Treatment planning for Enhanced Dynamic Wedge with the CMS focus/modulex treatment planning system

Abstract 

The current versions of the CMS treatment planning systems, the FOCUS system for three dimensional planning, and Modulex for two dimensional planning, both require modeling dynamic wedges as filters. In this paper we describe methods for generating dynamic wedge filters for treatment planning. In our previous work with dynamic wedge we used measured data to back project the filter that would have delivered the wedge shaped isodoses. With the current version of Enhanced Dynamic Wedge, we use the segmented treatment table (STT) to create filters. For each wedge angle we created a 30 cm filter, for which the field is truncated by blocks according to the dynamic jaw settings. We found the filters provided isodoses that were within 2° of the measured angles. Central axis dose was within 1% due to the fact the system does not account for beam hardening. Although an undesirable solution to model dynamic wedging, we found the filter method to be workable.

Keywords:  Dynamic wedge, Treatment planning, FOCUS, Modulex

No full text is available. To read the body of this article, please view the PDF online.