title: Crossover study of (99m)Tc-TRODAT-1 SPECT and (18)F-FDOPA PET in Parkinson's disease patients.
abstract: 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.
authors.affiliation: Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, Taiwan. wshuang@ms22.url.com.tw
authors.forename: Wen-Sheng
authors.initials: WS
authors.lastname: Huang
authors.forename: Yung-Hsiao
authors.initials: YH
authors.lastname: Chiang
authors.forename: Jiann-Chyun
authors.initials: JC
authors.lastname: Lin
authors.forename: Yuan-Hwa
authors.initials: YH
authors.lastname: Chou
authors.forename: Cheng-Yi
authors.initials: CY
authors.lastname: Cheng
authors.forename: Ren-Shyan
authors.initials: RS
authors.lastname: Liu
mesh_terms: 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
chemical_list: D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D014326:Tropanes; C104196:technetium Tc 99m TRODAT-1; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine