title: PET imaging of human gliomas with ligands for the peripheral benzodiazepine binding site.
abstract: Human gliomas were imaged in vivo using ligands for the peripheral-type benzodiazepine binding site (or omega 3 binding site) and positron emission tomography (PET). Although gliomas have a high density of the peripheral-type benzodiazepine binding site, PET scans with a selective ligand for this site, [11C] Ro5-4864, failed to demonstrate higher radioactivity levels in human gliomas than in brain. In vitro studies of surgically removed specimens of human glioma demonstrated little binding of Ro5-4864 but high levels of binding of another selective ligand, PK 11195. Scans with [11C]PK 11195 demonstrated increased radioactivity in glioma compared to brain in 8 of 10 patients. Radioactivity in tumor and the ratios of radioactivity in tumor to that in remote gray and in white matter correlated significantly with the specific activity of [11C]PK 11195, suggesting that accumulation represents saturable high-affinity binding. We conclude that the PK 11195 manifests greater binding than Ro5-4864 to the peripheral-type benzodiazepine binding site on human gliomas and that human gliomas can be successfully imaged using [11C]PK 11195 and PET.
authors.affiliation: Department of Neurology, University of Michigan, Ann Arbor.
authors.forename: L
authors.initials: L
authors.lastname: Junck
authors.forename: J M
authors.initials: JM
authors.lastname: Olson
authors.forename: B J
authors.initials: BJ
authors.lastname: Ciliax
authors.forename: R A
authors.initials: RA
authors.lastname: Koeppe
authors.forename: G L
authors.initials: GL
authors.lastname: Watkins
authors.forename: D M
authors.initials: DM
authors.lastname: Jewett
authors.forename: P E
authors.initials: PE
authors.lastname: McKeever
authors.forename: D M
authors.initials: DM
authors.lastname: Wieland
authors.forename: M R
authors.initials: MR
authors.lastname: Kilbourn
authors.forename: S
authors.initials: S
authors.lastname: Starosta-Rubinstein
mesh_terms: D001570:Benzodiazepinones / Q000378:metabolism*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D005910:Glioma / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D011963:Receptors, GABA-A / Q000378:metabolism*; D014055:Tomography, Emission-Computed
chemical_list: D001570:Benzodiazepinones; D011963:Receptors, GABA-A; C028513:4'-chlorodiazepam