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John D. Boice, Jr.


John D. Boice Jr is past President of the National Council on Radiation Protection and Measurements and Professor of Medicine at Vanderbilt University. He is an international authority on radiation effects and served on the Main Commission of the International Commission on Radiological Protection and on the United Nations Scientific Committee on the Effects of Atomic Radiation. He directs the Million Person Study of Low- Dose Health Effects.

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Lawrence T. Dauer

Lawrence T. Dauer is an Attending Physicist specializing in radiation protection at Memorial Sloan Kettering Cancer Center in the Departments of Medical Physics and Radiology. He is a Council and former Board member of the NCRP, served as a member of the ICRP Committee 3, Protection in Medicine, and serves NCRP as the Scientific Director for the Million Person Study.


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Isaf Al-Nabulsi

Isaf Al-Nabulsi currently serves as Acting Director at the Office of Domestic and International Health Studies within the Office of Health and Safety, Office of Environment, Health, Safety and Security at the U.S. Department of Energy (DOE). Dr. Al-Nabulsi is responsible for managing and coordinating day-to-day activities associated with domestic and international health studies, including the Million Person Study.

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Armin Ansari

Armin Ansari is the Radiological Assessment Team Lead at the Centers for Disease Control and Prevention (CDC) serving as subject matter expert in CDC’s radiation emergency preparedness and response activities since 2002. He is a fellow and past president of the Health Physics Society and an adjunct associate professor of nuclear and radiological engineering at Georgia Institute of Technology. He serves on the National Council on Radiation Protection and Measurements (NCRP), provides consultancy to the International Atomic Energy Agency (IAEA) and serves as member of the United States delegation to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).

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Paul Blake


Paul Blake is a civilian health physicist with the Defense Threat Reduction Agency (DTRA), Fort Belvoir, VA, USA. DTRA safeguards America and its allies from weapons of mass destruction by providing capabilities to reduce, eliminate, and counter the threat, and mitigate its effects. He co-leads the Nuclear Test Personnel Review Program, which confirms participation and reconstructs radiation doses for U.S. atomic veterans.

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Steve Blattnig


Steve Blattnig is currently at NASA Langley Research Center and has been working on a wide variety of different aspects of space radiation research for the last 20 years. He is one of the primary developers of the NASA Standard for Models and Simulations, NASA-STD-7009. More recently, his focus has been on the development of probabilistic risk methodology and radiation biology modeling for effects including acute radiation syndrome, cancer, cardiovascular disease, and degenerative central nervous system diseases. He was the project manager for the space radiation transport and measurement project and was the PI of the space radiation risk assessment project.

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Emily A. Caffrey


Emily A. Caffrey is President of Radian Scientific, currently supporting Risk Assessment Corporation in independent environmental dose and risk assessments. Her research includes environmental dose assessment and computational dosimetry methods. Her expertise is in statistical methods and uncertainty analysis, source term reconstruction and development, and nuclear engineering.

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Sarah S. Cohen


Sarah S. Cohen is a Senior Managing Epidemiologist at EpidStrategies, a Division of ToxStrategies, where she directs observational research studies in the areas of pharmacoepidemiology, nutritional epidemiology, and occupational epidemiology as well as leads large data management projects and statistical analyses. She is an Adjunct Assistant Research Professor of Medicine in the Department of Medicine at Vanderbilt University School of Medicine. She has been a collaborator on the Million Person Study of Low-Dose Health Effects for nearly twenty years, providing analytic support as well as co-authoring numerous publications.

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Ashley P. Golden


Ashley P. Golden is a senior biostatistician and Director of ORISE Health Studies at Oak Ridge Associated Universities where she conducts multidisciplinary projects in occupational epidemiology, radiation exposure and dosimetry, medical surveillance, and environmental assessments. She has been a collaborator on the Million Person Study of Low-Dose Health Effects for eight years.

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Kathryn D. Held

Kathryn D. Held is President of the National Council on Radiation Protection and Measurements (NCRP) and an Associate Radiation Biologist and Associate Professor, Department of Radiation Oncology, Massachusetts General Hospital/Harvard Medical School. She has served on review panels for numerous federal agencies including the National Institutes of Health, the National Aeronautics and Space Administration, and the U.S. Army Medical Research and Material Command programs and other organizations such as the Radiological Society of North America and Brookhaven National Laboratory and is on the Editorial Boards of several journals. She is a past President of the Radiation Research Society and a member of the Board of the Radiation Research Foundation.

