Basic Properties of an Ultrasonic Probe with a Through Hole for Puncture and Detection Principle of a Puncture Needle

We fabricated an ultrasonic probe with a through hole for needle puncture. The probe consists of a ring-shaped transducer around the hole for detecting the needle tip and 12 fan-shaped transducers around the ring-shaped transducer for observing the lesion area. A B-mode image was obtained for inserting a needle into pig liver. We investigated the phase of the signals from the needle tip using an ultrasonic probe having separated transmitter and receiver elements. From the experimental results the detection principle of the needle tip was explained by edge waves.