- 标题
- 摘要
- 关键词
- 实验方案
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Cobalt/Manganese Oxides as Theragnosis Nanoplatforms With Magnetic Resonance/Near-Infrared Imaging for Efficient Photothermal Therapy of Tumors
摘要： The combination of near-infrared (NIR) response and imaging response is a hot research area in which the functions of nanomaterials are maximized. However, the types of such materials reported so far present problems such as requiring complex synthesis. In this study, hydrophilic, porous, and hollow cobalt/manganese oxide (CMO) nanocrystals (NCs) were successfully prepared via a facile and green hydrothermal route. The CMO NCs show strong near-infrared (NIR) absorption, which results from their defect structure due to the coexistence of Co2+ and Co3+ in the as-prepared CMO NCs. Thus, the CMO NCs exhibit excellent photothermal performance, showing photothermal efficiency of up to 43.2%. In addition, the CMO NCs possess good magnetic resonance (MR) imaging performance, with longitudinal relaxivity (r1) of up to 3.48 mM?1 s?1. Finally, for the first time, we prove that the CMO nanocrystals are a promising photothermal agent. Our work provides insights into the application of Mn-based control agents and photothermal agents for photothermal theragnosis therapy.
关键词： cobalt/manganese oxides,photothermal agents,magnetic resonance imaging,photothermal theragnosis therapy,near-infrared absorption
更新于2025-09-16 10:30:52
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[Methods in Molecular Biology] || Multifunctional Magnetic Nanoparticles-Labeled Mesenchymal Stem Cells for Hyperthermia and Bioimaging Applications
摘要： Magnetic nanoparticles have demonstrated considerable capacity for theranosis purposes due to their unique characteristics, including magnetic properties, comparable size to biomolecules, favorable conjugations of drugs and biomolecules, ability to labeling, and capability of sensing, separation, detection, and targeted drug delivery. They could be exploited in magnetic resonance imaging as the contrast agents and also warmed as exposed to an external magnetic AC ?eld that could be applied in hyperthermia. Here, progresses and advances in the strategy and assembly of ?uorescent magnetic nanoparticles are presented for stem cell tracing and drugs/biomolecules targeting into cells.
关键词： Conjugation,Fluorescent probe,Stem cell tracing,Magnetic resonance imaging,Magnetic nanoparticles,Hyperthermia
更新于2025-09-12 10:27:22
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Light-Emitting Diode Photobiomodulation After Cerebral Ischemia
摘要： Photobiomodulation (PBM) therapy is a promising therapeutic approach for several pathologies, including stroke. The biological effects of PBM for the treatment of cerebral ischemia have previously been explored as a neuroprotective strategy using different light sources, wavelengths, and incident light powers. However, the capability of PBM as a novel alternative therapy to stimulate the recovery of the injured neuronal tissue after ischemic stroke has been poorly explored. The aim of this study was to investigate the low-level light irradiation therapy by using Light Emitting Diodes (LEDs) as potential therapeutic strategy for stroke. The LED photobiomodulation (continuous wave, 830 nm, 0.2–0.6 J/cm2) was firstly evaluated at different energy densities in C17.2 immortalized mouse neural progenitor cell lines, in order to observe if this treatment had any effect on cells, in terms of proliferation and viability. Then, the PBM-LED effect (continuous wave, 830 nm, 0.28 J/cm2 at brain cortex) on long-term recovery (12 weeks) was analyzed in ischemic animal model by means lesion reduction, behavioral deficits, and functional magnetic resonance imaging (fMRI). Analysis of cellular proliferation after PBM was significantly increased (1 mW) in all different exposure times used; however, this effect could not be replicated in vivo experimental conditions, as PBM did not show an infarct reduction or functional recovery. Despite the promising therapeutic effect described for PBM, further preclinical studies are necessary to optimize the therapeutic window of this novel therapy, in terms of the mechanism associated to neurorecovery and to reduce the risk of failure in futures clinical trials.
关键词： magnetic resonance imaging,intracerebral hemorrhage,photobiomodulation therapy,ischemic stroke,functional recovery,animal model
更新于2025-09-12 10:27:22
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Reference-Based Integral MR-EPT:Simulation and Experiment Studies on the 9.4T MRI
摘要： Current integral-equation (IE) based MR electrical properties tomography (EPT) methods utilize simulated incident radio-frequency (RF) fields, which are inaccurate and lead to reconstruction errors. To improve the accuracy and practicability of IE-based MR-EPT methods, a new approach is presented that obtains the incident fields using reference subjects and RF field mapping techniques. The Incident field approximation (IFA) is first demonstrated in this paper. This approximation assumes that two imaged subjects with similar coil/subject interactions will have similar incident RF fields, thus one can feed the estimation of the incident fields within the imaged subject into the calculation of those within a homogeneous subject (reference subject). This is done by measuring the total RF fields (??1+) of the reference using field mapping techniques, using the known EPs of the reference subject and by rearranging Ampere’s Law and the integral equations. The calculated incident RF fields are then used to reconstruct the EPs’ distribution with a three-dimensional (3D) integral-based MR-EPT method. Numerical simulation results indicated that the incident RF fields obtained from the reference subject provide accurate 3D reconstruction of EPs with less than 16% root mean square error (RMSE) in noise-free scenario while the conventional IE method had more than 28% RMSE. The phantom-based experiments at 9.4T MRI system have also been conducted to evaluate the performance of the proposed method and the results indicated that the proposed method achieved desirable robustness against the noise in practical scenario with less than 21% RMSE while the conventional differential equation-based method showed worse than 37% RMSE.
