[Advantages and disadvantages of a 5.7 MeV linear accelerator compared to a 60Co-unit (author's transl)].

A comparison between a 60Co therapy unit and a 5.7 MeV linac shows the following advantages of the accelerator: 1. More favourable depth dose distribution with an improvement of the field homogeneity in the midplane for mantle techniques by a factor of 3 without the use of compensating filters. 2. Change of the maximum from 4 to 12 mm depth and thereby better skin sparing and greater dose tolerance of the skin and subcutaneous tissue. 3. Up to 10 times less penumbra. 4. Increased and stable dose rate of approximately 250 rd/min. At the moment the main disadvantages are the 20 to 30% higher purchase and running costs, and furthermore a downtime of at least 1 week per year for servicing and repair.