ESTABLISHMENT OF MEASUREMENTS METHOD FOR COMPACT BONE MINERAL DENSITY BY HELICAL SCAN CT WITH HA-C REFERENCE

完成了本课题的主要目的，即建立以HA-C为参照的螺旋CT密质骨密度测量方法。新参照物的特点是：(1)新参照物的材料由羟基磷灰石和纯碳组成。(2)100%参考文献的CT数高于密质骨。(3)经人体身体检验，新的柱状参考物高3.4~5.7 mm，直径13.05±0.10m，由两种材料组成：本实验室根据Shimoda(1990)方法制备的羟基磷灰石(HA)和99.9%的碳(C)：(Soekawa Chemical Tokyo)。用玛瑙砂浆和捣锤按100、80、60、40、20%的准确重量比制成羟基磷灰石和碳粉的细颗粒混合物后，用配备真空泵的金属模具和压力机(岛津，600公斤/厘米)压制每个混合样品。这五个步骤HA-…在准确测量C颗粒的重量和体积后，更多地使用C颗粒作为CT标准。因此，参考单位根据每个颗粒的羟基磷灰石含量表示单位体积(Mm)的HA重量(Mg)。螺旋CT图像作为CT值的测试测量使用的人身体配备参照物在下颌骨门区。CT扫描条件为：层厚1 mm工作台前进速度1 mm/s：X线管电压1 mm/s，120KV管电流75~175 mA。各参照物CT值在2583.1±25.28~351.91±17.66之间，各参照物CT值与HA mg/mm呈正相关(r=0.9996)。下颌骨致密骨最大CT值为1665.9±198.43，单位体积HA重量换算值为1.393 mg/mm~3。对新的参考文献的CT值进行测试后，用人体身体活检法检验参考文献的有效性。对20~60岁女性的临床骨密度测试表明，人类下颌骨的骨密度最大值出现在30岁时，然后随着年龄的增长而下降。有人认为应该尽快进行更广泛的研究。较少

The main purpose of this prefect, i.e. establishment of measurements method for compact bone mineral density by helical scan CT with HA-C reference were completed. The features of this new reference were as furrows ; (1) The materials of new reference is consist of hydroxyapatite and pure carbon. (2) The CT number of 100% references have higher than compact bone. (3) The accuracy were verified by the examination using human cadavers.The new columnar shape references, 3.4 - 5.7 mm in height and 1 3.05 + 0.10 m diameter, consists of two materials : hydroxyapatite (HA) which was prepared in our laboratory according to the Shimoda (1990) method, and 99.9% carbon(C) : (Soekawa Chemicals Tokyo). After using an agate mortar and pestle to make a mixture of fine granules of hydroxyapatite and carbon powder using at the exact weight ratios of 100, 80, 60, 40, 20%, each mixed sample was pressed using a metal mold and presser (shimazu, at 600kg/cm2) equipped with a vacuum pump. These five step HA- … More C pellets were used as a CT standard after measuring their accurate weight and volume. The unit of references, therefore, represented HA weight (mg) per unit volume (mm) according to the hydroxyapatite contents of each pellet. The spiral CT images were taken as a test measurement of CT value using a human cadaver equipped with the references at the menton region of mandible. The CT images were taken under the following conditions : slice thickness 1 mm table forward speed, 1mm/sec : X-ray tube voltage, 120kV tube current ranges between 75 - 175mA. The CT values of the references were in a range between 2583.1±25.28〜351.91±17.66, and the CT value to HA mg/mm of each reference showed positive linear regression (r= 0.9996). The maximum CT value of the compact bone in the mandible was 1665.9±198.43, and the conversion value in HA weights per unit volume was 1.393mg/mm3. After the test measurements of the CT value of the new references in regard to human com-pact bone the validity of the references was examined by biopsy using human cadaver.The clinical test measuring of BMD in age twenties to sixties woman showed that the maximum BMD values of compact bone in human mandible were seen at thirties and then decreased with ageing. It is considered that more extensive studies should be done quickly. Less