Universität Tübingen
Optimierte Applizierung von intensitätsmodulierter Strahlentherapie
Abstract
A method for the delivery of intensity modulated radiotherapy (IMRT) with a multileaf collimator (MLC) by means of static multileaf modulation is presented. A sequencing algorithm (sequencer) was developed which bears the following characteristics: A new method of approximizing the optimized, freely modulated fluence weight distributions by deliverable ones was developed. In particular, the strategy aims at minimizing the introduced modifications by using variable fluence weight increments instead of equidistant levels for the approximation. A comparison with the conventional strategy for several test cases demonstrates the superiority of the method. A new approach of determining the series of segments for the application of the deliverable treatment plan was developed. It was specifically designed for the MLC model used at the University Hospital of Tübingen (UKT), but the strategies developed for this specific MLC can also be applied to other designs in a slightly modified way. The method takes considerations about the shape and weight of the segments into account to force the algorithm to end up with reasonable segments from a technical and clinical point of view. Further strategies aim at eliminating the dosimetrically least important segments to reduce the treatment time. The sequencer was integrated into the inverse planning algorithm developed at the UKT to be able to consider the series of segments during the optimization of the dose distribution. Modifications due to the sequencing are compensated for and the final dose distribution satisfies the dose prescription. The performance characteristics of inverse planning with the integrated sequencer demonstrate the potential to optimize treatment plans with respect to the quality of the dose distribution. Furthermore, it can be shown that our concept is superior to forward planning for complex cases and to conventional inverse planning in general.
Author and committee
dc:creator, dc:contributor.*- Author
-
- Bär, Werner
Identifiers
dc:identifier.*- Identifier
- hdl:10900/44282