scholarly journals An Adjustable Dark-Field Acoustic-Resolution Photoacoustic Imaging System with Fiber Bundle-Based Illumination

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 262
Author(s):  
Yuhling Wang ◽  
De-Fu Jhang ◽  
Tsung-Sheng Chu ◽  
Chia-Hui Tsao ◽  
Chia-Hua Tsai ◽  
...  
Keyword(s):  
Real Time ◽  
Imaging System ◽  
Structural Information ◽  
Photoacoustic Imaging ◽  
Biological Tissues ◽  
Dark Field ◽  
Design Concept ◽  
High Frequency Ultrasound

Photoacoustic (PA) imaging has become one of the major imaging methods because of its ability to record structural information and its high spatial resolution in biological tissues. Current commercialized PA imaging instruments are limited to varying degrees by their bulky size (i.e., the laser or scanning stage) or their use of complex optical components for light delivery. Here, we present a robust acoustic-resolution PA imaging system that consists of four adjustable optical fibers placed 90° apart around a 50 MHz high-frequency ultrasound (US) transducer. In the compact design concept of the PA probe, the relative illumination parameters (i.e., angles and fiber size) can be adjusted to fit different imaging applications in a single setting. Moreover, this design concept involves a user interface built in MATLAB. We first assessed the performance of our imaging system using in vitro phantom experiments. We further demonstrated the in vivo performance of the developed system in imaging (1) rat ear vasculature, (2) real-time cortical hemodynamic changes in the superior sagittal sinus (SSS) during left-forepaw electrical stimulation, and (3) real-time cerebral indocyanine green (ICG) dynamics in rats. Collectively, this alignment-free design concept of a compact PA probe without bulky optical lens systems is intended to satisfy the diverse needs in preclinical PA imaging studies.

scholarly journals Characterization of a Fiber Bundle-Based Real-Time Ultrasound/Photoacoustic Imaging System and Its In Vivo Functional Imaging Applications

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 820
Author(s):  
He Leng ◽  
Yuhling Wang ◽  
De-Fu Jhang ◽  
Tsung-Sheng Chu ◽  
Chia-Hui Tsao ◽  
...  
Keyword(s):  
User Interface ◽  
Real Time ◽  
In Vivo Imaging ◽  
Fiber Bundle ◽  
Imaging System ◽  
Structural Information ◽  
Photoacoustic Imaging ◽  
Numerical Aperture ◽  
Biological Tissues

Photoacoustic (PA) imaging is an attractive technology for imaging biological tissues because it can capture both functional and structural information with satisfactory spatial resolution. Current commercially available PA imaging systems are limited by their bulky size or inflexible user interface. We present a new handheld real-time ultrasound/photoacoustic imaging system (HARP) consisting of a detachable, high-numerical-aperture (NA) fiber bundle-based illumination system integrated with an array-based ultrasound (US) transducer and a data acquisition platform. In this system, different PA probes can be used for different imaging applications by switching the transducers and the corresponding jackets to combine the fiber pads and transducer into a single probe. The intuitive user interface is a completely programmable MATLAB-based platform. In vitro phantom experiments were conducted to test the imaging performance of the developed PA system. Furthermore, we demonstrated (1) in vivo brain vasculature imaging, (2) in vivo imaging of real-time stimulus-evoked cortical hemodynamic changes during forepaw electrical stimulation, and (3) in vivo imaging of real-time cerebral pharmacokinetics in rats using the developed PA system. The overall purpose of this design concept for a customizable US/PA imaging system is to help overcome the diverse challenges faced by medical researchers performing both preclinical and clinical PA studies.

scholarly journals In vivo imaging of swimming micromotors using hybrid high-frequency ultrasound and photoacoustic imaging

2020 ◽  
Author(s):  
Azaam Aziz ◽  
Joost Holthof ◽  
Sandra Meyer ◽  
Oliver G. Schmidt ◽  
Mariana Medina-Sánchez
Keyword(s):  
High Frequency ◽  
Imaging System ◽  
Ex Vivo ◽  
Photoacoustic Imaging ◽  
Imaging Techniques ◽  
High Frequency Ultrasound ◽  
Living Organisms ◽  
And Function ◽  
Frequency Ultrasound

