生物光声层析成像中超声探测器特性对图像质量的影响及解决方法

Influence of Ultrasonic Detector Characteristics on Image Quality in Biological Photoacoustic Tomography and its Solution

生物光声层析成像(PAT)是一种多物理场耦合的新型复合功能成像方法,对肿瘤和心血管疾病等的早期检测和准确诊断具有极高的研究价值。在PAT图像重建中,为了简化问题,通常假设超声探测器是具有全向响应的理想点探测器,在目标周围形成一个连续完整的测量面,且不考虑探测器的空间脉冲响应(SIR)和电脉冲响应(EIR)对成像质量的影响。但在实际应用中,这一理想假设会导致成像分辨率和图像质量的下降。从有限孔径效应、SIR和EIR、方向性、扫描半径、有限测量角度和有限带宽以及位置不确定性等6个方面,就超声探测器特性对图像重建的影响,综述相应的解决方法,对比不同方法的优缺点以及适用范围,并展望未来可能的发展方向。

Biomedical photoacoustic tomography( PAT) is an emerging hybrid functional imaging modality by multi-physics coupling for early detection and accurate diagnosis of tumors and cardiac vessel diseases. For simplicity,most PAT image reconstruction methods are based on an ideal assumption that the photoacoustically generated ultrasonic waves are collected by an ideal point-like detector with an omnidirectional response forming a continuous and complete measuring surface around the object. The influence of the spatial impulse response( SIR) and electrical impulse response( EIR) of the detector on the reconstruction quality is not considered.However,in practical applications,this assumption is usually infeasible,resulting in the reduction in the imaging resolution and the degradation of the image quality. This paper aimed to analyze the influence of the characteristics of the ultrasonic detector on PAT image reconstruction including limited aperture effect,SIR and EIR,directivity,scanning radius,limited view-angle and frequency bandwidth,and positional uncertainty.Moreover,the solutions to above problems were summarized and their advantages,limitations,applications,and potential developments in the future were discussed as well.