关键词： specific absorption rate,magnetic resonance imaging,integral equation,Electrical property tomography
更新于2025-09-11 14:15:04
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Application of fused image in detecting abnormalities of temporomandibular joint
摘要： Objectives: To present a method for image fusion of cone-beam computed tomography (CBCT)/computed tomography (CT) and magnetic resonance imaging (MRI) and to explore whether the image data sets fused in such a way could aid the detection of temporomandibular joint (TMJ) anatomical structures and lesions. Methods: There were five cases included in this study. One case was space occupying lesion giant cell tumor of tendon sheaths (GCTTS), one case was chronic inflammation in the condyle, one case was articular disc calcification of the bilateral TMJs, and the other two cases were temporomandibular joint disorders (anterior disc displacement without reduction). The digital imaging and communications in medicine (DICOM) format data of CT/CBCT and MRI of the cases were collected, and then imported to the Amira visual software where the registration process was conducted. Based on the different scan model, the registration process could be separated into automatic registration of CT/CBCT with quadrature slice MR images and the semi-automatic registration of CT/CBCT with oblique slice MR images by altering the registration parameters. Rigid transform model and the similarity metric of normalization mutual information (NMI) was used for registration in the present study. Results: The relationship between the soft mass and hard tissue was shown clearly in the fused images when compared to sole observation of CBCT/CT or MR images. The fused images could define the tumor outline and the destructive bone clearly in the same image. The fused results helped the observers to ensure uncertain defects which could not be confirmed only by one image data set. Conclusions: The CT/CBCT and MR images could be fused to aid detection of TMJ anatomical structures and related lesions.
关键词： multi-detector computed tomography,magnetic resonance imaging,diagnosis,cone-beam computed tomography,temporomandibular joint
更新于2025-09-11 14:15:04
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PACS-Based Multimedia Imaging Informatics (Basic Principles and Applications) || Digital Medical Imaging
摘要： The chapter discusses the fundamentals of digital medical imaging, including two-dimensional (2-D) and three-dimensional (3-D) imaging techniques, image compression, and the integration of imaging informatics with patient imaging workflows. It covers various imaging modalities such as computed radiography (CR), digital mammography, nuclear medicine imaging, ultrasound imaging, and magnetic resonance imaging (MRI), highlighting their principles, applications, and the challenges in archiving and transmitting large datasets.
关键词： digital medical imaging,computed radiography,ultrasound imaging,digital mammography,PACS,2-D imaging,image compression,3-D imaging,nuclear medicine imaging,magnetic resonance imaging
更新于2025-09-10 09:29:36
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Imaging the Microstructure of the Human Fetal Heart
摘要： Almost 50 years have elapsed since the seminal anatomic studies of Streeter et al1 showed that the fibers of the myocardium are arranged in a crossing helical pattern. During this time, numerous ex vivo studies of myocardial fiber architecture have been performed with magnetic resonance diffusion tensor imaging (DTI). In addition, recent advances in gradient strength and acceleration techniques now allow DTI of the entire heart to be performed in vivo.2,3 DTI also allows microstructural information to be integrated with magnetic resonance–derived metrics of myocardial strain, function, and viability.4–6
关键词： myocardium,magnetic resonance imaging,heart defects, congenital,heart,diffusion tensor imaging,Editorial
更新于2025-09-10 09:29:36
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Aberrant visual pathway development in albinism: From retina to cortex
摘要： Albinism refers to a group of genetic abnormalities in melanogenesis that are associated neuronal misrouting through the optic chiasm. We perform quantitative assessment of visual pathway structure and function in 23 persons with albinism (PWA) and 20 matched controls using optical coherence tomography (OCT), volumetric magnetic resonance imaging (MRI), diffusion tensor imaging and visual evoked potentials (VEP). PWA had a higher streamline decussation index (percentage of total tractography streamlines decussating at the chiasm) compared with controls (Z = ?2.24, p = .025), and streamline decussation index correlated weakly with inter-hemispheric asymmetry measured using VEP (r = .484, p = .042). For PWA, a significant correlation was found between foveal development index and total number of streamlines (r = .662, p < .001). Significant positive correlations were found between peri-papillary retinal nerve fibre layer thickness and optic nerve (r = .642, p < .001) and tract (r = .663, p < .001) width. Occipital pole cortical thickness was 6.88% higher (Z = ?4.10, p < .001) in PWA and was related to anterior visual pathway structures including foveal retinal pigment epithelium complex thickness (r = ?.579, p = .005), optic disc (r = .478, p = .021) and rim areas (r = .597, p = .003). We were unable to demonstrate a significant relationship between OCT-derived foveal or optic nerve measures and MRI-derived chiasm size or streamline decussation index. Our novel tractographic demonstration of altered chiasmatic decussation in PWA corresponds to VEP measured cortical asymmetry and is consistent with chiasmatic misrouting in albinism. We also demonstrate a significant relationship between retinal pigment epithelium and visual cortex thickness indicating that retinal pigmentation defects in albinism lead to downstream structural reorganisation of the visual cortex.
