As a molecular imaging modality, photoacoustic (PA) imaging has been in the spotlight because it can provide an optical contrast image of physiological information and a relatively deep imaging depth. However, its sensitivity is limited despite the use of exogenous contrast agents due to the background PA signals generated from nontargeted absorbers, such as blood and boundaries between different biological tissues. In addition, clutter artifacts generated in both in-plane and out-of-plane imaging region degrade the sensitivity of PA imaging. We propose a method to eliminate the nontargeted PA signals. For this study, we used a dual-modal ultrasound (US)-PA contrast agent that is capable of generating both the backscattered US and PA signals in response to the transmitted US and irradiated light, respectively. The US images of the contrast agents are used to construct a masking image that contains the location information about the target site and is applied to the PA image acquired after contrast agent injection. In vitro and in vivo experimental results demonstrated that the masking image constructed using the US images makes it possible to completely remove nontargeted PA signals. The proposed method can be used to enhance the clear visualization of the target area in PA images.

中文翻译：

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消除用于光声和超声成像的非目标光声信号

作为一种分子成像方式，光声（PA）成像已经成为人们关注的焦点，因为它可以提供生理信息的光学对比图像和相对较深的成像深度。但是，由于使用了非目标吸收剂（例如血液和不同生物组织之间的边界）生成的背景PA信号，尽管使用了外源性造影剂，但其灵敏度仍然受到限制。另外，在平面内和平面外成像区域两者中产生的杂波伪像降低了PA成像的灵敏度。我们提出了一种消除非目标PA信号的方法。在本研究中，我们使用了一种双模态超声（US）-PA造影剂，它能够分别响应所透射的US和照射的光而产生反向散射的US和PA信号。体外 和 体内实验结果表明，使用US图像构造的掩蔽图像可以完全去除非目标PA信号。所提出的方法可用于增强PA图像中目标区域的清晰可视化。