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1.
肿瘤早期检测是精准并高效诊疗癌症的关键因素。荧光成像技术凭借其高灵敏度、高时空分辨率、无电离辐射和无创实时成像等优点,在生物医学领域,尤其在肿瘤检测方面展现出了广泛的应用前景。近红外光穿过生物组织时,受到的吸收和散射较少,因此在生物成像方面体现了高信噪比和强组织穿透能力。在众多荧光探针中,近红外发光的量子点探针因其量子产率高、抗光漂白性强、发射光可调和稳定性良好等特点在荧光成像方面显示出突出的优势。本文基于量子点探针的近红外荧光成像技术在肿瘤显影中的应用,介绍了量子点优异的光学性能,并重点讨论了硫化铅(PbS)和硫化银(Ag2S)近红外发光量子点探针在肿瘤成像方面的研究进展,并对近红外发光量子点探针的应用前景进行了展望。  相似文献   

2.
正据J Biophotonics(2018 Apr10:2201800034.doi:10.1002/jbio.201800034.)2018年4月10日报道,中国科学院深圳先进技术研究院医工所生物医学光学与分子影像研究室在光声消化道内镜成像领域取得新进展。该研究团队成功研制可进行360°全视场成像的光声/超声双模内镜成像系统,并可同时获取消化道壁血管(光声图像)和消化道壁组织结构(超声图像)的三维信息。肿瘤的发生、发展及转移与肿瘤滋养血管密切相关,在肿瘤形成的初早期,就会出现滋养血管的形态学和功能学上的变化。光  相似文献   

3.
微波热声成像(TAI)是一种新型的非侵入、非电离式无损医学成像方式,因其同时具有超声成像的高分辨率和微波成像的高对比度优势,近年来受到广泛的关注。本综述介绍了微波热声成像的技术原理、成像系统及成像特点。以乳腺癌的检测应用研究为例,介绍了TAI的高分辨率及高对比度在解决相应临床问题中的优势,并以此说明了TAI如何在医学诊断及治疗中发挥作用。最后,本综述从多方面、多视角介绍了TAI在医学诊断中的潜在应用前景,并针对TAI技术在现有医学诊断中面临的挑战,对该技术未来研究发展态势进行了展望。  相似文献   

4.
模拟微血管的光声成像技术研究   总被引:1,自引:0,他引:1  
目的:为了实现较深层组织内微血管的光声成像。方法:采用波长532nm、重复频率10Hz的脉冲激光作为激励源,宽带非聚焦针状探头以圆周扫描的方式采集时域光声信号,二维光学吸收分布图像由时域后向投影算法重建,以线扩展函数为依据测量系统的成像空间分辨率。结果:成像空间分辨率0.1mm,模拟微血管网络的光声图像与原始样品完全吻合。结论:对组织内癌症病灶的早期诊断具有较大的意义。  相似文献   

5.
光声显微成像兼具高光学组织对比度,以及超声的高穿透深度和高空间分辨率的优点。但一方面在光声显微成像中,组织深层目标易被浅表目标屏蔽,另一方面其横向分辨率与焦深的矛盾一直限制了光声显微的成像质量。针对这两个问题,本实验搭建了一套基于超声分辨的光声显微成像系统。其采用一种非共轴的照明-探测方式来减少浅层组织对深层信息的影响,并且采用一种新的焦区积分算法来进行数据的处理,结合多次纵向变焦扫描来实现深层组织的高分辨探测。仿体实验表明,该方法可以在不同纵向深度上保持约0.6 mm的横向分辨率,与理论值相接近。裸鼠肿瘤成像结果表明,本文所提出的方法可以比普通的背向探测声聚焦光声显微成像方法在深度方向上获取更多的信息。随着超快脉冲激光和高速扫描方式的发展,本文所提出的方法有望在脑部血管成像、宫颈癌内窥成像、浅表肿瘤成像等方面得到较好的应用。  相似文献   

6.
基于时域光声信号的谱分析技术是一种能够提供生物组织结构和功能信息的非侵入式检测技术,其结合了光学模态的高对比度和超声模态在深层组织中的高分辨率两重特性,可对不同波长光激发下的目标生物组织的光声信号数据集进行处理分析。相较于传统光谱检测,该技术不易受被测对象形状、形态的限制和光散射的影响,使其对较深层组织的检测仍具有较高灵敏度。相较于光声成像,该技术无需引入图像重建算法且专注于实现定量分析。综述时域光声信号的谱分析技术在生物组织、生物体液、生物呼出气体检测中的应用,介绍相关研究所采用的改进实验系统或不同信号处理方法,阐述该技术的研究进展与发展方向。  相似文献   

7.
血管内光声(IVPA)成像是近年来发展起来的一种微创血管内成像技术,结合了光声信号激发阶段光吸收较高的对比度和光声信号发射阶段超声检测较高的分辨率,根据斑块成分对光的吸收差异检测和区分动脉粥样硬化斑块,可对斑块的形态和成分做更为全面的了解。介绍IVPA成像系统的研究现状、血管内超声(IVUS)/IVPA组合成像导管的设计与改进,以及在光谱成像、热成像、分子成像和对冠状动脉支架成像方面的应用现状,指出目前存在的问题,并对未来的研究进行展望。  相似文献   

8.
免疫应答的重要特征是运动性。双光子或多光子荧光显微成像技术以其组织器官穿透性深、光漂白及光毒性低等独特优势,成为活体内研究免疫应答过程的重要工具。本文首先介绍双光子活体成像技术的方法学原理及技术特点,随后简述其引入免疫学的历史。最后,本文重点从技术运用的角度,概括总结了双光子活体成像技术在免疫学研究中的应用。  相似文献   

