Fleming David E B, Crook Samantha L, Evans Colby T
Physics Department, Mount Allison University, Sackville, NB, Canada.
Physics Department, Mount Allison University, Sackville, NB, Canada.
Appl Radiat Isot. 2019 Mar;145:170-175. doi: 10.1016/j.apradiso.2018.12.033. Epub 2018 Dec 31.
A mono-energetic X-ray beam from a portable X-ray fluorescence device was used to excite characteristic X-rays from zinc in a series of nail clipping phantoms. Twenty nail clipping phantoms having equal zinc concentrations of 40 µg/g, but with different physical characteristics, were measured individually for 300 s using a small diameter (1 mm) X-ray beam. Energy spectra obtained from the measurements were analyzed using PyMca software. Zinc signal size varied widely between the different clippings, with a relative standard deviation of 41% observed in the combined signal from zinc Kα and Kβ characteristic X-rays. Three different normalization approaches were introduced to account for variation in the amounts of sample interrogated by the X-ray beam. All three approaches produced similar results, and successfully reduced the relative standard deviation to between 12% and 13%. A clear trend was still observed, however, between the normalized zinc signal and the thickness of clipping measured. To account for this effect, normalized signals were adjusted to calculate "thickness-corrected" values. The relative standard deviation of these thickness-corrected values was 6.2%. Reproducibility of measurement from individual clippings was excellent, with relative standard deviations on the order of 1%, with or without normalization. Overall, this new method of measuring zinc in nail shows promise for the assessment of zinc status in humans using a portable device. The method is sensitive, rapid, and requires only a single nail clipping.
使用便携式X射线荧光设备发出的单能X射线束，激发一系列指甲剪模拟物中锌的特征X射线。对20个锌浓度均为40μg/g但物理特性不同的指甲剪模拟物，使用小直径（1mm）X射线束分别测量300秒。使用PyMca软件分析测量获得的能谱。不同指甲剪之间锌信号大小差异很大，在锌Kα和Kβ特征X射线的组合信号中观察到相对标准偏差为41%。引入了三种不同的归一化方法，以考虑X射线束照射的样品量的变化。所有三种方法都产生了相似的结果，并成功地将相对标准偏差降低到12%至13%之间。然而，在归一化锌信号和测量的指甲剪厚度之间仍观察到明显的趋势。为了考虑这种影响，对归一化信号进行调整以计算“厚度校正”值。这些厚度校正值的相对标准偏差为6.2%。无论是否进行归一化，单个指甲剪测量的再现性都非常好，相对标准偏差约为1%。总体而言，这种测量指甲中锌的新方法有望使用便携式设备评估人体锌状态。该方法灵敏、快速，只需要剪下单个指甲。
