A Micro Ultrasonic Scalpel Using Hydrothermal PZT Thin Film

Abstract

A transducer for a micro ultrasonic scalpel has been fabricated. The micro ultrasonic scalpel can be used with an endoscope for a non-abdominal operation or micro surgery, for example, through a microscope. The ultrasonic transducer was 9.8 mm long and 2.7 mm wide and has stepped horn to amplify vibration velocity; tip of the horn is 0.6 mm wide. The scalpel vibrated in longitudinal mode at about 278 kHz resonance frequency. The piezoelectric material was lead zirconate titanate (PZT) that was deposited by the hydrothermal method. This is because the hydrothermal deposition film transducer has superior performance in vibration velocity. The vibration velocity at the tip of the horn in longitudinal direction was 4.0 m/s with 40 Vp-p driving voltage in both side electrodes. To demonstrate a beneficial effect of the scalpel, a cutting test that the transducer was stuck into pork fat was carried out. Efficient cutting performance was demonstrated using the transducer sized for an endoscope.