Quantitative Analysis of Bone Destruction by an Intra-oral Fluoroscopic TV System

我们研制的牙科X射线电视系统主要由以下几部分组成：1）牙科X射线机用X射线管（50 kVp，5 mA），带开口锥体，直径：2.0cm，2）用于X射线管和探测器之间关系的磁传感器，3）口腔内荧光玻璃纤维光学内窥镜，4）SIT TV摄像机，5）用于图像存储的帧存储器，6）CRT监视器，7）VTR，8）惠普惠普-本系统采用高灵敏度的电视系统，以最小的辐射剂量获得足够的电视图像，并对骨矿物质进行了定量分析该系统通过以下步骤进行：1）获得与测试件中的骨矿物质以羟基磷灰石计的重量相对应的光度值; 2）基于测试件的TV图像确定校准函数，并且准备用于计算骨矿物质的量的程序。3）通过比较由人下颌骨的TV图像计算的一部分干骨的矿物质量与由原子吸收光谱法测定的同一部分中的钙的量，证实了该系统的可靠性。X线电视图像与本法测得的钙量相吻合，对70 mg以上骨标本误差为1.1 ~ 5.0%，对2例儿童下颌骨滤泡囊肿术后愈合情况作了客观评价。

The dental X-ray TV system we have developed has the following components.1) X-ray tube for dental X-ray apparatus (50kVp,5mA) with an open-end cone, diameter:2.0cm, 2) Magnetic sensor for the relation of X-ray tube and detector, 3) Intra-oral fluoroscopic glassfiber optics endoscope, 4) SIT TV camera, 5) Frame-memory for image storage, 6) CRT monitor, 7) VTR, 8) Hewlett-Packard HP-85 microcomputer for image analysisThis system is designed to obtain an adequate TV image at a minimized radiation dose by employing a highly sensitive TV system.The quantitative analysis of bone mineral by this TV system is carried out by the following procedure.1) The value of luminosity corresponding to the weight of the bone mineral in the test piece in terms of hydroxy-apatite is obtained.2) A calibration function is determined on the basis of the TV image of the test piece, and a program is prepared for calculating the quantity of the bone mineral.3) The reliability of this system is confirmed by comparing the mineral quantity of a part of dry bone of a human mandible calculated from its TV image with the quantity of calcium in the same part determined by atomic absorption spectrophotometry.4) The value calculated from the X-ray TV image and the calcium quantity determined by the above method coincided, with errors ranging from 1.1 to 5.0 percent in the case of a bone specimen weighing 70mg or upwards.We showed objective evaluation of the healing condition after operation on two cases of folicullar cysts of the mandible in children.