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Current Scientific Advisory Committee

SAC History
SAC Meetings
All SAC Members, past and present

Thomas L. Rucker – Scientific Member

SAC Rucker

RUCKER, Thomas L., Ph.D.  

Scientific Member, Chair

10/1/2015 – 3/31/2025

Dr. Rucker has more than 40 years of experience in analytical chemistry; radiochemistry; radiological detection and measurement; dose assessment; environmental and waste management; and nuclear material disposition, control, accountability, and non-proliferation. His experience in radiochemistry and radiation detection and measurement includes laboratory management; laboratory automation; research and development; quality assurance/quality control (QA/QC) program management; information management, and statistical analysis. He has extensive experience in alpha and gamma spectroscopy, liquid scintillation counting, and nuclear nondestructive and field analysis techniques. Dr. Rucker also has extensive experience in radioanalytical data evaluation and validation. Dr. Rucker’s dose assessment experience includes the interpretation and implementation of radiation protection regulations in technical basis documents for internal dosimetry, establishment of internal dosimetry bioassay programs; and evaluation of nuclear accident dosimetry programs.

Janet M. Benson – Scientific Member

BENSON, Janet M., Ph.D.

Scientific Member

4/1/2020 – 3/31/2023

Dr. Benson’s areas of research include examining the efficacy, pharmacokinetics/toxicokinetics and safety of potential new therapeutics, including small molecules, natural products, and gene therapies. Dr. Benson also has had extensive experience in the design and conduct of inhalation studies, including toxicokinetic and mechanistic evaluations of metals, solvents, natural products, and select agents. Her laboratory has developed animal models of ocular, dermal, and pulmonary injury in which to examine the efficacy of new therapeutics. As Principal Investigator of the NHLBI Gene Therapy Resources Program, she assisted NHLBI investigators in designing IND-enabling safety and efficacy studies that are implemented at Lovelace. She has over 30 years experience in the conduct of studies under Good Laboratory Practice Guidelines for Government and Industry Sponsors.

Luiz Bertelli – Scientific Member


Scientific Member
(Health Physics)

4/1/2018 – 3/31/2024

Luiz Bertelli has been an internal dosimetriest at Argonne National Laboratory since 2003, and he previously worked at Argonne National Laboratory. He has worked in internal dosimetry modeling and interpretation of monitoring of radiation workers for 40 years, including 18 years in Brazil where he was responsible for calculating all internal doses and evaluating initial efficacy of Prussian Blue for all age groups due to the Goiania radioactive accident. Dr. Bertelli has been a member of the International Commisssion on Radiologial Protection (ICRP) Task Group on Dose Calculations since 1995, and was a member of ICRP Committee 2 from 2013-2017. He has been a member of the National Council on Radiation Protection and Measurements (NCRP) since 2019, and has served on NCRP’s Program Area Committee 6 on Radiation Measurements and Dosimetry since 2013. He is also a faculty member with the Radiation Emergency Assistance Center / Training Site (REAC/TS) and an active collaborator with the Latin American branch of the International Atomic Energy Agency. Dr. Bertelli received his PhD in biophysics from the Federal University of Rio de Janeiro, Brazil in 1990, and was a post-doctoral fellow at the University of Utah’s Environmental Radiation Toxicology Laboratory from 1991-1995.

Heather J. Hoffman – Scientific Member

HOFFMAN, Heather J., Ph.D.

