- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
A thermo-sensitive fluorescent agent based method for excitation light leakage rejection for fluorescence molecular tomography
摘要： Fluorescence molecular tomography (FMT) is widely used in preclinical oncology research. FMT is the only imaging technique able to provide three-dimensional distribution of fluorescent probes within thick highly scattering media. However, its integration into clinical medicine has been hampered by its low spatial resolution caused by the undetermined and ill-posed nature of its reconstruction algorithm. Another major factor degrading the quality of FMT images is the large backscattered excitation light component leaking through the rejection filters and coinciding with the weak fluorescent signal arising from a low tissue fluorescence concentration. In this paper, we present a new method based on the use of a novel thermo-sensitive fluorescence probe. In fact, the excitation light leakage is accurately estimated from a set of measurements performed at different temperatures and then is corrected for in the tomographic data. The obtained results show a considerable improvement in both spatial resolution and quantitative accuracy of FMT images due to the proper correction of fluorescent signals.
关键词： Excitation Light Leakage,Biomedical Imaging,Fluorescence Molecular Tomography
更新于2025-09-23 15:23:52
-
Carbon Nanomaterials for Bioimaging, Bioanalysis, and Therapy || Photoacoustic Imaging with Carbon Nanomaterials
摘要： Photoacoustic imaging is a novel, noninvasive biomedical imaging modality that has evolved considerably over the last few decades. As a label‐free imaging modality using both endogenous and exogenous contrast agent it has shown many advantages to safely and effectively differentiate diseased tissue from healthy tissues at a deeper depth. While endogenous light‐absorbing objects in living subjects such as hemoglobin, melanin, and glucose, have been useful in imaging, the use of exogenous contrast agents can improve the detection sensitivity and specific tissue‐targeting capabilities of photoacoustic imaging modality further. The carbon nanomaterial has been found to be one of the best contrast agents for photoacoustic imaging, which has strong absorption properties and great biocompatibility. This chapter covers the basic introduction of photoacoustic imaging and the application of carbon nanomaterials contrast agent such as imaging‐guided therapy and multimodal imaging in photoacoustic imaging.
关键词： photoacoustic imaging,contrast agents,photothermal therapy,photodynamic therapy,multimodal imaging,biomedical imaging,carbon nanomaterials
更新于2025-09-23 15:22:29
-
Edge-illumination x-ray phase contrast imaging restoration using discrete curvelet regularization transform
摘要： This article considers the problem of recovering edge-illumination x-ray phase contrast (EIXPC) images from a set of potentially Poisson noisy projection measurements. The authors cast a recovery as a sparse regularization problem based on Anscombe multiscale variance stabilizing transform (MS-VST) with fast discrete curvelet transform which was applied to simulated edge-illumination x-ray phase contrast images. For accurate modelling, the noise characteristics of the EIXPCi data are used to determine the relative importance of each projection. Two implementations of curvelet sparse regularization transforms were applied, including the unequally-spaced fast Fourier transform and the wrapping-based transform. The algorithms were evaluated in terms of contrast improvement, quality of image restoration, object perceptibility, and peak signal-to-noise ratio. The methods provide nearly optimal solution without excessive memory and recovery time requirement. The performance of the proposed algorithms is demonstrated through a series of complex numerical geometric and anthropomorphic phantom studies. The results of numerical simulations demonstrate that the discrete curvelet transform with MS-VST is fast and robust, and it can effectively improve image quality, preserve and enhance edges and restore lost information while signi?cantly reducing the noise. Additionally, both sparse sampling and decreasing x-ray tube current (i.e. noisy data) lead to the reduction of radiation dose in the x-ray imaging.
