[Medical and physical aspects of quality assurance in radio-oncology]

A more extensive interpretation of quality control in radio-oncology is opposed to the conception mostly restricted to technical inspections. A review is given of the most important medical and physical aspects of an optimized radiotherapy. Some examples are chosen from the great number of national and international recommendations agreed upon in order to standardize the measures of quality control. Finally some simple radiobiologic models are presented and the corresponding precision requirements are compared with the uncertainties of the dose determination resulting in clinical practice.