Short Acquisition Time PET Quantification Using MRI-Based Pharmacokinetic Parameter Synthesis

Background and Objectives. To determine the most appropriate technique for tumour followup in experimental therapeutics, we compared ultrasound (US) and magnetic resonance imaging (MRI) to characterize ectopic and orthotopic colon carcinoma models. Methods. CT26 tumours were implanted subcutaneously (s.c.) in Balb/c mice for the ectopic model or into the caecum for the orthotopic model. Tumours were evaluated by histology, spectrofluorescence, MRI, and US. Results. Histology of CT26 tumour showed homogeneously dispersed cancer cells and blood vessels. The visualization of the vascular network using labelled albumin showed that CT26 tumours were highly vascularized and disorganized. MRI allowed high-resolution and accurate 3D tumour measurements and provided additional anatomical and functional information. Noninvasive US imaging allowed good delineation of tumours despite an hypoechogenic signal. Monitoring of tumour growth with US could be accomplished as early as 5 days after implantation with a shorter acquisition time (<5 min) compared to MRI. Conclusion. MRI and US afforded excellent noninvasive imaging techniques to accurately follow tumour growth of ectopic and orthotopic CT26 tumours. These two techniques can be appropriately used for tumour treatment followup, with a preference for US imaging, due to its short acquisition time and simplicity of use.

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Time-resolved mid-infrared dual-comb spectroscopy

Scientific Reports ◽

10.1038/s41598-019-53825-8 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 10

Author(s):

Muhammad A. Abbas ◽

Qing Pan ◽

Julien Mandon ◽

Simona M. Cristescu ◽

Frans J. M. Harren ◽

...

Keyword(s):

Spectral Resolution ◽

Vibrational Excitation ◽

High Spectral Resolution ◽

Acquisition Time ◽

Time Resolved ◽

Short Acquisition Time ◽

Mid Infrared ◽

Infrared Wavelength ◽

Potential Applications ◽

Kinetics Of

AbstractDual-comb spectroscopy can provide broad spectral bandwidth and high spectral resolution in a short acquisition time, enabling time-resolved measurements. Specifically, spectroscopy in the mid-infrared wavelength range is of particular interest, since most of the molecules have their strongest rotational-vibrational transitions in this “fingerprint” region. Here we report time-resolved mid-infrared dual-comb spectroscopy, covering ~300 nm bandwidth around 3.3 μm with 6 GHz spectral resolution and 20 μs temporal resolution. As a demonstration, we study a CH4/He gas mixture in an electric discharge, while the discharge is modulated between dark and glow regimes. We simultaneously monitor the production of C2H6 and the vibrational excitation of CH4 molecules, observing the dynamics of both processes. This approach to broadband, high-resolution, and time-resolved mid-infrared spectroscopy provides a new tool for monitoring the kinetics of fast chemical reactions, with potential applications in various fields such as physical chemistry and plasma/combustion analysis.

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Retinal Imaging of Infants on Spectral Domain Optical Coherence Tomography

BioMed Research International ◽

10.1155/2015/782420 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 26

Author(s):

Anand Vinekar ◽

Shwetha Mangalesh ◽

Chaitra Jayadev ◽

Ramiro S. Maldonado ◽

Noel Bauer ◽

...

Keyword(s):

Spectral Domain ◽

Current Status ◽

Acquisition Time ◽

Imaging Device ◽

Short Acquisition Time ◽

Visual Potential ◽

Detailed Assessment ◽

First Year Of Life ◽

Sd Oct

Spectral domain coherence tomography (SD OCT) has become an important tool in the management of pediatric retinal diseases. It is a noncontact imaging device that provides detailed assessment of the microanatomy and pathology of the infant retina with a short acquisition time allowing office examination without the requirement of anesthesia. Our understanding of the development and maturation of the infant fovea has been enhanced by SD OCT allowing an in vivo assessment that correlates with histopathology. This has helped us understand the critical correlation of foveal development with visual potential in the first year of life and beyond. In this review, we summarize the recent literature on the clinical applications of SD OCT in studying the pathoanatomy of the infant macula, its ability to detect subclinical features, and its correlation with disease and vision. Retinopathy of prematurity and macular edema have been discussed in detail. The review also summarizes the current status of SD OCT in other infant retinal conditions, imaging the optic nerve, the choroid, and the retinal nerve fibre in infants and children, and suggests future areas of research.

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Single Photon, Time-Gated, Phasor-based Fluorescence Lifetime Imaging Through Highly Scattering Medium

10.1101/686998 ◽

2019 ◽

Cited By ~ 1

Author(s):

Rinat Ankri ◽

Arkaprabha Basu ◽

Arin Can Ulku ◽

Claudio Bruschini ◽

Edoardo Charbon ◽

...

