Abstract: Apparatus and methods for locating a target in a living body are provided. A three-dimensional frame carries a plurality of infrared light emitting diodes, and this frame is placed on a table. The infrared LEDs are strobed by a computer. The position of the infrared LEDs is monitored by a pair of infrared sensitive cameras and stored in a computer. The frame is then removed and a living body is placed within or closely adjacent to the volume. An ultrasonic probe is hand held within the volume and is provided with a plurality of infrared LEDs so that the probe can be monitored by the cameras. The positions of the probe LEDs are compared in the computer with the initial position of the frame LEDs so that the position of the probe can be determined quite accurately, and the position of the target in the body can be displayed on a computer monitor.