In Situ Monitoring of Cauterization with a Biopsy Needle Using Impedance Characteristics of Embedded Piezothermal Elements
نویسندگان
چکیده
This paper presents a method for monitoring biological tissue cauterization using the variation in the electromechanical impedance characteristics of the piezothermal heating elements used for tissue ablation. Piezoelectric ultrasonic heaters microfabricated from lead zirconate titanate (PZT) with 200 μm diameter and 100 μm thickness are embedded in a 20-gauge biopsy needle. A modified Butterworth-Van-Dyke circuit is used to model the variation in impedance characteristics of the PZT before and after cauterization. After tissue cauterization, the fundamental antiresonance frequency and the peak impedance magnitude decrease by 0.6 MHz and 900 ohms, respectively.
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