RT Journal Article
SR Electronic
T1 Three-Time-Point PET Analysis of <sup>68</sup>Ga-FAPI-46 in a Variety of Cancers
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 618
OP 622
DO 10.2967/jnumed.122.264941
VO 64
IS 4
A1 Naeimi, Mahnoosh
A1 Choyke, Peter L.
A1 Dendl, Katharina
A1 Mori, Yuriko
A1 Staudinger, Fabian
A1 Watabe, Tadashi
A1 Koerber, Stefan A.
A1 Röhrich, Manuel
A1 Debus, Jürgen
A1 Kratochwil, Clemens
A1 Haberkorn, Uwe
A1 Giesel, Frederik L.
YR 2023
UL http://jnm.snmjournals.org/content/64/4/618.abstract
AB A growing family of 68Ga-fibroblast activation protein inhibitor (FAPI) PET probes has shown promise in imaging a variety of medical conditions. 68Ga-FAPI-46, in particular, has emerged as unique for both its diagnostic and its theranostic applications; however, the optimal timing of PET remains unclear. Therefore, we evaluated uptake at 3 time points after 68Ga-FAPI-46 administration in a spectrum of tumor types. Methods: The cohort consisted of 43 patients with diverse cancer diagnoses undergoing 68Ga-FAPI-46 PET/CT at 3 time points (10 min, 1 h, and 3 h). We determined the tracer uptake based on SUVmean and SUVmax and on tumor-to-background-ratios (TBRs) (SUVmax/SUVmean). Results: There were 171 lesions in the 43 patients. Comparing all lesions at different time points, the mean SUVmax was maximal at 10 min (8.2) and declined slightly at 1 h (8.15) and 3 h (7.6) after tracer administration. Similarly, the mean SUVmax log still had a similar pattern in primary lesions at 10 min, 1 h, and 3 h (n = 30; 0.98, 1.01, and 0.98, respectively), lymph node metastases (n = 37; 0.82, 0.84, and 0.81, respectively), and distant metastases (n = 104; 0.81, 0.79, and 0.74, respectively). TBR also showed nonsignificant differences at the 3 times. Conclusion: 68Ga-FAPI-46 PET/CT imaging revealed remarkably stable tumor and background uptake as determined by SUV metrics and maintained high TBRs within 3 h of injection. Thus, it may be possible to scan with 68Ga-FAPI-46 within 10–20 min of injection, improving workflow and decreasing patient wait times. Confirmation of these findings in a larger cohort is under way.