New research highlights critical gaps. Most clinical research studies that use imaging techniques such as amyloid positron emission tomography (PET) scans do not take into account the radiation doses that participants have already received from previous medical procedures. As brain imaging techniques become more widely used in medical research, especially following the recent approval of new Alzheimer’s disease treatments by the U.S. Food and Drug Administration, questions have arisen about how much radiation study participants accumulate over their lifetime medical scans. Although radiation exposure from PET imaging is generally considered acceptable when used for direct patient care, the risks are less clear when exposure is performed solely for research purposes, especially when there is no direct benefit to participants. Researchers developed and tested a systematic screening protocol to address this gap and found it made a meaningful difference in keeping participants safe.
Published in Ochsner Journalthe study “Development and Implementation of Radiation Safety Screening Protocols for Clinical Research Using Amyloid Positron Emission Tomography Imaging” reviewed 92 clinical research studies involving amyloid PET imaging listed on ClinicalTrials.gov. The researchers found that only 1% of these studies provided specific radiation exposure thresholds as exclusion criteria, and 37% reported no screening for prior radiation exposure.
To fill this gap, the research team developed a radiation safety screening protocol and implemented it in the Successful Aging After Elective Surgery (SAGES) study, a longitudinal research study of adults aged 70 and older. When the researchers applied this screening procedure to 101 prospective study participants, they found that 17% (almost 1 in 5) had received enough prior radiation to disqualify them for the study’s amyloid PET scan. Older adults have more accumulated radiation from diagnostic imaging over many years, so their total lifetime dose may exceed the safety threshold for additional elective research-related exposures, a factor that researchers have not systematically considered.
Imaging through exposure to ionizing radiation is becoming increasingly popular in both clinical and research applications. When used for research purposes, the risk of additional radiation exposure should be carefully considered, especially for research studies that may not directly benefit participants. To assess the risk of participating in an imaging test, we estimated previous radiation exposure and developed and implemented a safety screening procedure to ensure safe participation in the test. To increase the safety of research participants, we suggest that clinicians and researchers consider implementing similar methods for estimating prior radiation exposure. ”
Tamara G. Fong, MD, lead study author, Hinda Arthur Marcus Institute on Aging Associate Scientist, Hebrew Senior Life
The authors call for a standardized approach to tracking cumulative radiation exposure over a lifetime so that research participants, especially older adults who may have undergone diagnostic tests over a period of years, are not unwittingly put at increased risk when volunteering for research that may not directly benefit them. By developing and sharing screening protocols through the SAGES study, researchers provide a practical and reproducible model that other researchers can adapt to their own research studies.
This research was supported by the National Institute on Aging under project grants P01AG031720 and R33AG071744.
sauce:
Hebrew Senior Life Hinda and Arthur Marcus Institute on Aging
Reference magazines:
Fong, T.G. Others. (2026). Development and implementation of a radiation safety screening protocol for clinical research using amyloid positron emission tomography imaging. Ochsner Journal. DOI: 10.31486/toj.25.0095. https://www.ochsnerjournal.org/content/early/2026/05/27/toj.25.0095
