Diagnostic Accuracy of Gallium-68-DOTATATE PET/CT Compared to Indium-111-pentetreotide Scintigraphy (SPECT/CT) for Gastroenteropancreatic Neuroendocrine Tumors

The investigators hypothesize that the new imaging method Gallium-68-DOTATATE has a higher diagnostic value in the detection of neuroendocrine tumors than the established imaging method Indium-111-Octreoscan. Therefore, the investigators will perform both imaging procedures in patients with suspected or confirmed neuroendocrine tumors. Subsequently, the investigators will compare the diagnostic performance of both methods.