Comparison of the absorbed dose measurement methods for high-energy electron beams

Objective To study the difference in the measurement of the absorbed dose in water between the dosimetry protocols of IAEA TRS-398 and TRS-277 for high-energy electron beams.Methods The differences were compare in absorbed doses from 6 kinds of electron beams among the three methods of using cylindrical chamber,plane-parallel chamber and cross-calibrated plane-parallel chamber which was calibrated in user' s high-energy electron beam according to IAEA TRS-398 and IAEA TRS-277.Results The difference in absorbed doses measured,following the two protocols,was 0.4％-2.3％ for planeparallel chamber,0.6％-2.2％ for cylindrical chamber,and 0.5％-2.0％ for cross-calibrated chamber.The differences in measured absorbed doses between the two dosimetry protocols were slight.Conclusions The methods used to determine absorbed dose to water recommanded by IAEA TRS-398 for high-energy beams are more accurate and more suitable for clinical users to measure compared to the TRS-277. Key words: Radiotherapy;  Dosimetry;  Absorbed dose;  Ionization chamber