Comparison of Diagnostic Performances of 68Ga-DOTATATE PET-CT and 18F-FDOPA PET-CT in Paragangliomas and Pheochromocytomas Evaluation

Comparison of Diagnostic Performances of 68Ga-DOTATATE PET-CT and 18F-FDOPA PET-CT in Paragangliomas and Pheochromocytomas Evaluation: Monocentric Prospective Study

18F-FDOPA PET-CT is currently the gold standard in the evaluation of Pheochromocytomas and Paragangliomas (PHEO - PGL) since these tumors can also decarboxylate amino acids such as dihydroxyphenylalanine (DOPA). This property is common to tumors of the APUD system (Amine Precursor Uptake and Decarboxylation). In recent years, PET (Positron Emission Tomography) imaging using peptide receptors has gained an increasing role in the management of NETs. The use of somatostatin agonists, radiolabeled with gallium-68 (68Ga) enables targeting of Somatostatin receptors (SSTRs) with a PET resolution. This has improved diagnosis of SSTRs-expressing tumors, including PGLs.

In the present study, the investigators have chosen DOTATATE (Nal3-octreotate) rather than other agonists (DOTATOC and DOTANOC), because of its higher affinity for SST2 which is the most overexpressed subtype in PHEO/PGL. However, performances of 18F-FDOPA PET-CT and 68Ga-DOTATATE PET-CT have never been compared in this clinical setting.

Inclusion Criteria:

Age ≥ 18

• PHEO or PGL: initial staging or restaging
• Reference imaging within the last 2 months: multiphasic cervico-thoracoabdominal CT scan, 18F-FDOPA PET-CT and head and neck MRI (if head and neck localization

Exclusion Criteria:

Pregnant or breast-feeding woman