Electron fluence correction factors for conversion of dose in plastic to dose in water.

摘要: In radiationdosimetry protocols, plastic is allowed as a phantom material for the determination of absorbed dose to water in electron beams. The fluence correction factor needed conversion measured water. There are large discrepancies among recommended values well factors when polystyrene used material. Using Monte Carlo technique, we have calculated incident clinical beam energies between 5 and 50 MeV function depth clear polystyrene, white PMMA materials compared results with those protocols experimental from published data. calculations, beams simulated using EGS4 user-code BEAM variety medical accelerators. study shows that our factor, φ p w , energy Ē o little dependence on other aspects quality. However at d max indirectly influenced by quality since they vary also varies Calculated range 1.005–1.045 phantom, 1.005–1.038 0.996–1.016 phantom. Our about 1–2% higher than determined according AAPM TG-25 protocol or polystyrene. explain some variations data because its dependence. A simple formula derived which gives R 0.6 −0.1 any 25 three plastics: PMMA. makes careful distinction corresponding IAEA Code Practice quantity, h m .