ORIGINAL ARTICLE   

The Quarterly Journal of Nuclear Medicine and Molecular Imaging 2022 June;66(2):148-55

DOI: 10.23736/S1824-4785.19.03175-3

Copyright © 2019 EDIZIONI MINERVA MEDICA

language: English

Imaging of dopamine transporter with [18F]LBT-999: initial evaluation in healthy volunteers

Nicolas ARLICOT ^{1, 2, 3} ✉, Johnny VERCOUILLIE ^{2, 3}, Cécile MALHERBE ^{1, 2}, Rudy BIDAULT ², Valérie GISSOT ³, Serge MAIA ^{1, 2}, Laurent BARANTIN ², Jean-Philippe COTTIER ^{2, 4}, Jean-Bernard DELOYE ⁵, Denis GUILLOTEAU ^{2, 3 6}, Maria-Joao RIBEIRO ^{2, 3, 7}

¹ CHRU de Tours, Unit of Radiopharmacy, Tours, France; ² UMR 1253, iBrain, University of Tours, Tours, France; ³ INSERM CIC 1415, University Hospital of Tours, Tours, France; ⁴ CHRU de Tours, Department of Neuroradiology, Tours, France; ⁵ Zionexa, Paris, France; ⁶ CHRU de Tours, Department of In Vitro Nuclear Medicine, Tours, France; ⁷ CHRU de Tours, Department of In Vivo Nuclear Medicine, Tours, France

BACKGROUND: The aim of this study was to evaluate in healthy human brain the distribution, uptake, and kinetics of [¹⁸F]LBT-999, a PET ligand targeting the dopamine transporter, to assess its ability to explore dopaminergic innervation, using a shorter protocol, more convenient for patients than currently with [¹²³I]ioflupane.
METHODS: After intravenous injection of [¹⁸F]LBT-999, 8 healthy subjects (53-80y) underwent a dynamic PET-scan. Venous samples were concomitantly obtained for metabolites analysis. Time activity curves (TACs) were generated for several ROIs (caudate, putamen, occipital cortex, substantia nigra and cerebellum). Cerebellum was used as reference region to calculate binding potentials (BPND).
RESULTS: No adverse events or detectable pharmacological effects were reported. [¹⁸F]LBT-999 PET revealed a good cerebral distribution, with an intense and symmetric uptake in both putamen and caudate (BPND of 6.75±1.17 and 6.30±1.17, respectively), without other brain abnormal tracer accumulation. Regional TACs showed a plateau from the maximal uptake, 20min pi, to the end of the acquisition for both caudate and putamen, whereas uptake in substantia nigra decreased progressively. A faster clearance and lowest BPND values were observed in both cortex and cerebellum. Ratios to the cerebellum exhibit value of about 3 in substantia nigra, close to 10 for both caudate and putamen, and remained around the value of 1 in cortex. The parent fraction of [¹⁸F]LBT-999 in plasma was 80%, 60% and 45% at 15, 30 and 45 min pi, respectively.
CONCLUSIONS: These findings support the usefulness of [¹⁸F]LBT-999 for a quantitative clinical evaluation of presynaptic dopaminergic innervation.

KEY WORDS: Radiopharmaceuticals; Positron-emission tomography; Dopamine plasma membrane transport proteins; Parkinson disease