Meet the "Ask the Experts" Editors

by Emily Caffrey, Ask the Experts Editor

Do you have a question about radiation safety? Both health physicists and members of the public have questions and are finding help on the Health Physics Society (HPS) website "Ask the Experts" (ATE) feature. Since the inception of the feature a number of years ago, over 13,000 questions have been submitted. Many of these questions and answers have been posted under a number of categories on the site. Questions, whether posted or not, either are answered personally by an appropriate expert or a formal answer is not given because the question is not in the field of radiation safety. In the latter case, a recommendation is made to the questioner as to where the information might be obtained.

An average of 10 to 12 questions come in per week. How many people does it take to manage this workload? Currently we have a team of about 20 editors and more than 300 experts who participate in the ATE feature. When a question is submitted, the person is asked to select a category. The question then goes to the topic editor responsible for that particular category. The topic editor or one of their experts provides an answer as a personal response directly to the questioner.

The topic editors also consider each question to determine if it might be of interest to the public. If so, they review it for technical and scientific accuracy and then forward it to me. I review it again for scientific accuracy, consistency, editorial appropriateness, and grammar. It is then posted on the ATE part of the HPS site, where it can be searched.

We have found that many media personnel use the information we have posted under our ATE section of the HPS website. For more specific information, media personnel can contact HPS Web Operations Editor in Chief Kelly Classic.

Bios and photos of the ATE editors follow.

Editor, "Ask the Experts"

Emily Caffrey graduated in 2016 with her PhD in radiation health physics from Oregon State University. She is now a scientific consultant with Risk Assessment Corporation, specializing in performance assessments and independent environmental dose and risk assessments. She helped in the development of a new health physics program at the University of Alabama at Birmingham in 2016 and is actively involved in the Alabama Chapter of the HPS, serving as its president from 2017 to 2019. Emily holds a BS in nuclear engineering from Oregon State University and during her academic tenure was selected as an ARCS Scholar and an Endeavor Fellow for Australia's Nuclear Science and Technology Organization. She is also active in the National Council on Radiation Protection and Measurements (NCRP), where she served on SC1-25 examining recent literature on the linear no-threshold model. Her technical expertise includes ionizing radiation dosimetry, statistics, and communications.


Kamran Vaziri received his PhD in nuclear physics from Utah State University in 1987, doing his doctoral thesis work at Los Alamos National Laboratory. He then worked on nuclear physics experiments at the University of Colorado Nuclear Physics Laboratory and later joined Rensselaer Polytechnic Institute, working on experiments at Brookhaven National Laboratory, Jefferson Lab, and Massachusetts Institute of Technology Bates Linear Accelerator Center. Kamran joined Fermilab's Radiation Physics group in 1992. He has been working on radiation physics problems and reviews of different accelerators and experiments. As a radiation physicist, his responsibilities include radiation physics modeling and calculation in support of experiments and accelerator designs, site radiation measurements and instrumentation, environmental measurements, regulatory issues, and serving as Fermilab radiation safety interlocks coordinator and national emission standards for hazardous air pollutants (NESHAP) coordinator. He is the radiation safety coordinator for the NOvA experiment at Fermilab. Kamran has coauthored more than 100 scientific and technical papers regarding radiation physics and nuclear physics. He is an occasional book and article reviewer for Health Physics. He has taught a radiation physics course at the US Particle Accelerator School and has taught radiation monitoring and environmental monitoring courses at the HPS professional development school. He is the past president of the HPS Accelerator Section.

Cell Phones, Micro/Radio Waves, Radar, and Powerlines

Kenneth R. Foster received a PhD degree in physics from Indiana University, Bloomington, in 1971. After serving with the US Navy from 1971 to 1976, he joined the University of Pennsylvania, where he is currently professor emeritus of bioengineering. His technical research has focused on health and safety as related to radiofrequency energy, with approximately 160 papers related to interactions of electromagnetic fields with biological systems ranging from biophysical mechanisms of interaction to heating of tissue by microwave energy. In addition, he has written and spoken extensively on a broad range of topics including medical technology and health, risks of technology, and ethical issues related to biomedical technology. As well as being emeritus member of the HPS, he is coeditor in chief of BioMedical Engineering OnLine. He is a registered professional engineer, a fellow of the Institute of Electrical and Electronics Engineers, and a fellow of the American Institute of Medical and Biological Engineering. In 2016, he received the d'Arsonval Award from the Bioelectromagnetics Society for contributions to the field of bioelectromagnetics. He has been active for many years in committees that set limits for human exposure to electromagnetic fields and other issues related to health and safety.

