Early and late FAPI-46 PET acquisition yield near equivalent biodistribution and cancer staging

Ziel/Aim Positron-Emission-Tomography (PET) using small-ligands of the fibroblast activation protein (FAP) was recently introduced. However, the optimal uptake time was not defined yet. Here, we systematically compare early (~ 10 min p.i.) and late (~ 60 min p.i.) FAPI-46 imaging in patients with various cancers.

Methodik/Methods This is a retrospective single-institutional study. Imaging was performed at the Essen University Hospital, Germany. Sixty-nine patients who underwent dual time-point imaging for either re-staging (n = 52, 75 %) or staging (n = 17, 25 %) of cancer were included. Patients underwent two acquisitions; early (mean 11 min, SD 4) and late (mean 66 min, SD 9). Mean Injected activity was 148 MBq (SD 33).

Ergebnisse/Results In total, 400 lesions were detected in 69 patients. Two of 400 (0.5 %) lesions were only seen in early time-point imaging but not in late time-point imaging. On a per-patient level, there was no significant difference between SUV_max of hottest tumor lesions (P = 0.73). Organ uptake demonstrated significant early-to-late decrease in SUV_mean (P < 0.001, respectively). On a per-lesion basis, a slight increase of SUV_max was observed (Median increase of SUV_max: 0.4, P= 0.03).

Schlussfolgerungen/Conclusions In conclusion, early (~ 10 min p.i.) and late (~ 60 min p.i.) FAPI-46 imaging yield near equivalent biodistribution and lesion detection. For improved feasibility and scan volume we implement early FAPI-46 PET in future clinical and research protocols.

Publication History

Article published online:
08 April 2021