Driving electronics for low-intensity therapeutic ultrasound transducers
File(s)
Author(s)
Ilbilgi Yildiz, Betul
Type
Thesis or dissertation
Abstract
In therapeutic ultrasound, an array of transducers can be used to focus and steer an ultrasound beam, allowing several localised regions in the body to be treated. An electronic driving system coordinates the emission from each of the array's transducers to achieve steering and constructive interference at the target location. However, imaging or thermal ablation-focused design of commercially available multi-channel arrays and their drivers renders them unsuitable (higher frequency range >1MHz) or prohibitively expensive (costs> $100000) for other therapeutic applications, such as microbubble-based methods. This project aimed to design a cost-effective ultrasound system for low-intensity microbubble-based therapeutic ultrasound applications.
First a low-complex, affordable single-channel driver that could be used in driving arrays with high element counts was designed. Two digital signals from a microcontroller (0–3.3V) were used to control the amplitude and frequency of the single-channel driver. The results of the single-channel driver showed that the driving circuit was tuneable in the frequency range of 0.1–1 MHz and producing short pulses with amplitudes between 0-150 V. Then our system was scaled into an 8-channel driver and then a 16-channel driver to drive dome-shaped multi-channel arrays. Coupled with the custom arrays, electronic beam steering and focusing were demonstrated. The system is effective and affordable for therapeutic ultrasound arrays with higher element counts. The overall cost of a 128-channel driver circuit was estimated to less than $1600, excluding the power supply and the control unit.
Finally, a dynamic matching network was designed to improve the effectiveness of therapeutic ultrasound systems while offering a cost-efficient option for matching networks implemented with multiple frequencies. Experimental results demonstrate the effectiveness of the dynamic matching network in improving peak-negative pressure (PNP) from 66.6 % to 422.52 % for different transducers and frequencies.
First a low-complex, affordable single-channel driver that could be used in driving arrays with high element counts was designed. Two digital signals from a microcontroller (0–3.3V) were used to control the amplitude and frequency of the single-channel driver. The results of the single-channel driver showed that the driving circuit was tuneable in the frequency range of 0.1–1 MHz and producing short pulses with amplitudes between 0-150 V. Then our system was scaled into an 8-channel driver and then a 16-channel driver to drive dome-shaped multi-channel arrays. Coupled with the custom arrays, electronic beam steering and focusing were demonstrated. The system is effective and affordable for therapeutic ultrasound arrays with higher element counts. The overall cost of a 128-channel driver circuit was estimated to less than $1600, excluding the power supply and the control unit.
Finally, a dynamic matching network was designed to improve the effectiveness of therapeutic ultrasound systems while offering a cost-efficient option for matching networks implemented with multiple frequencies. Experimental results demonstrate the effectiveness of the dynamic matching network in improving peak-negative pressure (PNP) from 66.6 % to 422.52 % for different transducers and frequencies.
Version
Open Access
Date Issued
2024-01-06
Date Awarded
2024-08-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Choi, James J.
Sponsor
Turkey. Millî Eğitim Bakanlığı
Publisher Department
Bioengineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)