[Phase 1 clinical study of 123I-FP-CIT, a new radioligand for evaluating dopamine transporter by SPECT (II): Tracer kinetics in the brain].
The kinetics of 123I-FP-CIT in the brain for healthy subjects were studied. Twelve dynamic SPECT data sets (0- to 6-hr after an intravenous injection) from a Phase 1 clinical trial of 123I-FP-CIT were analyzed. Tracer concentrations in the striatum, midbrain, cerebellum and cerebral cortex were measured on the SPECT images co-registered with the corresponding MR images. High tracer accumulation was observed in the striatum, which peaked at 60 min post-injection, followed by slow elimination (3%/hr). The kinetics were similar both in the cerebellum and in the cerebral cortex, which peaked at 15 min post-injection, followed by rapid elimination. Tracer accumulation in the midbrain was higher than in the cerebellum and cerebral cortex. The striatal specific/nonspecific binding ratio ((striatal-occipital)/occipital concentration ratio) was stable at 3-hr post-injection and later at a value of 3, suggesting that the specific binding of 123I-FP-CIT could be evaluated from a single SPECT image at 3- to 6-hr post-injection. The specific/nonspecific binding ratio at 4-hr post-injection showed a negative correlation with aging (r = -0.70, p = 0.01), with a decrease rate of 11%/decade (95% confidence interval: 3%-19%/decade).
Takano
K
K
Department of Radiology, Mie University School of Medicine.
Matsumura
K
K
Watanabe
Y
Y
Yamada
T
T
Kubo
H
H
Naitou
Y
Y
Narita
Y
Y
Kuzuhara
S
S
Takeda
K
K
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D002352:Carrier Proteins / Q000032:analysis*; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis*; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins / Q000032:analysis*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014326:Tropanes
D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; D004298:Dopamine