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

本项目旨在建立一种基于显微CT的硬组织精细结构矿物质浓度的无损定量测量方法。为实现这一目标，我们设计了以下四个主要研究：1)影响Micro-CT密度的因素的基础研究；2)Micro-CT定量测量矿物浓度测量仪的提出和研制；3)本研究在人牙本质中的应用；4)矿化硬组织中Micro-CT图像伪影减少方法的发展。1)影响Micro-CT密度的因素的基础研究。显微CT图像的密度受测量时样本大小和放大倍数的影响。还观察到了散射辐射引起的空气旋转起伏和图像重建的原理，以及X射线光谱引起的图像中密度的不均匀。2)准…测量仪的研制使用Micro-CT对矿物浓度进行更准确的测量。该测量仪是由铝杯制成的柱状物，内部装有四种不同浓度的羟基磷灰石和碳的混合物。由已知的标准矿物质密度数据绘制校正线性回归直线，确定未知样品的矿物质密度。3)本研究在人牙本质中的应用。用该仪器测量了26~78岁人牙本质样本的矿物质含量。结果表明，正常牙本质和半透明牙本质中的矿物质含量均有所增加。4)矿化硬组织显微CT图像伪影去除方法的研究。为了减少显微CT图像中的伪影，我们提出了一种将样品嵌入补偿材料中的方法，所有结果表明本项目的目标是成功的。然而，该方法的准确度验证研究仍在继续，如密度的重复测量、与化学分析的比较等。较少

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