Scientific Member
(Epidemiology, Biostatistics)

10/1/2016 – 3/31/2023

After earning my PhD in Biostatistics from Virginia Commonwealth University in 2005, I began my career as an Assistant Professor of Epidemiology and Biostatistics at The George Washington University. Since then, I have expanded my research interests across a vast array of application fields, including HIV/AIDS prevention, care, and treatment; breast and lung cancer; diabetes; cardiovascular disease; and environmental and occupational health. I have developed a solid foundation of statistical theory applicable to a wide range of disciplines and strong skills for successfully communicating statistical concepts to researchers and students. Currently, I serve as a biostatistician for the Elizabeth Glaser Pediatric AIDS Foundation contributing to and developing study designs and data analysis plans, analyzing data, and interpreting study results. I am also an active member in the GWU Biostatistics and Epidemiology Consulting Service, which has enhanced my knowledge of the multifaceted issues related to HIV/AIDS behavioral and prevention studies. Incorporating my research experiences into my classroom has enhanced my graduate-level courses, including Biostatistical Applications for Public Health, Use of SAS for Data Management and Data Analysis, Advanced Data Analysis, Advanced SAS, Applied Survival Data Analysis for Public Health, and Quantitative Methods.

Timothy J. Ledbetter – Ethics Representative

SAC Ledbetter

LEDBETTER, Timothy J., D.Min., B.C.C.

Ethics Representative

10/1/2013 – 3/31/2023

I am honored to be invited to offer support from the perspective of ethical considerations to the good work of the USTUR Advisory Committee. This appointment follows the conclusion of a most enjoyable term serving on the Central Department of Energy Institutional Review Board (CDOEIRB) as a non-scientific community member. In addition, I have been privileged to assist the Battelle-PNNL IRB in a similar capacity over the past 16 years. I have found congruency of concerns and discernment processes between research ethics and clinical ethics. In my capacity as member and co-chair of biomedical and hospice ethics committees, I have come to appreciate the vital and critical importance of clear and consistent ethical deliberation practices. Toward this end, I have extensively utilized what I believe is the seminal work on clinical ethics, Clinical Ethics 7th ed., by AR Jonsen, M Siegler & WJ Winslade (2010, McGraw-Hill). (Albert R. Jonsen is a godfather of the modern ethics movement and co-author of the Belmont Report which established primary ethical principles.) Several years ago, the PNNL IRB manager at that time and I developed and utilized a human subjects protection discernment protocol based on this text. Finally, in my vocation as hospital and hospice chaplain, I have learned the importance of finding ways to help survivors and future generations benefit from knowledge gained from the past and present. My desire is to appreciate and further the mission and values of the USTUR and assist wherever I can to its unique contributions to the health of our communities and world.

Arthur W. “Bill” Stange – Scientific Member

STANGE, Arthur W. “Bill”, Ph.D.

Scientific Member
(Occupational Health)

10/1/2016 – 3/31/2023

Dr. Arthur W. “Bill” Stange has over 30 years’ experience in epidemiology, environmental health, and occupational health exposure assessments. Throughout his career, he has been involved in numerous industrial hygiene monitoring and medical surveillance programs, and has created computer procedures for monitoring and characterizing employee illnesses, injuries, and absenteeism. Dr. Stange has advised Fortune 100 corporate medical and management directors concerning the implications of hazardous occupational exposures, designed procedures for tracking and characterizing employee illness and developed management training programs concerning employee productivity. Dr. Stange is presently the Manager of Health Studies for Oak Ridge Associated Universities, and is responsible for health studies data collection, epidemiologic analyses, and the publication of findings for the National Supplemental Screening Program (NSSP), a U.S. Department of Energy (DOE) Former Worker Medical Screening Program. He has provided epidemiological oversight and analysis of medical surveillance findings for the DOE Rocky Flats Plant Beryllium Medical Surveillance Program and the Oak Ridge Associated Universities Nationwide Beryllium Medical Surveillance Program. Dr. Stange is an active member of the Beryllium Health and Safety Committee (BHSC) that promotes activities and efforts to help individuals better understand and prevent beryllium-induced conditions and illnesses, including beryllium sensitization and chronic beryllium disease. On the BHSC he serves as the co-chair of the Medical and Epidemiology Subcommittee, which focuses on understanding the health effects associated with beryllium. He attained his PhD in Epidemiology from Colorado State University, completed a Master of Science in Cellular Biology from the University of Nebraska-Lincoln, and received his Bachelor of Science in Biology from Nebraska Wesleyan University.