Martin Šefl gave a seminar presentation to undergraduate students from Whitman College in Walla Walla, Washington. His presentation, which is a part of the Mathematical Sciences Foundry Talks series, explained how a principal component regression was used to estimate the total amount of plutonium in the entire skeleton, based on the activity concentrations in a limited subset of bones. This approach is preferred to calculating an arithmetic mean, because it reduces the risk of bias for non-representative bone sampling, utilizes all available information, and reduces the uncertainty.

Seminar slides (PPTX with animation)
Seminar slides (PDF)

On September 19, Martin Šefl will give a seminar presentation to undergraduate mathematics and statistics students from Whitman College in Walla Walla, Washington. His presentation, which is a part of the Mathematical Sciences Foundry Talks series, will describe how a principal component regression can be used to estimate the total amount of plutonium in the entire skeleton, based on the activity concentrations in a limited subset of bones. When a person wills their entire body to the USTUR, laboratory staff measure the amount of plutonium in each of the 90 bone samples that are removed from the right side of the body. It is a straightforward task to add up all of individual bone activities, and multiply by two, to estimate the amount of plutonium in the entire skeleton. However, the bulk of donations to the USTUR are partial body donations, where typically two to eight bones are donated to the USTUR for radiochemical analysis. The concentration of plutonium in these bones must be used to calculate the concentration in the entire skeleton, which can then be used, along with the skeletal weight, to calculate the total activity in the skeleton. There are several methods for estimating the skeletal concentration from a limited subset of bones, and each method has its limitations. Notably, a multiple regression is not an appropriate tool for calculating the concentration of plutonium in the skeleton, because bone concentrations are highly correlated with each other. A principal component regression addresses the multicollinearity among bones, making it a more appropriate tool for this application. A brief introduction to principal component regression will be provided, and its application for estimating the plutonium concentration in the skeleton will be discussed.

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George Tabatadze was reappointed as a member of the WSU Radiation Safety Committee (RSC), which he has served on since 2019. His new appointment has a three-year term, and ends in August 2025. The RSC establishes and ensures compliance with radiation protection policies, reviews applications for and approves use of radioactive materials and radiation producing machines, and audits Radiation Safety Office records.

Dr. Tabatadze is a research assistant professor at the USTUR, where he maintains and operates radiation detection instrumentation, heads up the laboratory’s effort to revise its quality assurance plan, and conducts quantitative analysis of data. He has served as a member of several organizations, including the Board of Trustees for the Herbert M. Parker Foundation, the Health Physics Society’s International Collaboration Committee, and the Columbia Chapter of the Health Physics Society, where he is a past president and is currently serving as a council member.

Daniel Strom, an adjunct professor at the USTUR, has been nominated to serve as a primary member on the Hanford Advisory Board, where he will represent local and regional public health. The Hanford Advisory Board provides “informed recommendations and advice to the U.S. Department of Energy (DOE), the U.S Environmental Protection Agency (EPA), and the Washington Department of Ecology (Ecology) on selected major policy issues related to the cleanup of the Hanford site.”⁽¹⁾ Dr. Strom is currently serving a two-year term as an alternate member of the board.

⁽¹⁾ https://www.hanford.gov/page.cfm/hab

Sara Dumit has been selected to receive the 2022 John D. Boice Young Investigator Award from the National Council on Radiation Protection and Measurements. Dr. Dumit completed her PhD in pharmaceutical sciences at Washington State University. Her research utilized USTUR data to study the decorporation of plutonium from the human body during treatment with chelating agents such as DTPA. She continues to study actinide chelation and develop biokinetic models as a part of her work as a Health Physicist at Los Alamos National Laboratory (LANL). During 2021, Dr. Dumit also had the distinction of attending the Lindau Nobel Laureate Meeting. The meeting, which was held virtually, provided her with the unique opportunity to interact with Nobel Laureates from around the world.

