizes guidance from the National Council on Radiation Protection and Measurements (NCRP) to reconstruct organ-specific radiation absorbed doses with evaluation of their accompanying uncertainties. The dosimetry aspects for the MPS are challenging in that they address diverse exposure scenarios for diverse occupational groups being studied over a period of up to 70 y. Specific dosimetric reconstruction issues differ among the varied exposed populations considered: atomic veterans, U.S. Department of Energy workers, nuclear power plant workers, medical radiation workers, industrial radiographers, submariners, and radium dial painters. While a major source of radiation exposure to the study population comes from external gamma- or x-ray sources, for some of the study groups there is also a meaningful component of radionuclide intakes that requires internal radiation dosimetry assessments. In addition, the MPS performs dosimetry record linkages across all cohorts and from multiple sources to provide comprehensive annual doses for the working career for each individual.
|
WAM-A.2
10:20 MPS Hanford Cohort Dosimetry: Internal Dose Reconstruction Approaches CE Samuels*, Oak Ridge Center for Radiation Protection Knowledge (CRPK)
; RW Leggett, Oak Ridge Center for Radiation Protection Knowledge (CRPK); SY Tolmachev, U.S. Transuranium and Uranium Registries (USTUR)
Abstract: The Hanford site began operations in 1943 as part of the Manhattan Project. The site was first used to produce plutonium for the bomb that helped end WWII. After the war, production of plutonium was ramped up to meet the challenges of the Cold War. Research and development efforts were gradually expanded to include non-defense projects such as development of heat sources and production of medical isotopes. Over the years, large quantities of many different radionuclides were handled in site laboratories, and large volumes of radioactive wastes were produced in reactor operations. Bioassay data indicate relatively high intakes of a variety of radionuclides by Hanford workers. As part of the Million Person Study (MPS), ORNL is performing internal dose reconstructions for workers at the Hanford Site. Dose reconstructions are based on the latest biokinetic models of the International Commission of Radiological Protection (ICRP) or site-specific variations of those models. The Hanford database includes over 300,000 bioassay measurements for over 20,000 workers, and over 2,000 incident reports. Additional information comes from bioassay data and post-mortem tissue analyses of plutonium and americium for 28 individuals who worked at Hanford and voluntarily donated their bodies (partially or entirely) to the United States Transuranium and Uranium Registries (USTUR). The early stages of the dose reconstructions have been aimed at identifying the most important internal emitters to which the workers were exposed, and performing scoping exercises to identify workers with highest intakes of those radionuclides. Conclusions regarding the dosimetrically dominant internal emitters at Hanford will be discussed, and our methods of reconstructing doses from those radionuclides will be described.
|
WAM-A.3
10:40 External radiation doses to the brain in the Hanford worker cohort. MB Bellamy*, MSKCC
Abstract: The Hanford Site was established during World War II as part of the Manhattan Project, the secret U.S. program to develop an atomic bomb. Its mission was to produce plutonium for use in atomic bombs. The site's legacy continues to this day, as it is now in the process of environmental cleanup and site restoration.
This presentation will outline the methodology used to calculate the external radiation dosimetry associated with the brains of Hanford workers for use in the Million Person Epidemiology Study. The worker doses were calculated using historical and current worker records. In addition, occupational records were used to determine the types of radiation exposure at the Hanford site, and badging data was used to estimate the individual worker's exposure to radiation from 1944-1998. Photon and neutron dosimetry was used to calculate the external radiation dosimetry for Hanford workers accurately. The dosimetry data was then used to estimate the radiation doses received by Hanford workers throughout their careers.
As part of the Million Person Epidemiology Study, these worker doses will be used to assess the health risks associated with their exposure to radiation. Radiation epidemiology can be used to assess the link between radiation exposure and the development of diseases such as Parkinson's, which may help to understand the effect of radiation on cognitive function. Accurate radiation dosimetry is essential for epidemiological studies as it enables researchers to identify potential health effects better and estimate the potential risks to the population.
|
WAM-A.4
11:20 Radium Dial Painter Dosimetry: Person-Centered Innovations NE Martinez*, Clemson University; Oak Ridge National Lab
; DW Jokisch, Francis Marion University; Oak Ridge National Lab; C Samuels, Oak Ridge National Laboratory; RW Leggett, Oak Ridge National Laboratory; S Tolmachev, US Transuranium and Uranium Registries; M Avtandilashvili, US Transuranium and Uranium Registries; G Tabatadze, US Transuranium and Uranium Registries; R Goans, MJW Corporation; L Dauer, Memorial Sloan Kettering Cancer Center; JD Boice, Jr, Vanderbilt-Ingram Cancer Center; National Council on Radiation Protection and Measurements
Abstract: Current progress in radium dial painter (RDP) dosimetry within the Million Person Study is discussed along with our initial community engagements and public collaborations. Although dose reconstruction is often approached as a ‘pure’ science, the importance of people, relationships, and stories should be center stage. Progress in RDP dosimetry is a true collaborative effort between multiple generations of scientists as well as the RDPs themselves and their family and friends. Current work builds on the innovation and foresight of those who came before us some 100 years ago and draws on the recorded experiences of the dial painters coupled with community knowledge. The person-centered approach adopted in this work is two-fold: (1) recognition and incorporation of prior personal experience and scientific accomplishments and (2) improving individualized dose determination as practical and possible. For the latter, approaches include use of individual measurements at multiple times following chronic intake of radium; applying reference models corresponding to an individual’s age at exposure and length of exposure; improvements to age and sex dependent models (particularly for females); evaluation over the lifetime of workers; consideration of intake rate by workplace and workplace practice; and potential incorporation of biodosimetry. The overarching goal is to enhance the understanding of lifetime risk from intakes of radionuclides for this classic epidemiologic study (Martinez et al. IJRB 2022)* which has been foundational for radiation protection guidance from the Manhattan Project to the present. The humanity of the young girls and women studied as early as 1915 will not be forgotten.
*Financial support for the RDP study is provided by the US Department of Energy (Grants DE-AU0000042 and DE-AU0000046) and the National Aeronautics and Space Administration (Cooperative Agreement 80NSSC17M0016).
|
WAM-A.5
11:40 NCRP SC 1-28, Recommendations on Statistical Approaches to Account for Dose Uncertainties in Radiation Epidemiologic Risk Models HM Cullings*, RERF
Abstract: Accurate exposure estimation in radiation epidemiological studies is critical for precision health risk assessment. Failure to account appropriately for uncertainties and model assumptions could lead to biased results in dose-response analyses and interpretation. However, the dose assessment in many such studies is subject to considerable uncertainties, and several approaches have been suggested to incorporate the dose uncertainties into dose-response models. DOE has requested that NCRP evaluate and compare different analytic and statistical approaches and to prepare a commentary providing guidance on the impact and interpretation of different strategies used for analyzing dose-response relationships when doses are uncertain under varying exposure scenarios. NCRP has formed Scientific Committee SC1-28, Recommendations on Statistical Approaches to Account for Dose Uncertainties in Radiation Epidemiologic Risk Models. The goal is to provide guidance on dose-response statistical modeling methodologies that incorporate dose uncertainties and to evaluate the advantages and drawbacks of the approaches that are currently in use. The NCRP will prepare a commentary covering studies of external and internal exposures and provide guidance relative to both shared and unshared uncertainty in dose calculations and the statistical uncertainties therein. Of particular interest are dose-response statistical methods in epidemiologic studies of internal emitters where doses are calculated using exposure and retention models with many parameters, and each parameter has uncertainties.
|
