Clinical application and quantitative evaluation of generator-produced copper-62-PTSM as a brain perfusion tracer for PET.
Copper-62-pyruvaldehyde bis(N4-methylthiosemicarbazone) copper II (62Cu-PTSM) has been proposed as a generator-produced positron-emitting tracer for perfusion imaging. To evaluate the characteristics of 62Cu-PTSM as a cerebral perfusion tracer, brain PET images of 62Cu-PTSM were compared with cerebral blood flow (CBF).


METHODS
Following an intravenous injection of 62Cu-PTSM, a serial dynamic PET scan was performed for 10 min with arterial sampling in 10 subjects. CBF was measured by 15O-labeled water before the 62Cu-PTSM study.


RESULTS
Dynamic PET scan with octanol-extracted arterial input function indicated the presence of significant back-diffusion of 62Cu-PTSM from the brain within 3 min after injection, followed by stable activity from 3 to 10 min. Comparison with 15O-water PET demonstrated less contrast between high- and low-flow regions in 62Cu-PTSM image and a nonlinear relationship of flow and 62Cu-PTSM uptake, which suggests the underestimation of CBF in high-flow regions due to the existence of back-diffusion.


CONCLUSIONS
Although 62Cu-PTSM can be used widely for evaluation of brain perfusion with PET, kinetic analysis and correction may be needed to quantify regional CBF.
Okazawa
H
H
Department of Nuclear Medicine, Kyoto University, Japan.
Yonekura
Y
Y
Fujibayashi
Y
Y
Nishizawa
S
S
Magata
Y
Y
Ishizu
K
K
Tanaka
F
F
Tsuchida
T
T
Tamaki
N
N
Konishi
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation; D003301:Copper Radioisotopes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D010477:Perfusion; D013882:Thiosemicarbazones; D014055:Tomography, Emission-Computed
D003301:Copper Radioisotopes; D009942:Organometallic Compounds; D013882:Thiosemicarbazones; C052629:copper pyruvaldehyde bis(N(4)-methylthiosemicarbazone) complex