关键词： x-ray imaging,x-ray phase-contrast,curvelet regularization,biomedical imaging
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Vilnius, Lithuania (2018.11.8-2018.11.10)] 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Deep Neural Network-based Feature Descriptor for Retinal Image Registration
摘要： Feature description is an important step in image registration workflow. Discriminative power of feature descriptors affects feature matching performance and overall results of image registration. Deep Neural Network-based (DNN) feature descriptors are emerging trend in image registration tasks, often performing equally or better than hand-crafted ones. However, there are no learned local feature descriptors, specifically trained for human retinal image registration. In this paper we propose DNN-based feature descriptor that was trained on retinal image patches and compare it to well-known hand-crafted feature descriptors. Training dataset of image patches was compiled from nine online datasets of eye fundus images. Learned feature descriptor was compared to other descriptors using Fundus Image Registration dataset (FIRE), measuring amount of correctly matched ground truth points (Rank-1 metric) after feature description. We compare the performance of various feature descriptors applied for retinal image feature matching.
关键词： artificial neural networks,biomedical imaging,machine learning,image registration,retinal images,feature descriptors
更新于2025-09-23 15:22:29
-
Normalization of <sup>11</sup> C-autoradiographic images for semi-quantitative analysis of woody tissue photosynthesis
摘要： To understand plant survival and mortality during drought it is important to gain better insights into the different mechanisms contributing to both the carbon budget and the hydraulic functioning of plants. However, the role of internally transported carbon dioxide (CO2) in xylem together with related woody tissue photosynthesis is often neglected. Trees contain large amounts of CO2 (often between 3 and 10%, and sometimes exceeding 20%), which is substantially higher than the atmospheric CO2 concentration (c. 0.04%). It is known that a portion of this locally respired CO2 escapes to the atmosphere during transport and that photosynthetic active cells in woody tissues or leaves can fix another portion. A new approach for direct visualization of woody tissue (stem) photosynthesis is presented in this study and using a radioactive 11C-tracer and autoradiographic imaging. To allow semi-quantitative comparison of woody tissue photosynthesis between different branches, a normalization method is required. We developed such a normalization technique by taking into account: (i) the radioactivity at the start of the experiment; (ii) the labeling time; (iii) the start and (iv) duration of exposure of the branch to the autoradiographic phosphor screen. In addition to these time-related parameters, we also accounted for total transpiration during the labeling experiment.
关键词： biomedical imaging,woody tissue photosynthesis,positron autoradiography
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Kiev (2018.4.24-2018.4.26)] 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Simulated Phantom Projections for Reconstruction Quality Control in Digital Tomosynthesis
摘要： IMASIM software was used to generate sets of X-ray projections for quality control in digital tomosynthesis. Corresponding projections of a polymethylmethacrylate(PMMA) phantom with the same size were taken using x-ray tomosynthesis imaging equipment. A specially designed fiduciary marker bead phantom was used to measure the relative positions of imaging system elements. A good correspondence was found between real and simulated projections and reconstructed slices. The ability to create simulated projections with predefined imperfections gives valuable benefits to analysis of overall tomosynthesis performance.
关键词： X-ray applications,digital X-ray tomosynthesis,quality control,biomedical imaging,numerical simulation
更新于2025-09-23 15:22:29
-
[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Colloidal CdSe Nanocrystals as a Material for Optoelectronics and Biomedical Imaging
摘要： Cadmium selenide nanocrystals were prepared in water phase chemistry technique with gelatin, polivinil alcohol, lactose, triton-100 acting as capping agent. Structures were characterized using scanning electron microscopy (SEM), visible absorption and photoluminescence spectroscopies. Influence of component concentrations and technological parameters on nanocrystals average size and properties was studied
关键词： photoluminescence,optical,selenide,optoelectronics,biomedical imaging,cadmium,nanocrystals,absorption
更新于2025-09-23 15:21:21
-
High-contrast, fast chemical imaging by coherent Raman scattering using a self-synchronized two-colour fibre laser
摘要： Coherent Raman scattering (CRS) microscopy is widely recognized as a powerful tool for tackling biomedical problems based on its chemically specific label-free contrast, high spatial and spectral resolution, and high sensitivity. However, the clinical translation of CRS imaging technologies has long been hindered by traditional solid-state lasers with environmentally sensitive operations and large footprints. Ultrafast fibre lasers can potentially overcome these shortcomings but have not yet been fully exploited for CRS imaging, as previous implementations have suffered from high intensity noise, a narrow tuning range and low power, resulting in low image qualities and slow imaging speeds. Here, we present a novel high-power self-synchronized two-colour pulsed fibre laser that achieves excellent performance in terms of intensity stability (improved by 50 dB), timing jitter (24.3 fs), average power fluctuation (<0.5%), modulation depth (>20 dB) and pulse width variation (<1.8%) over an extended wavenumber range (2700–3550 cm?1). The versatility of the laser source enables, for the first time, high-contrast, fast CRS imaging without complicated noise reduction via balanced detection schemes. These capabilities are demonstrated in this work by imaging a wide range of species such as living human cells and mouse arterial tissues and performing multimodal nonlinear imaging of mouse tail, kidney and brain tissue sections by utilizing second-harmonic generation and two-photon excited fluorescence, which provides multiple optical contrast mechanisms simultaneously and maximizes the gathered information content for biological visualization and medical diagnosis. This work also establishes a general scenario for remodelling existing lasers into synchronized two-colour lasers and thus promotes a wider popularization and application of CRS imaging technologies.
