微型X射线数字成像系统的测试与应用

研制了一套采用X射线敏感CCD作为成像探测器的微型数字成像系统并用于牙科诊断。应用牙齿模型与分辨率测试卡对系统的辐射剂量和分辨率进行了测试,采用分段线性校正对CCD与转换屏耦合下的响应不均匀性进行校正,并通过计算线性相关系数辨别瑕疵像元以避免误判。测试了系统在高分辨率、小工作幅面X射线检测方面的应用效果。结果显示,系统分辨率高于10lp/mm,在获得相近对比度图像的条件下,所需的辐射剂量仅为胶片的10%,图像非均匀性相对校正前可降低27.5%。得到的结果表明,系统满足高分辨率、低辐射剂量的使用要求,在微小物体X射线检测方面具有较大的应用潜力。

Test and application of compact digital X-ray imaging system

A compact digital X-ray imaging system which adopts an X-ray sensitive CCD as an imaging detector was introduced for the dental imaging. A tooth model and a resolution testing card were used to test the revolution and radiographic dosage, respectively, and the subsection linearity correction was used to calibrate the nonuniformity of coupling of CCD and switch screen. In order to identify the bad pixel, a linear correlation coefficient was calculated to avoid the misjudgement. The imaging system was applied to an X-ray detection required a high resolution and a small work-area and the results show that the resolution of imaging system is higher than 10 lp/mm, radiographic dosage is less than 10% in contrast with that of X-ray film, and the calibrated nonuniformity of image has reduced by 27.5%. Obtained results prove that the system can satisfy the system requirements of high-revolution, low- radiographic dosage, and has a strong applied potential in X-ray detection for small objects.