SC 6-9: U.S. Radiation Workers and Nuclear Weapons Test Participants Radiation Dose Assessment

Members only

The U.S. Department of Energy (DOE) grant includes funding for an NCRP report on the comprehensive dose assessment requirements and methodologies for the Million Person Study. The dosimetric issues involved are complex and differ among the varied exposed populations under evaluation: atomic veterans, DOE workers exposed to both penetrating radiation and intakes of radionuclides, nuclear power plant workers, medical radiation workers, and industrial radiographers.

SC 6-9 is envisioned to cover the specifics of practical dose reconstruction for the ongoing epidemiologic studies with uncertainty analysis evaluation. Strengths and limitations of the approaches taken will be covered, as will brief mention of other unique exposure circumstances such as those among astronauts and the military personnel in Japan after the Fukushima nuclear reactor accident.

The Committee will study all dosimetric circumstances in the occupational setting, while also addressing environmental circumstances such as fallout. It should become a textbook on practical dose reconstruction approaches for epidemiologic studies. Methods to estimate doses from internal intakes of radionuclides will be developed as will approaches to combine external and internal radiation for dose assessment. The focus with be on providing the best estimate of organ absorbed dose and not high-sided estimates as used in compensation programs. Actual data developed from the Million Person Study, and not theoretical possibilities, will be used throughout, including workers employed at more than one facility during their career. An outline for ways to combine the varied dosimetric and epidemiologic data will be provided and practical examples will be used throughout.

SC 6-9 will provide a peer review of the extensive dosimetry approaches taken in the Million Person Study which could not practically be published elsewhere. The approach is to build upon, enhance, and expand previous NCRP reports (NCRP Reports Nos. 158, 163, 164, and 171). Useful examples for estimating the uncertainties in external doses for atomic veterans and medical x-ray technologies already exist (NCRP Report No. 158) and will provide helpful initial guidance.

The first meeting was held April 2–3, 2013 at the Oak Ridge Associated Universities in Oak Ridge, Tennessee. The following presentations were made:

  • Background of the Million Worker Study and Dosimetry Committee (Boice);
  • Status of the Study of Nuclear Weapons Manufacturing Workers (Eckerman);
  • Military Participants at U.S. Atmospheric Nuclear Weapons Tests (the Eight Series Study) (Beck);
  • Radiation Exposure Information Reporting System (Hagemeyer);
  • Representation of the Uncertainty in Complex Dosimetry Systems (Stram); and
  • Resources for Dose Reconstruction Developed for EEOICPA (Toohey).

It was concluded that the principal objective of the report is to provide guidance in the derivation of organ doses and their uncertainty for epidemiologic studies, with a focus on organ doses for the components of the Million Person Study.

A review of a draft outline for the report was conducted, and a revised outline (including writing assignments) was prepared and distributed. A follow-up webinar was held June 19, 2013. The first rough drafts were discussed in some detail by each author, specific advice was provided to the authors on the content of each section, and the next steps were discussed.

Draft material was assembled and was distributed to Committee members on September 15, 2013. The main elements of the working outline are:

  • Introduction
  • Common Aspects of Organ Dose Assessment;
  • Guidance on Organ Dose Assessments for Million Worker Study Populations;
    • Radiation Workers at Large-Scale Production Facilities;
    • Nuclear Weapons Test Participants;
    • Nuclear Power Plant Workers;
    • Medical Radiation Workers; and
    • Industrial Radiographers
  • Commentary on Supplemental Populations; and
  • Conclusions and Recommendations.

A meeting was held October 1–2, 2013 in Oak Ridge, Tennessee to review the draft and develop the next steps. The schedule for the next steps is:

  • submission of revised sections to the Staff Consultant no later than January 31, 2014 (sooner if available);
  • preparation and distribution by the NCRP Staff Consultant of the new consolidated draft to all members by March 31, 2014;
  • teleconference/webinar (optional) in early April 2014 to set the agenda for the next meeting; and
  • scheduling of the next meeting in Oak Ridge, Tennessee, April 29–30, 2014.

