基于声透镜成像系统的光声层析成像  

Photoacoustic tomography imaging based on an acousticlens imaging system

作　　者：陈湛旭[1] 唐志列[1] 万巍[2] 何永恒[1] 

机构地区：[1]华南师范大学物理与电信工程学院,广州510631 [2]华南师范大学信息光电子科技学院,广州510631

出　　处：《物理学报》2006年第8期4365-4370,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60377009);广东省自然科学基金(批准号:05005926)资助的课题.~~

摘　　要：光声成像是采用“光激发超声波成像”的新型成像技术,它是检测强散射介质内部光吸收分布的一种有效医学影像技术.用短脉冲激光照射强散射介质(如生物组织),强散射介质由于光声效应产生超声信号,使用具有成像能力的声透镜把声压分布成像于像面上,然后利用具有空间分辨能力的阵列光声传感器,把同一像面上的光声信号强度记录下来,最后根据光声信号强度的空间分布进行图像重组.根据成像系统物像共轭原理,同一物平面的光声信号到达像面的时延相等,而不同物面的光声信号到达同一个探测器平面的时延各不相同,因此,利用BOXCAR的门控积分技术,控制BOXCAR采样门的不同时延就能获得散射介质内不同层面的光声图像.实验成功地获得了强散射介质内不同层面的光声层析图像,图像清晰,对比度高.这种层析成像方法不需要复杂的重建算法,可以实现快速层析成像.Photoacoustic tomography is a new type of medical imaging technology based on the measurement of laser-induced ultrasonic waves. It can detect the light absorption distribution of the target hidden inside optically turbid or opaque tissues. When a short laser pulse illuminates the scattering medium, such as biological tissue, the scattering media will generate ultrasound signals which are linearly proportional to the optical absorption of the media. The ultrasound signals are imaged with an acoustic lens. According to the imaging principle of lens, the photoacoustic signals from a plane in scattering media require the same delay time to reach the image plane, and the signals from different planes require different delay time to reach the same detecting plane. A BOXCAR was used to hold on the same delay-time, and a 64-element linear transducer army was one-dimensionally scanned on an imaging plane to acquire the acoustic pressure distribution, and the signals were recorded and reconstructed by a computer. By scanning the sampling gate of BOXCAR, the photoacoustic images of different planes in the media can be obtained. We experimentally obtained photoacoustic tomography images on different planes of the scattering media successfully. The images are vivid and contrast clearly with the background. This method directly provides images of absorbing structures without the need of computational reconstruction.

关 键 词：光声层析成像 声透镜 光声信号 

分 类 号：TN27[电子电信—物理电子学]