Computers and Consumer Products

Orhan SuleimanOrhan Suleiman is involved in a variety of Food and Drug Administration (FDA) initiatives involving human research with radiolabeled drugs, imaging in drug development, and drug safety issues. His current tenure in FDA's drug center complements his earlier experience in the Center for Devices and Radiological Health, where he was responsible for the Nationwide Evaluation of X-Ray Trends (NEXT) survey program and was actively involved in the Mammography Quality Standards Act of 1992. He served as the executive secretary of FDA's Technical Electronic Products Radiation Safety Standards Committee and was responsible for consumer products such as sunlamps, cellular telephones, personnel security systems, and medical products such as fluoroscopy and computed tomography (CT). He served as the NCRP subcommittee chair (Consumer Products) for the 2009 report on radiation exposure to the US population and also represents the FDA on the Nuclear Regulatory Commission's (NRC) advisory committee on the medical use of isotopes. Orhan received his BS (1970) and MS (1972) from the University of Florida and his PhD (1989) from the Johns Hopkins School of Hygiene and Public Health. He is a fellow of the American Association of Physicists in Medicine (AAPM). He has served on a variety of national and international organizations and numerous committees and has published and lectured extensively. 

Decommissioning and Radioactive Waste Disposal

Nick Altic is a certified health physicist and project manager with the Oak Ridge Associated Universities (ORAU). His primary responsibilities include management and the technical direction of independent verification activities at radiologically remediated sites for the US Department of Energy, US Nuclear Regulatory Commission, and other federal entities. In addition to his experience at ORAU, Nick also served as the instrumentation program manager for a commercial power reactor. Areas of expertise include instrumentation, nondestructive assay techniques, and implementation of MARSSIM-based radiological surveys. He holds graduate and undergraduate degrees in health physics from Idaho State University and Purdue University, respectively.

Environmental and Background Radiation

Jan Johnson is a certified health physicist with over 50 years of experience in radiation health physics including radiation worker training, environmental and occupational radiation protection, and radiation risk assessment. She was a member of the faculty at Colorado State University (CSU), initially as a research associate, eventually managing the CSU Environmental Health Services Department. Since leaving CSU in 1995, she has worked as a consultant in radiation protection, primarily involving the uranium-recovery industry. She was a member of the Environmental Protection Agency Science Advisory Board Radiation Advisory Committee from 1995 to 2003 and served on the Colorado Radiation Advisory Committee until 2013. She is a fellow of the HPS and received the Society's Founders Award in 2013.

Health Physics Society and AAHP

Howard Dickson received an undergraduate degree in education and a master's degree in physics. He began his career teaching health physics at ORAU and went on to a diverse 40-year health and safety career with leadership positions at Oak Ridge National Laboratory (ORNL), at the Nevada Test Site, and with Bechtel National at Three Mile Island, EG&G, in support of homeland security, and at Johnson Controls at Livermore National Laboratory. He is an HPS fellow, past president, past treasurer, and past director and a recipient of the HPS Elda E. Anderson Award. He served as HPS Web Operations editor in chief. He has also served as treasurer and past president of the American Academy of Health Physics (AAHP) and has received the Joyce Davis Award from AAHP. In addition to being a certified health physicist, Howard is a certified industrial hygienist and a certified safety professional.


Ray Johnson directed the Radiation Safety Academy from 1985 to 2007 until merging with Dade Moeller & Associates, where he now serves as vice president for training. From 1970 to 1985, he served as a commissioned officer in the US Public Health Service on a permanent assignment to the US EPA, where he served as chief of the Radiation Surveillance Branch. From 1988 to 2006, he managed a contract for radiation safety services at the National Institutes of Health. He has been a member of the HPS since 1966 and served on the Executive Committee for nine years as secretary, treasurer, and president. He has also served local chapters for over 40 years—in particular the Baltimore-Washington Chapter, where he edited its newsletter for 25 years, served as president in 1990, and is now an honorary life member. He has chaired and served on many HPS committees, including as chair of the History Committee since 2004. He is currently treasurer of the AAHP. He is a fellow of the HPS and certified by the ABHP since 1983. He has graduate degrees from Massachusetts Institute of Technology and Harvard and spent six years on doctoral studies at Rensselaer Polytechnic Institute. He has over 30 professional-society awards and has authored over 500 book chapters, articles, professional papers, training manuals, technical reports, and presentations on radiation safety and radiation risk communication. 

