1. VIT University, School of Advanced Sciences, Department of Physics, Vellore, Tamil Nadu 632004, India
2. Christian Medical College, Department of Nuclear Medicine, Vellore, Tamil Nadu 632004, India
3. Christian Medical College, Department of Radiation Oncology, Vellore, Tamil Nadu 632004, India
4. University of Washington, School of Medicine, Departments of Radiology and Radiation Oncology, Seattle, Washington 98195, United States