RT Journal Article
SR Electronic
T1 FAPI-74 PET/CT Using Either <sup>18</sup>F-AlF or Cold-Kit <sup>68</sup>Ga Labeling: Biodistribution, Radiation Dosimetry, and Tumor Delineation in Lung Cancer Patients
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 201
OP 207
DO 10.2967/jnumed.120.245084
VO 62
IS 2
A1 Giesel, Frederik L.
A1 Adeberg, Sebastian
A1 Syed, Mustafa
A1 Lindner, Thomas
A1 Jiménez-Franco, Luis David
A1 Mavriopoulou, Eleni
A1 Staudinger, Fabian
A1 Tonndorf-Martini, Eric
A1 Regnery, Sebastian
A1 Rieken, Stefan
A1 El Shafie, Rami
A1 Röhrich, Manuel
A1 Flechsig, Paul
A1 Kluge, Andreas
A1 Altmann, Annette
A1 Debus, Jürgen
A1 Haberkorn, Uwe
A1 Kratochwil, Clemens
YR 2021
UL http://jnm.snmjournals.org/content/62/2/201.abstract
AB 68Ga-fibroblast activation protein inhibitors (FAPIs) 2, 4, and 46 have already been proposed as promising PET tracers. However, the short half-life of 68Ga (68 min) creates problems with manufacture and delivery. 18F (half-life, 110 min) labeling would result in a more practical large-scale production, and a cold-kit formulation would improve the spontaneous availability. The NOTA chelator ligand FAPI-74 can be labeled with both 18F-AlF and 68Ga. Here, we describe the in vivo evaluation of 18F-FAPI-74 and a proof of mechanism for 68Ga-FAPI-74 labeled at ambient temperature. Methods: In 10 patients with lung cancer, PET scans were acquired at 10 min, 1 h, and 3 h after administration of 259 ± 26 MBq of 18F-FAPI-74. Physiologic biodistribution and tumor uptake were semiquantitatively evaluated on the basis of SUV at each time point. Absorbed doses were evaluated using OLINDA/EXM, version 1.1, and QDOSE dosimetry software with the dose calculator IDAC-Dose, version 2.1. Identical methods were used to evaluate one examination after injection of 263 MBq of 68Ga-FAPI-74. Results: The highest contrast was achieved in primary tumors, lymph nodes, and distant metastases at 1 h after injection, with an SUVmax of more than 10. The effective dose per a 100-MBq administered activity of 18F-FAPI-74 was 1.4 ± 0.2 mSv, and for 68Ga-FAPI-74 it was 1.6 mSv. Thus, the radiation burden of a diagnostic 18F-FAPI-74 PET scan is even lower than that of PET scans with 18F-FDG and other 18F tracers; 68Ga-FAPI-74 is comparable to other 68Ga ligands. FAPI PET/CT supported target volume definition for guiding radiotherapy. Conclusion: The high contrast and low radiation burden of FAPI-74 PET/CT favor multiple clinical applications. Centralized large-scale production of 18F-FAPI-74 or decentralized cold-kit labeling of 68Ga-FAPI-74 allows flexible routine use.