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.
|Number of pages||9|
|Journal||Transactions of Japanese Society for Medical and Biological Engineering|
|Publication status||Published - 2010 Dec 13|
- Kinetic analysis
- Patlak analysis
ASJC Scopus subject areas
- Biomedical Engineering