Signal-Generation Hardware for the Next Generation Chalmers Hyperthermia System

Abstract

Microwave hyperthermia is a promising complementary cancer treatment alongside conventional treatments such as chemotherapy and radiotherapy. By heating a target area to 40 − 44◦ C using an antenna array, cytotoxic effects from traditional methods are enhanced in targeted cells. There are multiple versions of hyperthermia but the focus of this thesis is microwave hyperthermia, specifically the Chalmers Ultra Wideband Hyperthermia System. The purpose is to create a more compact version of the first hyperthermia system with frequency control per channel while also keeping correct documentation for future work and regulatory adherence. The project was divided into two phases. The first phase involved analyzing the legacy system to establish the requirements for its successor. This resulted in direct digital synthesis (DDS) being chosen as the new signal generation method and a overview for a 17 DDS-based system, alongside extra designed parts for control, calibration and amplification. A Quality Management System was also set up within the documentation for potential future work on the system. This newly developed system would be more compact, have a higher phase-shift resolution while incorporating frequency control per channel. The second part of the project consisted of validating and testing the DDS using a third party DDS Shield for Arduino Mega 2560. By comparing the DDS’s frequency accuracy, stability, amplitude flatness and edge quality to the previous analog wave oscillator it was confirmed that the DDS would be a suitable replacement. Finally a Two-Channel Proof of Concept was implemented to prove that two DDS boards could be synchronized using a single reference clock. Although there was a random phase shift between the two boards, it was shown that synchronization was possible as they reliably were able to get in phase with each other. While the current DDS board could be used to replace the wave oscillator of the current system without further changes, there are many future developments available. The main one is to finish up the 17-DDS system hardware and testing it, introducing changes to the calibration system and following up on the regulatory pathway are all possible options.