Keyword(s):

Fluorescence Lifetime ◽

Fluorescence Intensity ◽

Single Photon ◽

Acquisition Time ◽

Fluorescence Signal ◽

Wide Field ◽

Fluorescence Lifetime Imaging ◽

Short Acquisition Time ◽

Lifetime Imaging

AbstractFluorescence lifetime imaging (FLI) is a powerful tool for in vitro and non-invasive in vivo biomolecular and cellular investigations. Fluorescence lifetime is an intrinsic characteristic of any fluorescent dye which, to some extent, does not depend on excitation intensity and signal level. However, when used in vivo with visible wavelength emitting fluorophores, FLI is complicated by (i) light scattering as well as absorption by tissues, which significantly reduces fluorescence intensity, (ii) tissue autofluorescence (AF), which decreases the signal to noise ratio and (iii) broadening of the decay signal, which can result in incorrect lifetime estimation. Here, we report the use of a large-frame time-gated single-photon avalanche diode (SPAD) imager, SwissSPAD2, with a very short acquisition time (in the milliseconds range) and a wide-field microscopy format. We use the phasor approach to convert each pixel’s data into its local lifetime. The phasor transformation provides a simple and fast visual method for lifetime imaging and is particularly suitable for in vivo FLI which suffers from deformation of the fluorescence decay, and makes lifetime extraction by standard fitting challenging. We show, for single dyes, that the phasor cloud distribution (of pixels) increases with decay broadening due to scattering and decreasing fluorescence intensity. Yet, as long as the fluorescence signal is higher than the tissue-like phantom AF, a distinct lifetime can still be clearly identified with an appropriate background correction. Lastly, we demonstrate the detection of few hundred thousand A459 cells expressing the fluorescent protein mCyRFP1 through highly scattering phantom layers, despite significant scattering and the presence of the phantom AF.

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Gas-Solid Flow in a Fluidized-Particle Tubular Solar Receiver: Off-Sun Experimental Flow Regimes Characterization

Energies ◽

10.3390/en14217392 ◽

2021 ◽

Vol 14 (21) ◽

pp. 7392

Author(s):

Ronny Gueguen ◽

Guillaume Sahuquet ◽

Samuel Mer ◽

Adrien Toutant ◽

Françoise Bataille ◽

...

Keyword(s):

Acquisition Time ◽

Internal Diameter ◽

Short Acquisition Time ◽

Wide Range ◽

Temporal Pressure ◽

Secondary Air ◽

Fluidized Particle ◽

Solar Power Tower ◽

Fluidized Particles ◽

Solar Receiver

The fluidized particle-in-tube solar receiver concept is promoted as an attractive solution for heating particles at high temperature in the context of the next generation of solar power tower. Similar to most existing central solar receivers, the irradiated part of the system, the absorber, is composed of tubes in which circulate the fluidized particles. In this concept, the bottom tip of the tubes is immersed in a fluidized bed generated in a vessel named the dispenser. A secondary air injection, called aeration, is added at the bottom of the tube to stabilize the flow. Contrary to risers, the particle mass flow rate is controlled by a combination of the overpressure in the dispenser and the aeration air velocity in the tube. This is an originality of the system that justifies a specific study of the fluidization regimes in a wide range of operating parameters. Moreover, due to the high value of the aspect ratio, the particle flow structure varies along the tube. Experiments were conducted with Geldart Group A particles at ambient temperature with a 0.045 m internal diameter and 3 m long tube. Various temporal pressure signal processing methods, applied in the case of classical risers, are applied. Over a short acquisition time, a cross-reference of the results is necessary to identify and characterize the fluidization regimes. Bubbling, slugging, turbulent and fast fluidization regimes are encountered and the two operation modes, without and with particle circulation, are compared.

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Ultraviolet-visible/near infrared spectroscopy and hyperspectral imaging to study the different types of raw cotton

Journal of Spectral Imaging ◽

10.1255/jsi.2020.a18 ◽

2020 ◽

Author(s):

Mohammad Al Ktash ◽

Otto Hauler ◽

Edwin Ostertag ◽

Marc Brecht

Keyword(s):

