光声成像作为一种既能提供光学高对比度又能实现声学大成像深度的新兴医学影像技术, 可通过对肿瘤滋养血管的三维成像, 为癌症的早期诊断提供一种全新的高灵敏检测方法。本文针对消化道肿瘤的临床成像需求, 提出了一种内部光激发、外部声探测的透射共轴式光声消化道内窥成像系统, 并通过仿体与离体生物组织的成像实验, 与现有的反射非共轴式光声内窥成像系统的成像性能进行了对比。实验结果表明, 在仿体样品中, 透射共轴式光声内窥成像系统的信噪比相对反射非共轴式系统最高提高了43.3 dB, 成像深度增大了28.4%; 而离体生物组织中, 在10.7 mm深处, 其信噪比也提高了9.7 dB。实验验证了本设计有效提高了光声信号的探测灵敏度, 使该系统相较现有反射式系统具备更优的成像信噪比和成像深度, 为光声消化道内窥技术推向临床提供了一种具有重要应用潜力的实施方法。

Photoacoustic imaging is an emerging medical imaging technique combining the high contrast of optical imaging and the superior penetration depth of ultrasound imaging. It can provide detailed three-dimensional images of the feeding vessels of tumors, which is essential for the early diagnosis of cancer. In this study, we developed a transmissive coaxial photoacoustic digestive tract endoscopic imaging system using internal optical illumination and external ultrasonic detection. The phantom imaging results indicated that the transmissive system has a much better performance than the reflective non-coaxial system with a 43.3 dB higher Signal-to-Noise Ratio (SNR) and 28.4% better imaging depth. Ex vivo imaging results indicated that the transmissive system has a 9.7 dB higher SNR at a depth of 10.7 mm compared with the reflective system. The transmissive coaxial photoacoustic endoscopic imaging system, which exhibited a higher SNR and better imaging depth than the reflective system, shows that this design improves the detection sensitivity effectively. The significant improvements suggest that the developed photoacoustic endoscopy has great potential for translation into a broad range of clinical applications in gastroenterology.