Homeland Security/Security Screening

Tom O'Connell has an extensive background in radiation safety and chemical, biological, radiological, nuclear, and high-yield explosives (CBRNE) response. He is a fellow of the HPS and is an expert instructor for the International Atomic Energy Agency. He maintains Pro Board accreditation as a National Fire Protection Association Fire Service Instructor II through the Massachusetts Fire Training Council and holds an MS degree in radiological sciences and protection from the University of Massachusetts Lowell. He recently retired from the Massachusetts Department of Public Health after 37-plus years in public service. The last 12 years he served as the department liaison to the Massachusetts Department of Fire Services Hazardous Materials Response Division.

During his service to the Commonwealth, he was an on-scene responder to various hazardous materials incidents. In his liaison role, he coordinated connecting public safety and public health response with the health care infrastructure.

Tom teaches radiation safety and emergency response to all types of responders around the world. For more than 30 years he has worked with and provided practical aspects of response and interdiction training to fire departments, emergency medical services, law enforcement organizations, the Federal Bureau of Investigation, emergency management officials, hazardous materials teams, and regulatory and foreign government representatives.

Industrial Radiation and Radiation Effects

John Hageman is a certified health physicist, radiation safety officer, and principal scientist at Southwest Research Institute® (SwRI®). He has a BS in physics from the University of Texas (UT) at Arlington and an MS in radiological sciences-medical health physics from the UT Health Science Center at San Antonio. At SwRI he is responsible for the use of a large variety of radionuclides under a broad radioactive material license issued for research and development. He is also responsible for the safe operation of a large variety of radiation-producing machines used for laboratory analysis and the High-Level Radiation Effects Facility, which is licensed for sealed sources of 60Co and 137Cs. He holds a patent on a charged-particle powered battery and has consulted in the design analyses for hot cells and accelerator shielding. He was a manager with the Center for Nuclear Waste Regulatory Analyses at SwRI for several projects for the NRC's high-level radioactive waste program. He also worked with Westinghouse Electric Corporation as a nuclear plant engineer, where he supervised plant operations and the training of Naval officers at the Idaho Naval Reactors Facilities. For the HPS, he is an associate editor of Operational Radiation Safety (1999–present), was a member of the Board of Directors (2003–2005), became a fellow in 2004, and served as treasurer-elect/treasurer (2009–2012).

Instrumentation and Radiation Basics

George Chabot is currently professor emeritus at the University of Massachusetts Lowell, where he previously served as professor of radiological sciences in the Physics Department and, for many years, as radiation safety officer for the university. He serves as a consultant in radiation science and radiation protection to public utilities, industry, medical facilities, government agencies, and others. His earlier work experience includes employment as an analytical organic chemist in private industry and six years of work as a radiochemist and in the training group of the Radiological Health Branch of the US Public Health Service (now the FDA). He has been active in the HPS, the AAHP, the NCRP, and other scientific organizations. His formal education includes a BA degree in chemistry from Harvard University, an MS in industrial hygiene/radiological health from the Harvard School of Public Health, and a PhD in analytical chemistry from the University of Lowell. He is the author of numerous publications that include refereed journal articles, book chapters, reports, and manuals dealing with various aspects of radiation science and protection, especially in areas of radiation dosimetry and radiation measurement.

Lasers, Infrared, and Ultraviolet

Paul Charp is a governmental health physicist with over 30 years of experience in the fields of environmental health physics, radiation biology, and radiation safety. He has evaluated the public health impacts from hazardous waste sites contaminated with radioactive materials, including sites related to the Manhattan Project as well as uranium mining and milling. Besides working in the public health sector, he is also a part-time instructor in the radiological and nuclear engineering and medical physics programs at Georgia Tech. While in the former Biology Division at the Oak Ridge National Laboratory, Paul studied the effects of ultraviolet light on the damage and repair of human cells at the molecular and biochemical levels. A member of the HPS since 1989, he has served on many committees and is a member of the Homeland Security, Medical Physics, and Environmental/Radon Society Sections.