A revised consolidated draft was distributed to the Committee on April 1, 2014 in preparation for the next meeting on April 29–30, 2014. The draft material was augmented and the overall outline is now:

  • Executive Summary
  • Introduction
  • Common Aspects of Organ Dose Assessment
  • Guidance on Organ Dose Assessments for MWS Populations
  • Radiation Workers at Large-Scale Production Facilities
  • Nuclear Weapons Test Participants
  • Nuclear Power Plant Workers
  • Medical Radiation Workers
  • Industrial Radiographers
  • Conclusions and Recommendations
  • Appendix A. Historical Background on Personal Monitoring
  • Appendix B. Internal Dosimetry Quantities and Units
  • Appendix C. Details of Case Studies for Rocketdyne and Mound Workers
  • Appendix D. Supplemental Populations of Interest
  • Astronauts
  • Exposed Military and Dependent Populations (Fukushima)
  • U.S. Transuranium and Uranium Registries
  • REAC/TS Accident Registry
  • Mayak Production Association

At the April 2014 meeting in Oak Ridge, the Committee went through the draft first for general comments and then section by section. Each author was advised on specific aspects of the content and assigned to make the agreed revisions for the next draft. As a result the outline will be adjusted once again when the revised material is compiled. The schedule for the next steps is:

  • Teleconference/webinar (July 28, 2014) to assess progress;
  • Submission of updated sections (no later than September 1, 2014);
  • Distribution of a new consolidated draft to all members (October 1, 2014); and
  • Next meeting in Oak Ridge, Tennessee on October 28–29, 2014.

An updated draft (dated July 18, 2014) was distributed and a teleconference was held on July 28, 2014 with all the available members. Progress on the writing assignments was reviewed and further refined. The schedule for the next steps was reaffirmed.

Draft material had been augmented and a consolidated draft (October 2014) was distributed to Committee members on October 17, 2014. At the fourth meeting (October 28–29, 2014 in Oak Ridge), the draft was reviewed for overall organization and content section by section, resulting in some significant adjustments to the outline in order to bring all the main principles and guidance from the Committee on derivation of organ doses and their uncertainty into one location. In particular, the original Section 3 (Common Aspects of Organ Dose Assessment and Uncertainty Analysis) will be retitled and structured in the following manner:

  • 3. Principles of Occupational Dose Reconstruction for Use in Epidemiologic Studies
    • 3.1 Identification of the Subjects
      • 3.1.1 Review of the Site History
      • 3.1.2 Selection of Subjects
    • 3.2 Determination of Exposure Scenarios
      • 3.2.1 Review of Worker Files
      • 3.2.2 Interview of Selected Workers
    • 3.3 Analysis of Available Information
      • 3.3.1 External Sources
        • Film Badges Available
        • No Film Badges Available
      • 3.3.2 Internal Sources
        • Bioassay Data Available
        • No Bioassay Data Available
    • 3.4 Estimation of Organ Doses
      • 3.4.1 External Sources
        • Badges Available
        • No Film Badges Available
      • 3.4.2 Internal Sources
        • Bioassay Data Available
        • No Bioassay Data Available
    • 3.5 Estimation of Uncertainties
      • 3.5.1 Types of Uncertainty
      • 3.5.2 Evaluation of Uncertainties
      • 3.5.3 Representation of Uncertainties in Doses
      • 3.5.4 Effects of Dosimetric Uncertainties in Dose-Response Analysis
      • 3.5.5 Incorporating Dosimetric Uncertainties in Dose-Response Analysis

As a result of this restructuring, the section author(s) will make adjustments (additions, deletions, movement of material) in their respective sections as was determined during the review of each section. The progress on restructuring Section 3 and the first two parts of Section 4 on the specific dose assessments for each of the Million Person Study populations [Section 4.1 (Radiation Workers in Large-Scale Production Facilities) and Section 4.2 (Nuclear Weapons Test Participants)] was reviewed during the past quarter.

At the January 22 webinar, a revised Section 3 was discussed and its structure was further adjusted. The main adjustment was in the presentation and discussion of uncertainties. Section 3 would retain information on uncertainties in the estimation of organ doses. The remaining text would be moved to two appendices: one on general definitions and concepts of uncertainty; the other on applying the uncertainty in the organ doses to the evaluation of the overall uncertainty in radiation risk for epidemiologic studies.

At the February 17 teleconference, it was agreed that the guidelines in the reworked Section 3 could be applied to the sections on each of the Million Person Study populations. It was also agreed that the two appendices on uncertainty could be merged into one appendix. Text has been added to Section 2 that explains how the information on uncertainty is now organized in the report. The participants were surveyed on the likely submission timeframes for revised sections. Other updates already received included material on converting exposure to personal dose equivalent and discussion of cranial-caudal and caudal-cranial exposure geometries.