For more information about Dr. Dumit’s selection for this award, visit the NCRP website.

In December, the USTUR mailed its 2021 Registrant newsletter to living Registrants and deceased Registrants’ next of kin. This year’s newsletter discussed the unexpected opportunity provided by Covid-19 to focus on research involving existing data. Other topics included information about the Health Physics Society’s “Ask the Experts” webpage, and a status update on the USTUR’s plans to ask living Registrants to submit a urine sample for actinide analysis.

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Martin Šefl received an award from the Czech Society for Radiation Protection for his paper “Inhalation of soluble plutonium: 53-year follow-up of Manhattan Project worker,” which was published in the peer-reviewed journal Health Physics. The award was for the best work written by a young scientist in the field of radiation protection. His paper models the biokinetics of plutonium in a Registrant who was one of 26 Manhattan Project workers known informally as the “UPPU Club.” This group of plutonium-exposed workers were followed up by Los Alamos National Laboratory on a regular basis. Mr. Šefl’s work determined that the worker inhaled a combination of soluble and insoluble plutonium, and calculated doses associated with that intake.

Maia Avtandilashvili was appointed as a member of the National Council on Radiation Protection and Measurements (NCRP) Scientific Committee (SC) 6-13 on methods and models for estimating organ doses from intakes of radium, and Sergei Tolmachev will serve as a subject matter expert for the committee. SC-13 will prepare a commentary that will discuss approaches for determining organ doses following intakes of radium. It will also describe methods for assessing uncertainties associated with dose assessments, and for estimating doses to workers without measurement data, based upon doses to workers with measurement data and similar work histories.

A PhD candidate from the School of the Environment at WSU is conducting part of his research at the USTUR’s radiochemistry laboratory. Alexander Reyes is studying the amount of selenium in organisms collected from Omak Lake, the largest saltwater lake in Washington State. The lake is highly alkaline, which highly favors production of selenate ions in surface waters. Mr. Reyes’ research will assess the uptake of and bioaccumulation of selenium in organisms through different trophic levels of the food web, including various types of zooplankton, midges, invertebrates, and fish. Samples collected from Omak Lake were acid digested at the USTUR’s laboratory in preparation for inductively coupled plasma mass spectrometry (ICP-MS) analysis at WSU’s GeoAnalytical Lab in Pullman, WA.

During 2020, COVID restrictions meant that USTUR staff largely worked from home, and many scientific conferences were cancelled. Indeed, this slowed down certain operational aspects of the Registries, such as analyzing tissues for actinides. However, it also provided an unexpected opportunity for faculty to focus on research involving existing data. During 2021 alone, USTUR faculty have been preparing 11 papers for publication in scientific journals. Six will have a USTUR faculty member as the lead author, and six have already been submitted to and/or published in a journal. Additionally, scientific conferences have resumed using virtual, in-person, or hybrid formats. So far this year, USTUR faculty have authored eleven presentations at three conferences, and anticipate giving four additional presentations at the upcoming Radiation Research Meeting in October.

Journal Articles (Published or Accepted)

Avtandilashvili et al. Four-decade follow up of plutonium contaminated puncture wound treated with Ca-DTPA. DOI: 10.1088/1361-6498/ac04b8

Šefl et al. Inhalation of Soluble Plutonium: 53-year Follow-up of Manhattan Project Worker. DOI: 10.1097/HP.0000000000001396

Poudel et al. Long-term retention of plutonium in the respiratory tracts of two acutely-exposed workers: Estimation of bound fraction. DOI: 10.1097/HP.0000000000001311

Martinez et al. Radium dial workers: back to the future. DOI: 10.1080/09553002.2021.1917785

Conferences

Health Physics Society Midyear Workshop, May 23-26
Health Physics Society Annual Meeting, July 25-29
WSU College of Pharmacy and Pharmaceutical Sciences Research Day, August 13
Radiation Research Society Meeting, October 3-6