Development and Application of Efficient Portal Imaging Solutions

Abstract

The central subject of this thesis is to derive clinically applicable methods to measure and improve the reproducibility of treatment delivery in radiotherapy by means of portal imaging. The most important criteria that such methods should meet, apart from being effective, is that (1) they are relatively simple to implement and (2) the additional workload required in daily practice is small. This approach was inspired by the observation that routine application of portal imaging in clinical practice, according to well-defined protocols, remains relatively rare. Below, we first sketch the general aims and practice of radiotherapy. From this brief overview, a number of aspects become apparent that are essential to the work described in the following chapters. In particular, the meaning of systematic and random geometrical errors in radiotherapy is emphasised.