At the April 28–29, 2015 meeting in Oak Ridge, three very informative presentations were made: two addressing methods of treating uncertainties in the derivation of organ doses and in the evaluation of dose-response relationships; the third on the unique composition of the radiation environment in space. The presentations were:

  • Advances and Methods to Characterize and Correct for Uncertainties and Exposures in Epidemiologic Studies (Simon and Hoffman) (invited);
  • Using Multiple Realizations of Dose Estimates to Account for Dosimetry Error in Epidemiological Dose-Response Analysis (Stram); and
  • Space Radiation Environment (Zeitlin)

The current full draft (April 2015) was distributed to Committee members on April 12, 2015. The draft had been reorganized as decided at the October 2014 meeting and two subsequent teleconferences on January 22 and February 17. The current contents (main sections) are listed below:

  1. Executive Summary
  2. Introduction
  3. General Approach to Organ Dose Reconstruction for the Million Person Study
  4. Application of General Approach to the Million Person Study Populations
    • 4.1 Radiation Workers at Large-Scale Production Facilities
    • 4.2 Nuclear Weapons Test Participants
    • 4.3 Nuclear Power Plant Workers
    • 4.4 Medical Radiation Workers
    • 4.5 Industrial Radiographers
  5. Conclusions
    • Appendix A: Supplemental Populations of Interest to Dose Assessment for Epidemiologic Studies
      • A.1 Astronauts
      • A.2 Mayak Production Association
      • A.3 U.S. Transuranium and Uranium Registries
      • A.4 REAC/TS Accident Registry
    • Appendix B: Overall Distributions of Cumulative Lifetime Doses for the Populations in the Million Person Study
    • Appendix C: Uncertainties in Dosimetry and their Application to Risk Assessment
    • Appendix D: Internal Dosimetry Quantities and Units
    • Appendix E: Historical Influence of Guidance, Recommendations, Regulations and Standards on Personal Monitoring Performance and Dosimetry Results
    • Appendix F: Conversion Coefficients Relating Personal Dose Equivalent to Organ Dose for Photons

During the 2 d meeting the Committee reviewed each section and provided feedback on specific details to the section authors for follow-up revisions. Two sections [4.3 (Nuclear Power Plant Workers) and 4.4 (Medical Radiation Workers)] were discussed in more detail. The discussions of Sections 4.3 and 4.4 centered on the many challenges faced in deriving organ doses from available personal monitoring records and other work-related information when the specific exposure conditions for individuals in the study groups are not directly known.

The schedule of next steps is:

  • May – October 2015 … Follow-up with section authors on specific details and subgroup interactions or meetings as needed
  • Mid-October 2015 … Distribute current draft
  • November 3–4, 2015 … Next meeting (Oak Ridge, Tennessee)

As of September 30, 2015, advances have been made in updating the sections and the schedule remains unchanged.

At the November 3–4, 2015 meeting in Oak Ridge, John Boice provided an update on the status of various components of the ongoing epidemiologic study. Of note, the title of the study for this NCRP report is now “One Million U.S. Persons Study of Low Dose Radiation Health Effects” in place of the title found in previous published papers and supplementary descriptions, which was “One Million U.S. Radiation Workers and Veterans Study.”

On November 4, an informative slide presentation “Historical Medical Images for NCRP MPS Report” (Stephen Balter) was provided. The series of slides showed the nature and use of medical equipment from as early as 1910 through as late as 1990.

The current full draft (October 2015) was distributed to Committee members on October 25, 2015. During the 2 d meeting the Committee reviewed each section and provided feedback on specific details to the section authors for follow-up revisions. The discussions centered on what further actions were necessary to bring the draft to a point where it would be ready for PAC 6 and expert review. A list of potential expert reviewers was generated by the SC 6-9 membership.

The planned timetable to produce the PAC 6/expert review draft is:

  • November through December 2015 … submit revisions and updated sections (as soon as ready)
  • December 1, 2015… Section 4.3 (Nuclear Power Plant Workers) members met (New York City)
  • December 16, 2015 … Section 4.4 (Medical Radiation Workers) members met (Bethesda)
  • February 1, 2016 … distribute current draft
  • February 18–19, 2016… next meeting of full Committee (if needed) (Oak Ridge, Tennessee)… final editing of draft
  • March 1, 2016 … distribution of draft for PAC 6/expert review

A detailed overview of the Million Worker Study was published in the November 2012 issue of Health Physics News and can be accessed at: Nov-2012_Million_Worker.pdf

