Establishment of non-destructive quantitative measurements of the mineral concentrations for the fine structure in hard tissue by using micro CT

本项目拟建立一种利用微ct对硬组织精细结构中矿物质浓度进行无损定量测量的方法。为了完成这一目标，我们设计了以下四个主要研究：1)微ct密度影响因素的基础研究，2)微ct矿物浓度定量测量仪器的提出与研制，3)本研究在人牙本质上的应用，4)矿化硬组织微ct图像伪影还原方法的开发。1)微ct密度影响因素的基础研究。微ct图像的密度受测量时样本量和放大倍数的影响。通过散射辐射和图像重建的原理观察到空气的波动，以及X射线光谱引起的图像密度的不均匀。2)提出并研制了一种微型ct定量测量矿物浓度的仪器。测量仪器设计为柱状铝杯，内部装有四种不同浓度的羟基磷灰石和碳的混合物。根据已知的标准矿物密度数据，绘制校正线性回归线，确定未知样品的矿物密度。3)本研究在人牙本质上的应用。利用这些仪器，对年龄在26岁至78岁之间的人类牙本质样本进行了矿物质含量的测量。结果表明，正常牙本质和半透明牙本质中矿物质含量均有所增加。4)矿化硬组织显微ct图像伪影还原方法的发展研究。为了减少微CT图像的伪影，我们开发了一种将样品嵌入补偿材料的方法。总的来说，结果表明这个项目的目标是成功完成的。但是，这种方法的准确性还有待进一步的验证研究，如密度测量的重复、与化学分析的比较等。少

This project was planed to establish of non-destructive quantitative measurements of mineral concentrations for fine structure in hard tissue by using micro-CT. To complete of this aim, we designed four main studies as follows ; 1)basic studies of the factors influencing density of micro-CT, 2)proposal and manufacture of the measuring instrument for quantitative measurements of mineral concentrations by using micro-CT, 3)the application of this study for the human dentine, 4)development of artifact reduction method for micro-CT image in mineralized hard tissue.1)Basic studies of the factors influencing density of micro-CT. The density of the micro-CT images were affected by sample size and magnification at the measurements. It were also observed that air revel fluctuation by scattered radiation and a principle of reconstruction of the images, and the uneven nesses of the density in the image caused by the spectrum of X rays.2)Proposal and manufacture of the measuring instrument for qua … More ntitative measurements of mineral concentrations by using micro-CT. The measuring instrument was designed for columnar shape made by aluminum cup which inside equipped with four different concentrations of the mixture of hydroxyapatite and carbon. And the unknown samples of the mineral density were determined by drawing the calibration linear regression line from the data of known the standard mineral density.3)Application of this study for the human dentine. Using the instruments, the mineral contents of human dentine samples age 26 to 78 were measured. As a result, increasing of the mineral contents in both normal and translucent dentine was observed.4)Developmental study of the artifact reduction method for micro-CT image in mineralized hard tissue. To reduce the artifact of micro CT images, we developed a method that the samples were embedded in compensating materials.Over all results indicates the aim of this project were completed successfully. However, the confirmation studies of the accuracy by this method were still remaining, such as repeats of measurements of the density, comparison with chemical analysis and so on. Less