Crossover study of (99m)Tc-TRODAT-1 SPECT and (18)F-FDOPA PET in Parkinson's disease patients.
99mTc-TRODAT-1 ([2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]ethanethiolato(3-)-N2,N2',S2,S2']oxo-[1R-(exo-exo)]) is a potential agent for dopamine transporter (DAT) SPECT, whereas 6-(18)F-fluoro-L-dopa ((18)F-FDOPA) PET has been used for the quantitative assessment of presynaptic nigrostriatal dopaminergic function. The current study investigated the relationship between the 2 imaging modalities in evaluating patients with Parkinson's disease (PD).


METHODS
Twenty patients in whom PD was diagnosed by generally accepted criteria were recruited. In addition to visual inspection, specific uptake ratios (SURs) of (99m)Tc-TRODAT-1 in the striatum and putamen were measured bilaterally. For PET, all patients received 100 mg of carbidopa 90 min before (18)F-FDOPA (300 MBq) injection. Images were acquired between 120 and 150 min after injection, using a whole-body PET scanner with settings identical to those for the SPECT studies. The SURs for PET were calculated similarly to those for SPECT. Individual SURs of the striatum or putamen from SPECT were correlated with the corresponding PET values using linear regression.


RESULTS
A consistent image pattern between SPECT and PET was achieved by visual inspection except for 3 cases. In 1 case (a patient with Hoehn and Yahr Scale I PD), the SPECT images were more compatible with the patient's clinical findings whereas PET showed nearly normal uptake. In the other 2 cases (both patients with Hoehn and Yahr Scale II PD), PET correlated better with the clinical findings. The caudate and putamen nuclei were more discernable on PET. An acceptable correlation of SUR, however, was found between SPECT and PET in both the striatum and the putamen (P < 0.01 for both).


CONCLUSIONS
The comparability of (99m)Tc-TRODAT-1 SPECT and (18)F-FDOPA PET suggests that (99m)Tc-TRODAT-1 SPECT may provide a reliable alternative to (18)F-FDOPA PET in the evaluation of clinical PD patients.
Huang
Wen-Sheng
WS
Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, Taiwan. wshuang@ms22.url.com.tw
Chiang
Yung-Hsiao
YH
Lin
Jiann-Chyun
JC
Chou
Yuan-Hwa
YH
Cheng
Cheng-Yi
CY
Liu
Ren-Shyan
RS
D000368:Aged; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism; D018592:Cross-Over Studies; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014326:Tropanes / Q000493:pharmacokinetics
D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D014326:Tropanes; C104196:technetium Tc 99m TRODAT-1; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine