Methods for measuring acoustic power of an ultrasonic neurosurgical device

Petošić, Antonio and Ivančević, Bojan and Svilar, Dragoljub and Štimac, Tihomir and Paladino, Josip and Orešković, Darko and Jurjević, Ivana and Klarica, Marijan (2011) Methods for measuring acoustic power of an ultrasonic neurosurgical device. Collegium Antropologicum, 35 (Suppl.). pp. 107-13. ISSN 0353-3735

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Abstract

Measurement of the acoustic power in high-energy ultrasonic devices is complex due to occurence 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.

Abstract in Croatian

METODE ZA MJERENJE AKUSTIČKE SNAGE IZVORA ULTRAZVUKA U NEUROKIRURGIJI ----- Mjerenje akustičke snage visoko-energetskih ultrazvučnih izvora je složeno zbog pojave kavitacije ispred vrha sonotrode. Uobičajeno je koristiti samo jednu metodu za mjerenje izlazne akustičke snage, međutim u ovome istraživanju su primjenjene i uspoređene sve tri preporučene metode vrednovanja ultrazvučnog izvora. Prva metoda se temelji na karakterizaciji pretvarača i sastoji se od mjerenja pomaka sonotrode i ulazne električne impedancije oko pobudne frekvencije s različitim razinama privedene električne snage. Druga metoda se temelji na mjerenju prostorne raspodjele magnitude tlaka ultrazvučnog izvora u »gluhom« bazenu. Princip akustičkog reciprociteta se koristi za određivanje isijane akustičke snage ekvivalentnih izvora na frekvencijskim komponentama prisutnim u spektru ultrazvučnih valova. Treća metoda se temelji na kalorimetrijskom mjerenju apsorbirane akustičke snage u vodi. Elektromehaničkom karakterizacijom sonotrode dobivena je vrijednost elektroakustičkog koeficijenta iskorištenja od 40% do 60% što je približno jednako vrijednosti dobivenoj mjerenjem isijane akustičke snage u »gluhom« bazenu u linearnom načinu rada sonotrode kada nema kavitacije. Kada je prisutna kavitacijska aktivnost ispred vrha sonotrode, nastali oblak mjehurića značajano smanjuje isijanu akustičku snagu. Izlazna akustička snaga dobivena kalorimetrijskom metodom je veća od isijane akustičke snage izmjerene ostalim metodama. U budućim istraživanjima mjereni akustički parametri će se povezati s biološkim učincima u neuralnom i drugim tkivima.

Item Type: Article
Departments: Katedra za farmakologiju
Hrvatski institut za istraživanje mozga
Katedra za neurologiju
Depositing User: Marijan Šember
Status: Published
Creators:
CreatorsEmail
Petošić, AntonioUNSPECIFIED
Ivančević, BojanUNSPECIFIED
Svilar, DragoljubUNSPECIFIED
Štimac, TihomirUNSPECIFIED
Paladino, JosipUNSPECIFIED
Orešković, DarkoUNSPECIFIED
Jurjević, IvanaUNSPECIFIED
Klarica, MarijanUNSPECIFIED
Date: January 2011
Date Deposited: 04 Mar 2011
Last Modified: 23 Sep 2011 16:11
Subjects: /
Related URLs:
    URI: http://medlib.mef.hr/id/eprint/961

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