The optimal imaging time for [99Tcm]TRODAT-1/SPET in normal subjects and patients with Parkinson's disease

Nucl Med Commun. 2001 Feb;22(2):151-4. doi: 10.1097/00006231-200102000-00006.


Imaging of dopamine transporters (DATs) in the brain using [99Tcm]TRODAT-1 showed excellent pharmacokinetics for estimation of transporter concentrations. It has been reported that there may be differences in the binding kinetics of DAT radiotracers to DATs between normal subjects and patients with Parkinson's disease (PD). The aim of this study was to determine an optimal time point for (99Tcm]TRODAT-1 brain single photon emission tomography (SPET) acquisition that provides stable target to non-target ratios reflecting the DAT concentration in the brain. Serial [99Tcm]TRODAT-1 brain SPET images 2, 3 and 4 h after intravenous injection of [99Tcm]TRODAT-1 (925 MBq) were performed in five healthy subjects and nine PD patients. Regions of interests were drawn, and caudate/occipital (C/O) and putamen/occipital (P/O) specific to non-specific [99Tcm]TRODAT-1 binding ratios were calculated. The C/O and P/O ratios in healthy subjects showed consistent increases with time, but in PD patients, the C/O and P/O ratios of [99Tcm]TRODAT-1 reached a stable level at 3 h post-injection. There was a statistically significant difference (P < 0.001) between PD and normal subjects at 4 h post-injection for both the C/O and the P/O ratios. In conclusion, we recommend the acquisition of [99Tcm]TRODAT-1 SPET images at 4 h post-injection, as at this time point the C/O and P/O ratios can be used to discriminate between PD patients and healthy subjects.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Basal Ganglia / diagnostic imaging
  • Carrier Proteins* / pharmacokinetics
  • Dopamine Plasma Membrane Transport Proteins
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Injections, Intravenous
  • Male
  • Membrane Glycoproteins*
  • Membrane Transport Proteins*
  • Middle Aged
  • Nerve Tissue Proteins*
  • Organotechnetium Compounds* / pharmacokinetics
  • Parkinson Disease / diagnostic imaging*
  • Parkinson Disease / metabolism
  • Radiopharmaceuticals* / pharmacokinetics
  • Tomography, Emission-Computed, Single-Photon
  • Tropanes* / pharmacokinetics


  • Carrier Proteins
  • Dopamine Plasma Membrane Transport Proteins
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • Organotechnetium Compounds
  • Radiopharmaceuticals
  • SLC6A3 protein, human
  • Tropanes
  • technetium Tc 99m TRODAT-1