Head to head comparison of [¹⁸F]SiTATE versus [¹⁸F]DOPA-PET in patients with neuroendocrine tumors

In neuroendocrine tumors molecular imaging methods play a key role, either targeting the somatostatin receptor or catecholamine pathways. [¹⁸F]SiTATE is a somatostatin receptor-targeting peptide that uses silicon fluoride acceptor (SiFA) radiochemistry, overcoming disadvantages of Gallium-68 labelled DOTA compounds. Here we present the first prospective data of [¹⁸F]SiTATE compared to [¹⁸F]DOPA-PET in NET patients.

38 patients with suspected neuroendocrine tumors were prospectively included. All patients underwent both [¹⁸F]DOPA-PET and [¹⁸F]SiTATE-PET. The diagnostic performances were compared on a per-patient and per-lesion basis.

22 of 38 patients did not show [¹⁸F]DOPA- or [¹⁸F]SiTATE-PET positive disease. [¹⁸F]DOPA-PET was rated as the more accurate imaging modality in three cases and [¹⁸F]SiTATE-PET in four cases. [¹⁸F]SiTATE-PET showed a significantly higher sensitivity on a per lesion basis compared to [¹⁸F]DOPA-PET (n = 143; sensitivity [¹⁸F]SiTATE: 86.7%; [¹⁸F]DOPA: 73.4%; p = 0.016). Relative quantitative uptake values were not significantly different ([¹⁸F]SiTATE median Tumor to Background Ratio max (TBR_max): 8.2; [¹⁸F]DOPA TBR_max: 6.5; p = 0.247).

In this first prospective study, [¹⁸F]SiTATE-PET provided high tumor to background ratios in the majority of NET patients with complementary results to [¹⁸F]DOPA-PET.