SU‐E‐T‐605: Performance Evaluation of MLC Leaf‐Sequencing Algorithms in Head‐And‐Neck IMRT

Abstract

Purpose:To investigate the efficiency of three multileaf collimator (MLC) leaf‐sequencing algorithms proposed by Galvin et al, Chen et al and Siochi et al using external beam treatment plans for head‐and‐neck intensity modulated radiation therapy (IMRT).Methods:IMRT plans for head‐and‐neck were created using the CORVUS treatment planning system. The plans were optimized and the fluence maps for all photon beams determined. Three different MLC leaf‐sequencing algorithms based on Galvin et al, Chen et al and Siochi et al were used to calculate the final photon segmental fields and their monitor units in delivery. For comparison purpose, the maximum intensity of fluence map was kept constant in different plans. The number of beam segments and total number of monitor units were calculated for the three algorithms.Results:From results of number of beam segments and total number of monitor units, we found that algorithm of Galvin et al had the largest number of monitor unit which was about 70% larger than the other two algorithms. Moreover, both algorithms of Galvin et al and Siochi et al have relatively lower number of beam segment compared to Chen et al. Although values of number of beam segment and total number of monitor unit calculated by different algorithms varied with the head‐and‐neck plans, it can be seen that algorithms of Galvin et al and Siochi et al performed well with a lower number of beam segment, though algorithm of Galvin et al had a larger total number of monitor units than Siochi et al.Conclusion:Although performance of the leaf‐sequencing algorithm varied with different IMRT plans having different fluence maps, an evaluation is possible based on the calculated number of beam segment and monitor unit. In this study, algorithm by Siochi et al was found to be more efficient in the head‐and‐neck IMRT.The Project Sponsored by the Fundamental Research Funds for the Central Universities (J2014HGXJ0094) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.