Quantitative Study in Absorption of Mandible Caused by Aging and Disease

衰老和疾病引起的下颌骨吸收的定量研究

• 批准号: 04454481
• 负责人: NAGAO Masanori
• 金额: $ 4.42万
• 依托单位: Tokyo Medica and Dental University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04454481/
• 关键词: Absorption of mandible; dual energy subtraction; quantitative image; bone mineral content

Absorption of mandible is caused by aging, desease, and prosthetic Factors. It is difficult to estimate these absorption, and if possible, that is useful information for the prosthetic treatment, design and prognosis of prosthetics. Therefore, there were many studies in absorption of mandible with the tool of radiology, histology and biochemistry. But, there was no quantitative study in absorption of mandible and no method which can make quantitative measurements of bone mineral content. In this respect, we developed a sistem which can produce a quantitative image of bone mineral content. The system consists of a radiographing system and an image processor. Two radiograms were taken with dual X-ray energy in a single exposure using an X-ray beam dichromized by a tin filter. The image processing included the corrections of the film characteristics and heterogeneity in the X-ray field, and the dual energy subtraction in which the effect of the high energy component of the dichromized beam on the tube side image as corrected. In order to determine conditions of exposure of X-ray and some parameters of image analysis, experiments using wedge phantoms made of mixtures of epoxy resin and bone mineral-equvalent materials in various fractions were performed. The results as follows : the best tube potetials were from 60kV to 70kV.10x10 pixels image sample was suitable for image processing and it could make the best accuracy for the measurement of bone mineral content.

下颌骨吸收是由年龄、疾病、假体因素等引起的。很难估计这些吸收，如果可能的话，这是有用的信息，修复治疗，设计和预后的修复。因此，人们从放射学、组织学、生物化学等方面对下颌骨的吸收进行了大量的研究。但是，目前对下颌骨的吸收还没有定量的研究，也没有定量测量骨矿含量的方法。在这方面，我们开发了一个系统，可以产生骨矿物质含量的定量图像。该系统由一个射线照相系统和一个图像处理器组成。在单次曝光中使用双X射线能量拍摄两张X射线照片，X射线束由锡过滤器光化。图像处理包括胶片特性和X射线场中不均匀性的校正，以及双能量减影，其中校正了准直束的高能分量对管侧图像的影响。为了确定X射线的曝光条件和图像分析的一些参数，使用由环氧树脂和骨矿物等效材料以不同比例混合制成的楔形体模进行实验。结果如下：最佳管电压范围为60 ~ 70 kV。10 × 10像素的图像样本适合于图像处理，可使骨矿含量测量的准确度最高。