PT  - JOURNAL ARTICLE
AU  - Frederik L. Giesel
AU  - Sebastian Adeberg
AU  - Mustafa Syed
AU  - Thomas Lindner
AU  - Luis David Jiménez-Franco
AU  - Eleni Mavriopoulou
AU  - Fabian Staudinger
AU  - Eric Tonndorf-Martini
AU  - Sebastian Regnery
AU  - Stefan Rieken
AU  - Rami El Shafie
AU  - Manuel Röhrich
AU  - Paul Flechsig
AU  - Andreas Kluge
AU  - Annette Altmann
AU  - Jürgen Debus
AU  - Uwe Haberkorn
AU  - Clemens Kratochwil
TI  - 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
AID  - 10.2967/jnumed.120.245084
DP  - 2021 Feb 01
TA  - Journal of Nuclear Medicine
PG  - 201--207
VI  - 62
IP  - 2
4099  - http://jnm.snmjournals.org/content/62/2/201.short
4100  - http://jnm.snmjournals.org/content/62/2/201.full
SO  - J Nucl Med2021 Feb 01; 62
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.