Five-Year Persistent 18 F-FAPI-74 Uptake in Radiation-induced Hepatic Fibrosis Following Proton Beam Therapy for Hepatocellular Carcinoma.
Yuki Narita, Shinya Komori, Shinobu Adaniya et al.
✦ AI-curated · Sources linked
Case in brief
A 79-year-old man treated with proton beam therapy for hepatocellular carcinoma had stable T2-weighted hyperintensity in the irradiated liver region on follow-up MRI, without enlargement or mass formation. Five years after treatment, a new hepatocellular carcinoma arose elsewhere in the liver. FDG PET showed no apparent uptake in the irradiated region, but 18F-FAPI-74 PET showed persistent uptake there. The imaging findings were considered consistent with chronic radiation-induced fibroinflammatory change.
What made this case unusual
FAPI-74 uptake persisted in the irradiated region five years after proton beam therapy despite no apparent FDG uptake and no MRI evidence of an enlarging mass.
Diagnostic / clinical pearl
Persistent FAPI uptake in an irradiated liver region may reflect chronic fibroinflammatory change; interpret it alongside MRI morphology and FDG findings rather than assuming it represents recurrent tumor.
Why it matters
This case suggests FAPI PET can depict radiation-related tissue changes years after proton beam therapy.