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[IEEE 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Krakow, Poland (2018.10.16-2018.10.18)] 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - A novel method to explore intrarenal arterial tree using micro-CT
摘要： The minimally invasive approach for renal surgeries, among others, requires preoperative determination of intrarenal arteries. Their proper identification based on standard preoperative CT images is still not a fully solved problem. Therefore, we decided to resolve this issue by providing a tree topology model using post-mortem kidneys. The number of vessels that compose intrarenal tree is so large, that it cannot by analyzed manually without the aid of image processing techniques. So that, the vessels has to be first depicted using an imaging technique that enables to provide superior resolution in comparison to standard CT scan. In this paper, we present a research on various injection materials enabling to fill the vascular beds in order to scan them using micro-CT and further reconstruct as a 3D model. The evaluated materials were chosen so that they are widely available and affordable. We compare them in terms of their ability to absorb ionizing radiation and penetrate vascular beds (density, viscosity), homogeneity, solidification rate, resistance to solvents and durability. We also present the technique of injecting kidney arteries with the use of the selected material - two-part epoxy adhesive with 10% iodine. In contrast to standard corrosive endocast preparation, in our case there is no need to remove soft parenchymal tissue which takes about two weeks using corrosive materials such as strong acids and bases. The proposed filling material enables to enhance vascular tree to such extend that micro-CT scans of the whole kidneys can be performed. This enables instantaneous substance injection and imaging without permanently destroying the soft tissue material. This approach can be used in various scenarios in which a filling material with the ability to increase radiation absorption is required and there is a need to maintain the integrity of the structure. To the best of our knowledge, this is the first such attempt. The obtained vascular trees by the means of micro-CT confirm the validity of the presented approach.
关键词： cast,micro-CT,3D vascular tree,minimally invasive surgery,contrast agents,ability to absorb ionizing radiation,kidney surgery,injection materials,kidney
更新于2025-09-23 15:23:52
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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
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Tomodensitométrie spectrale?: de la double énergie à la multiénergie
摘要： Standard computed tomography imaging allows the differentiation between anatomic structures based on their X-ray global attenuation difference. This difference, due to the Compton and photoelectric effects, depends essentially on the effective atomic number and electronic density of the elements evaluated. Spectral dual energy CT expends the capabilities of standard CT by distinguishing elements of same attenuation by their difference of Compton and photoelectric effects. The purpose of this didactic content is to introduce principles and explain the technology of spectral CT imaging, based on the attenuation difference at two different energies. Moreover, evolutions towards spectral multienergy CT will be introduced.
关键词： K-edge,Dual energy CT,Spectral CT,Spectral photon-counting CT,Contrast agents,Virtual monoenergetic image
更新于2025-09-23 15:22:29
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Amphiphilic nanoaggregates with bimodal MRI and optical properties exhibiting magnetic field dependent switching from positive to negative contrast enhancement
摘要： Mixed micelles based on amphiphilic gadolinium(III)-DOTA and europium(III)-DTPA complexes were synthesized and evaluated for their paramagnetic and optical properties as potential bimodal contrast agents. Amphiphilic folate molecule for targeting the folate receptor protein, which is commonly expressed on the surface of many human cancer cells, was used in the self-assembly process in order to create nanoaggregates with targeting properties. Both targeted and non-targeted nanoaggregates formed mono-disperse micelles having distribution maxima of 10 nm. The micelles show characteristic europium(III) emission with quantum yields of 2% and 1.1% for the non-targeted and targeted micelles respectively. Fluorescence microscopy using excitation at 405 nm and emission at 575-675 nm was employed to visualize nanoaggregates in cultured HeLa cells. The uptake of folate-targeted and non-targeted micelles is already visible after 5 hour incubation, and was characterized with the europium(III) emission which is clearly observable in the cytoplasm of the cells. The very fast longitudinal relaxivity r1 of ca. 26 s-1 mM-1 per gadolinium(III) ion was observed for both micelles at 60 MHz and 310 K. Upon increasing the magnetic field to 300 MHz the nanoaggregates exhibited a large switching to transversal relaxivity with r2 value of ca. 52 s-1 mM-1 at 310 K. Theoretical fitting of the 1H NMRD profiles indicate that the efficient T1 and T2 relaxations are sustained by the favorable magnetic and electron-configuration properties of the gadolinium(III) ion, rotational correlation time and coordinated water molecule. These nanoaggregates could have versatile application as a positive contrast agent at currently used magnetic imaging field strengths and a negative contrast agent in higher field applications, while at the same time offering the possibility for the loading of hydrophobic therapeutics or targeting molecules.
关键词： bimodal contrast agents,gadolinium,nanoaggregates,optical imaging,micelle,high field MRI
更新于2025-09-23 15:22:29
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Self-assembled Ln(III) cyclen-based micelles and AuNPs conjugates as candidates for luminescent and magnetic resonance imaging (MRI) agents
摘要： The tetra-substituted heptadentate cyclen (1,4,7,10-tetraazacyclododecane) based Eu(III)/Tb(III)/Gd(III)-complexes 1.Ln and 2.Ln were developed. 1.Eu/Tb and 2.Eu/Tb were employed in the formation of luminescent self-assembling ternary structures, and we demonstrate that only in the presence of appropriate sensitizing antennae, was the lanthanide-emission of 1.Eu/Tb and 2.Eu/Tb ‘switched on’. 1.Gd/2.Gd were developed as potential MIR contrast agents, and employed in NMRD-measurements, where their relaxivity was investigated, and their (relatively high) r1 values determined. The formation of a self-assembled micelle-type structure was clearly observed for 2.Gd. The functionalised gold nanoparticles 1.Ln-AuNP were also synthesized from 1.Ln. As for the free complexes, the Ln-emission was ‘switched on’ for 1.Eu/Tb-AuNP in the presence of the antennae. NMRD measurements indicated that the relaxivity for the 1.Gd-AuNP systems was very high, with a value of 445 s-1mM-1 (at 400 MHz), demonstrating the cumulative effect of the relatively high number of 1.Gd complexes on the surface of the AuNP.