关键词： Coherent Raman scattering,CRS microscopy,biomedical imaging,fibre laser,nonlinear optical imaging
更新于2025-09-23 15:21:01
-
[Fundamental Biomedical Technologies] Advanced High-Resolution Tomography in Regenerative Medicine (Three-Dimensional Exploration into the Interactions between Tissues, Cells, and Biomaterials) || Introduction to X-Ray Micro-tomography
摘要： X-ray computed tomography (CT) represents one of the most powerful 3D non-destructive imaging techniques exploited in clinics to help the diagnostic process of many diseases. The progress achieved in the realization of detectors, in x-ray tube technology, and in the computational power of modern hardware has led to its translation toward micrometer and sub-micrometer range resolution applications. Micro-CT and nano-CT systems based on conventional micro-focus x-ray tubes or newest generation liquid-metal-jet anode (MetalJet) systems are, today, available and largely applied in biomedical research for in vitro studies of biomaterials, scaffolds, bones, teeth, etc. as well as for morphologic and functional studies on excised organs and small animals. Absorption-based imaging is the basis for the most common modality of CT scanners; however, the recent developments of x-ray sources based on synchrotron laboratories and capable to reach unprecedented characteristics of brilliance and intensity have allowed the implementation of innovative imaging approaches. These techniques exploit the refraction of x-rays in the matter instead of their absorption, overcoming the intrinsic limitation of conventional techniques and broadening the utility of micro-CT. In this chapter an overview of the basics of micro-CT will be given, starting from the sources characteristics, then describing the x-ray interactions with matter, and finally addressing the image formation principles. In this latter paragraph, particular attention will be reserved to phase-sensitive techniques, highlighting their potentials to improve biomedical research.
关键词： Nano-CT,Micro-CT,Phase-sensitive techniques,Biomedical imaging,X-ray computed tomography
更新于2025-09-23 15:21:01
-
[IEEE 2018 New Generation of CAS (NGCAS) - Valletta, Malta (2018.11.20-2018.11.23)] 2018 New Generation of CAS (NGCAS) - High-Resolution ADCs for Biomedical Imaging Systems
摘要： With the rapid development of biomedical imaging systems, the requirement of the accuracy of an Analog-to-Digital Converter (ADC) becomes more and more critical. Traditional Nyquist-rate analog to digital data converters cannot meet the requirement any more. Sigma-Delta analog to digital data converter, which makes a trade-off between speed and accuracy, can achieve an ideal accuracy by employing the oversampling and noise-shaping technology. In this work, a Verilog-AMS model for sigma-delta modulator is built, including the topologic, the order of stage, oversampling rate, system parameters, etc. On the basic of theoretical analysis and scienti?c ?ow path, ?nally, a third-order 1-bit sigma-delta modulator is designed and optimized, whose performance agrees well with the theoretical module.
关键词： Analog-to-Digital Converter,Σ? ADC,Successive Approximation Register(SAR) ADC,Oversampling,Biomedical Imaging Systems
更新于2025-09-23 15:19:57