Doracy P Fontenla1, Gary A Ezzell2. 1. Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10065-6007 (Tel: 212-639-8759; E-mail: doracy@earthlink.net). 2. Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona 85054 (Tel: 480-301-5413; E-mail: Ezzell.Gary@mayo.edu).