Title Vrednovanje točkastog izvora ultrazvuka velike snage za minimalno invazivnu kirurgiju Author Alan Štimac Mentor Bojan Ivančević (mentor)Committee member Borivoj Modlic (predsjednik povjerenstva)Committee member Bojan Ivančević (član povjerenstva)Committee member Vjera Krstelj (član povjerenstva)Committee member Stanko Tonković (član povjerenstva)Committee member Davor Ježek (član povjerenstva)Granter University of Zagreb Defense date and country 2003-04-24, Croatia Scientific / art field, TECHNICAL SCIENCES Universal decimal classificationUDC ) 621.3 - Electrical engineering Abstract Interdisciplinarnom suradnjom na znanstveno-istraživačkim projektima na području primjene ultrazvuka velike snage u neurokirurgiji, uočena je mogućnost primjene točkastog izvora ultrazvuka velike snage u postupcima minimalno invazivne neurokirurgije. Dotadašnji načini nekontaktne primjene ultrazvuka visoke akustičke energije potaknuli su ideju o prijenosu ultrazvučne energije putem elastičnog žičanog valovoda. Pokrenut je razvoj nove vrste neurokirurške endoskopske kontaktne ultrazvučne sonde – noža koji je 1999.g. rezultirao funkcionalnim prototipom – NECUP I. Stalno unapređivanje i usavršavanje interdisciplinarnih znanja o primjeni kontaktnog ultrazvuka velike snage u kirurgiji, rezultiralo je izradom poboljšanog uređaja NECUP 2. U okviru ovog rada pokušalo se predočiti rezultat teoretskih i eksperimentalnih istraživanja na polju generiranja i širenja ultrazvuka velike snage, kao i primjene u minimalno invazivnoj kirurgiji. U dijelu primijenjenih teoretskih istraživanja glavni cilj bio je postaviti teoretske osnove metoda osnivanja ultrazvučnih pretvarača koje omogućuju realizaciju optimalnog tehničkog rješenja točkastog izvora ultrazvuka za minimalno invazivnu kirurgiju. Predočen je opis generiranja i prijenosa ultrazvučne energije s ultrazvučnog pretvarača pomoću mehaničkih koncentratora na endoskopski nastavak koji je moguće prilagoditi određenoj kirurškoj upotrebi. Analizom su određeni uvjeti prijenosa i transformacije akustičke energije s ultrazvučnog pretvarača na endoskopski nastavak. U okviru analize koncentratora mehaničke enregije, modeliranjem s pomoću metode konačnih elemenata, provedena je parametarska optimizacija oblika i karakteristika. U okviru eksperimentalnog dijela predložene su metode za verifikaciju dobivenih rezultata, metode za definiranje djelovanja titanske žice promjera 1,6 mm kao endoskopskog nastavka i eksperimentalne metode za vrednovanje električnih i akustičkih karakteristika točkastog izvora ultrazvuka velike snage. Provedba akustičkih mjerenja u odječnom bazenu omogućila je mjerenje isijane akustičke snage, zvučnog tlaka, raspodjele zvučnog tlaka u slobodnom zvučnom polju (V i H ravnina) i stupnja iskorištenja ultrazvučne sonde. S Alan Štimac Doktorska disertacija 177 jedne strane, rezultati ovog istraživanja predstavljaju poticaj primjeni ultrazvuka velike snage u minimalno invazivnoj kirurgiji, dok s druge strane rezultati eksperimentalnog dijela istraživanja ukazuju na potrebu za periodičkim umjeravanjem tih ili sličnih uređaja.
Abstract (english) During interdisciplinary collaboration in scientific-research programmes in the field of high power ultrasound applications in neurosurgery, a possibility to apply highpower ultrasonic point sources for minimally invasive neurosurgery has been noticed. Earlier experiences with noncontact applications of high energy ultrasound have induced the idea of ultrasonic energy transfer through an elastic wire waveguide. Development of a new type of neurosurgical endoscopic contact ultrasonic probe – knife, which started in 1999, has resulted in a fully functional prototype (NECUP 1). Further advances in interdisciplinary knowledge on contact applications of high-power ultrasound in general surgery, eventually resulted in development of an improved contact ultrasonic surgical system (NECUP 2). The scope of this thesis is to present the results of theoretical and experimental research in the field of generation and propagation of high-power ultrasound as well as of its application in minimally invasive surgery. Theoretical part of the thesis covers methods for calculation and modelling of optimised ultrasonic transducers giving a basis for design of a high-power ultrasonic point source for minimally invasive surgery. Generation and transmission of ultrasonic waves from the ultrasonic transducer, through the mechanical concentrator to the endoscopic tool and the ability for adaptation to different surgical applications have been described. By means of the conducted analysis, terms of transmission and transformation of the acoustic energy from the ultrasonic transducer to the endoscopic tool have been determined. In the analysis of the mechanical concentrators, with the help of finite elements method modelling, parametric optimisation of the concentrator shape and length has been conducted. In the experimental part of the thesis, methods for verification of the theoretical results have been presented. This includes methods for validation the performance of the 1,6 mm titanium wire as an endoscopic tool and experimental methods for assessment of electric and acoustic characteristics of the high-power ultrasonic point source. The emitted acoustic power, sound pressure distribution in the free field (vertical and horizontal plane) and the efficiency Alan Štimac Doktorska disertacija 179 coefficient of the ultrasonic probe have been determined experimentally by measurements in an anechoic hydroacoustical tank. The results of this research present a stimulus for application of high-power ultrasound in the minimally invasive surgery, while the experimental results indicates the need for metrological supervision of this and similar surgical equipment.
Keywords
Ultrazvuk velike snage
miminalno invazivna kirurgija
endoskopski nastavak
modeliranje konačnim elementima
akustičko mjerenje
Keywords (english)
High power ultrasound
minimally invasive surgery
endoscopic tool
finite element modelling
acoustic measurements in anechoic tank
Language croatian URN:NBN urn:nbn:hr:168:640882 Study programme Title: Doctoral study programme "Electrical Engineering and Computing" Catalog URL http://lib.fer.hr:8080/cgi-bin/koha/catalogue/detail.pl?biblionumber=29021&searchid=pY2MfDbX Type of resource Text Extent 189 str. ; 30 cm File origin Born digital Access conditions Closed access Terms of use Created on 2019-05-14 07:49:25
