Research Of Fast Photoacoustic Imaging System Based On Annular Array Detector

Ultrasonic imaging, X-ray imaging technology, Nuclear medical imaging, Magnetic resonance imaging, as the main technology in the field of biomedical medical imaging have been causing people’s attention and continuous development; However, there are some disadvantages in these traditional technology. Photoacoustic imaging is a new nondestructive medical imaging technology has attracted much scientific interest and research. Photoacoustic imaging technology combines advantages of both ultrasound imaging and optical imaging, can provide non-invasive, high resolution, high contrast tissue imaging. Currently photoacoustic imaging technology has become one of the research focuses in biomedical engineering. Many researchers have achieved fruitful results that use photoacoustic tomography for breast cancer detection, brain imaging, vascular structure imaging. In this dissertation, research of fast photoacoustic imaging system based on annular array detector of the software design, hardware structures, image reconstruction and experiments. The main tasks in this paper are included five parts as follows:(1)Introduces the traditional biomedical medical imaging technology and its disadvantage, the advantages of photoacoustic imaging technology, photoacoustic effect and medical applications. This dissertation discusses the basic principle of annular array detector imaging and photoacoustic image reconstruction methods.(2)Construct the photoacoustic imaging system, The Q switch Nd:YAG laser produced by LOTIS TII company as a radiation source and an annular array detector as imaging platforms.(3)Using LABVIEW software to write the photoacoustic imaging system control program, combined with the PCI-1757 UP, GPIB-USB etc. constitutes the photoacoustic signal acquisition system.(4)The fast photoacoustic imaging system based on annular array detector is applied to capture the photoacoustic signals and the total time of data acquisition and transferring is within 4s. And the time of image reconstruction with MATLAB is within 20 s, which fully meet the requirements of fast imaging experiments, and has great development potential.(5)The fast photoacoustic imaging system based on annular array detector is successfully applied to the experimental research of mice brain, large size animal brain and pig eyes, and obtained the relevant experimental data and photoacoustic image. Furthermore, in this paper we analyses how to improve the photoacoustic imaging resolution and contrast;and accumulate experimental experience performed on large size animal brain; and also provides relevant experimental methods in eye detection with photoacoustic imaging.