 First, a single-use, disposable pad ActiSticker is attached to the patients skin over the point of needle insertion as selected by the interventionist. The pad incorporates reference objects that are easily detectable both on CT images and visually. A volume CT scan, covering at least the pad, the target lesion and adjacent structures is then performed. Next, the CT images from the volume scan are transferred to the ActiSight computer where the operator marks the target of the procedure, as well as all the reference points on the ActiSticker. Next, an optical sensor, also single-use and disposable, is attached to the top of the needle. By optically detecting all the reference points and relating them to their known positions on the CT images, the system can calculate the position of the top and the tip of the needle with relation to the target lesion. During the procedure, the system shows the user, on a graphic computer display, whether the needle is aimed directly at the target and how far the tip of the needle is from the intended target to help the user aim the insertion and guidance of the needle to the target. 