NCRP gratefully acknowledges financial and other research support for this work from: the federal agencies (National Aeronautics and Space Administration, National Cancer Institute, U.S. Department of Defense /Defense Threat Reduction Agency, U.S. Department of Energy, U.S. Department of Veterans Affairs, U.S. Environmental Protection Agency, and U.S. Nuclear Regulatory Commission); the national laboratory collaborators (Los Alamos National Laboratory, Oak Ridge Institute for Science and Education, and Oak Ridge National Laboratory); from academic/research institutions (the Fred Hutchinson Cancer Research Center, Harvard University, University of Southern California, and Vanderbilt University); and from private-sector collaborators (International Epidemiology Institute, Landauer, Inc., Oak Ridge Associated Universities, and Risk Assessment Corporation).

The membership of SC 6-9 is:

Bouville A


Bouville A

was born and educated in France. He came to the United States in 1984 to work for the National Cancer Institute (NCI). His initial assignment was to estimate the thyroid doses received by the American people from 131I released by the nuclear weapons tests that were conducted at the Nevada Test Site in the 1950s. This study led to the assessment of doses from nuclear weapons tests conducted at other sites all over the world, as well as to a large number of dosimetry studies related to the Chernobyl nuclear reactor accident. He was the head of the Dosimetry Unit of the Radiation Epidemiology Branch at NCI until he retired at the end of 2010. Throughout his career, Dr. Bouville actively participated in the preparation of scientific reports under the umbrella of international organizations, notably the United Nations Scientific Committee on the Effects of Atomic Radiation, the International Commission on Radiological Protection, the International Commission on Radiation Units and Measurements, the World Health Organization, the International Atomic Energy Agency, and the Nuclear Energy Agency.

Regarding U.S. organizations, Dr. Bouville was a member of NCRP for 12 y, became a Distinguished Emeritus Member in 2011, and is currently Chair of Scientific Committee 6-9 on the dosimetry for the Million-Worker Study. He has served on numerous National Academy of Science committees, is a Lifetime Associate of the National Academies, and is currently a member of the Committee on the analysis of cancer risks in populations near nuclear facilities. For all his achievements, Dr. Bouville was a recipient of the Presidential Rank Meritorial Award in 2003.

andre bouville, Chair



received his PhD in physics from the University of Cincinnati in 1973. He spent the first part of his career at Argonne National Laboratory in both research and operational health physics. He recently retired from Oak Ridge Associated Universities, where he served as director of the Radiation Internal Dose Information Center, as Senior Health Physicist for the Radiation Emergency Assistance Center/Training Site, Director of Dose Reconstruction Programs, and Associate Director of the Independent Environmental Assessment and Verification Program. He is currenly employed by M.H. Chew and Associates.

He is certified in comprehensive practice by the American Board of Health Physics, was the 2008 to 2009 President of the Health Physics Society, is a member and director of NCRP, Treasurer of the International Radiation Protection Association, and Chair of the Scientific Advisory Committee for the U.S. Transuranium and Uranium Registries. His specialties are internal radiation dosimetry, dose reconstruction, and radiological emergency response. Dr. Toohey has 125 publications in the open literature, and is a retired Lt. Colonel, U.S. Army Reserve.

richard e. toohey, Co-Chair
Beck H


Beck H

was a physicist for the U.S. Department of Energy (DOE)/ERDA/Atomic Energy Commission for over 36 y. Mr. Beck retired in 1999 as the Director of the Environmental Science Division of the DOE Environmental Measurements Laboratory (EML) in New York City and is presently a self-employed consultant specializing in environmental radiation dose reconstructions. During his tenure at EML, he also served as Director of the EML Instrumentation Division, and as Acting Deputy Director of the Laboratory. Mr. Beck has authored well over 100 publications in the areas of radiation physics, radiation measurement, dose reconstruction, environmental radiation, and radiation dosimetry. He served as Scientific Vice President for Radiation Measurements and Dosimetry of NCRP from 1996 to 2003, and in 2004 was elected to Distinguished Emeritus membership in NCRP. From 2004 to 2006, he served as a member of the National Academy of Sciences, National Research Council (NAS/NRC) Board on Radiation Effects Research /Nuclear and Radiation Studies Board.

