1943 — 2026
by Richard J. Vetter, PhD, CHP
Longtime Health Physics Society member Joel E. Gray, PhD, passed away peacefully on 23 April 2026 in Milwaukee, Wisconsin.
Joel was born and raised in Carlisle, Pennsylvania, and served in the United States Air Force from 1963 to 1967. He earned his bachelor of science in optical sciences in photographic sciences and engineering, summa cum laude, from the Rochester Institute of Technology in 1970. He continued his education with a master of science in optical sciences from the University of Arizona in 1974 and a PhD in radiological sciences from the University of Toronto in 1977. During his graduate studies, Joel was awarded a contract from the US Food and Drug Administration (FDA) to develop foundational texts on quality assurance in medical imaging. These publications, along with his later book, Quality Control in Diagnostic Imaging (1983), contributed to quality control standards in the field of medical imaging.
Joel joined the Department of Radiology at Mayo Clinic in Rochester, Minnesota, in 1977 as the first medical physicist in the department. His primary areas of interest were image quality in medical and dental imaging and optimization of image quality and radiation dose. During his career, he made lasting contributions of medical physics, including the reduction in radiation exposure to patients. He also founded a clinical medical physics residency program at Mayo Clinic and helped develop and obtain FDA approval for Lorad’s (later Hologic) first digital mammography system. Later, while working at Landauer, Inc., he helped develop the microStarii patient dosimetry system using optically stimulated dosimetry material. After leaving Landauer, Joel founded DIQUAD, LLC in 2006, a firm that evaluates dental image quality and dose. He served as president until 2025. While serving as president, he developed patented technology to monitor radiation doses and image quality of dental x-ray units through a mail-based system.
Joel published two books on quality control in medical imaging under contract with the FDA. He was also the primary author of Quality Control in Diagnostic Imaging: A Quality Control Cookbook, which is in use worldwide and translated into Chinese. He also wrote over 170 refereed publications and numerous book chapters and he presented lectures and refresher courses worldwide.
Joel participated in several international organizations and served on numerous national and international advisory committees, including the International Commission on Radiological Protection Committee 3, Radiation Protection in Medicine, various projects of the International Atomic Energy Agency (IAEA), and the World Health Organization. He coauthored eight publications for the IAEA and participated in educational programs for the IAEA in several countries.
Joel was elected to the Council of the National Council on Radiation Protection and Measurements (NCRP) in 1986 and served on numerous committees, producing NCRP Report No. 9, Quality Assurance for Diagnostic Imaging; NCRP Report No. 147, Structural Shielding Design for Medical Imaging Facilities; and NCRP Report No. 160, Ionizing Radiation Exposure of the Population of the United States. He also served as a technical consultant for several NCRP commentaries and reports. He was named Distinguished Emeritus Member of NCRP in 2005.
Joel will be remembered for his intellect and for his dedication to medical physics and improving patient safety, including reduction of patient dose. Throughout his life, Joel loved to travel. He visited more than 56 countries, embracing both business and leisure opportunities. He travelled as often as he c
ould and developed long-lasting friendships worldwide.
Joel also enjoyed all aspects of food and wine—cooking, entertaining, dining out, and trying new selections. He loved sharing a good glass of wine with his friends and spending time with his son, Adam, his daughter, Kiersten, and his five grandchildren.