LOS ANGELES -- Six out of ten patients underreport recent vaccinations before undergoing F-18 FDG-PET imaging, according to research shared May 30 at the Society of Nuclear Medicine and Molecular Imaging (SNMMI) meeting.
The finding casts doubt on the reliability of current verbal screening protocols, said presenter Lauren Cosgrove of the Mayo Clinic in Rochester, MN.
"The significant underreporting of vaccinations which we identified indicates that current verbal screening leads to miscommunication and risk of false positive reports of cancer," she said. "If the verbal screening step could be eliminated, technologists could streamline the screening process."
Lauren Cosgrove of the Mayo Clinic in Rochester, MNAuntMinnie
Vaccinations can prompt FDG uptake in lymph nodes that make interpretation of F-18 FDG-PET scans tricky, Cosgrove explained, noting that this makes accurate reporting of vaccination history critical.
"Increased nodal FDG uptake has been observed after influenza and COVID‑19 vaccinations, mimicking metastatic disease and prompting unnecessary follow‑up imaging or biopsy," she said. "At Mayo Clinic, technologists verbally screen all patients for vaccinations received within the prior two months, relying on patient recall. Understanding the extent of misreporting is important for determining whether alternative or additional verification methods are needed."
Cosgrove and colleagues investigated how often patients inaccurately report vaccinations prior to receiving FDG-PET imaging via a study that included 150 randomly selected individuals who had a documented vaccination for influenza and/or COVID-19 within two months prior to an FDG-PET scan. They cross-checked electronic health records against verbal patient screening responses collected by technologists on the day of imaging between July and December 2025; the study's primary endpoint was the rate of false negative patient self-report -- that is, patients whose documented vaccination history was not elicited from the pre-scan verbal interview.
The group found that 60% of patients reported their vaccination history incorrectly. Among those who did so, 72.2% stated they had not received any vaccination in the preceding two months, despite electronic health record evidence to the contrary. The remaining 27.8% of patients reported a vaccination but described a non-intramuscular injection, which may not trigger the same clinical concern as intramuscular shot, the researchers explained.
Current practice at Mayo Clinic, as at many institutions, relies on technologist-administered verbal screening to identify recent vaccinations. This study indicates that technologist-administered verbal screening -- while well-intentioned -- may result in a substantial false negative rate, which suggests that "eliminating the verbal screening step in favor of direct electronic health record review could streamline the workflow and reduce the risk of missed vaccination history," Cosgrave said.
Her team acknowledged, however, that record-based vaccine reporting may also have limitations, which "leaves open the question of whether record-based screening alone would be fully sufficient and points to a direction for future inquiry."
Check out AuntMinnie’s full coverage of SNMMI 2026 on our ShowCast.
