The effect of levodopa therapy on dopamine transporter SPECT imaging with( 123)I-FP-CIT in patients with Parkinson's disease

Eur J Nucl Med Mol Imaging. 2005 Dec;32(12):1452-6. doi: 10.1007/s00259-005-1922-9. Epub 2005 Sep 8.


Purpose: The aim of this study was to evaluate, by means of (123)I-FP-CIT SPECT, the effect of chronic treatment with levodopa on striatal dopamine transporter (DAT) in patients with Parkinson's disease.

Methods: Fifteen patients under stable levodopa/carbidopa monotherapy were imaged twice: at baseline on medication and after at least 20 days of treatment wash-out. DAT levels were assessed from SPECT imaging for the entire striatum, the right and left striatum, the right and left putamen and the right and left caudate, as a ratio of regional brain activities using the formula: (striatal region of interest-occipital)/occipital.

Results: During levodopa wash-out, despite a worsening in patients' clinical disability (H&Y mean stage 2.53+/-0.58 versus 1.73+/-0.45 on therapy, p<0.001), striatal( 123)I-FP-CIT levels were not significantly different from those at baseline in any of the brain regions examined.

Conclusion: The results of this study suggest that levodopa does not affect( 123)I-FP-CIT brain imaging and confirm that it is not necessary to withdraw this medication to measure DAT levels with SPECT.

Publication types

  • Clinical Trial

MeSH terms

  • Aged
  • Antiparkinson Agents / administration & dosage
  • Artifacts
  • Brain / diagnostic imaging*
  • Brain / drug effects
  • Brain / metabolism*
  • Dopamine Plasma Membrane Transport Proteins / metabolism*
  • Drug Interactions
  • Female
  • Humans
  • Image Enhancement / methods
  • Levodopa / administration & dosage*
  • Male
  • Metabolic Clearance Rate / drug effects
  • Middle Aged
  • Parkinson Disease / diagnostic imaging*
  • Parkinson Disease / drug therapy
  • Parkinson Disease / metabolism*
  • Radiopharmaceuticals / pharmacokinetics
  • Tomography, Emission-Computed, Single-Photon / methods
  • Tropanes* / pharmacokinetics


  • Antiparkinson Agents
  • Dopamine Plasma Membrane Transport Proteins
  • Radiopharmaceuticals
  • Tropanes
  • 2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane
  • Levodopa