Improved Technique for Obtaining Teletherapy Portal Radiographs with High-Energy Photons

H & D curves were obtained for various film/screen combinations exposed to ⁶⁰Co, 4-MV, and 45-MV photons. Data indicate that contrast is enhanced more by light-emitting screens than by lead screens or direct exposure. Flexible film cassettes are more comfortable for the patient, and extra-large film can be used for larger patients.