Development and Characterization of a Small Ring-Shaped Ultrasonic Probe for Biopsies

A small ultrasonic probe capable of precise control of needle position is required for biopsies taken in abdominal surgery and laparoscopic surgery. We fabricated a small size ring-shaped probe with a through hole to insert the needle. The probe simultaneously detects the object in front of it, e.g., a lesion, and the tip of the needle. The error of the insertion depth measured by this detection was estimated to be less than 10.1% at a depth of more than 5 mm when the inner diameter of the probe was 1.1 mm and the outer diameter of the needle was 0.6 mm. The results of an experiment using a stomach wall specimen indicate that the position of the needle can be precisely controlled because the needle is directly below the probe.