. 2016 Jun 17;34(4):260–264. doi: 10.3857/roj.2015.01571
Copyright © 2016. The Korean Society for Radiation Oncology
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.