Title
Geometric algorithms for static leaf sequencing problems in radiation therapy
Abstract
The static leaf sequencing (SLS) problem arises in radiation therapy for cancer treatments, aiming to accomplish the delivery of a radiation prescription to a target tumor in the minimum amount of delivery time. Geometrically, the SLS problem can be formulated as a 3-D partition problem for which the 2-D problem of partitioning a polygonal domain (possibly with holes) into a minimum set of monotone polygons is a special case. In this paper, we present new geometric algorithms for a basic case of the 3-D SLS problem (which is also of clinical value) and for the general 3-D SLS problem. Our basic 3-D SLS algorithm, based on new geometric observations, produces guaranteed optimal quality solutions using Steiner points in polynomial time; the previously best known basic 3-D SLS algorithm gives optimal outputs only for the case without any Steiner points, and its time bound involves a multiplicative factor of a factorial function of the input. Our general 3-D SLS algorithm is based on our basic 3-D SLS algorithm and a polynomial time algorithm for partitioning a polygonal domain (possibly with holes) into a minimum set of x-monotone polygons, and has a fast running time. Experiments and comparisons using real medical data and on a real radiotherapy machine have shown that our 3-D SLS algorithms and software produce treatment plans that use significantly shorter delivery time and give better treatment quality than the current most popular commercial treatment planning system and the most well-known SLS algorithm. Some of our techniques and geometric procedures (e.g., for the problem of partitioning a polygonal domain into a minimum set of x-monotone polygons) are interesting in their own right.
Year
DOI
Venue
2004
10.1145/777792.777805
Int. J. Comput. Geometry Appl.
Keywords
Field
DocType
network flows,imrt,3-d partition problem,monotone polygons,geometric algorithm,3-d sls algorithm,polygon partition,minimum set,radiation therapy,general 3-d sls algorithm,static leaf,leaf sequencing,sls problem,well-known sls algorithm,general 3-d sls problem,basic 3-d sls algorithm,polygonal domain,3-d sls problem,treatment planning,polynomial time,network flow
Partition problem,Multiplicative function,Computer science,Factorial,Time complexity,Monotone polygon,Special case,Flow network,Discrete mathematics,Polygon,Combinatorics,Mathematical optimization,Algorithm
Journal
Volume
Issue
ISSN
14
4-5
0218-1959
ISBN
Citations 
PageRank 
1-58113-663-3
11
1.22
References 
Authors
14
5
Name
Order
Citations
PageRank
Danny Z. Chen1214.50
Xiaobo Sharon Hu22004208.24
Shuang Luan37211.46
Chao Wang440427.12
Xiaodong Wu585977.06