Medical and Dental Equipment/Shielding

Kenneth Duke LovinsKennith "Duke" Lovins is a medical health physicist and is certified by the ABHP. He has an MS degree in health physics from the University of Cincinnati and a BHS degree in radiological health science from the University of Kentucky. He has been employed by Unicon Physics, Inc., in Cincinnati, Ohio, since 1995 and provides consulting services to hospitals and clinics. His responsibilities include performing nuclear medicine department audits, developing quality-assurance programs for diagnostic radiology departments, performing quality-control testing on x-ray equipment, and providing training and membership on a number of radiation safety committees. Previously, he was a health physicist at the VA Medical Center in Lexington, Kentucky. He is a member of the HPS, the AAPM, the Conference of Radiation Control Program Directors, and the Cincinnati Radiation Society. He was a member of the joint HPS/AAPM working group to develop an ANSI standard for fetal radiation dose calculations.

Medical and Dental Patient Issues

Deirdre Elder is a certified health physicist with an undergraduate degree in engineering physics from Colorado School of Mines and a master's degree in radiological health sciences (health physics) from Colorado State University. She is the radiation safety manager and laser safety officer for University of Colorado Hospital, Longs Peak Hospital, Highlands Ranch Hospital, and other facilities in the UCHealth system. Her responsibilities include providing radiation safety and laser safety training to residents, fellows, and staff. Deirdre is an active member of the HPS and has served on several committees. She was the president of the Central Rocky Mountain Chapter and secretary/treasurer of the Medical Section. She is also a certified medical laser safety officer and a member of the Laser Institute of America.

Medical and Dental Patient Issues

Victoria (Vicki) Morris is a retired medical radiation safety officer. Currently, she is a consultant. A major portion of her consulting assignments involves auditing nuclear medicine and radiation oncology programs. Vicki has a bachelor of science in environmental health and a master of science in health sciences, both from Purdue University. Vicki is certified by the ABHP and is currently a member of the ABHP Board. She is a fellow of the HPS and has served on several Society committees, including serving one term as a board member and one term as president for the Medical Health Physics Section. Vicki is active with local chapters of the HPS. She served 22 years on the board of the Cincinnati Radiation Society, including one term as president and three terms as secretary. In addition, Vicki served on the state of Ohio Radiation Advisory Board and several Ohio radiation regulation development committees.

Nuclear Power, Devices, and Accidents

Joel Cehn is a native of Waterbury, Connecticut. He received his bachelor of science degree in physics from Worcester Polytechnic Institute in Massachusetts and a master of science degree in engineering from North Carolina State University. As an independent, board-certified health physicist, Joel measures radiation levels around nuclear power plants, research laboratories, and hospitals and at many varied locations in the United States and abroad. His work involves measurements of radioactivity in soil and groundwater, as well as measuring and estimating radiation doses to workers and the public. He has written and spoken extensively on exposure to radiation and its effects and has conducted numerous training sessions. He has served as an expert witness in several cases involving radiation and, in his spare time, creates educational kits for teaching about radiation. Joel lives in Central California and is past president of the local HPS chapter.

Nuclear Medicine Patient Issues

Xiaoqian (Carol) Wen is a certified health physicist and radiation safety officer at Christiana Care Health System in Newark, Delaware, where she oversees the radiation safety operations and activities for multiple hospitals and outpatient imaging sites. Carol started her career working as a radiation safety specialist at the University of Cincinnati (UC) after receiving her master's degree in health physics from UC. Later she worked as a health physicist and medical health physicist at the University of Maryland, Baltimore, and the University of Pennsylvania, respectively. Carol is passionate about protecting patients, caregivers, the general public, and the environment from unnecessary radiation exposure and is engaged with discussions and problem solving for all levels of radiation protection issues throughout Christiana Care Health System. Currently, Carol is a member of the HPS, the AAPM, the Delaware Valley Society for Radiation Safety, and the Delaware Valley Chapter of AAPM.

