Quantitative backscattered electron imaging is an established method to map mineral content distributions in bone and to determine the bone mineralization density distribution (BMDD). The method we applied was initially validated for a scanning electron microscope (SEM) equipped with a tungsten hairpin cathode (thermionic electron emission) under strongly defined settings of SEM parameters. For several reasons, it would be interesting to migrate the technique to a SEM with a field emission electron source (FE-SEM), which, however, would require to work with different SEM parameter settings as have been validated for DSM 962. The FE-SEM has a much better spatial resolution based on an electron source size in the order of several 100 nanometers, corresponding to an about \(10^5\) to \(10^6\) times smaller source area compared to thermionic sources. In the present work, we compare BMDD between these two types of instruments in order to further validate the methodology. We show that a transition to higher pixel resolution (1.76, 0.88, and 0.57 μm) results in shifts of the BMDD peak and BMDD width to higher values. Further the inter-device reproducibility of the mean calcium content shows a difference of up to 1 wt% Ca, while the technical variance of each device can be reduced to \(\pm 0.17\) wt% Ca. Bearing in mind that shifts in calcium levels due to diseases, e.g., high turnover osteoporosis, are often in the range of 1 wt% Ca, both the bone samples of the patients as well as the control samples have to be measured on the same SEM device. Therefore, we also constructed new reference BMDD curves for adults to be used for FE-SEM data comparison.

定量背散射电子成像是绘制骨中矿物质含量分布图和确定骨矿化密度分布 (BMDD) 的成熟方法。我们应用的方法最初在扫描电子显微镜 (SEM) 上进行了验证，该显微镜在严格定义的 SEM 参数设置下配备了钨发夹阴极（热电子发射）。出于多种原因，将该技术迁移到具有场发射电子源 (FE-SEM) 的 SEM 会很有趣，但是，这需要使用不同的 SEM 参数设置，如已针对 DSM 962 验证的那样。FE -SEM 具有更好的空间分辨率，基于电子源尺寸在几个 100 纳米的数量级，对应于大约\(10^5\)到\(10^6\)与热离子源相比，源面积小数倍。在目前的工作中，我们比较了这两种类型的仪器之间的 BMDD，以进一步验证该方法。我们表明，过渡到更高的像素分辨率（1.76、0.88 和 0.57 μm）会导致 BMDD 峰和 BMDD 宽度向更高的值移动。此外，平均钙含量的设备间再现性显示出高达 1 wt% Ca 的差异，而每个设备的技术差异可以减少到\(\pm 0.17\)重量％钙。请记住，由于疾病（例如高周转骨质疏松症）导致的钙水平变化通常在 1 wt% Ca 的范围内，因此必须在相同的 SEM 上测量患者的骨骼样本和对照样本设备。因此，我们还为成人构建了新的参考 BMDD 曲线，用于 FE-SEM 数据比较。