Photoacoustic imaging principle and analysis of the images by MSOT

Photoacoustic imaging, also called optoacoustic tomography, is a non-destructive biomedical imaging technique which employs acoustic detection to image optical absorption contrast with high-resolution deep into scattering tissue. Photoacoustic imaging overcomes the limit of high light scattering in the tissue and realized in vivo high-resolution and high-contrast imaging in the deep tissue. Photoacoustic imaging technology has been rapid development in recent years and make constantly breakthrough from a technical level to the application level. This paper describes the basic principles of photoacoustic imaging technology and make an example analysis by multispectral optoacoustic tomography （MSOT）.

PERFORMANCE OF BLIND DECONVOLUTION IN OPTOACOUSTIC TOMOGRAPHY

In this paper,we consider the use of blind deconvolution for optoacoustic(photoacoustic)imaging and investigate the performance of the method as means for increasing the resolution of the reconstructed image beyond the physical restrictions of the system.The method is demonstrated with optoacoustic measurement obtained from six-day-old mice,imaged in the near-infrared using a broadband hydrophone in a circular scanning configuration.Wefind that estimates of the unknown point spread function,achieved by blind deconvolution,improve the resolution and contrast in the images and show promise for enhancing optoacoustic images.

A multifunctional nanoaggregate-based system for detection of rheumatoid arthritis via Optoacoustic/NIR-Ⅱ fluorescent imaging and therapy via inhibiting JAK-STAT/NF-κB/NLRP3 pathways

Rheumatoid arthritis(RA)is a debilitating autoimmune disease that causes chronic pain and serious complications,presenting a significant challenge to treat.Promising approaches for treating RA involve signaling pathways modulation and targeted therapy.To this end,a multifunctional nanosystem,TPC-U@HAT,has been designed for RA therapy,featuring multitargeting,dual-stimuli response,and on-demand drug release capabilities.TPC-U@HAT is composed of a probe/prodrug TPC,a JAK1 kinase inhibitor upadacitinib,and the drug carrier HAT.TPC is composed of an aggregation-induced emission(AIE)-active NIR-II chromophore TPY and an NF-κB/NLRP3 inhibitor caffeic acid phenethyl ester(CAPE),connected via boronic ester bond which serves as the reactive-oxygen-species-responsive linker.The carrier,HAT,is created by grafting bone-targeting alendronate and hydrophobic tocopheryl succinate onto hyaluronic acid chains,which can encapsulate TPC and upadacitinib to form TPC-U@HAT.Upon intravenous injection into mice,TPC-U@HAT accumulates at inflamed lesions of RA through both active and passive targeting,and the overexpressed hyaluronidase and H_(2)O_(2) therein cleave the hyaluronic acid polymer chains and boronate bonds,respectively.This generates an AIE-active chromophore for detection and therapeutic evaluation of RA via both optoacoustic imaging and NIR-II fluorescent imaging and concomitantly releases CAPE and upadacitinib to exert efficacious therapy by inhibiting NF-κB/NLRP3 and JAK-STAT pathways.

Adding fifth dimension to optoacoustic imaging: volumetric time-resolved spectrally enriched tomography

Optoacoustics provides a unique set of capabilities for bioimaging,associated with the intrinsic combination of ultrasound-and light-related advantages,such as high spatial and temporal resolution as well as powerful spectrally enriched imaging contrast in biological tissues.We demonstrate here,for the first time,the acquisition,processing and visualization of five-dimensional optoacoustic data,thus offering unparallel imaging capacities among the current bioimaging modalities.The newly discovered performance is enabled by simultaneous volumetric detection and processing of multispectral data and is further showcased here by attaining time-resolved volumetric blood oxygenation maps in deep human vessels and real-time tracking of contrast agent distribution in a murine model in vivo.

光声成像在光动力疗法研究中的应用

组织氧合作用和光敏剂应用在疾病诊治中都有着重要的作用,因此其实时在体无损检测很有意义。光动力疗法涉及光敏剂、光和氧分子三大要素,其疗效受组织氧合作用影响。本文对光声成像(PAI)、光声寿命成像(PALI)和多光谱光声层析成像(MSOT)等光声成像技术在光动力疗法的研究和应用中的使用现状进行了综述。对相关设备系统在检测光敏剂、组织氧分压和微血管损伤等方面的应用原理和技术分别进行了介绍,并总结了这些技术的应用前景。

Functional optoacoustic neuro-tomography for scalable whole-brain monitoring of calcium indicators

Non-invasive observation of spatiotemporal activity of large neural populations distributed over entire brains is a longstanding goal of neuroscience.We developed a volumetric multispectral optoacoustic tomography platform for imaging neural activation deep in scattering brains.It can record 100 volumetric frames per second across scalable fields of view ranging between 50 and 1000 mm^(3) with respective spatial resolution of 35–200μm.Experiments performed in immobilized and freely swimming larvae and in adult zebrafish brains expressing the genetically encoded calcium indicator GCaMP5G demonstrate,for the first time,the fundamental ability to directly track neural dynamics using optoacoustics while overcoming the longstanding penetration barrier of optical imaging in scattering brains.The newly developed platform thus offers unprecedented capabilities for functional whole-brain observations of fast calcium dynamics;in combination with optoacoustics'well-established capacity for resolving vascular hemodynamics,it could open new vistas in the study of neural activity and neurovascular coupling in health and disease.

多光谱光声层析成像及其在生物医学中的应用

多光谱光声层析成像(MSOT)技术是一种将多光谱成像与光声层析成像(PACT)技术相结合的新技术,该技术利用不同生物组织的光谱吸收特性,用多组不同波长的短脉冲激光照射组织以产生组织特异性的光声信号,从而更好地进行光声成像和组分识别。MSOT兼具光学成像的高灵敏度、高分辨率优势和超声成像可对数厘米深组织成像的长处,同时又能弥补光学成像深度有限和超声成像对比度差的短处,能够实现深层组织的高分辨率、高对比度、高穿透深度的实时无损伤成像。迄今为止,MSOT已应用于肿瘤内光吸收粒子的检测、血管结构和血液氧合作用的评价、生物荧光蛋白的成像以及乳腺癌患者检测的初步研究。随着光声成像系统的不断改进,MSOT与生物标记物(如荧光试剂、金纳米颗粒等)结合对体内分子进行成像,在生物医学中得到了广泛的应用。本文简要综述了MOST的成像原理、实验装置及其性能特点,着重总结了其在生物医学领域的最新应用进展,尤其是在新生血管成像、肿瘤的早期诊断及肿瘤的原位成像方面。