[18F]AlF-NOTA-octreotide PET imaging of the somatostatin receptor in neuroendocrine tumors: comparison with [68Ga]Ga-DOTATATE and evaluation of routine clinical use.

Gallium-68 labelled somatostatin analogue ([68Ga]Ga-DOTA-SSA) PET/CT is currently the golden standard for somatostatin receptor imaging in neuroendocrine tumors (NETs). However, its widespread implementation in clinical practice is limited by practical and economic issues related to 68Ge/68Ga-generators. Fluorine-18 offers several advantages to tackle these issues. Recent developments in radiopharmacy have allowed to replace a gallium-68 atom by fluorine-18, leading to promising clinical translations of fluorine-18-labelled somatostatin analogues (SSAs), such as [18F]AlF-NOTA-octreotide ([18F]AlF-OC). Our goal is to validate the use of [18F]AlF-OC as an alternative for [68Ga]Ga-DOTA-SSA in clinical PET imaging of NETs. First, we will perform an inter-observer agreement analysis on images from 75 patients with a NET scanned with both [18F]AlF-OC PET/CT and [68Ga]-DOTA-SSA PET/CT and evaluate clinical impact of using [18F]AlF-OC PET/CT. Second, we will appraise the use of [18F]AlF-OC PET/CT in a retrospective study with 150 patients scanned in routine clinical practice by evaluating lesion detection and disease extent, by performing a semi-quantitative analysis of tracer uptake and by comparing the performance with other available diagnostic modalities. We aim to provide solid evidence for the widespread use of [18F]AlF-OC PET/CT in PET centers with limited access to [68Ga]Ga-DOTA-SSA.