1 Department of Radiation Oncology, Institut Claudius Regaud, Centre de Lutte Contre le Cancer de Toulouse, Toulouse, France.
2 Departments of Radiation Oncology and Neurological Surgery, University of California, San Francisco, San Francisco, California.
3 Departments of Radiation Oncology and Neurological Surgery, University of California, San Francisco, San Francisco, California. Electronic address: dhaaskogan@radonc.ucsf.edu.