Dynamic PET/CT scan of 68Ga-FAPI-04 for the optimal acquisition time in suspected malignant hepatic cancer patients.

Abstract

Dynamic PET/CT scan of 68Ga-FAPI-04 in patients with suspected malignant hepatic lesions were retrospectively analyzed to find the optimal acquisition time with better lesion detection rate. Twenty-two patients with lesions confirmed by CT or MRI were performed with dynamic 68Ga-FAPI-04 PET/CT scan. Tracer uptake of lesions and normal organs at different time points were analyzed. Standardized uptake value (SUV) and tumor-to-background (TBR) were calculated based on the quantification of images. SUV of normal organs decreased rapidly from 10 to 30min and decreased gradually from 30 to 60min. Besides, the uterus showed a particularly high uptake in all patients (12.62 ± 4.58 at 10min p.i., 12.04 ± 3.99 at 30min p.i., 10.92 ± 2.38 at 60min p.i.). SUV of lesions decreased gradually, while TBR increased from 10- to 60-min post-injection. Visual analysis verified a comparable lesion detectability of 30min and 60min with images of 10min showing a decreased lesion detection number. This study revealed that similar detection rates were achieved at both 30 and 60min, suggesting a static scan at 30min to be appropriate in the clinic. Besides, although with high lesion uptake, early 68Ga-FAPI-04 PET imaging at 10min after tracer injection could cause missed lesion detection.