Policy, Guidelines, Standards, Regulations

Margaret Cervera came to health physics accidentally after a winding career path that included work in the service industry and veterinary medicine, as well as stints as a research microbiologist, pharmaceutical chemist, and cell biologist. Her formal education includes a BS in microbiology and chemistry with a certificate in biotechnology from Colorado State University. She went on to complete her master's degree in health physics at Colorado State University, serving along the way as president of the student chapter of the HPS. Upon graduation in 2009, Margaret quit her job as a forklift driver loading beer at the Anheuser-Busch brewery and reported for duty as a staff health physicist at the NRC. Her professional specialty is physical security of byproduct materials, but occasionally she has branched out into nuclear reactor regulation.

Pregnancy and Radiation

Barbara L. Hamrick received a BS and MS in physics from the University of California (UC) Irvine in 1985 and 1987, respectively. She earned a law degree in 1999 from Loyola Law School in Los Angeles and is an active member of the California State Bar. In 2002, she was certified by the ABHP. She is currently the radiation safety officer at UC, Irvine Health, where she manages the Radiation Safety Program, keeping the environment safe for patients, workers, and the public. Prior to joining the UC Irvine Health team, she spent nearly 20 years as a health physicist in regulatory agencies, including the US Nuclear Regulatory Commission, Los Angeles County Radiation Management, and the California Department of Public Health. Professional activities include serving on the US Environmental Protection Agency's Radiation Advisory Committee, service on three committees of the National Academy of Sciences, and serving as a council member on the NCRP. She is also a past president of the HPS.

Radiation Safety Careers

Richard BreyRichard Brey is a full professor and director of the Health Physics Program at Idaho State University (ISU). Additionally, he serves as the director of the Environmental Assessment Laboratory at ISU. He holds an AAS degree in nuclear power technology from Terra Technical College. He also holds BS, MS, and PhD degrees in health physics from Purdue University. While at Purdue University, Richard was an Environmental Restoration and Waste Management fellow, an HPS Fellowship recipient, and an Institute of Nuclear Power Operations graduate fellow. Prior to this, he worked in applied health physics at the Donald C. Cook Nuclear Power Station in Bridgman, Michigan. He is a member of the HPS, the American Nuclear Society, and the American Conference of Governmental Industrial Hygienists. He has served as secretary and also as a president of the Eastern Idaho Chapter of the HPS. He is certified by the ABHP.


Fred BaesFred Baes received a BS in biology at the University of Tennessee in 1972 and an MS in biology at Emory University in 1977. He then began a career at ORNL, where initially he developed computer codes, models, and data bases for assessing doses from radionuclides and risks from hazardous chemicals through terrestrial food-chain pathways. Later he became involved in air-pollution studies and explored the use of chemical analysis of tree rings as biomonitors for trace metal pollution and the effects of air pollution and acid deposition on forests. He later became a regulatory analyst and training instructor for the DOE, developing workshops on environmental laws and regulations and serving as editor of two newsletters on environmental laws and regulations. This latter work eventually evolved into an Internet-based effort, and Fred is now the webmaster for the DOE Office of Environmental Policy and Guidance website. In 1999 Fred became the webmaster for the HPS.

Technical Editor

Craig Little has 40 years of experience in radioecology and radiation protection. He did his graduate research in the grasslands surrounding the Rocky Flats Plant. During his career, Craig has worked on radiological issues for the DOE, the NRC, the EPA, the US Department of Defense, and the National Institute for Occupational Safety and Health. He established the Oak Ridge National Laboratory office in Grand Junction, Colorado, in support of the DOE Uranium Mill Tailings Remedial Action project and led that office for 18 years. He is currently president and senior scientist for Two Lines Inc. Radiation Risk Consultants. He is focused on occupational and environmental dose modeling, licensing of new uranium-production facilities, training of radiation workers, technical editing, and litigation support for a variety of private clients. He is a member of the Radiation Advisory Committee for the Colorado Department of Public Health and Environment. He currently serves as editor in chief of Operational Radiation Safety and is an associate editor of Health Physics. He also serves as federal agency liaison for the HPS.

Editorial Associate

Sharon Hebl     
Sharon Hebl