[18F]FETO for adrenocortical PET imaging: a pilot study in healthy volunteers

• Published in: European journal of nuclear medicine and molecular imaging 2006-06, Vol.33 (6), p.669-672
• Main Authors: Wadsak, Wolfgang, Mitterhauser, Markus, Rendl, Gundula, Schuetz, Matthias, Mien, Leonhard Key, Ettlinger, Dagmar E, Dudczak, Robert, Kletter, Kurt, Karanikas, Georgios
• Format: Article
• Language: English
• Subjects: Adrenal Cortex - diagnostic imaging; Adrenal Cortex - metabolism; Adult; Female; Humans; Imidazoles - pharmacokinetics; Male; Metabolic Clearance Rate; Middle Aged; Organ Specificity; Pilot Projects; Positron-Emission Tomography; Radiopharmaceuticals - pharmacokinetics; Reference Values; Tissue Distribution; Whole Body Imaging
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-005-0062-6

Functional imaging of the adrenal cortex by means of PET may play an important clinical role. Recently, we presented the synthesis and first evaluation of a novel 11beta-hydroxylase inhibitor, [(18)F]FETO, in rats displaying high tracer accumulation in the adrenals. In this study, we aimed to investigate for the first time the potency of [(18)F]FETO as a PET tracer for the adrenal cortex in humans. An average preparation yielded 1-2 GBq of [(18)F]FETO ready to use. Ten healthy volunteers aged 24-57 years (five male and five female) were included in the study. After i.v. administration of 365 MBq [(18)F]FETO (246-391 MBq), dynamic images were acquired in 2D standard mode in 14 frames over 45 min. Afterwards, whole-body scanning was performed. In addition to visual interpretation, semi-quantitative analysis using standardised uptake values (SUVs) was conducted. [(18)F]FETO distribution was similar in all scanned volunteers. Visually, pronounced accumulation of [(18)F]FETO was found in the adrenals, whereas moderate uptake was observed-at least in some of the subjects-for liver, renal calices, gallbladder, stomach walls and pancreas. Kidney and bowels showed only faint uptake. Median SUVs for the right and left adrenal glands were 15.6 (10.0-28.6) and 15.7 (10.3-35.9), respectively. The reference tissue (liver) displayed a median SUV of 2.5 (2.2-4.6). [(18)F]FETO is a valuable tracer for adrenocortical PET imaging, combining the longer half-life of( 18)F with a high 11beta-hydroxylase selectivity. In accordance with our findings in rats, FETO PET revealed very high accumulation in the adrenal glands in healthy volunteers.