Diagnostic accuracy of digitized dental radiographs

许多因素可能决定数字化口腔内X线片的诊断准确性。传统的胶片射线照片是用三种不同的数字转换器数字化的：一台激光扫描仪、一台鼓扫描仪和一台电视摄像机。不同像素大小、灰度级和图像处理的数字图像被显示在三个不同的视频监视器上，并由10名牙医进行评估。通过受试者工作特性分析，以近中面龋的发现率作为诊断准确率的指标，比较不同因素对诊断的影响。由鼓式扫描仪数字化的图像具有最好的诊断准确性。在个人计算机的低成本视频监视器上可以获得足够的诊断精度。为了诊断目的，发现像素尺寸为100 mm、灰度级为32的数字图像对于口腔内放射照片是可以接受的。这些结果为建立任何口腔内X线片的数字图像采集系统提供了实用指南，将对数据存储的需求降至最低。

A number of factors may determine the diagnostic accuracy of digitized intraoral radiographs. Conventional film radiographs were digitized with three different digitizers, a laser-scanner, a drum-scanner, and a TV camera. Digital images, varying in pixel size and gray level and image processing, were displayd on three different video-monitors and assessed by 10 dentists. The detectability of incipient proximal surface caries was used as an index of the diagnostic accuracy and the effect of the different factors compared by means of receiver operating characteristic analysis. Image digitized by the drum-scanner were found to have the best diagnostic accuracy. Sufficient diagnostic accuracy could be attained on the low-cost video monitor of a personal computer. Digital images with a pixel size of 100mm and 32 gray levels were found to be acceptable for intraoral radiographs, for diagnostic purposes. These results provide a practical guide for establishing a digital image acquiring system for any intraoral radiographs, reducing demands on data storage to a minimum.