1. Department of Radiology, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA.
2. Department of Medical Physics, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA.
3. Department of Medicine, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA.
4. Department of Epidemiology and Biostatistics, Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA.
5. Department of Materials Science and Engineering, Cornell University, 330 Bard Hall, Ithaca, NY 14853, USA.