scholarly journals A Review of Endogenous and Exogenous Contrast Agents Used in Photoacoustic Tomography with Different Sensing Configurations

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5595 ◽  
Author(s):  
Victor T.C. Tsang ◽  
Xiufeng Li ◽  
Terence T.W. Wong
Keyword(s):  
Contrast Agents ◽  
Biomedical Imaging ◽  
Imaging Modality ◽  
Biological Tissues ◽  
Tissue Imaging ◽  
Imaging Tool ◽  
Endogenous Contrast ◽  
Deep Tissue Imaging ◽  
Molecular Specificity ◽  
System Configurations

Optical-based sensing approaches have long been an indispensable way to detect molecules in biological tissues for various biomedical research and applications. The advancement in optical microscopy is one of the main drivers for discoveries and innovations in both life science and biomedical imaging. However, the shallow imaging depth due to the use of ballistic photons fundamentally limits optical imaging approaches’ translational potential to a clinical setting. Photoacoustic (PA) tomography (PAT) is a rapidly growing hybrid imaging modality that is capable of acoustically detecting optical contrast. PAT uniquely enjoys high-resolution deep-tissue imaging owing to the utilization of diffused photons. The exploration of endogenous contrast agents and the development of exogenous contrast agents further improve the molecular specificity for PAT. PAT’s versatile design and non-invasive nature have proven its great potential as a biomedical imaging tool for a multitude of biomedical applications. In this review, representative endogenous and exogenous PA contrast agents will be introduced alongside common PAT system configurations, including the latest advances of all-optical acoustic sensing techniques.

scholarly journals Nanophosphor-Based Contrast Agents for Spectral X-ray Imaging

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1092 ◽  
Author(s):  
Kevin Smith ◽  
Matthew Getzin ◽  
Josephine J. Garfield ◽  
Sanika Suvarnapathaki ◽  
Gulden Camci-Unal ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Ligand Exchange ◽  
Photon Counting ◽  
Tissue Imaging ◽  
Ct Guided ◽  
X Ray ◽  
X Ray Imaging ◽  
Deep Tissue Imaging ◽  
Water Dispersibility ◽  
Lower Contrast

Lanthanide-based nanophosphors (NPhs) are herein developed as contrast agents for spectral X-ray imaging, highlighting the chemical, macromolecular and structural differences derived from ligand exchange on computed tomography (CT) and solvent dispersibility. Taking advantage of the ability of spectral X-ray imaging with photon-counting detectors to perform image acquisition, analysis, and processing at different energy windows (bins), enhanced signal of our K-edge materials was derived, improving sensitivity of CT imaging, and differentiation between water, tumor-mimic phantoms, and contrast materials. Our results indicate that the most effective of our oleic acid-stabilized K-edge nanoparticles can achieve 2–4x higher contrast than the examined iodinated molecules, making them suitable for deep tissue imaging of tissues or tumors. On the other hand, ligand exchange yielding poly(acrylic acid)-stabilized K-edge nanoparticles allows for high dispersibility and homogeneity in water, but with a lower contrast due to the high density of the polymer grafted, unless further engineering is probed. This is the first well-defined study that manages to correlate NPh grafting density with CT numbers and water dispersibility, laying the groundwork for the development of the next generation CT-guided diagnostic and/or theranostic materials.

scholarly journals Recent Progress on Near-Infrared Photoacoustic Imaging: Imaging Modality and Organic Semiconducting Agents

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1693 ◽  
Author(s):  
Doyoung Jung ◽  
Suhyeon Park ◽  
Changho Lee ◽  
Hyungwoo Kim
Keyword(s):  
Recent Progress ◽  
Near Infrared ◽  
Photoacoustic Imaging ◽  
Imaging Modality ◽  
Point Of Care ◽  
Tissue Imaging ◽  
Nir Imaging ◽  
Precise Diagnosis ◽  
Deep Tissue Imaging ◽  
Review Reports

Over the past few decades, the photoacoustic (PA) effect has been widely investigated, opening up diverse applications, such as photoacoustic spectroscopy, estimation of chemical energies, or point-of-care detection. Notably, photoacoustic imaging (PAI) has also been developed and has recently received considerable attention in bio-related or clinical imaging fields, as it now facilitates an imaging platform in the near-infrared (NIR) region by taking advantage of the significant advancement of exogenous imaging agents. The NIR PAI platform now paves the way for high-resolution, deep-tissue imaging, which is imperative for contemporary theragnosis, a combination of precise diagnosis and well-timed therapy. This review reports the recent progress on NIR PAI modality, as well as semiconducting contrast agents, and outlines the trend in current NIR imaging and provides further direction for the prospective development of PAI systems.

