【作者】 王婷婷；

【导师】 赵会娟；

【作者基本信息】 天津大学 ， 生物医学工程， 2012， 硕士

【摘要】 相对于目前临床应用的乳腺影像方法,漫射光层析成像(Diffuse Optical Tomography, DOT)因其良好的特异性以及实时、安全性而成为有潜力的乳腺影像新技术。在此基础上发展起来的荧光层析成像(Fluorescence Diffuse Optical Tomography,FDOT)采用吲哚菁绿(Indocyanine green, ICG)作为荧光增强剂,可使图像对比度比DOT高2-4倍。FDOT不仅可采用产率作为重建参数,也可通过同时重建荧光寿命为癌症的早期诊断提供组织体功能信息,从而提高乳腺癌早期诊断的准确率。光学成像中的传统探测模式采用光纤与成像仓直接接触进行测量。这种接触测量方式限制了数据规模和空间分辨率的提高,调节过程繁琐、耗时,并且在光纤匹配以及调整中易出现误差。为解决以上问题,本组以现有的单通道基于时间相关单光子计数(Time-Correlated Single Photon Counting Techniques, TCSPC)的时间分辨测量系统为基础,搭建了适于在体乳房成像的时域非接触式空间光扫描系统,相对于传统测量方法本方案可增大空间采样量、减小测量误差,提高空间分辨率。为实现系统的连续扫描及集成控制,利用集成了Qt插件的Visual Studio 2008平台进行了集成控制软件开发,实现了连续测量扫描以及测量曲线的实时显示等功能。利用仿体实验对所搭建系统进行了验证。在DOT实验中,利用该系统对目标仿体中异质体的吸收与约化散射系数进行了成像。在FDOT实验中,分别对单目标体和双目标体进行成像。基于本组已发展的DOT和FDOT图像重建算法进行了图像重建,结果表明: DOT实验中光学参数重建值与实际值基本相符,重建目标与真实目标位置大小相符;FDOT单目标体实验中对荧光目标的产率与寿命进行重建;通过荧光产率的重建可有效对中心距为20mm、边距为15mm的目标体进行分辨进行分辨且能够实现不同浓度的双目标体相对定量重建。实验结果证明了该系统重建组织体光学参数以及进行荧光层析成像的可行性,进一步发展可推动应用于乳腺癌检测的光学层析技术发展。更多还原

【Abstract】 Compared with the current breast imaging methods such as mammography, ultrasonic imaging and nuclear magnetic resonance, diffuse optical tomography (DOT) becomes one of the most promising breast imaging technique due to its advantages of good specialty, sensitivity and safety. Based on the technology of DOT, fluorescence diffuse optical tomography (FDOT) introduces Indocyanine Green (ICG) as fluorescence enhancement agent, which can greatly improve the image contrast. Tumor-to-normal tissue contrast based on FDOT with the fluorophore Indocyanine Green is two-to-four-fold higher than contrast obtained with traditional diffuse optical tomography. FDOT can not only reconstruct the yield but also the lifetime, which improves the accuracy of early cancer diagnosis and provides functional information for the early cancer diagnosis.Conventionally, tomography imaging systems require the use of a number of detector fibers put in contact with the object of investigation, which limits the data scale and the improvement of spatial resolution. In order to solve above problems, a time domain noncontact fluorescence tomography system towards the early diagnosis of breast cancer is developed. The time domain system based on the time-correlated single photon counting technique (TCSPC) is adopted to provide both the high sensitivity in detection and good capability in multi-parameter reconstruction. Compared with the conventional contact measurement mode, the noncontact system with light scanning can provide more measurement data for improving the spatial resolution of the images. The controlling software is developed on the platform of Visual Studio 2008 integrated with Qt and the functions of continuous measurement and real-time display of the measurement curves are realized.The performance of the system is evaluated with measurements on solid phantoms. In the DOT experiment, both the absorption coefficient and the scattering coefficient can be well constructed. The reconstructed value is corresponded to the real value and the reconstructed position and size of the target can well reflect the real position and size; In the FDOT experiments, for the phantom with single fluorescent target, the fluorescence yield and lifetime were simultaneously reconstructed with good quality. For the phantom with two fluorescent targets, the targets with the center-to-center separation of 20mm and the edge separation of 15mm can be distinguished. Measurements also show that the reconstructed yields are linear to the concentration of the fluorescence dye. The results demonstrated the potential of the system in the in vivo diagnosis of the early breast cancer.更多还原