Thomas Kalinowski
Multileaf collimator field segmentation without tongue--and--groove effect
Preprint series: Preprints aus dem Fachbereich Mathematik, Universität Rostock
92C50 Medical applications (general)
90C90 Applications of mathematical programming
Abstract: We present an algorithm for optimal step--and--shoot intensity modulated radiation therapy without interleaf collision and with elimination of tongue--and--groove effects. Adapting the concepts of \cite{Kal03a} we characterize the minimal number of monitor units as the maximal weight of a path in a properly constructed weighted digraph. We also show that this number of monitor units can be realized by an unidirectional plan, thus proving that the algorithm of Kamath {\sl et al.} \cite{Kam04a} is monitor unit optimal in general and not only for unidirectional leaf movement. Our characterization of the minimal number of monitor units has the advantage that it can be used to derive a heuristic for the reduction of the number of segments following the ideas of \cite{Kal03b}.
Keywords: leaf sequencing, radiation therapy optimization, intensity modulation, multileaf collimator, IMRT