Imaging of C-X-C Motif Chemokine Receptor 4 Expression in 690 Patients with Solid or Hematologic Neoplasms Using 68 Ga-Pentixafor PET

In recent years, molecular imaging addressing the C-X-C motif chemokine receptor 4 (CXCR4) has increasingly been used in various clinical settings. Here, we aimed to assess radiopharmaceutical uptake and image contrast to determine the most relevant clinical applications for CXCR4-directed imaging. We also investigated the impact of specific activity on scan contrast. Patients ( = 690) with a variety of neoplasms underwent a total of 777 PET/CT scans with Ga-Pentixafor, serving as the CXCR4-specific radioligand. A semiquantitative target lesion analysis was conducted (providing SUV and target-to-blood pool ratio [TBR], defined as SUV [from target lesion] divided by SUV [from blood pool]). The applied specific activity (in MBq/μg) was compared with semiquantitative assessments. Of the 777 scans, 242 did not show discernible uptake in disease sites, leaving 535 PET scans (68.9%) for further analysis. Very high tracer uptake (SUV > 12) was found in multiple myeloma ( = 113), followed by adrenocortical carcinoma ( = 30), mantle cell lymphoma ( = 20), adrenocortical adenoma ( = 6), and small cell lung cancer ( = 12). Providing information on image contrast, comparable results for TBR were recorded, with TBR (>8) in multiple myeloma, mantle cell lymphoma, and acute lymphoblastoid leukemia ( = 6). When comparing specific activity with semiquantitative parameters, no significant correlation was found for SUV or TBR ( ≥ 0.612). In this large cohort, Ga-Pentixafor demonstrated high image contrast in a variety of neoplasms, particularly for hematologic malignancies, small cell lung cancer, and adrenocortical neoplasms. The present analysis may provide a roadmap for detecting patients who may benefit from CXCR4-targeted therapies.