Output correction factors for small static fields in megavoltage photon beams for seven ionization chambers in two orientations - perpendicular and parallel
Output correction factors for small static fields in megavoltage photon beams for seven ionization chambers in two orientations - perpendicular and parallel
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DOI：
10.1002/mp.13894
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发表时间：
2019-11-25
期刊：
影响因子：
3.8
通讯作者：
Huq, M. Saiful
中科院分区：
文献类型：
--
作者：
Casar, Bozidar;Gershkevitsh, Eduard;Huq, M. Saiful
目的 本工作的目标是为四个兆伏光子束中两个线性加速器上的七个小体积电离室提供一大组特定于探测器的输出校正因子，利用束中电离室的垂直和平行方向，标称场尺寸范围为 0.5 cm(2) x 0.5 cm(2) 到 10 cm(2 )x 10 cm(2)。本研究是我们小组进行的广泛研究的第二部分。方法 在两台直线加速器（Elekta Versa HD 和 Varian TrueBeam）上通过实验确定 6 和 10 MV 光束的输出校正因子 kQclin、Qreffclin、fref，适用于 7 个微型和微型电离室 IBA CC04、 IBA 剃刀、PTW 31016 3D PinPoint、PTW 31021 3D Semiflex、PTW 31022 3D PinPoint、PTW 31023 PinPoint 和 SI Exradin A16。 Exradin W1 塑料闪烁体和 EBT3 放射变色薄膜用作参考探测器。结果 对于所有电离室，平行方向的输出校正因子 kQclin、Qreffclin、fref 值低于垂直方向的输出校正因子值。我们研究集中的五个电离室 IBA Razor、PTW 31016 3D PinPoint、PTW 31022 3D PinPoint、PTW 31023 PinPoint 和 SI Exradin A16 满足 TRS-483 操作规范中建议的要求，即 0.95
Purpose The goal of the present work was to provide a large set of detector-specific output correction factors for seven small volume ionization chambers on two linear accelerators in four megavoltage photon beams utilizing perpendicular and parallel orientation of ionization chambers in the beam for nominal field sizes ranging from 0.5 cm(2) x 0.5 cm(2) to 10 cm(2 )x 10 cm(2). The present study is the second part of an extensive research conducted by our group. Methods Output correction factors kQclin,Qreffclin,fref were experimentally determined on two linacs, Elekta Versa HD and Varian TrueBeam for 6 and 10 MV beams with and without flattening filter for nine square fields ranging from 0.5 cm(2 )x 0.5 cm(2 )to 10 cm(2 )x 10 cm(2), for seven mini and micro ionization chambers, IBA CC04, IBA Razor, PTW 31016 3D PinPoint, PTW 31021 3D Semiflex, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16. An Exradin W1 plastic scintillator and EBT3 radiochromic films were used as the reference detectors. Results For all ionization chambers, values of output correction factors kQclin,Qreffclin,fref were lower for parallel orientation compared to those obtained in the perpendicular orientation. Five ionization chambers from our study set, IBA Razor, PTW 31016 3D PinPoint, PTW 31022 3D PinPoint, PTW 31023 PinPoint, and SI Exradin A16, fulfill the requirement recommended in the TRS-483 Code of Practice, that is, 0.95