AbstractID: 7100 Title: Study on Attenuation and Backscatter Characteristics of ThermoShield Material for 6, 9, and 12 MeV Electron Beam
Thermo-Shield (T-S) is a new shielding material that can be used for skin collimation for high
energy electron radiation therapy treatment. The transmission through T-S material is measured
for 6, 9, and 12 MeV electron beams for Varian 2100C linear accelerator placing chamber at the
depth of surface and dmax of electron beam. The measurement comparison between lead and T-S
is given. We found that to determine the thickness of T-S needed to reduce the electron beam
transmission to less than 5%, it is necessary to place the chamber at phantom surface. The
thickness of T-S material required for adequate attenuation is approximately 3.5 times thicker
than that of lead. Electron backscattering characteristics of Thermo-Shield are also investigated
and compared with those of lead. The presence of the Thermo-Shield resulted increasing in the
percentage depth ionization due to backscattering is about 40% to 65% depending on the electron
energy, the phantom depth, and the thickness of T-S. It is also found that the increasing in
percentage ionization due to Thermo-Shield is about 10% less than that causes by lead.