Navi-Robot in Conjunction with a CT equipment to Guide Precision Biopsies

This paper presents the first in vitro use of Navi-Robot to guide precision biopsies, after identification of the region to be sampled from the analysis of CT scan data. Before introducing the patient into the CT ring, three small plastic disks of a determined thickness are secured horizontally with tape on the patient’s skin, two on the shoulders and one in correspondence to the iliac crest prominence, since these points have minimal if no motion during breathing. Then, while the doctor examines the result, a software, of which a first edition has been already developed, locates automatically the position of the disks in the CT coordinates system, thus establishing the base for a common frame of reference. Once the doctor decides the region to be sampled, eventually fixing also the direction of penetration, these data are supplied to the Navi-Robot, together with the disks coordinates in the CT coordinate systems. At this point, with the patient still on the CT stretcher, and Navi-Robot in navigation mode, the tip of the end effector is brought into contact with the centre of the three disks, and the new position to be assumed by the end effector is computed. Finally, passing to robot mode, the requested position is assumed, while the depth of penetration is also supplied.