The influence of time sampling scheme on kinetic parameters obtained from compartmental modeling of a dynamic PET study - A Monte Carlo study

Compartmental modeling of dynamic PET data enables quantification of tracer kinetics in vivo, through the obtained model parameters. The dynamic data is sorted into frames during or after the acquisition, with a sampling interval usually ranging from 10 s to 300 s. In this study we wanted to investigate the effect of the chosen sampling interval on kinetic parameters obtained from a 2-tissue model, in terms of bias and standard deviation, using a complete Monte Carlo simulated dynamic ¹⁸F_FLT PET study. The results show that the bias and standard deviation in parameter Kl is small regardless of sampling scheme or noise in the time-activity curves (TACs), and that the bias and standard deviation in k₄ is large for all cases. The bias in Va is clearly dependent on sampling scheme, increasing for increased sampling interval. In general, a too short sampling interval results in very noisy images and a large bias of the parameter estimate, and a too long sampling interval also increases bias. Noise in the TACs is the largest source of bias.