Erazo F, Brualla L, Lallena A M
Instituto del Cáncer - SOLCA, Cuenca, Ecuador; Escuela de Tecnología Médica, Facultad de Medicina, Universidad de Cuenca, Cuenca, Ecuador.
NCTeam, Strahlenklinik, Universitätsklinikum Essen, Hufelandstraße 55, D-45122 Essen, Germany.
Phys Med. 2017 Jun;38:76-80. doi: 10.1016/j.ejmp.2017.05.053. Epub 2017 May 16.
The quality correction factor [Formula: see text] for electron beams was calculated for three thimble ionization chambers, namely, NE2571, NE2571A and NE2581A. The Monte Carlo code PENELOPE was used to estimate the overall correction factor f of these chambers for electron beams with nominal energies ranging between 6 and 22MeV, corresponding to a Varian Clinac 2100 C/D. A Co beam was used as reference quality Q. Also eight monoenergetic electron beams reproducing the quality index R of the Clinac beams were considered. The [Formula: see text] factors were calculated as the ratio between f and [Formula: see text] . Those obtained for the NE2571 ionization chamber show a nice agreement with those calculated by Muir and Rogers with EGSnrc. As it occurred to other ionization chambers analyzed in previous works, the [Formula: see text] factors found for the monoenergetic beams are larger (smaller) than those corresponding to the Clinac beams at low (high) R values, the differences being slightly above 0.5%. Finally, the [Formula: see text] factors obtained in the case of the NE2571A chamber are systematically ∼0.5% below those of its predecessor chamber, the NE2571.
针对三种指形电离室，即NE2571、NE2571A和NE2581A，计算了电子束的质量校正因子[公式：见原文]。使用蒙特卡罗代码PENELOPE估算这些电离室对于标称能量在6至22MeV之间的电子束的总体校正因子f，这对应于瓦里安Clinac 2100 C/D。使用钴束作为参考质量Q。还考虑了八个再现Clinac束质量指数R的单能电子束。[公式：见原文]因子计算为f与[公式：见原文]的比值。在NE2571电离室中获得的结果与Muir和Rogers使用EGSnrc计算的结果显示出良好的一致性。正如在先前工作中分析的其他电离室那样，在低（高）R值下，单能束的[公式：见原文]因子比Clinac束的相应因子大（小），差异略高于0.5%。最后，在NE2571A电离室情况下获得的[公式：见原文]因子系统地比其前身电离室NE2571的低约0.5%。
