Is it rational to treat pneumonia with exogenous surfactant?

1042 Objectives: The theranostic twins [68Ga]Pentixafor and [177Lu]Pentixather for chemokine-directed endoradiotherapy (ERT) were recently developed. We aimed to evaluate feasibility of non-invasive CXCR4 PET/CT imaging using [68Ga]Pentixafor in comparison to 68Ga-DOTA-D-Phe-Tyr3-octreotide ([68Ga]DOTATOC) and 18F-fluorodeoxyglucose ([18F]FDG) in gastroenteropancreatic neuroendocrine tumors (GEP-NET). Methods: 12 patients with histologically proven GEP-NET underwent [68Ga]DOTATOC, [18F]FDG and [68Ga]Pentixafor PET/CT. Scans were analyzed on a patient as well as on a lesion basis. Results: On a patient basis, all G1 NET (n=3) were [68Ga]DOTATOC-positive and [68Ga]Pentixafor-negative; [18F]FDG-PET yielded positive results in 2/3 patients. [68Ga]DOTATOC was the superior tracer in all cases. All G2 NET (n=4) were both SSTR- and [18F]FDG-positive, whereas CXCR4-positivity could only be observed in half of the cases (2/4). [68Ga]Pentixafor did not yield additional information in any G1 or G2 NET. Investigating G3 NET, 5/5 subjects were rated [18F]FDG positive. CXCR4- and SSTR-PET identified lesions in 4/5 patients each. Of note, the majority of the [68Ga]Pentixafor-positive subjects presented with Ki67 of 蠅85%, whereas well-differentiated tumors did not demonstrate relevant CXCR4 receptor expression. Conclusion: Increasing chemokine receptor expression could be non-invasively observed in NET with increasing tumor dedifferentiation. CXCR4-directed ERT can be envisioned for selected patients demonstrating increasing malignancy or [68Ga]DOTATOC negative findings. Research Support: n/a