Boyce T M, Bloebaum R D, Bachus K N, Skedros J G
Bone & Joint Research Laboratories, VA Medical Center, Salt Lake City, UT 84148.
Scanning Microsc. 1990 Sep;4(3):591-600; discussion 600-3.
Backscattered electron (BSE) imaging shows promise for orthopaedic and bone research. BSE images of bone may be captured on-line directly from the scanning electron microscope (SEM), and then analyzed to produce a backscattered electron profile (BSEP), a modified image graylevel histogram which is representative of the mineral content in bone. The goals of this work were 1) develop a reproducible graylevel calibration technique for bone specimens, and 2) determine a conservative time interval during which SEM operating conditions would remain stable. Calibration standards containing pure aluminum and pure magnesium wires were placed in the SEM with human cancellous bone. Baseline imaging conditions were first established by adjusting the SEM until the bone image displayed good resolution and graylevel separation between regions of different mineral content. Microscope brightness and contrast controls were randomly changed to initiate the new operating conditions of another imaging session, and graylevel values from the calibration metals were used to readjust the microscope back to baseline operating conditions. Weighted mean graylevel values of the BSEPs from calibration trials were compared to those of the baseline. Data showed that bone images could be reproduced within 1.2 percent. It was also concluded that our equipment required calibration checks at 20 minute intervals.
背散射电子（BSE）成像在骨科和骨骼研究方面显示出前景。骨骼的BSE图像可以直接从扫描电子显微镜（SEM）在线捕获，然后进行分析以生成背散射电子轮廓（BSEP），这是一种经过修改的图像灰度直方图，代表骨骼中的矿物质含量。这项工作的目标是：1）为骨标本开发一种可重复的灰度校准技术，以及2）确定SEM操作条件保持稳定的保守时间间隔。将含有纯铝线和纯镁线的校准标准物与人类松质骨一起放入SEM中。首先通过调整SEM来建立基线成像条件，直到骨图像显示出良好的分辨率以及不同矿物质含量区域之间的灰度分离。随机改变显微镜的亮度和对比度控制，以启动另一次成像 session 的新操作条件，并使用校准金属的灰度值将显微镜重新调整回基线操作条件。将校准试验中BSEP的加权平均灰度值与基线的进行比较。数据表明，骨图像可以在1.2%的范围内重现。还得出结论，我们的设备需要每隔20分钟进行一次校准检查。
