PET imaging of human gliomas with ligands for the peripheral benzodiazepine binding site.
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.
Junck
L
L
Department of Neurology, University of Michigan, Ann Arbor.
Olson
J M
JM
Ciliax
B J
BJ
Koeppe
R A
RA
Watkins
G L
GL
Jewett
D M
DM
McKeever
P E
PE
Wieland
D M
DM
Kilbourn
M R
MR
Starosta-Rubinstein
S
S
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
D001570:Benzodiazepinones; D011963:Receptors, GABA-A; C028513:4'-chlorodiazepam