连续波THz-CT的折射问题研究  

Refraction problems in continuous wave THz-CT

作　　者：郭风雷[1] 张明月[2] 肖征[2] 李向军[1] 刘建军[1] 

机构地区：[1]中国计量学院信息工程学院太赫兹技术与应用研究所,浙江杭州310018 [2]南京军区杭州疗养院海勤疗养区,浙江杭州310002

出　　处：《红外与激光工程》2015年第3期969-973,共5页Infrared and Laser Engineering

基　　金：南京军区医药卫生科研项目(12MA115);国家质检总局科技计划(2013QK030);浙江省公益技术应用研究(2013C31088)

摘　　要：设计了基于返波振荡器的连续波太赫兹CT成像实验装置,实现了用连续太赫兹波对三维物体的CT断层成像。虽然可以得到较好的重建图像,但由于折射率大于1.5的材料对太赫兹射线折射较强而影响成像质量。首先通过对聚四氟乙烯模型进行扫描获得投影数据,并利用滤波反投影算法对投影数据进行重建得到断层图像,然后分析了高折射对投影探测及图像重建的影响。最后对人体牙齿样本进行投影扫描和断层重建,获得的断面图像可以反映牙齿内部结构,但由于牙齿高折射率的影响,成像精度和分辨率有待进一步提高。而且牙釉质的厚度会严重影响太赫兹波在牙齿中的透射深度。研究结果可以为提高连续波太赫兹CT成像质量提供参考,促进其在医学成像特别是牙齿等骨骼成像中的应用。Terahertz CT setup was designed and constructed by backward wave Oscillator which has been used to perform computed tomography of 3D objects. However, the imaging quality is affected by strong refraction from materials with the refractive index greater than 1.5 in objects. At first, the cross section image of a teflon modal was reconstructed from the projection dataset by the filtered backprojection algorithm, then high refraction effects were analyzed. Finally, a human tooth sample was scanned and the cross section images were reconstructed to reveal its internal structures. However, the accuracy and resolution of the images were still limited owing to the high refraction effects. And the terahertz transmission depth in teeth was seriously affected by the thickness of enamel. The results in paper are helpful to improve the imaging quality of THz-CT and promote its applications especially in biomedical imaging of human bones like human tooth.

关 键 词：计算机断层成像 太赫兹 连续波 高折射率 

分 类 号：R312[医药卫生—基础医学]