ABSTRACT
Radiotherapy is effective as a single modality. It is prescribed either alone or as an adjuvant therapy in more than half of all cancer patients. Improvements in radiotherapy have been considerable over the last two decades, in large measure owing to improvements in instrumentation, machine software and diagnostic techniques, enabling more accurate dose delivery to the tumour while minimizing the dose to surrounding healthy tissue. Despite these technical improvements, some patients still fail after radiotherapy and some still develop severe side-effects. Improvements are thus still needed. These improvements can, in principle, be achieved from the biological rather than the technical side.
