1 Department of Radiation Oncology, University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, USA.
2 Department of Radiation Oncology, University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, USA; Loma Linda University School of Medicine, Loma Linda, CA, USA.
3 Department of Radiation Oncology, University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, USA; Division of Biostatistics, University of California San Francisco, San Francisco, CA, USA.
4 Department of Radiation Oncology, University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, USA; Lawrence Berkeley National Laboratory, Berkeley, CA, USA.