Novel<sup>68</sup>Ga-FAPI PET/CT Offers Oncologic Staging Without COVID-19 Vaccine–Related Pitfalls
Tristan T. Demmert, Ines Maríc, Kelsey L. Pomykala, Katharina Lueckerath, Jens T. Siveke, Benedikt M. Schaarschmidt, Rainer Hamacher, Ken Herrmann, Wolfgang P. Fendler
Abstract
In the setting of ongoing SARS-CoV-2 vaccination, vaccine-related tracer uptake in locoregional lymph nodes has become a well-known issue in tumor staging by <sup>18</sup>F-FDG PET/CT. <sup>68</sup>Ga-FAPI PET/CT is a new oncologic imaging tool that may overcome this limitation. <b>Methods:</b> We assessed post-vaccine, head-to-head and same-day <sup>18</sup>F-FDG and <sup>68</sup>Ga-FAPI-46 PET/CT findings in a series of 11 patients from a large prospective imaging registry. All patients with documented tracer uptake in locoregional lymph nodes on PET/CT or PET/MRI, following vaccination within 6 weeks, were eligible for investigation. <b>Result:</b> Significant visual lymph node uptake adjacent to the injection site was noted in 11/11 (100%) patients with <sup>18</sup>F-FDG PET/CT versus 0/11 (0%) with <sup>68</sup>Ga-FAPI PET/CT. <sup>18</sup>F-FDG detected 73% and <sup>68</sup>Ga-FAPI PET/CT 94% of all tumor lesions. <b>Conclusion:</b> In this case-series study, <sup>68</sup>Ga-FAPI showed its potential to avoid <sup>18</sup>F-FDG-PET/CT post-vaccination pitfalls and presented superior tumor localization.