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- 2017
- spectral reconstruction
- interference
- polarization
- transform
- imaging spectrometer
- Optoelectronic Information Science and Engineering
- BITTT
- Zhejiang University
- Guilin University of Aerospace Technology
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Magnetic targeting core/shell Fe3O4/Au nanoparticles for magnetic resonance/photoacoustic dual-modal imaging
摘要： This study reports magnetic targeting guided magnetic (MR)/photoacoustic (PA) dual-modal imaging by core/shell Fe3O4/Au nanoparticles. In this work, MR imaging provides time-dependent tumor location, and PA imaging reveals high resolution vasculatures inside the tumor. It is noted that the synthesized Fe3O4/Au nanoparticles exhibited higher r2 value up to 329 mM?1 s?1 than previously reported T2 contrast agents. Furthermore, the Fe3O4/Au NPs are applied as a promising candidate for in vivo MR/PA imaging of tumors by intravenously injection into LNCaP tumor-beared mice. The MR/PA imaging results show a significantly enhanced MR/PA images in the tumor site. The prepared core/shell Fe3O4/Au nanoparticles will be widely applicable in multi-modal imaging.
关键词： Fe3O4/Au nanoparticles,Magnetic targeting,PA imaging,Dual-modal imaging,MR imaging
更新于2025-09-23 15:22:29
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Design Considerations for Murine Retinal Imaging Using Scattering Angle Resolved Optical Coherence Tomography
摘要： Optical coherence tomography (OCT), an optical imaging approach enabling cross-sectional analysis of turbid samples, is routinely used for retinal imaging in human and animal models of diseases affecting the retina. Scattering angle resolved (SAR-)OCT has previously been demonstrated as offering additional contrast in human studies, but no SAR-OCT system has been reported in detail for imaging the retinas of mice. An optical model of a mouse eye was designed and extended for validity at wavelengths of light around 1310 nm; this model was then utilized to develop a SAR-OCT design for murine retinal imaging. A Monte Carlo technique simulates light scattering from the retina, and the simulation results are confirmed with SAR-OCT images. Various images from the SAR-OCT system are presented and utility of the system is described. SAR-OCT is demonstrated as a viable and robust imaging platform to extend utility of retinal OCT imaging by incorporating scattering data into investigative ophthalmologic analysis.
关键词： angle resolved imaging,retinal imaging,optical coherence tomography,rodent imaging,scattering
更新于2025-09-23 15:22:29
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Pseudo-polarimetric method for dense haze removal
摘要： The scattering and absorption by the existing particles in turbid media severely degrading the image quality and decreasing the visibility distance, especially in dense turbid media. In this paper, we investigate the polarization property of hazy images in dense turbid media, and we propose a simple pseudo-polarimetric dehazing method for dense haze removal, which only requires a single image captured by the detector. By our proposed method, two orthogonal polarization sub-images are derived from the single original image, and then, based on these two sub-images, one can obtain the recovered image by using traditional polarimetric method. The real-word experimental results verify that, for the dense haze, our method based on a single image could have a comparable or better performance compared to the traditional polarimetric dehazing method with multiple images captured at different polarization states.
关键词： polarimetric imaging,Polarization,imaging through turbid media
更新于2025-09-23 15:22:29
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[IEEE 2018 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium) - Boston, MA, USA (2018.7.8-2018.7.13)] 2018 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium) - Sub-Diffraction Holographic Imaging with Resonant Scatterers in Proximity of the Objects
摘要： To overcome the well-known 'diffraction limit' in the resolution of electromagnetic imaging systems, we propose the use of resonant near-field scatterers incorporated in the holographic imaging techniques. These scatterers convert a portion of the evanescent spectrum in the proximity of the object to propagating spectrum which is measurable by the antenna in the far-field.