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Derek W. Jokisch


Derek W. Jokisch is Professor of Physics and Chair of the Department of Physics and Engineering at Francis Marion University in Florence, South Carolina. He holds a Joint Faculty Appointment at ORNL within the CRPK and is a member of ICRP Committee 2 on Doses from Radiation Exposure and is a member of the U.S. Scientific Review Group for the Department of Energy’s Russian Health Studies program.

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Richard W. Leggett


Dr. Richard W. Leggett is a research scientist in the Environmental Sciences Division at Oak Ridge National Laboratory. His physiological systems models of the human circulation, skeleton, and gastrointestinal transfer and systemic biokinetic models for many elements are used by the International Commission on Radiological Protection as dosimetry and bioassay models.

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Michael T. Mumma


Michael T. Mumma is the Director of Information Technology at the International International Epidemiology Field Station for Vanderbilt University Medical Center. He has over 20 years of experience in data analysis and conducting epidemiologic investigations. He has published on methodological topics, including geocoding and comprehensive radiation exposure assessment, and is currently developing methods to determining socioeconomic status based on residential history.

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Brian Quinn


Brian Quinn is a Medical Health Physicist at Memorial Sloan Kettering Cancer Center in New York. He has over 20 years of radiation protection experience in Medical Health Physics, radiological decommissioning and nuclear power. He has a Master’s degree in Applied Physics from Columbia University in New York, where he studied Medical Physics.

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Caleigh Samuels


Caleigh Samuels is an assistant staff scientist in the Center for Radiation Protection Knowledge at Oak Ridge National Laboratory. She received her BS in physics from Radford University, her MS in medical physics from Georgia Institute of Technology in 2018 and is currently working towards her PhD in nuclear engineering. Her research focuses on developing and enhancing biokinetic models used in radiation protection and dose reconstruction and application of advanced Monte Carlo techniques in dosimetric modeling.

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John E. Till

John E. Till is the founder and President of Risk Assessment Corporation with more than 40 years of experience in environmental dosimetry. He received the E.O Lawrence award from the Department of Energy in 1995 and delivered the L.S. Taylor lecture for the National Council on Radiation Protection and Measurements in 2013. He also served in the U.S. Navy Nuclear Submarine Program, retiring as a Rear Admiral in the US Naval Reserve in 1999.

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Sergei Y. Tolmachev


Sergei Y. Tolmachev is a Research Professor in the College of Pharmacy and Pharmaceutical Sciences, Washington State University, where he directs the United States Transuranium and Uranium Registries and the associated National Human Radiobiology Tissue Repository. He has over 20 years of experience in the development of analytical methods and in actinide analyses of environmental and biological samples. Dr. Tolmachev is currently a Council member of the NCRP and is vice-chair of NCRP Scientific Committee 6-12 ‘Development of Models for Brain Dosimetry for Internally Deposited Radionuclides’.

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R. Craig Yoder

R. Craig Yoder directed the technical activities and programs at Landauer, Inc. from 1983 through his retirement in 2015. In this capacity he influenced the technologies and measurement protocols used by the Company as it delivered dosimetry services around the world. He currently is using his historical knowledge to advise the MPS epidemiologists regarding the methods to translate personal monitoring information into mean absorbed doses to various organs. He is a Council member of the National Council on Radiation Protection.

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Joey Y. Zhou

Joey Y. Zhou is a senior epidemiologist in the Office of Health and Safety under the Office of Environment, Health, Safety and Security. He is the past DOE program manager for the agency’s participation in the Study of One Million U.S. Radiation Workers and Veterans. He also serves as the program manager for the United States Transuranium and Uranium Registries, the Russian Health Studies Program and the Radiation Emergency Assistance Center/Training Site. He has more than twenty years of scientific research and technical program management experience in the U.S. federal government. Prior to DOE, he worked at the Department of Defense, the Environmental Protection Agency, and the Department of Housing and Urban Development.

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