Hyperspectral Imaging ◽

Large Scale ◽

Near Infrared ◽

Dominant Role ◽

Principal Component ◽

Industrial Applications ◽

Acquisition Time ◽

Hydroxyl Groups ◽

Short Acquisition Time ◽

Different Types

Different types of raw cotton were investigated by a commercial ultraviolet-visible/near infrared (UV-Vis/NIR) spectrometer (210–2200 nm) as well as on a home-built setup for NIR hyperspectral imaging (NIR-HSI) in the range 1100–2200 nm. UV-Vis/NIR reflection spectroscopy reveals the dominant role proteins, hydrocarbons and hydroxyl groups play in the structure of cotton. NIR-HSI shows a similar result. Experimentally obtained data in combination with principal component analysis (PCA) provides a general differentiation of different cotton types. For UV-Vis/NIR spectroscopy, the first two principal components (PC) represent 82 % and 78 % of the total data variance for the UV-Vis and NIR regions, respectively. Whereas, for NIR-HSI, due to the large amount of data acquired, two methodologies for data processing were applied in low and high lateral resolution. In the first method, the average of the spectra from one sample was calculated and in the second method the spectra of each pixel were used. Both methods are able to explain ≥90 % of total variance by the first two PCs. The results show that it is possible to distinguish between different cotton types based on a few selected wavelength ranges. The combination of HSI and multivariate data analysis has a strong potential in industrial applications due to its short acquisition time and low-cost development. This study opens a novel possibility for a further development of this technique towards real large-scale processes.

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Electron Transfer based Ultra-bright Organic Afterglow Nanoprobe for Accurate Molecular Imaging in Mice

10.21203/rs.3.rs-1026824/v1 ◽

2021 ◽

Author(s):

Youjuan Wang ◽

Jing Guo ◽

Shiyi Liao ◽

Li Xu ◽

Qian Chen ◽

...

Keyword(s):

Electron Transfer ◽

Molecular Imaging ◽

Granzyme B ◽

Tissue Imaging ◽

Acquisition Time ◽

Deep Tissue ◽

Short Acquisition Time ◽

Ultra Low Power ◽

Deep Tissue Imaging ◽

Light Excitation

Abstract Afterglow luminescence can greatly improve the signal-to-background ratio (SBR) of molecule imaging in living animal owing to the no need of real-time light excitation. However, the relatively low luminescence of afterglow nanoprobe and attenuation of maximum intensity (afterglow photobleaching) usually lead to the insufficient sensitivity and the inaccurate quantification for repeated molecular imaging. Furthermore, the requirement of high power of light excitation (up to 1 W/cm2) may result in the inevitable phototoxicity, and the long acquisition time (up to 1 min) make it difficult to detect the rapid biological events. Herein, we design electron-rich trianthracene derivatives (TA)-based organic afterglow nanoparticles (TA-NPs) for high-sensitive, safe, lossless and longitudinal molecular imaging. Notably, a great enhancement of afterglow luminescence performance over the previous reported afterglow nanoparticles is achieved though electron transfer engineering (Table 1): Specifically, TA-NPs can be excited by room light with ultra-low power (58 µW/cm2) and with ultra-short acquisition time (0.01 s). The luminescent intensity of TA-NPs is ~ 500-fold of commonly used organic MEHPPV-based nanoparticles. Negligible afterglow photobleaching in mice is observed even after re-excitation for more than 15 cycles. Such ultra-bright afterglow enables the deep-tissue imaging (up to 6.0 cm) and the ultra-fast afterglow imaging of freely-moving mice in waken state. Moreover, TA-NPs can dynamically and accurately visualize subcutaneous tumor, orthotopic glioma and distinguish the plaque in carotid atherosclerosis. Finally, we develop an afterglow nanoprobe (TA-BHQ), activated only in the presence of Granzyme B, for tracking the time-sensitive Granzyme B activity as a direct way to monitor immunotherapeutic responses.

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Application of scanning electron diffraction in the transmission electron microscope for the characterisation of dislocations in minerals

Mineralogical Magazine ◽

10.1180/mgm.2018.144 ◽

2018 ◽

Vol 83 (1) ◽

pp. 71-79 ◽

Cited By ~ 1

Author(s):

Billy C. Nzogang ◽

Alexandre Mussi ◽

Patrick Cordier

Keyword(s):

Electron Diffraction ◽

Dark Field ◽

Perfect Crystal ◽

Crystal Defects ◽

Fine Tuning ◽

Acquisition Time ◽

Short Acquisition Time ◽

Transmission Electron ◽

Probe Location ◽

Scanning Electron

AbstractWe present an application of scanning electron diffraction for the characterisation of crystal defects in olivine, quartz and phase A (a high pressure hydrated phase). In this mode, which takes advantage of the ASTAR™ module from NanoMEGAS, a slightly convergent probe is scanned over the sample with a short acquisition time (a few tens of ms) and the spot patterns are acquired and stored for further post-processing. Originally, orientation maps were constructed from automatic indexing at each probe location. Here we present another application where images are reconstructed from the intensity of diffraction spots, producing either so-called ‘virtual’ bright- or dark-field images. We show that these images present all the characteristics of contrast (perfect crystal or defects) of conventional transmission electron microscopy images. Data are acquired with a very short time per probe location (a few tens of milliseconds), this technique appears very attractive for the characterisation of beam-sensitive materials. However, as the acquisition is done at a given orientation, fine tuning of the diffraction conditions at a given location for each reflection is not possible. This might present a difficulty for some precise, quantitative contrast analysis.

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