关键词： microwave and millimeter wave imaging,sub-diffraction imaging,resonant scatterers
更新于2025-09-23 15:22:29
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Bistatic SAR: Forecasting Spatial Resolution
摘要： This paper derives closed form expressions for bistatic synthetic aperture radar spatial resolution of a generalized system from the k-space or the wavenumber domain. These spatial resolution equations have not previously appeared in the literature. From these equations, significant resolution is found in both range and cross-range forecasting a forward-scatter bistatic synthetic aperture radar image when the elevation angles of each bistatic platform are significantly different. Simulation and lab tests demonstrated the forward scatter resolution.
关键词： image resolution,synthetic aperture radar,radar remote sensing,spatial resolution,radar imaging,bistatic radar,microwave imaging
更新于2025-09-23 15:22:29
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Doxorubicin and indocyanine green loaded superparamagnetic iron oxide nanoparticles with PEGylated phospholipid coating for magnetic resonance with fluorescence imaging and chemotherapy of glioma
摘要： Background: Glioma represents the most common malignant brain tumor. Outcomes of surgical resection are often unsatisfactory due to low sensitivity or resolution of imaging methods. Moreover, the use of traditional chemotherapeutics, such as doxorubicin (DOX), is limited due to their low blood–brain barrier (BBB) permeability. Recently, the development of nanotechnology could overcome these obstacles. Materials and methods: Hydrophobic superparamagnetic iron oxide nanoparticles (SPIO NPs) were prepared with the use of thermal decomposition method. They were coated with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG 2000) and DOX using a thin-film hydration method followed by loading of indocyanine green (ICG) into the phospholipid layers. Details regarding the characteristics of NPs were determined. The in vitro biocompatibility and antitumor efficacy were established with the use of MTT assay. In vivo fluorescence and magnetic resonance (MR) imaging were used to evaluate BBB penetration and accumulation of NPs at the tumor site. Antitumor efficacy was evaluated using measures of tumor size, median survival times, body weights, and H&E staining. Results: The multifunctional NPs generated had an average diameter of 22.9 nm, a zeta potential of -38.19 mV, and were capable of providing a sustained release of DOX. In vitro experiments demonstrated that the SPIO@DSPE-PEG/DOX/ICG NPs effectively enhanced cellular uptake of DOX as compared with that of free DOX. In vivo fluorescence and MR imaging revealed that the NPs not only effectively crossed the BBB but selectively accumulated at the tumor site. Meanwhile, among all groups studied, C6 glioma-bearing rats treated with the NPs exhibited the maximal degree of therapeutic efficacy, including smallest tumor volume, lowest body weight loss, and longest survival times, with no obvious side effects. Conclusion: These results suggest that the SPIO@DSPE-PEG/DOX/ICG NPs can not only function as a nanoprobe for MR and fluorescence bimodal imaging, but also as a vehicle to deliver chemotherapeutic drugs to the tumor site, to achieve the theranostic treatment of glioma.
