Background: Gallium-68-labeled somatostatin receptor positron emission tomography/computed tomography (PET/CT) is widely used for neuroendocrine tumour (NET) imaging, but implementation can be constrained by generator-dependent production and logistics. Fluorine-18 (18F) tracers may facilitate centralised production and broader access. We evaluated the diagnostic performance of [18F]AlF-NOTA-Octreotide (18F-OC) PET/CT for NET detection using histopathology as the reference standard.
Methods: In this cross-sectional diagnostic accuracy study, patients with suspected NET who underwent 18F-OC PET/CT and had histopathological confirmation were included. PET/CT positivity was defined a priori as standardised uptake value ≥8.3. We estimated sensitivity, specificity, predictive values, accuracy, likelihood ratios and 95% confidence intervals.
Results: Fifty-five patients were included (mean age 53.6 ± 15.1 years; 58.2% female). NET was confirmed in 39/55 (70.9%). PET/CT showed 92.3% sensitivity (36/39; 95% CI: 79.7–97.3) and 87.5% specificity (14/16; 95% CI: 64.0–96.5), with 94.7% positive predictive value, 82.4% negative predictive value and 90.9% accuracy. The positive likelihood ratio was 7.38, and the negative likelihood ratio was 0.09. False-negative cases were associated with small lesion size and/or biologically aggressive disease; false-positive cases showed mild uptake and were inflammatory on histopathology.
Conclusion: 18F-OC PET/CT demonstrated high diagnostic performance for NET detection in a histopathology-referenced cohort. Given the logistical advantages of 18F production and distribution, this tracer may support broader access to somatostatin receptor PET imaging in settings where 68Ga-based tracers are constrained.
