Reference dosimetry in the presence of a strong magnetic field is challenging. Ionisation chambers have shown to be strongly affected by magnetic fields. There is a need for robust and stable detectors in MRI-guided radiotherapy (MRIgRT). This study investigates the behaviour of the alanine dosimeter in magnetic fields and assesses its suitability to act as a reference detector in MRIgRT. Alanine pellets were loaded in a waterproof holder, placed in an electromagnet and irradiated by 60 Co and 6 MV and 8 MV linac beams over a range of magnetic flux densities. Monte Carlo simulations were performed to calculate the absorbed dose, to water and to alanine, with and without magnetic fields. Combining measurements with simulations, the effect of magnetic fields on alanine response was quantified and a correction factor for the presence of magnetic fields on alanine was determined. This study finds that the response of alanine to ionising radiation is modified ...

中文翻译：

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强磁场中的丙氨酸剂量测定：在MRI指导的放射治疗中用作转移标准。

在强磁场存在下的参考剂量测定法具有挑战性。电离室已经显示出受到磁场的强烈影响。在MRI引导的放射治疗（MRIgRT）中需要鲁棒且稳定的检测器。这项研究调查了丙氨酸剂量计在磁场中的行为，并评估了其在MRIgRT中作为参考检测器的适用性。将丙氨酸丸粒装载在防水支架中，放置在电磁体中，并以60 Co和6 MV和8 MV直线加速器束在一定的磁通密度范围内进行辐照。进行蒙特卡洛模拟以计算在有或没有磁场的情况下对水和丙氨酸的吸收剂量。将测量与模拟相结合，量化了磁场对丙氨酸响应的影响，并确定了存在于丙氨酸上的磁场的校正因子。这项研究发现，丙氨酸对电离辐射的反应得到了改善。