Diagnosis of Pheochromocytoma

is L 3, 4 dihydroxyphenylalanine (L-DOPA) labeled with the radioactive isotope 18F. In general, PPGLs belong to the group of neuroendocrine tumors. This heterogeneous group of tumors takes up amino acids, transforms them into biogenic amines (dopamine and serotonin) by decarboxylation and stores the amines in vesicles. L DOPA is a precursor of catecholamines (dopamine, norepinephrine and epinephrine). Epinephrine conversion to dopamine is catalyzed by the aromatic amino acid decarboxylase. According to previous and current studies, \[18F\]-DOPA PET is highly sensitive and specific for detection of PHEO/PGL67-69. However, there are only a few reports in the literature using \[18F\]-DOPA as a PET agent and particularly for patients with metastatic PPGLs. PET imaging will be done together with either a CT, an MRI or both modalities.

is an imaging agent developed at the NIH, that may improve specificity and sensitivity in the localization of PPGLs. \[18F\]-6F-DA enters cells via the membrane norepinephrine transporter. Once inside cells, \[18F\]-6F-DA is translocated via the vesicular monoamine transporter into storage vesicles, where the radioactivity is concentrated. After injection of \[18F\]-6F-DA, the much faster disappearance of \[18F\]-6F-DA-derived radioactivity from the bloodstream and non-neuronal cells than from chromaffin cells should enable rapid visualization of PPGLs by PET scanning.