Abstract
The aim of the study was to evaluate the perturbation correction factors at a reference depth for cylindrical ionization chambers in high-energy electron beams by means of the EGSnrc Monte Carlo user code cavity. The cylindrical chambers used in this study were the Farmer-type of PTW30010, PTW30011, PTW30012, and PTW30013 models. We calculated the wall correction factor, P wall, the cavity or electron fluence correction factor, P cav, the stem correction factor, P stem, the central electrode correction factor, P cel, and the overall perturbation correction factor, P Q, for each chamber. The calculated P cav values were higher by from 2 to 1% than those recommended by the IAEA-TRS-398 code of practice, in an energy range of 6–18 MeV. The P wall values almost agreed with the analytical calculation performed with IAEA-TRS-398. The P cel values agreed with those of Ma and Nahum, performed with IAEA-TRS-398. The P stem values were approximately 0.995 on average and were independent of the electron beam energy. P stem needs to be considered in future dosimetry protocols. The P Q values were higher from 1 to 2% than those of IAEA-TRS-398 in an energy range of 6–18 MeV.
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Ono, T., Araki, F. & Yoshiyama, F. Perturbation correction factors for cylindrical ionization chambers in high-energy electron beams. Radiol Phys Technol 3, 93–97 (2010). https://doi.org/10.1007/s12194-010-0082-1
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DOI: https://doi.org/10.1007/s12194-010-0082-1