An image is created of blood circulation deep (e.g. a plurality of millimeters) below the surface of living tissue to aid in evaluating a patient. A first beam (26) of circularly polarized light is directed forwardly (F) against an outer surface (14) of the tissue. Light that has penetrated to only a shallow depth before moving rearwardly and out of the tissue remains polarized and is blocked by a filter (38). Light that has penetrated to greater depths (12), is scattered more and becomes depolarized, and a portion of it passes through the depolarizing filter (38) and is focused on a photodetector (48) to create an image. Light spots (54) on the image that move, represent spaces between blood platelets (52) that are moving through a capillary, and indicates the velocity of blood through the capillary.