Endoscopy has been widely used in biomedical imaging and integrated with various optical and acoustic imaging modalities. Photoacoustic imaging (PAI), one of the fastest growing biomedical imaging modalities, is a noninvasive and nonionizing method that owns rich optical contrast, deep acoustic penetration depth, multiscale and multiparametric imaging capability. Hence, it is preferred to miniaturize the volume of PAI and develop an emerged endoscopic imaging modality referred to as photoacoustic endoscopy (PAE). It has been developed for more than one decade since the first report of PAE. Unfortunately, until now, there is no mature photoacoustic endoscopic technique recognized in clinic due to various technical limitations. To address this concern, recent development of new scanning mechanisms, adoption of novel optical/acoustic devices, utilization of superior computation methods and exploration of multimodality strategies have significantly promoted the progress of PAE toward clinic. In this review, we comprehensively reviewed recent progresses in single‐ and multimodality PAE with new physics, mechanisms and strategies to achieve practical devices for potential applicable scenarios including esophageal, gastrointestinal, urogenital and intravascular imaging. We ended this review with challenges and prospects for future development of PAE.

中文翻译：

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光声内窥镜：进展回顾。

内窥镜已被广泛用于生物医学成像，并与各种光学和声学成像方式集成在一起。光声成像（PAI）是发展最快的生物医学成像方法之一，是一种无创且非电离的方法，具有丰富的光学对比度，深的声穿透深度，多尺度和多参数成像功能。因此，优选的是使PAI的体积最小化并开发出被称为光声内窥镜（PAE）的内窥镜成像模式。自从PAE的第一份报告以来，它已经开发了十多年。不幸的是，由于各种技术限制，迄今为止在临床上还没有成熟的光声内窥镜技术。为了解决这个问题，最近开发了新的扫描机制，采用了新颖的光学/声学设备，先进的计算方法的运用和多模式策略的探索极大地促进了PAE走向临床的进展。在本文中，我们以新的物理，机制和策略全面综述了单模和多模PAE的最新进展，以实现针对食管，胃肠道，泌尿生殖道和血管内成像等潜在适用场景的实用设备。我们以PAE未来发展的挑战和前景结束了这次审查。实现针对潜在适用场景（包括食道，胃肠道，泌尿生殖器和血管内成像）的实用设备的机制和策略。我们以PAE未来发展的挑战和前景结束了这次审查。实现针对潜在适用场景（包括食道，胃肠道，泌尿生殖器和血管内成像）的实用设备的机制和策略。我们以PAE未来发展的挑战和前景结束了这次审查。