AUTHOR=Petereit Daniel Grant , Coleman C. Norman TITLE=Editorial: “Global Challenges in Radiation Oncology” JOURNAL=Frontiers in Oncology VOLUME=5 YEAR=2015 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2015.00103 DOI=10.3389/fonc.2015.00103 ISSN=2234-943X