Recent advances in radiation oncology have depended upon and are intertwined with subsequent scientific discoveries and the development of new techniques in the fields of radiation and molecular biology, physics, electrical engineering, surgery, and medical oncology. This volume describes how some of the recent discoveries in the radiological sciences have influenced the way radiation oncology is practised. As there are many advances in this field, the Editors have chosen to concentrate on selected topics in clinical radiotherapy, radiation physics and biology, and technical innovations that have had a major impact on radiation oncology in the past twenty years. It is hoped that the techniques described in this volume will increase tumor control and prolong patient survival and at the same time decrease radiation-induced side effects and complications.