scholarly journals Carbazole-Linked Near-Infrared Aza-BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep-Tissue Imaging

2017 ◽  
Vol 23 (27) ◽  
pp. 6570-6578 ◽  
Author(s):  
Yogesh Gawale ◽  
Nagappanpillai Adarsh ◽  
Sandeep Kumar Kalva ◽  
Joshy Joseph ◽  
Manojit Pramanik ◽  
...  
Keyword(s):  
Contrast Agents ◽  
Near Infrared ◽  
Tissue Imaging ◽  
Deep Tissue ◽  
Deep Tissue Imaging

Two-Dimensional Near-Infrared and Shortwave Infrared Molecular Aggregates: Taking Kasha’s Model to the Next Dimension

2019 ◽  
Author(s):  
Arundhati Deshmukh ◽  
Danielle Koppel ◽  
Chern Chuang ◽  
Danielle Cadena ◽  
Jianshu Cao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Photophysical Properties ◽  
Satellite Telemetry ◽  
Transition Dipole Moment ◽  
Short Wave ◽  
Tissue Imaging ◽  
Transition Dipole ◽  
Deep Tissue Imaging ◽  
Excitonic States ◽  
Shortwave Infrared

Technologies which utilize near-infrared (700 – 1000 nm) and short-wave infrared (1000 – 2000 nm) electromagnetic radiation have applications in deep-tissue imaging, telecommunications and satellite telemetry due to low scattering and decreased background signal in this spectral region. However, there are few molecular species, which absorb efficiently beyond 1000 nm. Transition dipole moment coupling (e.g. J-aggregation) allows for redshifted excitonic states and provides a pathway to highly absorptive electronic states in the infrared. We present aggregates of two cyanine dyes whose absorption peaks redshift dramatically upon aggregation in water from ~ 800 nm to 1000 nm and 1050 nm with sheet-like morphologies and high molar absorptivities (e ~ 10<sup>5 </sup>M<sup>-1</sup>cm<sup>-1</sup>). To describe this phenomenology, we extend Kasha’s model for J- and H-aggregation to describe the excitonic states of <i> 2-dimensional aggregates</i> whose slip is controlled by steric hindrance in the assembled structure. A consequence of the increased dimensionality is the phenomenon of an <i>intermediate </i>“I-aggregate”, one which redshifts yet displays spectral signatures of band-edge dark states akin to an H-aggregate. We distinguish between H-, I- and J-aggregates by showing the relative position of the bright (absorptive) state within the density of states using temperature dependent spectroscopy. Our results can be used to better design chromophores with predictable and tunable aggregation with new photophysical properties.

scholarly journals Continuous-Wave THz Imaging for Biomedical Samples

2020 ◽  
Vol 11 (1) ◽  
pp. 71
Author(s):  
Yaya Zhang ◽  
Chuting Wang ◽  
Bingxin Huai ◽  
Shiyu Wang ◽  
Yating Zhang ◽  
...  
Keyword(s):  
Medical Imaging ◽  
Biomedical Imaging ◽  
Continuous Wave ◽  
Biological Tissues ◽  
Thz Spectroscopy ◽  
Label Free ◽  
Thz Imaging ◽  
Malignant Tumours ◽  
Advantages And Disadvantages ◽  
Imaging Application

In the past few decades, the applications of terahertz (THz) spectroscopy and imaging technology have seen significant developments in the fields of biology, medical diagnosis, food safety, and nondestructive testing. Label-free diagnosis of malignant tumours has been obtained and also achieved significant development in THz biomedical imaging. This review mainly presents the research status and prospects of several common continuous-wave (CW) THz medical imaging systems and applications of THz medical imaging in biological tissues. Here, we first introduce the properties of THz waves and how these properties play a role in biomedical imaging. Then, we analyse both the advantages and disadvantages of the CW THz imaging methods and the progress of these methods in THz biomedical imaging in recent ten years. Finally, we summarise the obstacles in the way of the application of THz bio-imaging application technology in clinical detection, which need to be investigated and overcome in the future.

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