1 Radiation Therapy Services, Hospital México, Caja Costarricense de Seguro Social, San Jose, Costa Rica; Radiation Therapy Center Siglo 21, San Jose, Costa Rica.
2 Radiation Therapy Center Siglo 21, San Jose, Costa Rica; Hospital México and Clínica Bíblica, Caja Costarricense de Seguro Social, San Jose, Costa Rica.
3 Joint Radiation Oncology Center, David Grant Medical Center, Travis Air Force Base, Fairfield, California. Electronic address: stevenwdavis@gmail.com.