AbstractThe fast evolution of medical micro- and nanorobots in the endeavor to perform non-invasive medical operations in living organisms boosted the use of diverse medical imaging techniques in the last years. Among those techniques, photoacoustic (PA) tomography has shown to be promising for the imaging of microrobots in deep-tissue (ex vivo and in vivo), as it possesses the molecular specificity of optical techniques and the penetration depth of ultrasound imaging. However, the precise maneuvering and function control of microrobots, in particular in living organisms, demand the combination of both anatomical and functional imaging methods. Therefore, herein, we report the use of a hybrid High-Frequency Ultrasound (HFUS) and PA imaging system for the real-time tracking of magnetically driven micromotors (single and swarms) in phantoms, ex vivo, and in vivo (in mice bladder and uterus), envisioning their application for targeted drug-delivery.

scholarly journals Real-Time In Vivo Detection and Monitoring of Bacterial Infection Based on NIR-II Imaging

2021 ◽  
Vol 9 ◽  
Author(s):  
Sijia Feng ◽  
Huizhu Li ◽  
Chang Liu ◽  
Mo Chen ◽  
Huaixuan Sheng ◽  
...  
Keyword(s):  
Bacterial Infection ◽  
Real Time ◽  
Bacterial Infections ◽  
Near Infrared ◽  
Imaging System ◽  
Bacterial Load ◽  
Dynamic Imaging ◽  
In Vivo Detection

Treatment according to the dynamic changes of bacterial load in vivo is critical for preventing progression of bacterial infections. Here, we present a lead sulfide quantum dots (PbS QDs) based second near-infrared (NIR-II) fluorescence imaging strategy for bacteria detection and real-time in vivo monitoring. Four strains of bacteria were labeled with synthesized PbS QDs which showed high bacteria labeling efficiency in vitro. Then bacteria at different concentrations were injected subcutaneously on the back of male nude mice for in vivo imaging. A series of NIR-II images taken at a predetermined time manner demonstrated changing patterns of photoluminescence (PL) intensity of infected sites, dynamically imaging a changing bacterial load in real-time. A detection limit around 102–104 CFU/ml was also achieved in vivo. Furthermore, analysis of pathology of infected sites were performed, which showed high biocompatibility of PbS QDs. Therefore, under the guidance of our developed NIR-II imaging system, real-time detection and spatiotemporal monitoring of bacterial infection in vivo can be achieved, thus facilitating anti-infection treatment under the guidance of the dynamic imaging of bacterial load in future.

scholarly journals Photonic real-time monitoring of bacterial reduction in root canals by genetically engineered bacteria after chemomechanical endodontic therapy

2007 ◽  
Vol 18 (3) ◽  
pp. 202-207 ◽  
Author(s):  
Aguinaldo Silva Garcez ◽  
Silvia Cristina Nunez ◽  
José Luis Lage-Marques ◽  
Michael R. Hamblin ◽  
Martha Simões Ribeiro
Keyword(s):  
Real Time ◽  
Root Canal ◽  
Imaging System ◽  
Genetically Engineered ◽  
Microbial Infection ◽  
Bacterial Reduction ◽  
Culture Methods ◽  
Root Canals

Microbial infection plays an important role in the development of pulp necrosis and formation of periapical lesions. In vitro and in vivo research in this field, traditionally microbiological culture methods using paper point sampling and quantitative culture, faces difficulties in completely removing bacteria from the root canal system and analyzing sequential procedures. This study employed genetically engineered bioluminescent bacteria and a light-sensitive imaging system to allow real-time visualization of the infection. Ten extracted teeth incubated with P. aeruginosa were treated by mechanical instrumentation with K-files (#30 K-file, #35 K-file and #40 K-file) and chemical irrigation with sodium hypochlorite and hydrogen peroxide. Irrigation alone reduced the contamination in 18%; the first chemomechanical sequence (instrumentation with a #30 K-file + irrigation) provided 41% of reduction; the second sequence (#35 K-file + irrigation) achieved 62%; and the complete therapy (#30 K-file + #35 K-file + #40 K-file + irrigation) achieved 93% of bacterial reduction. These results suggest that the endodontic treatment is dependent on the association of a chemical and mechanical approaches and that root canal enlargement improves bacterial reduction probably because the irrigation has more access to the apical third.

scholarly journals Real-time and noninvasive tracking of injectable hydrogel degradation using functionalized AIE nanoparticles

