Optimal image sampling schedule for both image-derived input and output functions in PET cardiac studies

Optimal sampling schedule (OSS) design for both image-derived input and out put functions in tracer kinetic modeling with positron emission tomography (PET) is investigated, This problem is very important in noninvasive PET dy namic cardiac studies where both the input function, i.e., the plasma time- activity curve (PTAC), and the output function, i.e., the tissue time-activ ity curve (TTAC), are obtained simultaneously from the same sequence of PET images. The integral PET measurement is used in this study. The spillover correction for the cross contaminations in cardiac studies is incorporated into the OSS design procedure. A new target function based on the D-optimal criterion involving both the input and output sensitivity functions is pro posed, The fluorodeoxyglucose (FDG) model and a six-parameter PTAC model ar e used to illustrate the simultaneous OSS design for both the PTAC and TTAC . An OSS design consisting of six different scanning intervals is derived. Computer simulations are performed based on the estimated parameters from r eal studies to evaluate the effectiveness of the OSS, The double modeling a pproach is used in parameter estimation to simultaneously estimate the para meters involved, The results have shown that, for a wide range of parameter variations, the OSS is as effective as a conventional sampling schedule (C SS) and comparable parameter estimates can be obtained. Compared with the u se of the CSS, the use of the OSS leads to an approximately 70% reduction i n the storage space and data processing time.