Leaf Sequencing Algorithms for Segmented Multileaf Collimation Srijit Kamath†, Sartaj Sahni†, Jonathan Li‡, Jatinder Palta‡ and Sanjay Ranka† † Department of Computer and Information Science and Engineering, University of Florida, Gainesville, Florida, USA ‡ Department of Radiation Oncology, University of Florida, Gainesville, Florida, USA E-mail: srkamath@cise.ufl.edu Abstract. The delivery of intensity modulated radiation therapy (IMRT) with a multileaf collimator (MLC) requires the conversion of a radiation fluence map into a leaf sequence file that controls the movement of the MLC during radiation delivery. It is imperative that the fluence map delivered using the leaf sequence file is as close as possible to the fluence map generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. Optimization of the leaf sequencing algorithm has been the subject of several recent investigations. In this work, we present a systematic study of the optimization of leaf sequencing algorithms for segmental multileaf collimator beam delivery and provide rigorous mathematical proofs of optimized leaf sequence settings in terms of monitor unit (MU) efficiency under most common leaf movement constraints that include minimum and maximum leaf separation and leaf interdigitation. Our analytical analysis shows that leaf sequencing based on unidirectional movement of the MLC leaves is as good as bi-directional movement of the MLC leaves. Submitted to: Phys. Med. Biol.