The development of an in-vivo dosimeter for the application in radiotherapy

Abstract

The expectation for continual improvements in the treatment of cancer has brought quality assurance in radiotherapy under scrutiny in recent years. After a cancer diagnosis a custom treatment plan is devised to meet the particular needs of the patient's condition based on their prognosis. A cancer treatment plan will typically comprise of several cancer treatment technologies combining to form a comprehensive programme to fight the malignant growth. Inherent in each cancer treatment technology is a percentage error in treatment accuracy. Quality assurance is the medical practice to minimise the percentage error in treatment accuracy. Radiotherapy is one of the several cancer treatment technologies a patient might receive as part of their treatment plan, and in-vivo dosimetry is a quality assurance technology specifically designed to minimise the percentage error in the treatment accuracy of radiotherapy. This thesis outlines the work completed in the design of a next generation dosimeter for in-vivo dosimetry. The proposed dosimeter is intended to modernise the process of measuring the absorbed dose of ionising radiation received by the target volume during a radiotherapy session. To accomplish this goal the new dosimeter will amalgamate specialist technologies from the field of particle physics and reapply them to the field of medical physics. This thesis describes the design of a new implantable in-vivo dosimeter, a dosimeter comprising of several individual stages of electronics working together to modernise quality assurance in radiotherapy. Presented within this thesis are the results demonstrating the performance of two critical stages for this new dosimeter, including: the oating gate metal oxide field effective transistor, a radiation sensitive electronic component measuring an absorbed dose of radiation; and the micro antenna, a highly specialist wireless communications device working to transmit a high frequency radio signal. This was a collaborative project between Rutherford Appleton Laboratory and Brunel University. The presented work in this thesis was completed between March 2007 and January 2011.