PURPOSE: The application of radiolabelled inhibitors of cytochrome P450 enzymes is a novel approach for molecular imaging of adrenocortical masses to detect adrenal tumours. One potential tracer is radiolabelled iodometomidate (IMTO) with a common option for scintigraphic diagnosis and therapeutic applications. The aim of this study was to radiolabel iodometomidate with the positron-emitting radionuclide iodine-124 ((124)I) for the investigation of the biological behaviour and pharmacokinetics with positron emission tomography (PET). PROCEDURES: [(124)I]IMTO has been synthesized by oxidative radioiodo-destannylation, purified via semi-preparative HPLC and formulated in acetate-buffered saline, which contained ascorbic acid and ethanol to avoid radiolytic decomposition. Biological evaluation was performed in rats which received 5.5 ± 0.7 MBq [(124)I]IMTO in vivo. The radioactivity distribution (n = 3) has been dynamically imaged from 0-120 min after intravenous (i.v.) injection by small-animal PET. Regions of interest have been defined manually in the reconstructed PET images, and the activity concentration was expressed as percent injected dose per gram tissue (%ID/g). RESULTS: [(124)I]IMTO was prepared with a radiochemical yield of 83 ± 5 % (n = 3) and a radiochemical purity of >97 %. The final formulation of [(124)I]IMTO was stable for up to 48 h at room temperature. Two hours after i.v. administration in rats, radioactivity concentration in the adrenal glands were 2.1 ± 0.3 %ID/g, which was sufficient to achieve highest-contrast adrenal PET images. CONCLUSIONS: In the present study, the biological characteristics of radioiodinated metomidate were evaluated. [(124)I]IMTO appears as an attractive PET tracer for imaging of adrenals.
PURPOSE: The application of radiolabelled inhibitors of cytochrome P450 enzymes is a novel approach for molecular imaging of adrenocortical masses to detect adrenal tumours. One potential tracer is radiolabelled iodometomidate (IMTO) with a common option for scintigraphic diagnosis and therapeutic applications. The aim of this study was to radiolabel iodometomidate with the positron-emitting radionuclideiodine-124 ((124)I) for the investigation of the biological behaviour and pharmacokinetics with positron emission tomography (PET). PROCEDURES: [(124)I]IMTO has been synthesized by oxidative radioiodo-destannylation, purified via semi-preparative HPLC and formulated in acetate-buffered saline, which contained ascorbic acid and ethanol to avoid radiolytic decomposition. Biological evaluation was performed in rats which received 5.5 ± 0.7 MBq [(124)I]IMTO in vivo. The radioactivity distribution (n = 3) has been dynamically imaged from 0-120 min after intravenous (i.v.) injection by small-animal PET. Regions of interest have been defined manually in the reconstructed PET images, and the activity concentration was expressed as percent injected dose per gram tissue (%ID/g). RESULTS: [(124)I]IMTO was prepared with a radiochemical yield of 83 ± 5 % (n = 3) and a radiochemical purity of >97 %. The final formulation of [(124)I]IMTO was stable for up to 48 h at room temperature. Two hours after i.v. administration in rats, radioactivity concentration in the adrenal glands were 2.1 ± 0.3 %ID/g, which was sufficient to achieve highest-contrast adrenal PET images. CONCLUSIONS: In the present study, the biological characteristics of radioiodinated metomidate were evaluated. [(124)I]IMTO appears as an attractive PET tracer for imaging of adrenals.
Authors: Timothy J Burton; Isla S Mackenzie; Kottekkattu Balan; Brendan Koo; Nick Bird; Dmitri V Soloviev; Elena A B Azizan; Franklin Aigbirhio; Mark Gurnell; Morris J Brown Journal: J Clin Endocrinol Metab Date: 2011-11-23 Impact factor: 5.958
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Authors: Stefanie Hahner; Andrea Stuermer; Michael Kreissl; Christoph Reiners; Martin Fassnacht; Heribert Haenscheid; Felix Beuschlein; Martina Zink; Katharina Lang; Bruno Allolio; Andreas Schirbel Journal: J Clin Endocrinol Metab Date: 2008-04-08 Impact factor: 5.958
Authors: Iosif A Mendichovszky; Andrew S Powlson; Roido Manavaki; Franklin I Aigbirhio; Heok Cheow; John R Buscombe; Mark Gurnell; Fiona J Gilbert Journal: Diagnostics (Basel) Date: 2016-11-18