Zou Wei, Gao Jinlong, Jones Allen S, Hunter Neil, Swain Michael V
Biomaterial Research Unit, Faculty of Dentistry, University of Sydney, Australia.
Analyst. 2009 Jan;134(1):72-9. doi: 10.1039/b806884d. Epub 2008 Oct 18.
Laboratory micro-CT systems, although limited by beam hardening effect and instability of the source, have been utilized to measure mineral density in combination with specific image processing methods. However, few attempts have been made to accurately determine mineral density profiles in dentine due to the lack of suitable calibration standards. The aim of this study was to develop a calibration method to evaluate mineral density profiles in dentine including changes associated with dentinal caries. A series of K(2)HPO(4) solution phantoms in a concentration range between 0 and 0.9 g cm(-3)--coupled to a set of water infiltrated porous solid hydroxyapatite (HA) phantoms, with mineral densities ranging from 1.52 to 2.08 g cm(-3), was used in this investigation. First we evaluated the micrometer-scale homogeneity and noise in the HA phantoms using a commercial laboratory micro-CT system. Then an experimental validation was performed of the linearity over the entire density range of these two different calibration materials. The results show the HA phantoms extended the calibration curve obtained from K(2)HPO(4) solution phantoms to densities as high as 2.08 g cm(-3); the linearity remains stable at different energy levels. Finally, compared to the reference micro-CT calibration methods, the advantages of this new method are discussed. We conclude that this calibration method allows a more rational assessment of mineral density of dentine by micro-CT and has a promising potential for future studies.
实验室微型计算机断层扫描（micro-CT）系统虽然受到束硬化效应和源稳定性的限制，但已结合特定图像处理方法用于测量矿物质密度。然而，由于缺乏合适的校准标准，很少有人尝试准确测定牙本质中的矿物质密度分布。本研究的目的是开发一种校准方法，以评估牙本质中的矿物质密度分布，包括与牙本质龋相关的变化。本研究使用了一系列浓度范围在0至0.9 g/cm³之间的磷酸氢二钾（K₂HPO₄）溶液体模，并结合了一组水浸润的多孔固体羟基磷灰石（HA）体模，其矿物质密度范围为1.52至2.08 g/cm³。首先，我们使用商用实验室微型计算机断层扫描系统评估了HA体模中的微米级均匀性和噪声。然后对这两种不同校准材料在整个密度范围内的线性进行了实验验证。结果表明，HA体模将从K₂HPO₄溶液体模获得的校准曲线扩展到高达2.08 g/cm³的密度；在不同能量水平下线性保持稳定。最后，与参考微型计算机断层扫描校准方法相比，讨论了这种新方法的优点。我们得出结论，这种校准方法允许通过微型计算机断层扫描更合理地评估牙本质的矿物质密度，并具有未来研究的广阔潜力。
