68Ga-FAPI PET/CT: Tracer Uptake in 28 Different Kinds of Cancer

J Nucl Med. 2019 Jun;60(6):801-805. doi: 10.2967/jnumed.119.227967. Epub 2019 Apr 6.


The recent development of quinoline-based PET tracers that act as fibroblast-activation-protein inhibitors (FAPIs) demonstrated promising preclinical and clinical results. FAP is overexpressed by cancer-associated fibroblasts of several tumor entities. Here, we quantify the tumor uptake on 68Ga-FAPI PET/CT of various primary and metastatic tumors to identify the most promising indications for future application. Methods:68Ga-FAPI PET/CT scans were requested by various referring physicians according to individual clinical indications that were considered insufficiently covered by 18F-FDG PET/CT or other imaging modalities. All PET/CT was performed 1 h after injection of 122-312 MBq of 68Ga-FAPI-04. We retrospectively identified 80 patients with histopathologically proven primary tumors or metastases or radiologically unequivocal metastatic lesions of histologically proven primary tumors. Tumor uptake was quantified by SUVmax and SUVmean (60% isocontour). Results: Eighty patients with 28 different tumor entities (54 primary tumors and 229 metastases) were evaluated. The highest average SUVmax (>12) was found in sarcoma, esophageal, breast, cholangiocarcinoma, and lung cancer. The lowest 68Ga-FAPI uptake (average SUVmax < 6) was observed in pheochromocytoma, renal cell, differentiated thyroid, adenoid cystic, and gastric cancer. The average SUVmax of hepatocellular, colorectal, head-neck, ovarian, pancreatic, and prostate cancer was intermediate (SUV 6-12). SUV varied across and within all tumor entities. Because of low background in muscle and blood pool (SUVmax < 2), the tumor-to-background contrast ratios were more than 3-fold in the intermediate and more than 6-fold in the high-intensity uptake group. Conclusion: Several highly prevalent cancers presented with remarkably high uptake and image contrast on 68Ga-FAPI PET/CT. The high and rather selective tumor uptake may open up new applications for noninvasive tumor characterization, staging examinations, or radioligand therapy.

Keywords: FAPI; PET/CT; breast cancer; colorectal cancer; lung cancer.

MeSH terms

  • Biological Transport
  • Endopeptidases
  • Gallium Radioisotopes*
  • Gelatinases / antagonists & inhibitors*
  • Humans
  • Membrane Proteins / antagonists & inhibitors*
  • Neoplasm Metastasis
  • Neoplasms / diagnostic imaging*
  • Neoplasms / metabolism*
  • Positron Emission Tomography Computed Tomography*
  • Radioactive Tracers
  • Serine Endopeptidases


  • Gallium Radioisotopes
  • Membrane Proteins
  • Radioactive Tracers
  • Gallium-68
  • Endopeptidases
  • Serine Endopeptidases
  • fibroblast activation protein alpha
  • Gelatinases