Modification of a three-dimensional treatment planning system for the use of multi-leaf collimators in conformation radiotherapy.

The multi-leaf collimator of the DKFZ is designed as a low cost add-on device for conventional linear accelerators for radiotherapy. The technical specification of the computer controlled collimator is described briefly. A major limitation in the use of the wide capabilities of multi-leaf collimators in the clinic is still an appropriate treatment planning system. This paper describes treatment planning and dose calculation techniques for multi-leaf collimators and shows examples where the capabilities of the collimator are used extensively.