Dosimetry and uncertainty approaches for the million person study of low-dose radiation health effects: overview of the recommendations in NCRP Report No. 178

Abstract

Purpose

Scientific Committee 6–9 was established by the National Council on Radiation Protection and Measurements (NCRP), charged to provide guidance in the derivation of organ doses and their uncertainty, and produced a report, NCRP Report No. 178, Deriving Organ Doses and their Uncertainty for Epidemiologic Studies with a focus on the Million Person Study of Low-Dose Radiation Health Effects (MPS). This review summarizes the conclusions and recommendations of NCRP Report No. 178, with a concentration on and overview of the dosimetry and uncertainty approaches for the cohorts in the MPS, along with guidelines regarding the essential approaches used to estimate organ doses and their uncertainties (from external and internal sources) within the framework of an epidemiologic study.

Conclusions

The success of the MPS is tied to the validity of the dose reconstruction approaches to provide realistic estimates of organ-specific radiation absorbed doses that are as accurate and precise as possible and to properly evaluate 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 that are considered: atomic veterans, U.S. Department of Energy workers exposed to both penetrating radiation and intakes of radionuclides, nuclear power plant workers, medical radiation workers, and industrial radiographers. 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.

Keywords:

• NCRP
• dosimetry
• epidemiology
• radiation

Disclosure statement

The authors declare no personal conflicts of interest. The views expressed in this paper represent collective opinions of the authors and are not necessarily those of their professional affiliations.

Notes

1 The MPS has had a number of name changes over the years. The most recent is the Million Person Study of Low-Dose Radiation Health Effects (MPS). Both Million Worker Study (MWS) and MPS refer to the same program of studies.

2 Atomic veterans are military personnel who participated in the nuclear weapons testing program.

Additional information

Funding

This work was supported in part by grants from the U.S. Department of Energy [grant numbers: DE-AU0000042 and DE-SC0008944] awarded to the National Council on Radiation Protection and Measurements, which included interagency support from the U.S. Nuclear Regulatory Commission, the U.S. Environmental Protection Agency, and the National Aeronautics and Space Administration; a grant from the U.S. Nuclear Regulatory Commission [grant number: NRC-HQ‐60‐14‐G‐0011], grants from the Centers for Disease Control and Prevention [grant numbers: 5UE1EH000989 and 5NUE1EH001315], and grants from the National Aeronautics and Space Administration [grant numbers: NNX15AU88G and 80NSSC17M0016]. We acknowledge the support provided by the U.S. Department of Defense/Defense Threat Reduction Agency and the U.S. Department of Veterans Affairs. We acknowledge the leadership by the Chair of SC 6-9 Andre Bouville, the major support of the NCRP Secretariat, including, Managing Editor Cindy L. O’Brien, Office Manager Laura J. Atwell, and Executive Directors James Cassata (2012–2014), David Smith (2014–2016), and Kathy Held (2016–2018). We express our gratitude to the Council members for the time and effort devoted to the review of NCRP Report No. 178.

Notes on contributors

Lawrence T. Dauer

Lawrence T. Dauer, PhD, is Associate 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 Board member of the NCRP and served as a member of the ICRP Committee 3, Protection in Medicine.

André Bouville

André Bouville, PhD, is a leading expert on radiation dose reconstruction and led the Dosimetry Unit of the Radiation Epidemiology Branch at NCI until he retired at the end of 2010. He chaired NCRP SC 6-9 on the dosimetry for the Million Person Study, producing NCRP Report No. 178.

Richard E. Toohey

Richard E. Toohey, PhD is a physicist with over 45 years of experience in health physics, especially internal radiation dosimetry, dose reconstruction, and radiological emergency response. He recently retired from Oak Ridge Associated Universities, where he served as director of the Radiation Internal Dose Information Center and held other leadership roles.

John D. Boice

John D. Boice, Jr., ScD is a radioepidemiologist with over 40 years of experience. He is the President of the National Council on Radiation Protection and Measurements and a Professor of Medicine at Vanderbilt University. Dr. Boice is the creator and leader of the Million Person Study in the United States.

Harold L. Beck

Harold L. Beck, BS is a leading expert on radiation dose reconstruction with more than 50 years of experience in radiation dosimetry, radiation metrology, and dose reconstruction uncertainty. He served for over 36 years in various scientific and management positions in the Department of Energy Environmental Measurements Laboratory.