He currently serves as a member of the Veterans (federal advisory) Board on Dose Reconstruction and the U.S. Scientific Review Group, DOE Russian Health Studies Program. He has served as an expert member on a number of NCRP and NAS/NRC scientific studies related to radiation dosimetry and as Chair of two NCRP committees and one NCRP Program Committee. He is a member of the American Association for the Advancement of Science, the American Nuclear Society, and a Fellow of the Health Physics Society.

harold l. beck
Dr. Lawrence Dauer


is Associate Attending Physicist, and Associate Clinical Member in the Departments of Medical Physics and Radiology at Memorial Sloan-Kettering Cancer Center (MSKCC) in New York City. He earned an MS in Health Physics and a PhD in Adult Education. He is certified in comprehensive health physics by the American Board of Health Physics and is past chair of the Radiation Safety Committee of the American Association of Physicists in Medicine (AAPM), past President of the Greater New York Chapter of the Health Physics Society (HPS), Executive Council Member of the Medical Physics Section of the HPS, a Member of the Joint Safety Committee of the Society for Interventional Radiology and the American College of Radiology, past council member of the Radiological and Medical Physics chapter of the AAPM, and a member of editorial and review boards of several scientific journals. He serves as the Chair of the MSKCC Emergency Management Committee, a member of the Radiation Injury Treatment Network. In 2005, he received the Elda E. Anderson Award from HPS. He is a Council member and serves on he Board of Directors of the NCRP. He also serves as a member of the International Commission on Radiological Protection Committee 3 on protection in medicine, a member of the science council for the International Organization for Medical Physics, and was on the program committee for the International Atomic Energy Agency's International Conference on Radiation Protection in Medicine-Setting the Scene for the Next Decade. He serves on the Radiation Advisory Committee of the U.S. Environmental Protection Agency's Science Advisory Board. He has several publications in the topical areas of radiation protection and risks in the fields of detection, radiology, interventional radiology, x-ray imaging, nuclear medicine, and radiation oncology, as well as surgery and medicine.

lawrence t. dauer
Eckerman K


Eckerman K

in Radiological Physics from Northwestern University in 1972. Dr. Eckerman joined the Oak Ridge National Laboratory in 1979 as leader of the Dosimetry Research Group after working at Argonne National Laboratory and with the U.S. Nuclear Regulatory Commission. He is a member of Committee 2 of the International Commission on Radiological Protection and Chairman of its Task Group on Dose Calculations. In 1999 he received the Distinguished Scientific Achievement Award from the Health Physics Society and in 2001 the Loevinger-Berman Award from the Society of Nuclear Medicine.

keith f. eckerman
HagemeyerDDerek Hagemeyer
Miller D


Miller D

is Chief Medical Officer for Radiological Health at the Food and Drug Administration’s (FDA) Center for Devices and Radiological Health. He earned a BA from Yale University and an MD from New York University, and completed a residency in diagnostic radiology and a fellowship in interventional radiology at New York University Medical Center. He is board certified in Diagnostic Radiology and Vascular and Interventional Radiology. Prior to joining FDA, he practiced interventional radiology at the National Institutes of Health and the National Naval Medical Center in Bethesda, Maryland.

Dr. Miller was elected to NCRP in 2006. He currently serves as Co-Chair of Program Area Committee 4 (Radiation Protection in Medicine), Chair of the Nominating Committee, and as a member of several scientific committees. He is an author of NCRP Reports No. 168 and No. 172 and Statement No. 11. He also served as a member of International Commission on Radiological Protection (ICRP) Committee 3 (Protection in Medicine) from 2010 to 2017. He is an author of ICRP Publications 117 and 120. He was Vice-Chair for the U.S. Environmental Protection Administration’s Federal Guidance Report No. 14, is a consultant to the International Atomic Energy Agency, and is a member of the World Health Organization’s Core Group of Experts on radiation protection of patients and staff.

Dr. Miller was Professor of Radiology at the Uniformed Services University in Bethesda, Maryland from 1993 to 2012 and has served as Associate Editor of Radiology and the Journal of Vascular and Interventional Radiology. He is an author of more than 185 papers in peer-reviewed journals and more than 30 book chapters and reports, is a Fellow of the Society of Interventional Radiology (SIR) and the American College of Radiology (ACR) and is an Honorary Member of the American Association of Physicists in Medicine. He chaired SIR’s Safety and Health Committee from 1999 to 2011 and the ACR Guidelines Interventional Committee from 2008 to 2012. His research interests have centered on radiation protection in medicine.

donald l. miller



is a Staff Scientist in the Radiological Science and Engineering Group at Pacific Northwest National Laboratory in Richland, Washington and has been for the past 35 y. Mr. Napier works with the development and operation of models concerned with the environmental transport of radiological and chemical contaminants. His expertise and experience lie in the areas of radiation dose reconstruction, computer modeling, environmental analysis, and human health risk analysis.

