In the production of functional images certain hardware and software considerations are necessary for the rapid and accurate determination of kinetic parameters. The advent of the digital scintillation camera has made available increased accuracy of quantitation and ease of image handling, although its integrated computer system may not be optimal for program development presently. To reduce the deleterious effects of Poisson noise on parameter estimation, the single or multiple application of easily implemented smoothing operators in space and time is recommended as a first step in image processing. The properties of these operators are conveniently expressed in terms of their variance. Following smoothing, count or variance thresholding is performed to reduce computer processing time and eliminate extraneous background from functional images. Time-activity curves can be fit by a variety of mathematical functions, the most useful of which is probably the finite Fourier series. In a simulated gated blood-pool study of the left ventricle, with and without an aneurysm, it is found that increased smoothing of the original image data results in more accurate parameter determinations, to the extent that small regions of dissimilar temporal behavior are not obliterated.