基于探测超声的生物组织无损光声层析成像

Noinvasive Photoacoustic Tomography in Biological Tissue with Ultrasonic Probe Beam

利用一束单频探测超声穿过由脉冲激光照射产生的光声激发区域,使之与光致声场产生相互作用,光声信号将耦合到探测束上,再解调探测超声来重建光吸收区域的图像,可以得到丰富的组织信息.该信息不仅反映了组织中光吸收的特性,也反映了组织的声学特性.实验中,通过旋转超声探测器进行数据采集,并利用滤波反投影算法重建图像,可得到高信噪比的光声层析图像.由于激光的窄光谱线宽,其吸收是特征分子选择性的,所以此方法既是一种无损伤的结构层析成像方法,也可用于组织的功能成像.

A noinvasive method for photoacoustic tomography of medical diagnoses by using an ultrasonic probe beam is presented. When a pulse laser irradiates on biological tissues, a plane ultrasonic probe beam passes through the irradiated area,and the ultrasonic probe beam interacts nonlinearly with photoacoustic tomography wave. Abundant information can be taken out from the interaction area by demodulating the probe beam. On one hand, the information can reflect the optical properties of the tissue; on the other hand, it can also reflect acoustical properties of the tissue. In the experimentation, the circular measurement configuration combined with the filtered back projection （FBP） algorithm,very high signal to-noise ratio tomography images can be obtained. For the laser energy can be absorbed by the identity molecule of the tissues, it will provide a potential non-invasive imaging technique for biomedical diagnosis and functional imaging.