This paper presents the use of an array of piezoceramic microheaters embedded in a biopsy needle for tract cauterization. Circular PZT-5A heaters of 200 ÃÂÿm diameter and 70-80 ÃÂÿm thickness are embedded in the wall of a 20-gauge stainless steel needle. Finite element modeling suggests that a PZT array with no gap between the elements to be the most suitable design. The temperature profile generated is measured at two resonance modes: the radial mode (10.3 MHz) and the thickness mode (22.3 MHz). The needle surface exceeds the minimum target temperature rise of 33ÃÂðC for applied voltages of 17 VRMS and 14 VRMS for radial and thickness mode, respectively. The corresponding input powers are 236 mW and 325 mW, respectively. The tissue cauterization extends 1-1.25 mm beyond the perimeter of needle.
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