Development and clinical application of dual energy imaging in dental X-ray examination.

双能量成像技术已在许多X射线成像领域显示出其诊断潜力，如胸部X光摄影、乳房X光摄影和计算机断层摄影。本研究将单次曝光双能量成像技术应用于口内X线摄影，并利用数字图像处理技术产生选择性骨图像，从而在不受软组织阻碍的情况下准确测量牙槽骨密度。在传统的X线摄影系统中，使用一对用膜间滤光片隔开的口腔内胶片，并通过计算机图像处理从这些图像中分解出铝当量图像。通过计算机模拟和实验研究，研究了膜间滤光片的最佳材料和厚度。提出了一种适用于单曝光双能量成像的图像分解算法。此外，还对该方法测量骨矿含量的准确性进行了研究。研究结果如下：在口内X线摄影中，单曝光双能量成像可以分离出骨等效位像。0的铜箔。在目前的成像系统中，作为膜间滤光片的最佳厚度为1 mm。对于厚度小于16 mm的铝材，即使覆盖40 mm厚的Mix-DP作为软组织，该方法的骨矿含量测量误差仍为0.57 mm。单次曝光双能量成像有可能为传统的口腔内X线片增加进一步的诊断信息，而不需要额外的剂量，也不需要患者进行额外的检查。利用该技术，正片可用于常规X线诊断，骨等效象可用于定量测定牙槽骨的绝对矿物质含量。

The dual energy imaging technique has demonstrated its diagnostic potential in many areas of x-ray imaging, such as chest radiography, mammography, and computed tomography. In this research, single exposure dual energy imaging was applied to intraoral radiography and selective bone images were produced using digital image processing to allow accurate measurement of alveolar bone density without hindrance from soft tissue. A pair of intraoral films separated with an inter-film filter was used in a conventional radiographic system, and an aluminum equivalent image was decomposed from these images by computerized image processing. The optimum material and thickness of the inter-film filter was investigated by computer simulation and'experimental studies. An image decomposition algorithm was proposed for single exposure dual energy imaging. In addition, the accuracy of bone mineral content measurement by this method was also investigated. The results was shown as follows. Bone equivalent images could be separated by single exposure dual energy imaging in intraoral radiography. A copper foil of 0. I mm in thickness was found to be optimal as an inter-film filter in the present imaging system. Measurement error of bone mineral content in this method was 0.57 mm in aluminum thickness for an aluminum object of less than 16 mm thickness even though it overlaid with 40 mm thick Mix-DP as soft tissue. Single exposure dual energy imaging has a potential to add further diagnostic information to a conventional intraoral radiogram with no additional dosage and no additional examinations to the patient. With this technique, the front film can be used for conventional radiographic diagnosis and the bone equivalent image can be used to quantify the absolute mineral content of alveolar bone.