Keith F. Eckerman

Keith F. Eckerman, PhD is a leading expert in computational and phantom dosimetry, served on ICRP Committee 2, and is an Emeritus Member of the ICRP. He has received several scientific achievement awards, including the 39th Lauriston Taylor Lecturer for the NCRP. He is currently a retired staff member of the Environmental Sciences Division of the ORNL.

Derek Hagemeyer

Derek Hagemeyer, BS is the Associate Director for Human Health and Environment at ORAU. He serves as the principal investigator for the DOE Radiation Exposure Monitoring System and the US NRC Radiation Exposure Information and Reporting System projects. He is Vice Chairman of the international Information System on Occupational Exposure Working Group on Data Analysis.

Richard W. Leggett

Richard W. Leggett, PhD is a research scientist in the Environmental Sciences Division at Oak Ridge National Laboratory (ORNL). His main research is in physiological systems modeling, with primary applications to the biokinetics and dosimetry of radionuclides and radiation risk analysis. He is a member of ICRP Committee 2 and the Task Group on Internal Dosimetry.

Michael T. Mumma

Michael T. Mumma is the Director of Information Technology at the International Epidemiology Institute and the International Epidemiology Field Station for Vanderbilt University Medical Center. He has over 20 years of experience in data analysis and conducting epidemiologic investigations.

Bruce Napier

Bruce Napier, M.S. is a Staff Scientist in the Environmental Analysis and Engineering Group at PNNL. He is an expert in the areas of radiation dose reconstruction, computer modeling, environmental analysis, and human health risk analysis. Mr. Napier is a Scientific Vice President and past member of the Board of Directors of NCRP.

Kathy H. Pryor

Kathy H. Pryor, M.S. is currently on the NCRP Board of Directors and is Scientific Vice President of Program Area Committee 2. Ms. Pryor was Chief Health Physicist PNNL with previously experience in nuclear power and universities. Ms. Pryor served as President of the HPS, Chair of the ABHP, and is President of the AAHP.

Marvin Rosenstein

Marvin Rosenstein, Ph.D. is an NCRP consultant. He was Director, Office of Health Physics at the Center for Devices and Radiological Health, US FDA and previously served 33 y as a Commissioned Officer in the US PHS. He is a Distinguished Emeritus Member of NCRP and an Emeritus Member of ICRP Committee 3, Protection in Medicine.

David A. Schauer

David A. Schauer, Sc.D. is the Executive Secretary of the ICRU. He served as an officer in the U.S. Navy and on the faculty of the Radiology and Radiological Sciences Department at the Uniformed Services University of the Health Sciences. He previously served as NCRP Executive Director and is Executive Director Emeritus.

Sami Sherbini

Sami Sherbini, Ph.D. is a senior level advisor for health physics at the US NRC, where he has held progressively more technical positions in providing expertise to support rulemaking in radiation protection, nuclear medicine, and other radioactive materials regulation. Prior to the NRC, he worked in the commercial nuclear industry, including Three Mile Island.

Daniel O. Stram

Daniel O. Stram, is Professor in the Department of Preventive Medicine at the Keck School of Medicine of the University of Southern California. He served as a postdoctoral fellow in the Biostatistics Department of the Harvard School of Public Health and was a research associate at the RERF in Hiroshima, Japan.

James L. Thompson

James L. Thompson, B.S. initially served as a nuclear propulsion plant operator in the U.S. Navy, then became a health physicist working as a radioactive materials inspector for the Texas Department of Health, Bureau of Radiation Control, and currently is a Senior Health Physicist with the US NRC.

John E. Till

John E. Till, Ph.D. 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 in 1995 and delivered the L.S. Taylor lecture in 2013. He also served in the U.S. Navy Nuclear Submarine Program, retiring as a Rear Admiral in 1999.

R. Craig Yoder

R. Craig Yoder, Ph.D. directed Landauer’s technical activities relating to radiation dosimetry, particularly for applications in radiation protection for over 30 years. An internationally known expert in radiation monitoring, he led the development of optically stimulated luminescence. He is a member of NCRP and former President of the Council on Ionizing Radiation Measurements and Standards.

Cary Zeitlin

Cary Zeitlin, Ph.D. is a Research Scientist at Leidos Innovations Corporation, working in the Space Radiation Analysis Group at the NASA Johnson Space Center, with their programs in space radiation physics and biology. He performs operations and data analysis for the Radiation Assessment Detectors aboard the Curiosity Mars rover and the International Space Station.