Nanophotonics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 2063-2075
Author(s):  
Mengdi Zhang ◽  
Zengliang Wang ◽  
Pengzhou Huang ◽  
Guanwei Jiang ◽  
Changpeng Xu ◽  
...  
Keyword(s):  
Real Time ◽  
Photoacoustic Imaging ◽  
Fluorescent Detection ◽  
Interference Factor ◽  
Aggregation Induced Emission ◽  
Visual Degradation ◽  
Degradation Degree ◽  
Hydrogel System

AbstractVisually monitoring of the residual morphology and quantitatively determining the degradation degree of hydrogels applied in tissue repair therapy in a real-time and noninvasive manner were a crucial technological mean. Despite conventional organic fluorescent molecules commonly used as probe to capture the real-time clues of the labeled hydrogels, they still encounter obstacles, including intrinsic photobleaching, cytotoxicity, and unknown interference factor of degradation caused by the change from polymer structure of hydrogels, thus making it difficult to accurately obtain the information of the hydrogels in vivo. To address the hard nut, we designed the multifunctional hydrogel system with a real-time quantitative aggregation-induced emission fluorescent detection and photoacoustic imaging tracking based on tetraphenylethene (TPE) that possesses the trait of aggregation-induced emission and low photobleaching, bound on the surface of mesoporous dopamine microspheres (MPDAs), and subsequently loaded into the photo-crosslinked injectable hydrogels. In vitro results showed that MPDA-TPE had good compatibility, emitted strong fluorescence when embedded in hydrogels, and maintained stable fluorescence property unless the hydrogels were degraded. Meanwhile, a mathematical formula for the kinetic degradation of hydrogels was established between gravitational and visual degradation in vitro, which can be used to predict in vivo degradation. Furthermore, MPDA possessed the clear photoacoustic imaging effect to provide more accurate clues. The designed hydrogel system holds a potential role in prediction of the in vivo degradation of implanted materials in an accurate, convenient, and real-time noninvasive manner and is a meaningful treatment aid in tissue engineering.

In vivo and in vitro comparative assessment of the log-linearized Hunt–Crossley model for impact-contact modeling in physical human–robot interactions

2019 ◽  
Vol 233 (10) ◽  
pp. 1376-1391
Author(s):  
Fabien Courreges ◽  
Med Amine Laribi ◽  
Marc Arsicault ◽  
Joseph Absi ◽  
Said Zeghloul
Keyword(s):  
Real Time ◽  
Model Identification ◽  
Biological Tissues ◽  
Recursive Least Squares ◽  
Force Model ◽  
Experimental Conditions ◽  
Contact Impedance ◽  
Real Time Identification

In physical human–robot interactions, making the robot perceive in real time the mechanical contact impedance is critical for interactions safety, robot control and haptic rendering for robot teleoperation and can be achieved through online parametric model identification. Probing the viscoelastic properties of tissues is also a medical concern. For soft viscoelastic biological tissues, the Hunt–Crossley model is a contact force model computationally inexpensive while being accurate. As this model is non-linear, a log linear approximation has been proposed to achieve a fast and real-time identification using a recursive least squares approach. In this article, we want to regard the log-linearized expression of the Hunt–Crossley model no more as an approximation, but rather as a valuable empirical mechanical model of soft biological tissues. We show through experimental data fit and sophisticated statistical analysis that the log-linearized Hunt–Crossley model performs always closely to the Hunt–Crossley model and is even often slightly better. The experimental conditions investigated are related to impact and contact interactions, relevant in the context of Cobotics.

scholarly journals Signed Real-Time Delay Multiply and Sum Beamforming for Multispectral Photoacoustic Imaging

2018 ◽  
Vol 4 (10) ◽  
pp. 121 ◽  
Author(s):  
Thomas Kirchner ◽  
Franz Sattler ◽  
Janek Gröhl ◽  
Lena Maier-Hein
Keyword(s):  
Open Source ◽  
Real Time ◽  
Photoacoustic Imaging ◽  
Signal To Noise Ratio ◽  
Ultrasound Transducers ◽  
Full Spectrum ◽  
Simple Implementation