He is an author of the widely-used GENII computer code. Mr. Napier was the Chief Scientist for the Hanford Environmental Dose Reconstruction Project that evaluated releases from the Hanford Site during production of plutonium. He is now a Principal Investigator for the U.S./Russian Joint Coordinating Committee on Radiation Effects Research, working on the dose reconstructions at the Russian Mayak Production Association for both the workers at and the populations living near the points of atmospheric release and along the Techa River downstream. Mr. Napier is a member of the Board of Directors of NCRP, a committee member of the U.S. Environmental Protection Agency's Science Advisory Board and the National Academy of Sciences, a Fellow of the Health Physics Society, and Chair of oversight panels for the National Cancer Institute's Chernobyl Studies.

bruce a. napier



has been a member of Program Area Committee (PAC) 2 since 2007 and a member of NCRP since 2010. She has served on Scientific Committees 2-4, 2-5, 2-7, 1-19, and 6-9. Ms. Pryor is currently on the NCRP Board of Directors and is Scientific Vice President of PAC 2. She received her BS in Biology in 1979 and MS in Radiological Sciences in 1981, both from the University of Washington.

Ms. Pryor currently holds the position of Chief Health Physicist at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, and has provided management and technical support to the PNNL Radiation Protection Division since 1992. She also served as the Chief Radiological Engineer for the design of the Pit Disassembly and Conversion Project. Ms. Pryor has previously held radiation protection technical support positions at the San Onofre Nuclear Generating Station and the Trojan Nuclear Plant, and was the Radiation Safety Officer at the University of Southern California Health Sciences Campus.

Ms. Pryor is a Fellow member of the Health Physics Society (HPS) and served as President-Elect, President, and Past President from 2010 to 2013. She is certified in comprehensive practice by the American Board of Health Physics (ABHP), and served on the ABHP both as a member and Chair from 1998 to 2002. Ms. Pryor was awarded the William McAdams Outstanding Service Award by ABHP in 2007 and the John P. Corley Meritorious Service Award by the Columbia Chapter of HPS in 2003.

kathryn h. pryor



is Adjunct Associate Professor at Georgetown University and the University of Nevada Las Vegas. From 1984 to 2004, Dr. Schauer served in various scientific and leadership positions as an officer in the U.S. Navy. One of the highlights of his career was serving on the faculty of the Radiology and Radiological Sciences Department at the Uniformed Services University of the Health Sciences. In 2004, he was appointed Executive Director of the congressionally chartered NCRP. He served in this position until 2012 when he was named Executive Director Emeritus. During his time at NCRP the Council published 27 reports, four commentaries, one statement, and eight annual meeting proceedings.

Dr. Schauer received his ScD degree from Johns Hopkins University and he's a diplomate of the American Board of Health Physics. He sits on the editorial boards of Radiation Measurements and Radiation Protection Dosimetry. He has served on expert committees for the World Health Organization and International Atomic Energy Agency, and he's a Health Physics Program Evaluator for the Accreditation Board on Engineering and Technology.

david a. schauer
Stram D


Stram D

is Professor in the Department of Preventive Medicine at the Keck School of Medicine of the University of Southern California. He received his PhD in statistics from Temple University in 1983 and served as a postdoctoral fellow in the Biostatistics Department of the Harvard School of Public Health from 1984 to 1986. From 1986 to 1989 he was a research associate at the Radiation Effects Research Foundation in Hiroshima, Japan.

Dr. Stram's main areas of research are in the statistical problems that arise in the design, analysis and interpretation of epidemiological studies of cancer and other diseases. His work on radiation epidemiology studies includes: (1) helping to characterize the statistical nature of errors in dose estimates for the atomic-bomb survivor study, (2) developing a multi-level variance components model for the dosimetry used in the Colorado Plateau uranium miners cohort for the purpose of better understanding dose and dose-rate effects in those data, and (3) characterizing study power and sample size issues in epidemiologic studies in which a complex dosimetry system is used to estimate radiation dose. Besides the field of radiation epidemiology his past and current research has focused on statistical issues relevant to clinical trials of treatment for pediatric cancer, nutritional epidemiology studies, and to studies of the genetics of complex diseases. He is an elected fellow of the American Statistical Association and has authored or co-authored over 200 peer reviewed articles.

