A system (10) presents a graphic guidance object (46) in a display screen (40) to aid a surgeon in guiding a probe (12) from an initial point (82) relative to a body (14) along a desired trajectory (54) to a target (52). The graphic object (46) may be presented simultaneously with a live video image (44) from an endoscope and with tomogram images (42). The graphic object (46) includes a probe tip indicator (88) and a trajectory indicator (94). These indicators (88, 94) are positioned relative to one another to graphically indicate how far and in which direction to move a probe tip (36) to cause the probe tip (36) to intersect the desired trajectory (54). A roll orientation feature (118) and a distance-to-target feature (126) are included in the graphic object (46). The graphic object (46) changes in real time to track movement of the probe (12).