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BioMed Research International
Volume 2013 (2013), Article ID 309534, 10 pages
http://dx.doi.org/10.1155/2013/309534
Research Article

Similar-Case-Based Optimization of Beam Arrangements in Stereotactic Body Radiotherapy for Assisting Treatment Planners

1Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan
2Department of Radiology, The University of Tokyo Hospital, Tokyo 1138655, Japan
3Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan
4Division of Quantum Radiation Science, Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
5Department of Heavy Particle Therapy and Radiation Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan
6Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 8128582, Japan

Received 20 July 2013; Accepted 21 September 2013

Academic Editor: Noriyoshi Sawabata

Copyright © 2013 Taiki Magome et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. To develop a similar-case-based optimization method for beam arrangements in lung stereotactic body radiotherapy (SBRT) to assist treatment planners. Methods. First, cases that are similar to an objective case were automatically selected based on geometrical features related to a planning target volume (PTV) location, PTV shape, lung size, and spinal cord position. Second, initial beam arrangements were determined by registration of similar cases with the objective case using a linear registration technique. Finally, beam directions of the objective case were locally optimized based on the cost function, which takes into account the radiation absorption in normal tissues and organs at risk. The proposed method was evaluated with 10 test cases and a treatment planning database including 81 cases, by using 11 planning evaluation indices such as tumor control probability and normal tissue complication probability (NTCP). Results. The procedure for the local optimization of beam arrangements improved the quality of treatment plans with significant differences ( ) in the homogeneity index and conformity index for the PTV, V10, V20, mean dose, and NTCP for the lung. Conclusion. The proposed method could be usable as a computer-aided treatment planning tool for the determination of beam arrangements in SBRT.