daniel o. stram
Thompson J

James L. Thompson

Thompson Jserved in the U.S. Navy from 1989 until 1994 as a nuclear propulsion plant operator, during which time he received the Southwest Asia Service Medal while stationed onboard the USS Abraham Lincoln. He received a BS in Biology and Chemistry in 1998 from Stephen F. Austin State University. Upon graduation, he became a health physicist working as a radioactive materials inspector for the Texas Department of Health, Bureau of Radiation Control. His primary focus during this time was on the routine inspections of industrial licensees, as well as investigations into radiation overexposures and other events resulting from the use of industrial sources of radiation. In 2001, he became a health physics inspector with the U.S. Nuclear Regulatory Commission (NRC), where he was promoted to Senior Health Physicist. During his time at NRC, Mr. Thompson participated in numerous investigations into radiation exposure events and radioactive contamination events, most notably the plutonium contamination event at the National Institute of Standards and Technology in Boulder, Colorado in 2008. Another incident investigation that he performed was at the Basin Electric Power Cooperative in Wheatland, Wyoming, whereby 17 employees were inadvertently exposed to radiation from the misuse of fixed nuclear gauges. Mr. Thompson has served as an instructor for the NRC’s Inspection Procedures course, teaching the principles of industrial uses of nuclear material and associated inspection techniques. Also, he was a finalist for the Leadership Excellence Award at the Dallas-Fort Worth Federal Executive Board awards banquet in June 2012.

James L. Thompson



is President of Risk Assessment Corporation. He is a graduate of the U.S. Naval Academy and served in the U.S. Navy Nuclear Submarine Program and retired a Rear Admiral in the U.S. Naval Reserve in 1999. Dr. Till received an MS from Colorado State University in 1972 and a PhD from the Georgia Institute of Technology in 1976. In 1977 Dr. Till formed Risk Assessment Corporation to perform research on radionuclides released to the environment by nuclear facilities. His career has focused on the development of methods to estimate dose and risk to humans from radionuclides and chemicals in the environment. He has served on committees for the National Academy of Sciences, the International Commission on Radiological Protection, and the International Atomic Energy Agency. He has published widely in the open literature including the first textbook on radiological risk assessment published by the U.S. Nuclear Regulatory Commission in 1983 and an updated version, Radiological Risk Assessment and Environmental Analysis (2008).

In 1995, Dr. Till received the E.O. Lawrence Award from the U.S. Department of Energy in the field of Environmental Science and Technology. In addition to his scientific work, Dr. Till also owns and operates his family farm, growing corn and soybeans near Neeses, South Carolina.

john e. till
Yoder C


Yoder C

has directed Landauer's technical activities relating to radiation dosimetry, particularly for applications in radiation protection, since joining Landauer in 1983. Additionally, he oversees subsidiary and partner businesses located in Australia, Brazil, China, France, Mexico, Japan, Sweden and Turkey.

An internationally known expert in radiation monitoring, Dr. Yoder led Landauer's transition from film and thermoluminescent dosimetry technology to optically stimulated luminescence, an assignment that required strategic planning and direction in areas spanning scientific research, product development, manufacturing, laboratory operations and marketing. From 1993 to 2001, he was Vice President of Operations and managed Landauer's manufacturing and analytical laboratory activities in addition to overseeing research and development programs.

Dr. Yoder is a member of NCRP and former President of the Council on Ionizing Radiation Measurements and Standards. He has served on several national and international committees to develop dosimetry standards. He was a member of a National Research Council committee that examined the accuracy of film badge measurements made during atmospheric nuclear weapons testing. He currently heads the Advisory Committee for the School of Health Sciences at Purdue University.

Dr. Yoder earned his MS and PhD degrees in Bionucleonics at Purdue University and received a BS in Pre-Medicine from Davidson College. He also completed the Executive Program at Stanford University. He is Certified in Comprehensive Health Physics by the American Board of Health Physics.

r. craig yoder
Zeitlin C


Zeitlin C

is a Principal Science in the Space Science Division of Southwest Research Institute (SwRI), headquartered in San Antonio, Texas. Dr. Zeitlin has been at SwRI since 2008, working on the Radiation Assessment Detector (RAD) aboard the Curiosity Mars rover and a newer version of RAD for the International Space Station. Dr. Zeitlin received his BS from the University of California Berkeley in 1981 and his PhD in experimental high-energy particle physics from University of California Davis in 1988. His PhD research and postdoctoral work were done at the Stanford Linear Accelerator Center (SLAC), where he studied two-photon interactions and decays of the Z boson.

