【作者】 徐晓辉；

【导师】 李晖；

【作者基本信息】 福建师范大学 ， 光学， 2008， 硕士

【摘要】 近年来异军突起的光声成像(Photoacoustic or Optoacoustic imaging)技术被认为是一种有发展前景的成像模式。该技术以光致超声的物理效应为基础,通过检测超声信号来反映组织体的光能量吸收的差异;因此光声成像技术结合了光学成像和超声成像各自的优点,能够实现对组织体较大深度的高分辨率、高对比度的功能成像。根据光声成像以上的特点,本论文以基于聚焦换能器的扫描光声层析术为技术路线,探索其在乳腺癌早期诊断、鲜红斑痣皮肤评估以及体表深度血管成像方面应用的可行性。以下为本论文完成的主要工作:(1)概述了处于快速发展中的光声成像技术,包括物理机制、技术路线以及生物医学应用等,并对其发展阐述了自己的见解;(2)设计了实验项目的实施方案,并依此构建了本实验的第一套扫描光声成像系统;其中,该成像系统的控制软件是以LabVIEW为开发平台,实现了实验仪器的控制以及后续的数据处理和图像形成等工作;(3)探寻基于长焦距聚焦换能器的扫描光声成像技术在乳腺癌早期诊断方面的可行性。实验实现了乳腺组织模拟样品中不同尺寸光学吸收体的准确成像;(4)初步探索利用聚焦光声深度分辨技术对鲜红斑痣皮肤进行评估的可行性。实验中,以鲜红斑痣皮肤模拟样品为实验对象,实现了层状分辨、黑色素评估以及鲜红斑痣病变层厚度识别等工作;(5)构建了一套适用于体表较深处血管成像的扫描光声成像系统,并实现深度为5mm的模拟血管的三维成像。更多还原

【Abstract】 Photoacoustic imaging (also called optoacoustic imaging), which has come a long way in the last several years, is a promising imaging modality for biomedicine. Based on the photoacoustic effect, the technique can be used to map the energy deposition of biological tissue by detecting laser-induced ultrasound signals. So, the photoacoustic imaging which combines the advantages of optical and ultrasonic imaging can functionally images the biological tissue at high resolution and high contrast in relatively large depth. In view of the unique characteristics of photoacoustic imaging, a scanning photoacoustic imaging system which utilizes a focused ultrasound transducer is developed. And, the preliminary study of scanning photoacoustic imaging system for some biomedical applications which include early detection of breast cancer, assessing of port wine stain and imaging of blood vessels in the skin are investigated.The main works of this thesis are as follows:(1) The developing of photoacoustic imaging is reviewed, including mechanism, techniques and its biomedical applications. Then some personal views of development of photoacoustic imaging are presented.(2) We designed the program for the project of scanning photoacoustic imaging system, and then constructed the corresponding experimental setups. The control software of system, which includes instrument control and data processing, is developed by LabVIEW.(3) Scanning photoacoustic mammography, utilizing a focused transducer with extended focal zone, is studied. Phantom experiments demonstrate that the location, size and optical energy deposition of absorbers can be visualized correctly.(4) We explored the feasibility of focused photoacoustic depth profiling for port wine stain assessing. Phantom experiments show that epidermal melanin content, depth and thickness of port wine stain layer can be evaluated properly. Preliminary study shows that this method could be potential in diagnosis of PWS skin. (5) A scanning photoacoustic imaging system which implements to image the deep blood vessels of skin is constructed. Blood vessel at depth of 5 mm in skin phantom can be imaged in three dimensions.更多还原