Reconstruction of photoacoustic (PA) images acquired with clinical ultrasound transducers is usually performed using the Delay and Sum (DAS) beamforming algorithm. Recently, a variant of DAS, referred to as Delay Multiply and Sum (DMAS) beamforming has been shown to provide increased contrast, signal-to-noise ratio (SNR) and resolution in PA imaging. The main reasons for the use of DAS beamforming in photoacoustics are its simple implementation, real-time capability, and the linearity of the beamformed image to the PA signal. This is crucial for the identification of different chromophores in multispectral PA applications. In contrast, current DMAS implementations are not responsive to the full spectrum of sound frequencies from a photoacoustic source and have not been shown to provide a reconstruction linear to the PA signal. Furthermore, due to its increased computational complexity, DMAS has not been shown yet to work in real-time. Here, we present an open-source real-time variant of the DMAS algorithm, signed DMAS (sDMAS), that ensures linearity in the original PA signal response while providing the increased image quality of DMAS. We show the applicability of sDMAS for multispectral PA applications, in vitro and in vivo. The sDMAS and reference DAS algorithms were integrated in the open-source Medical Imaging Interaction Toolkit (MITK) and are available as real-time capable implementations.

scholarly journals Fluorescence/photoacoustic imaging-guided nanomaterials for highly efficient cancer theragnostic agent

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vu Hoang Minh Doan ◽  
Van Tu Nguyen ◽  
Sudip Mondal ◽  
Thi Mai Thien Vo ◽  
Cao Duong Ly ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Efficiency ◽  
Imaging System ◽  
Photoacoustic Imaging ◽  
Imaging Techniques ◽  
Non Invasive ◽  
Cell Ablation ◽  
Tumor Tissues

AbstractImaging modalities combined with a multimodal nanocomposite contrast agent hold great potential for significant contributions in the biomedical field. Among modern imaging techniques, photoacoustic (PA) and fluorescence (FL) imaging gained much attention due to their non-invasive feature and the mutually supportive characteristic in terms of spatial resolution, penetration depth, imaging sensitivity, and speed. In this present study, we synthesized IR783 conjugated chitosan–polypyrrole nanocomposites (IR-CS–PPy NCs) as a theragnostic agent used for FL/PA dual-modal imaging. A customized FL and photoacoustic imaging system was constructed to perform required imaging experiments and create high-contrast images. The proposed nanocomposites were confirmed to have great biosafety, essentially a near-infrared (NIR) absorbance property with enhanced photostability. The in vitro photothermal results indicate the high-efficiency MDA-MB-231 breast cancer cell ablation ability of IR-CS–PPy NCs under 808 nm NIR laser irradiation. The in vivo PTT study revealed the complete destruction of the tumor tissues with IR-CS–PPy NCs without further recurrence. The in vitro and in vivo results suggest that the demonstrated nanocomposites, together with the proposed imaging systems could be an effective theragnostic agent for imaging-guided cancer treatment.

Multi-mode light microscopy of microtubule assembly dynamics and chromosome movement in vivo and In vitro

1996 ◽  
Vol 54 ◽  
pp. 730-731
Author(s):  
E. D. Salmon ◽  
J. C. Waters ◽  
C. Waterman-Storer
Keyword(s):  
Imaging System ◽  
Ccd Camera ◽  
Transmitted Light ◽  
Microtubule Assembly ◽  
Live Cells ◽  
Optical Efficiency ◽  
Multiple Band ◽  
Multi Mode

We have developed a multi-mode digital imaging system which acquires images with a cooled CCD camera (Figure 1). A multiple band pass dichromatic mirror and robotically controlled filter wheels provide wavelength selection for epi-fluorescence. Shutters select illumination either by epi-fluorescence or by transmitted light for phase contrast or DIC. Many of our experiments involve investigations of spindle assembly dynamics and chromosome movements in live cells or unfixed reconstituted preparations in vitro in which photodamage and phototoxicity are major concerns. As a consequence, a major factor in the design was optical efficiency: achieving the highest image quality with the least number of illumination photons. This principle applies to both epi-fluorescence and transmitted light imaging modes. In living cells and extracts, microtubules are visualized using X-rhodamine labeled tubulin. Photoactivation of C2CF-fluorescein labeled tubulin is used to locally mark microtubules in studies of microtubule dynamics and translocation. Chromosomes are labeled with DAPI or Hoechst DNA intercalating dyes.

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