声透镜对多层样品的光声层析成像

由于光声效应产生光声压分布图像,所以当强散射介质中的模拟吸光组织在受到短脉冲激光照射时,该声压分布会经声透镜成像在像平面上。在像平面上利用线性超声探测器阵列获取光声信号并传递给高速数据采集卡进行数据采集,可由程序重构出光声图像。设计的光声层析成像系统可以采集记录一定深度的数据,成像时只要在所采集到的数据中选取不同列数即可同时获得强散射介质多层样品不同层面的光声图像。实验成功地获得了强散射介质内多层样品不同层面的光声层析图像。该成像方法无需进行复杂的算法重建,且可以同时实现多层样品不同切面的光声成像。

Photoacoustic Tomography of Multi-Layer Sample Using Acoustic Lens

When a short laser pulse illuminates the virtual absorber in a scattering medium, the absorber will generate pressure distribution which is linearly proportional to the optical absorption of the medium. The laser induced ultrasonic signals are imaged with an acoustic lens. A 64-element linear transducer array is one-dimensionally scanned on an imaging plane to acquire the acoustic pressure distribution by high speed acquisition card, and the signals are recorded and reconstructed by a computer. A new fast photoacoustic tomograph imaging system is demonstrated. It can acquire and record the data for a certain depth. The system can reconstructe different images from different planes at the same time only by selecting different numbers of columns in the datasheet. We experimentally obtain photoacoustic tomography images on different planes in the scattering media successfully. The images are vivid and contrast clearly with the background. This method directly provides images on different object planes of absorbing structures at the same time without the need of computational reconstruction.