Backscatter from High Atomic Number Materials in High Energy Photon Beams

High atomic number materials in high-energy photon beams produce an increased radiation level on the side of the material towards the radiation source. This added radiation has been termed backscattered radiation, although it must also contain characteristic radiation from the scattering material. The magnitude and distribution of this radiation were investigated principally for the photon beam from an 8 MeV medical linear accelerator, and also for the beam from a 60Co teletherapy unit.