Optimisation in HDR brachytherapy

New HDR machines supplied with stepping source systems give us an additional opportunity to optimise source distribution by modeling source dwell time. Different optimization algorithms are implemented in the commercial planning systems connected with HDR machines. The choice of proper optimization procedures is basic for Quality Assurance in brachytherapy planning. The main ideas of optimization algorithms implemented in PLATO system are presented. Some examples of gynaecological, intralumenal and interstitial brachytherapy are analyzed. Nonoptimised and “geometrically” optimized interstitial implants are compared. The advantages of optimization are discussed on the basic of dose-volume histograms. The danger of wrong optimization is also discussed. This work is supported by KBN Grant No 8T11E0440B