改进的同步迭代算法在光声血管成像中的应用

光声成像结合了光学成像和声学成像的优点，是一种高分辨率，高对比度的无损伤医学成像技术.一种改进的同步迭代算法应用于光声图像重建.仿真和模拟结果表明，与传统的代数迭代算法相比，在90°，135°，180°的有限场光声成像中，此算法对测量误差的校正和迭代次数的收敛上具有较大的优势，图像重建的速度和成像质量都有了明显的提高.实验中，一种圆形扫描结构的光声成像装置，用于180°的有限场扫描，利用改进的同步迭代算法，重建出了高对比度和高分辨率（60μm）的鸡胚胎光声血管图像.实验证明，这种算法的应用，大幅度减少了数据采集时间，为光声成像技术运用于实时监测血流灌注和肿瘤光动力治疗的血管损伤效应提供了潜在的应用价值. 关键词： 光声成像 有限角度 代数迭代算法 光声血管成像

Photoacoustic imaging of blood vessels based on modified simultaneous iterative reconstruction technique

Photoacoustics as a potential and noninvasive medical imaging technology，it combines the advantages of ultrasound imaging and optical imaging to provide high ultrasonic resolution and high optical contrast tissue images. A reconstruction algorithm named the modified simultaneous iterative reconstruction technique (MSIRT) using in limited-view data in photoacoustic imaging was studied. The simulation and experiments result demonstrated that MSIRT has good performance in photoacoustic imaging for limited-view data at angles 90°，135° and 180°. It works much better than traditional algebraic reconstruction algorithm in rectification of the measurement and the speed of convergence. A circular scan with a single-element transducer system was used to obtain photoacoustic signals through 180° in the experiment. This technique provides a high contrast and high resolution (about 60μm) photoacoustic imaging of blood vessels of a chicken embryo based on MSIRT. It greatly reduced the data acquisition time. This method could be potentially used to realtime monitoring of cerebral blood flow and the vascular damage during photodynamic therapy.