关键词： SPIO NPs,fluorescence imaging,chemotherapy,BBB,MR imaging
更新于2025-09-23 15:22:29
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Macrophage uptake switches on OCT contrast of superparamagnetic nanoparticles for imaging of atherosclerotic plaques
摘要： Background: Optical coherence tomography (OCT) is an intravascular, high-resolution imaging technique that is used to characterize atherosclerotic plaques. However, the identification of macrophages as important markers of inflammation and plaque vulnerability remains difficult. Here, we investigate whether the uptake of very small iron oxide particles (VSOP) in macrophages, that cluster in phagolysosomes and allow high-quality magnetic resonance imaging (MRI) of atherosclerotic plaques, and uptake of ferumoxytol nanoparticles enhance detection of macrophages by OCT. Materials and methods: RAW 264.7 macrophage cells were incubated with VSOP (1 and 2 mM Fe) that have been clinically tested and ferumoxytol (8.9 mM Fe) that is approved for iron deficiency treatment and currently investigated as an MRI contrast agent. The light scattering of control macrophages, nanoparticle-labeled macrophages (2,000,000 in 500 μL) and nanoparticle suspensions was measured in synchronous wavelength scan mode using a fluorescence spectrophotometer. For OCT analyses, pellets of 8,000,000 non-labeled, VSOP-labeled and ferumoxytol-labeled RAW 264.7 macrophages were imaged and analyzed on an OPTIS? OCT imaging system. Results: Incubation with 1 and 2 mM VSOP resulted in uptake of 7.1±1.5 and 12±1.5 pg Fe per cell, which increased the backscattering of the macrophages in spectrophotometry 2.5- and 3.6-fold, whereas incubation with 8.9 mM Fe ferumoxytol resulted in uptake of 6.6±2 pg Fe per cell, which increased the backscattering 1.5-fold at 700 nm. In contrast, backscattering of non-clustered nanoparticles in suspension was negligible. Accordingly, OCT imaging could visualize significantly increased backscattering and signal attenuation of nanoparticle-labeled macrophages in comparison with controls. Conclusion: We conclude that VSOP and, to a lesser extent, ferumoxytol increase light scattering and attenuation when taken up by macrophages and can serve as a multimodal imaging probe for MRI and OCT to improve macrophage detection in atherosclerotic plaques by OCT in the future.
关键词： intravascular,magnetic resonance imaging,multimodal imaging,optical coherence tomography,vulnerability,inflammation
更新于2025-09-23 15:22:29
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Underwater polarimetric imaging for visibility enhancement utilizing active unpolarized illumination
摘要： Underwater imaging is attractive but challenging. Images could be severely degraded by the particles in turbid water because of backscatter generation and signal light attenuation. In this paper, we focus on the scheme of underwater imaging and study the methods of visibility enhancement of turbid underwater images based on polarimetric imaging utilizing active unpolarized illumination. Compared with traditional polarimetric imaging using linearly polarized illumination, using unpolarized illumination ensures the polarization effect of the signal light could be neglected, no matter the depolarization degree of the object is high or low, which expands the application range of underwater polarimrteic imaging and makes the underwater polarimetric imaging scheme more reliable and robust. Experimentally, the visibility and the contrast of underwater images are enhanced effectively. In addition, it is demonstrated that our method is applicable for objects of different materials and different imaging distances in turbid water. The contrast of underwater images could be promoted at least 100%, meaning that this kind of technique can be potentially used in many underwater environments.
关键词： imaging through turbid media,polarimetric imaging,image enhancement
更新于2025-09-23 15:22:29
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Ordered assemblies of Fe3O4 and a donor-acceptor-type π-conjugated polymer in nanoparticles for enhanced photoacoustic and magnetic effects
摘要： We report that the ordered structure in the assemblies of iron oxide nanoparticles in conjugated polymer nanoparticles is the key to achieve better properties to realize multimodal theranostic agents for magnetic resonance and photoacoustic imaging. Hybrid nanoparticles of a conjugated polymer (PCPDTBT), a phospholipid (D8PE) with a primary amine polar head, and iron oxide (Fe3O4) nanoparticles were prepared by a phase-separated film shattering process by varying the iron oxide concentration while maintaining a fixed mixing ratio of PCPDTBT and D8PE. Notably, the hybrid nanoparticles assembled at a molar mixing ratio of 1:1:0.8 (PCPDTBT/D8PE/Fe3O4) exhibited the shortest transversal relaxation time, T2, and a photoacoustic signal 22 times higher than that obtained at the 1:1:0 mixing ratio. Structural analysis by X-ray diffraction together with the measurements of energy transfer by transient absorption spectroscopy confirmed that the structural ordering of these hybrid nanoparticles was responsible for their enhanced photoacoustic and magnetic properties.
关键词： Conjugated polymers,Photoacoustic imaging,Magnetic resonance imaging,Iron oxides,Hybrid nanoparticles
更新于2025-09-23 15:22:29
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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