Effect of SR-microCT radiation on the mechanical integrity of trabecular bone using in situ mechanical testing and digital volume correlation
Effect of SR-microCT radiation on the mechanical integrity of trabecular bone using in situ mechanical testing and digital volume correlation
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DOI：
10.1016/j.jmbbm.2018.08.012
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发表时间：
2018-12-01
影响因子：
3.9
通讯作者：
Tozzi, Gianluca
中科院分区：
文献类型：
--
作者：
Fernandez, Marta Peiia;Cipiccia, Silvia;Tozzi, Gianluca
利用同步辐射微计算机断层扫描（SR-microCT）来研究原位力学测试中微观结构与骨力学之间的关系越来越受欢迎。然而，众所周知，放射性x射线辐射的影响可以大大改变骨组织的力学性能。数字体积相关（DVC）已被广泛用于计算受阶梯机械载荷的骨标本的全场应变分布，但连续SR-microCT扫描造成的组织损伤尚未得到解决。因此，本研究的目的是通过DVC应用于不同暴露时间获得的原位SR- microct断层扫描，研究SR辐照引起的微损伤对小梁骨表观弹性特性的影响。结果显示，在高辐照剂量（类似于230 kGy）下，尽管表观弹性特性保持不变，但DVC如何能够识别出与可见微裂纹对应的高局部应变水平（> 10,000 mu epsilon）。尽管图像质量和DVC性能降低，但在低辐照剂量（类似于33 kGy）下未检测到微裂纹，骨可塑性得以保留。DVC结果提示组织局部恶化可能是由机械应变浓度引起的，即使在低累积剂量下，局部辐照水平也会进一步增强。
The use of synchrotron radiation micro-computed tomography (SR-microCT) is becoming increasingly popular for studying the relationship between microstructure and bone mechanics subjected to in situ mechanical testing. However, it is well known that the effect of SR X-ray radiation can considerably alter the mechanical properties of bone tissue. Digital volume correlation (DVC) has been extensively used to compute full-field strain distributions in bone specimens subjected to step-wise mechanical loading, but tissue damage from sequential SR-microCT scans has not been previously addressed. Therefore, the aim of this study is to examine the influence of SR irradiation-induced microdamage on the apparent elastic properties of trabecular bone using DVC applied to in situ SR-microCT tomograms obtained with different exposure times. Results showed how DVC was able to identify high local strain levels (> 10,000 mu epsilon) corresponding to visible microcracks at high irradiation doses (similar to 230 kGy), despite the apparent elastic properties remained unaltered. Microcracks were not detected and bone plasticity was preserved for low irradiation doses (similar to 33 kGy), although image quality and consequently, DVC performance were reduced. DVC results suggested some local deterioration of tissue that might have resulted from mechanical strain concentration further enhanced by some level of local irradiation even for low accumulated dose.