title: Methods for measuring acoustic power of an ultrasonic neurosurgical device.
abstract: Measurement of the acoustic power in high-energy ultrasonic devices is complex due to occurrence of the strong cavitation in front of the sonotrode tip. In our research we used three methods for characterization of our new ultrasonic probe for neuroendoscopic procedures. The first method is based on the electromechanical characterization of the device measuring the displacement of the sonotrode tip and input electrical impedance around excitation frequency with different amounts of the applied electrical power The second method is based on measuring the spatial pressure magnitude distribution of an ultrasound surgical device produced in an anechoic tank. The acoustic reciprocity principle is used to determinate the derived acoustic power of equivalent ultrasound sources at frequency components present in the spectrum of radiated ultrasonic waves. The third method is based on measuring the total absorbed acoustic power in the restricted volume of water using the calorimetric method. In the electromechanical characterization, calculated electroacoustic efficiency factor from equivalent electrical circuits is between 40-60%, the same as one obtained measuring the derived acoustic power in an anechoic tank when there is no cavitation. When cavitation activity is present in the front of the sonotrode tip the bubble cloud has a significant influence on the derived acoustic power and decreases electroacoustic efficiency. The measured output acoustic power using calorimetric method is greater then derived acoustic power, due to a large amount of heat energy released in the cavitation process.
authors.affiliation: University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, Croatia. antonio.petosic@fer.hr
authors.forename: Antonio
authors.initials: A
authors.lastname: Petosić
authors.forename: Bojan
authors.initials: B
authors.lastname: Ivancević
authors.forename: Dragoljub
authors.initials: D
authors.lastname: Svilar
authors.forename: Tihomir
authors.initials: T
authors.lastname: Stimac
authors.forename: Josip
authors.initials: J
authors.lastname: Paladino
authors.forename: Darko
authors.initials: D
authors.lastname: Oresković
authors.forename: Ivana
authors.initials: I
authors.lastname: Jurjević
authors.forename: Marijan
authors.initials: M
authors.lastname: Klarica
mesh_terms: D004867:Equipment Design; D019635:Neurosurgical Procedures / Q000295:instrumentation*; D014463:Ultrasonography / Q000295:instrumentation* / Q000592:standards