MEASUREMENT OF 3D STRAIN IN BONE BY TEXTURE CORRELATION

描述(改编自申请人的摘要)：本申请的 目的是开发一种非侵入性测量三维应变的方法 具有内部纹理的固体物体，特别是松质和皮质 骨头。实体内部的点的位置将使用 X射线层析显微镜，使用单色同步加速器X射线。这些 不同类型的机器的分辨率比“Micro CT”高好几倍 机器。固体中的位移和应变将使用 “纹理相关”是作者开发的一种跟踪方法 具有纹理的对象(如松质骨)中的可识别点，以及 计算位移场的应变。经过进一步的发展， 计算机算法将该方法从2D扩展到3D，进行了一系列测试 并将进行分析，以评估其准确性和敏感性 方法。在第一系列中，将测试一种均匀的泡沫材料 单轴压缩。均质圆柱体和带孔固体 将会受到考验。模拟试验的有限元模型将是 构造和分析。将有限元模型的结果进行比较 以纹理相关性方法作为评估图像质量的手段 后者。然后对松质骨进行相同的程序，从 猪的椎体和胫骨近端。材料属性将是 根据已发布的刚度/密度数据进行估计。最后，一系列 将使用来自XTM的较粗糙的数据集来评估 纹理数据需要获得可接受的分辨率和方法的精度。 分辨率较低的方法，如Micro-CT，可能会 采取适当的应变措施。

DESCRIPTION (Adapted from the applicant's Abstract): This application's goal is to develop a method for noninvasive measurement of 3D strain in solid objects with internal texture, particularly cancellous and cortical bone. The location of points internal to the solid will be determined using X-ray Tomographic Microscopy, using monochromatic synchrotron x-rays. These type of machines have resolutions several times greater than the "micro CT" machines. Displacement and strain in the solid will be determined using "texture correlation", a method developed by the authors for tracking identifiable points in an object with texture, such as cancellous bone, and computing strain from the displacement fields. After further development of computer algorithms to extend the method from 2D to 3D, a series of tests and analyses will be done to assess the accuracy and sensitivity of the method. In the first series, a uniform foam material will be tested in uniaxial compression. Both homogeneous cylinders and solids with a hole will be tested. A finite element model simulating the test will be constructed and analyzed. The finite element model results will be compared with the texture correlation method as a means of assessing the accuracy of the latter. The same procedure will then be done on cancellous bone from the vertebral body and proximal tibia of a pig. Material properties will be estimated from published stiffness/density data. Finally, a series of coarser data sets from the XTM will be used to assess the resolution of texture data needed to get acceptable resolution and accuracy of the method. It is possible that methods with less resolution, such as micro-CT, could give adequate strain measures.