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Monte Carlo calculations of the replacement correction factor, P repl, for cylindrical chamber cavities in clinical photon and electron beams

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Abstract

The purpose of this study was to calculate the replacement correction factor, P repl (the product P gr P fl in the AAPM’s notation, or the product p cav p dis in the IAEA’s notation), at a reference depth, d ref, for cylindrical chamber cavities in clinical photon and electron beams by Monte Carlo simulation. P repl was calculated for cavities with a combination of various diameters and lengths. P repl values calculated in photon and electron beams were typically higher than those recommended by the TG-51 and TRS-398 dosimetry protocols. P repl values for a Farmer chamber cavity were higher by 0.3 to 0.2 % and by 0.7 to 0.4 %, respectively, than data of TG-51 and TRS-398, at photon energies of 60Co to 18 MV. Similarly, the P repl values for electron beams were higher by 1.5 to 1.1 % than data for both protocols, in a range of 6–18 MeV. The P repl values depended upon the cavity diameter and length, especially for lower electron energies. We found that P repl values of cylindrical chamber cavities for photon and electron beams were significantly different from those recommended by TG-51 and TRS-398.

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Authors and Affiliations

  1. Department of Radiological Technology, Faculty of Life Sciences, Kumamoto University, 4-24-1, Kuhonji, Kumamoto, 862-0976, Japan

    Fujio Araki

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  1. Fujio Araki
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Correspondence to Fujio Araki.

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Araki, F. Monte Carlo calculations of the replacement correction factor, P repl, for cylindrical chamber cavities in clinical photon and electron beams. Radiol Phys Technol 5, 199–206 (2012). https://doi.org/10.1007/s12194-012-0154-5

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  • DOI: https://doi.org/10.1007/s12194-012-0154-5

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