Dr. Zeitlin moved from SLAC to the Lawrence Berkeley National Laboratory in 1991 to join an experimental nuclear physics group working for the National Aeronautics and Space Administration (NASA) to make ground-based measurements relevant to the transport of cosmic radiation through shielding materials and tissue. This began an association with NASA's programs in space radiation physics and biology that continues to the present. Dr. Zeitlin's current research interests are in the analysis of flight data returned from RAD and other space-borne detectors, as well as the development of improved compact spectrometers and dosimeters for spaceflight.

cary zeitlin
balterStephen Balter, Consultant
Brock T

Terry A. Brock

Brock Tis a senior health physicist with the U.S. Nuclear Regulatory Commission (NRC), where he has worked for 11 y. He is the current NRC program manager for the Radiation Exposure Information and Reporting System, the Analysis of Cancer Risks in Populations near Nuclear Facilities study, and the lead for the agency's participation in the One Million U.S. Radiation Workers and Veterans Heath Study. He is a current management board member and past Vice Chair of the Organisation for Economic Co-operation and Development / Nuclear Energy Agency 's Information System on Occupational Exposure. He's the agency liaison with NCRP and the International Commission on Radiological Protection and serves as the NRC representative on the Executive Committee of the Joint Coordinating Committee for Radiation Effects Research (Russian Health Studies). He has served as the project manager for the State-of-the-Art Reactor Consequence Analyses study and on the Risk Task Group that explored risk-informing the radioactive materials arena. Before NRC, he worked in health physics at a commercial nuclear power facility and at two universities. In addition to health physics, Dr. Brock has worked on environmental health and risk communication issues related to pesticides and hazardous substance clean-up sites. Dr. Brock holds a PhD in public health and MS in radiation heath physics and environmental health from Oregon State University. He holds a BS in health physics and industrial hygiene from Purdue University.

Terry A. Brock, Consultant
Leggett R

Richard Leggett

Leggett Ris a research scientist in the Environmental Sciences Division at Oak Ridge National Laboratory (ORNL). He received his PhD in mathematics from the University of Kentucky in 1972 and taught mathematics at the Ruhr University in Bochum, Germany, and the University of Tennessee before joining the Health Physics Division at ORNL in 1976. His main research interest is in physiological systems modeling, with primary applications to the biokinetics and dosimetry of radionuclides and radiation risk analysis. He is a member of Committee 2 of the International Commission on Radiological Protection (ICRP) and the ICRP Task Group on Internal Dosimetry. His physiological systems models of the human circulation, skeleton, and gastrointestinal transfer and his systemic biokinetic models for a number of elements are used by ICRP as dosimetry and bioassay models. He is the author of ICRP Publication 70, Basic Anatomical and Physiological Data for Use in Radiological Protection: The Skeleton and co-author of a number of other ICRP reports including the series of documents on doses to members of the public from intake of radionuclides (1989 to 1996), the updated Reference Man document (2002), and the Human Alimentary Tract Model (2006). He has authored over 100 open literature publications and in 1995 was named ORNL Author of the Year for the paper, “An Age-Specific Kinetic Model of Pb Metabolism in Humans.”

Richard Leggett, Consultant



is a consultant, currently concentrating on the preparation of scientific reports produced by NCRP in all subject areas. From 1982 to 1995, he was Director, Office of Health Physics at the Center for Devices and Radiological Health, U.S. Food and Drug Administration. He also served in a number of scientific and management positions related to radiation protection during his 33 y career as a Commissioned Officer in the U.S. Public Health Service, from 1962 to 1995. He received a BS in Chemical Engineering (University of Maryland, 1961), an MS in Environmental Engineering (Rensselaer Polytechnic Institute, 1966) and a PhD in Nuclear Engineering (University of Maryland, 1971). His technical work has concentrated on radiation dosimetry, particularly with regard to x rays used for medical diagnosis, epidemiological studies of exposed populations, and public radiation emergencies.

He is a Distinguished Emeritus Member of NCRP (after serving as a Council member for 18 y), and an Emeritus member of Committee 3 (Protection in Medicine) of the International Commission on Radiological Protection [after serving on Committee 3 for 28 y (1985 to 2013)]. He was also a member of the International Commission on Radiation Units and Measurements report committee that produced Report 74, Patient Dosimetry for X Rays Used in Medical Imaging.

marvin rosenstein, Staff Consultant
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Last modified: May 18, 2017