Evaluation of bias of the influx constant estimated by Patlak analysis for [18F]FDOPA PET: Influence of metabolites for [18F] FDOPA

Keisuke Matsubara, Hiroshi Watabe, Takuya Hayashi, Kotaro Minato, Hidehiro Iida

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Patlak analysis, which estimates the net FDOPA influx constant (Ki by linear regression of data acquired from [18F] FDOPA PET study, is widely employed in the diagnosis of neurological disorder, such as Parkinson's disease. In K estimation by Patlak analysis, it is assumed that the metabolites of radioligand do not diffuse out of the tissue during PET scan. However, [ 18F] F-Dopamine, synthesized from [18F] FDOPA, is rapidly metabolized and its metabolites diffuse from the tissue. We aimed at the evaluation of the effect of dopamine metabolism and the clearance of its metabolites on K estimated by Patlak analysis. For this purpose, we developed a model describing the detailed pathway of dopamine kinetics in the striatum, and a standard timeactivity curve (TAC) was generated based on this model and [ 18F] FDOPA PET data of a monkey. And TACs in case of altering the dopamine metabolism or the clearance of its metabolites were simulated.Then, we evaluated K1, values estimated by Patlak analysis for these simulated TACs. K was increased when the dopamine metabolism to DOPAC (κ dopac9) and the clearance of DOPAC and HVA (AfTc, k\?) were altered. The results suggest that K could be biased by the influence of the metabolism of dopamine and clearance of its metabolites. Therefore, it is important to consider these biases in the interpretation of K value estimated Patlak analysis.

Original languageEnglish
Pages (from-to)66-74
Number of pages9
JournalTransactions of Japanese Society for Medical and Biological Engineering
Volume48
Issue number1
Publication statusPublished - 2010 Dec 13
Externally publishedYes

Keywords

  • Kinetic analysis
  • PET
  • Patlak analysis
  • [F]fDOPA

ASJC Scopus subject areas

  • Biomedical Engineering

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