The use of a new class of image processing hardware, the image computer, is illustrated by application to gated cardiac studies. Digital filtering of a nine-view study consisting of 144 frames, each 64 x 64 pixels in size, is performed with use of the Wiener filter. During image display the operator may change the filter parameters. Refiltering is then performed essentially instantaneously, permitting truly interactive filter selection. Comparable digital filtering employing a fast conventional computer and display hardware is shown to be too slow to permit interactive filter modification. The image computer represents a new class of image processing equipment not previously available in nuclear medicine. These machines incorporate very large image memories with very tightly coupled, fast arithmetic processors and video display devices. With these new machines very computation-intensive calculations can now be performed interactively.