Plastic scintillation dosimeters (PSDs) have many properties that make them desirable for relative dosimetry with MRI-LINACs. An in-house PSD, Farmer ionisation chamber and Gafchromic EBT3 film were used to measure central axis percentage depth dose distributions (PDDs) at the Australian MRI-LINAC Mean errors were calculated between each detector’s responses, where the in-house PSD was on average within 0.7% of the Farmer chamber and 1.4% of film, while the Farmer chamber and film were on average within 1.1% of each other. However, the PSD systematically over-estimated the dose as depth increased, approaching a maximum overestimation of the order of 3.5% for the smallest field size measured. This trend was statistically insignificant for all other field sizes measured; further investigation is required to determine the source of this effect. The calculated values of mean absolute error are comparable to the those of trusted dosimeters reported in the literature. These mean absolute errors, and the ubiquity of desirable dosimetric qualities inherent to PSDs suggest that PSDs in general are accurate for relative dosimetry with the MRI-LINAC. Further investigation is required into the source of the reported systematic trends dependent on field-size and depth of measurement.

塑料闪烁剂量计 (PSD) 具有许多特性，使其成为 MRI-LINAC 相对剂量测定的理想选择。使用内部 PSD、Farmer 电离室和 Gafchromic EBT3 薄膜测量澳大利亚 MRI-LINAC 的中心轴百分比深度剂量分布 (PDD) 计算每个探测器响应之间的平均误差，其中内部 PSD 为平均值在农室的 0.7% 和电影的 1.4% 以内，而农夫室和电影的平均相差在 1.1% 以内。然而，随着深度的增加，PSD 系统地高估了剂量，对于测量的最小视野大小，接近 3.5% 的最大高估。对于所有其他测量的字段大小，这种趋势在统计上不显着；需要进一步调查以确定这种影响的来源。平均绝对误差的计算值与文献中报道的可信剂量计的计算值相当。这些意味着绝对误差，以及普遍存在的 PSD 固有的理想剂量学质量表明，对于使用 MRI-LINAC 的相对剂量学，PSD 通常是准确的。需要进一步调查所报告的系统趋势的来源，这取决于现场大小和测量深度。