关键词： magnetic resonance imaging,visual pathway,diffusion tensor imaging,albinism,optical coherence tomography
更新于2025-09-10 09:29:36
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Nitroxide-radicals–modified gold nanorods for in vivo CT/MRI-guided photothermal cancer therapy
摘要： This article presents a report of the synthesis, characterization, and biomedical application of nitroxide-radicals–modified gold nanorods (Au-TEMPO NRs) for imaging-guided photothermal cancer therapy. Patients and methods: Au nanorods were synthesized through seed-mediated growth method, 4-Amino-TEMPO was added and the reaction proceeded under magnetic stirring. Results: With a mean length of 39.2 nm and an average aspect ratio of approximately 3.85, Au-TEMPO NRs showed good photothermal ability when they were irradiated by 808-nm laser. Au-TEMPO NRs could be stored in PBS for more than 1 month, showed no cytotoxicity against both tumor and normal cells at a concentration of up to 3 mg/mL, and functioned as a dual-mode contrast agent for CT/magnetic resonance (MR) imaging in vitro and in vivo, due to their high X-ray attenuation of Au and good r1 relaxivity of nitroxide radicals. Further, they had a long retention time (~4 hours) in the main organs, which enabled a long CT/MR imaging time window for diagnosis. Bio-distribution results revealed that these Au-TEMPO NRs passively aggregated in the liver and spleen. After irradiation by 808-nm laser, Au-TEMPO NRs could ablate the solid tumor in 4T1 tumor-bearing mice, which implied they were a potential theranostic agent for dual-mode imaging and photothermal cancer therapy. Conclusion: This type of Au-TEMPO NRs with the abilities of CT/MR imaging and photothermal therapy, can play an active role in imaging-guided photothermal cancer therapy.
关键词： TEMPO,magnetic resonance imaging,PTT,Au NRs,computed tomography
更新于2025-09-10 09:29:36
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Comparison of treatment plans for a?high-field MRI-linac and a?conventional linac for esophageal cancer; Vergleich der Behandlungspl?ne von einem Hochfeld-MRT-Linac und einem konventionellen Linac beim ?sophaguskarzinom;
摘要： Purpose To compare radiotherapy treatments plans in esophageal cancer calculated for a high-?eld magnetic resonance imaging (MRI)-linac with plans for a conventional linac. Materials and methods Ten patients with esophageal squamous cell carcinomas were re-planned retrospectively using the research version of Monaco (V 5.19.03, Elekta AB, Stockholm, Sweden). Intensity modulated radiotherapy (IMRT) plans with a nine-?eld step-and-shoot technique and two-arc volumetric modulated arc therapy (VMAT) plans were created for the Elekta MRI-linac and a conventional linac, respectively. The prescribed dose was 60 Gy to the primary tumor (PTV60) and 50 Gy to elective volumes (PTV50). Plans were optimized for optimal coverage of the 60 Gy volume and compared using dose–volume histogram parameters. Results All calculated treatment plans met prede?ned criteria for target volume coverage and organs at risk dose both for MRI-linac and conventional linac. Plans for the MRI-linac had a lower number of segments and monitor units. No signi?cant differences between both plans were seen in terms of V20Gy of the lungs and V40Gy of the heart with slightly higher mean doses to the heart (14.0 Gy vs. 12.5 Gy) and lungs (12.8 Gy vs. 12.2 Gy). Conclusion Applying conventional target volume and margin concepts as well as dose-fractionation prescription re- veals clinically acceptable dose distributions using hybrid MRI-linac in its current con?guration compared to standard IMRT/VMAT. This represents an important prerequisite for future studies to investigate the clinical bene?t of MRI-guided radiotherapy exploiting the conceptional advantages such as reduced margins, plan adaptation and biological individual- ization and hypofractionation.
关键词： Intensity-modulated radiotherapy,Volumetric modulated arc therapy,Organs at risk,Squamous cell carcinomas,Magnetic resonance imaging
更新于2025-09-10 09:29:36