关键词： gold nanoparticles,lanthanides,Supramolecular chemistry,luminescence,MRI contrast agents,cyclen complexes
更新于2025-09-23 15:19:57
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Bioinspired magnetic nanoparticles as multimodal photoacoustic, photothermal and photomechanical contrast agents
摘要： Nanoparticles from magnetotactic bacteria have been used in conventional imaging, drug delivery, and magnetic manipulations. Here, we show that these natural nanoparticles and their bioinspired hybrids with near-infrared gold nanorods and folic acid can serve as molecular high-contrast photoacoustic probes for single-cell diagnostics and as photothermal agents for single-cell therapy using laser-induced vapor nanobubbles and magnetic field as significant signal and therapy amplifiers. These theranostics agents enable the detection and photomechanical killing of triple negative breast cancer cells that are resistant to conventional chemotherapy, with just one or a few low-energy laser pulses. In studies in vivo, we discovered that circulating tumor cells labeled with the nanohybrids generate transient ultrasharp photoacoustic resonances directly in the bloodstream as the basis for new super-resolution photoacoustic flow cytometry in vivo. These properties make natural and bioinspired magnetic nanoparticles promising biocompatible, multimodal, high-contrast, and clinically relevant cellular probes for many in vitro and in vivo biomedical applications.
关键词： theranostics,super-resolution,contrast agents,photomechanical,photoacoustic,magnetic nanoparticles,photothermal,circulating tumor cells,bioinspired,magnetotactic bacteria
更新于2025-09-19 17:15:36
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Azacalixphyrins as NIR photoacoustic contrast agents
摘要： Near-infrared (NIR) azacalixphyrins bearing aryl substituents strongly impacting the physico-chemical properties of the macrocycles were designed, enabling hyperchromic and bathochromic shifts of the absorption compared to their N-alkylated analogues. This engineering enhances the photoacoustic response under NIR excitation, making azacalixphyrins promising organic contrast agents that reach the 800–1000 nm range.
关键词： contrast agents,organic chromophores,photoacoustic imaging,NIR,azacalixphyrins
更新于2025-09-19 17:15:36
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Recent Progress on Near-Infrared Photoacoustic Imaging: Imaging Modality and Organic Semiconducting Agents
摘要： 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.
关键词： photoacoustic imaging,near-infrared,contrast agents,organic semiconductors
更新于2025-09-19 17:13:59
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A Novel Nano-approach for Targeted Inner Ear Imaging
摘要： During the last decade, there have been major improvements in imaging modalities and the development of molecular imaging in general. However detailed inner ear imaging still provides very limited information to physicians. This is unsatisfactory as sensorineural hearing loss is the main cause of permanent hearing loss in adults and at least 134 genetic mutations that result in congenital hearing loss have been identified. We are still unable, in most cases where gross anatomical changes are not observed, to determine the exact cause of hearing loss at a cellular or molecular level in patients using non-invasive techniques. This limitation in inner ear diagnostic modalities is a major obstacle behind the delay in discovering treatments for many of the causes of sensorineural hearing loss. This paper initially investigated the use of targeted gold nanoparticles as contrast agents for inner ear imaging. These nanoparticles have many useful characteristics such as being easy to target and possessing minimal cytotoxicity. We were able to detect the nanoparticles diffusing in the hair cells using confocal microscopy. Regrettably, despite their many admirable characteristics, the gold nanoparticles were unable to significantly enhance CT imaging of the inner ear. Consequently, we investigated liposomal iodine as a potential solution for the unsatisfactory CT contrast obtained with the gold nanoparticles. Fortunately, significant enhancement of the micro-CT image was observed with either Lugol’s solution or liposomal iodine, with Lugol’s solution enabling fine inner ear structures to be detected.
关键词： Targeted contrast agents,Liposomal iodine,Inner ear imaging,Gold nanoparticles
更新于2025-09-16 10:30:52
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Hybrid Nanostructures for Cancer Theranostics || Hybrid Nanostructures for In Vivo Imaging
摘要： Nanohybrids with well-defined optical properties and integrated functionalities are considered to be the most advanced next-generation blend of therapeutics and diagnostics: a simultaneous “theranostics”. Targeted delivery, real-time monitoring of administration, distribution, biotransformation, and elimination from the body are some of the beneficial attributes which have enabled it to get wide attention and acceptability. A spectrum of new-generation hybrid nanosystems for future biomedical applications has been fabricated, and has a variety of applications towards in vivo optical imaging, ultrasound (US) imaging, computed tomography (CT) of X-rays, magnetic resonance imaging (MRI), and positron emission tomography (PET). Multifunctional nanoparticles containing multiple contrast agents not only allow multimodal imaging but also improve the resolution of each of these imaging modalities. This chapter provides one of the most comprehensive detailed reports on the development of nanohybrids for cancer imaging to date.
关键词： Cancer imaging,Multimodal imaging,Theranostics,Contrast agents,Nanohybrids
更新于2025-09-10 09:29:36