9.
近年来,由于计算机和电子学的发展.诊断性影象学已取得了引人注目的进展。人们采用这些技术识别肿瘤是期望显著提高癌症患者的诊断、手术治疗和监护的技术水平。在对癌症患者进行影象诊断的过程中,成像过程必须考虑肿瘤的特有特征,包括肿瘤的总的形态和自然发生过程,随着技术越来越完善,人们认为肿瘤的微小扩散以及对周围组织结构涉及程度对治疗方案  相似文献   

10.
纳米粒技术在生物医学领域的应用,为今后肿瘤的检测和诊断方法提供了广阔的前景。半导体量子点在生物医学领域逐渐受到了广泛的关注。文章就基于量子点的多功能纳米材料在多模态成像和癌症治疗中的应用做了简单的概述。首先介绍基于量子点的多功能纳米粒子的多模态成像;其次介绍基于量子点的多功能纳米粒在癌症治疗中的研究应用,其中包含了同时成像和化学治疗、同时成像和光动力学治疗,以及同时成像和基因传递的研究。最后,对基于量子点的多功能纳米粒的生物医学应用前景进行了展望。  相似文献   

11.
In this study, we monitor the progress of vasculature in early tumor growth using photoacoustic imaging over a 20 day period after subcutaneous inoculation of breast cancer tumor cells in a mouse. With 532 nm laser pulses employed as an irradiation source, the photoacoustic images were obtained through the photoacoustic signals received by a hydrophone in orthogonal mode. The morphological characteristics of vasculature in tumor region are clearly resolved in the photoacoustic images, and the change in structure as well as the increase in density can be identified. Moreover, the average photoacoustic signal strength of vasculature in tumor region, which is highly correlated with the total hemoglobin concentration of blood, is enhanced during early tumor growth. These results indicate the feasibility of detecting early stage tumor and monitoring the progress of anti-angiogenic therapy by photoacoustic imaging.  相似文献   

12.
In the postgenomic era, imaging techniques are playing an important role in visualizing gene expression in vivo. This work represents the first demonstration of photoacoustic tomography (PAT) for reporter gene imaging. Rats inoculated with 9L/lacZ gliosarcoma tumor cells are imaged with PAT before and after injection of X-gal, a colorimetric assay for the lacZ-encoded enzyme beta-galactosidase. Using far-red optical illumination, the genetically tagged tumors in rats are clearly visualized by PAT following the assay. The spatial resolution is quantified to be less than 400 microm, while 500-nM-level sensitivity is demonstrated. With the future development of new absorption-based reporter gene systems, it is anticipated that photoacoustic technology will provide a valuable tool for molecular imaging research.  相似文献   

13.
Understanding the tumor microenvironment is critical to characterizing how cancers operate and predicting their response to treatment. We describe a novel, high-resolution coregistered photoacoustic (PA) and pulse echo (PE) ultrasound system used to image the tumor microenvironment. Compared to traditional optical systems, the platform provides complementary contrast and important depth information. Three mice are implanted with a dorsal skin flap window chamber and injected with PC-3 prostate tumor cells transfected with green fluorescent protein. The ensuing tumor invasion is mapped during three weeks or more using simultaneous PA and PE imaging at 25 MHz, combined with optical and fluorescent techniques. Pulse echo imaging provides details of tumor structure and the surrounding environment with 100-μm(3) resolution. Tumor size increases dramatically with an average volumetric growth rate of 5.35 mm(3)/day, correlating well with 2-D fluorescent imaging (R = 0.97, p < 0.01). Photoacoustic imaging is able to track the underlying vascular network and identify hemorrhaging, while PA spectroscopy helps classify blood vessels according to their optical absorption spectrum, suggesting variation in blood oxygen saturation. Photoacoustic and PE imaging are safe, translational modalities that provide enhanced depth resolution and complementary contrast to track the tumor microenvironment, evaluate new cancer therapies, and develop molecular contrast agents in vivo.  相似文献   

14.
Photoacoustic imaging is a biomedical imaging modality that provides functional information, and, with the help of exogenous contrast agents, cellular and molecular signatures of tissue. In this article, we review the biomedical applications of photoacoustic imaging assisted with exogenous contrast agents. Dyes, noble metal nanoparticles, and other constructs are contrast agents which absorb strongly in the near-infrared band of the optical spectrum and generate strong photoacoustic response. These contrast agents, which can be specifically targeted to molecules or cells, have been coupled with photoacoustic imaging for preclinical and clinical applications ranging from detection of cancer cells, sentinel lymph nodes, and micrometastasis to angiogenesis to characterization of atherosclerotic plaques. Multi-functional agents have also been developed, which can carry drugs or simultaneously provide contrast in multiple imaging modalities. Furthermore, contrast agents were used to guide and monitor the therapeutic procedures. Overall, photoacoustic imaging shows significant promise in its ability to assist in diagnosis, therapy planning, and monitoring of treatment outcome for cancer, cardiovascular disease, and other pathologies.  相似文献   

15.
The use of a novel all-optical photoacoustic scanner for imaging the development of tumor vasculature and its response to a therapeutic vascular disrupting agent is described. The scanner employs a Fabry-Perot polymer film ultrasound sensor for mapping the photoacoustic waves and an image reconstruction algorithm based upon attenuation-compensated acoustic time reversal. The system was used to noninvasively image human colorectal tumor xenografts implanted subcutaneously in mice. Label-free three-dimensional in vivo images of whole tumors to depths of almost 10 mm with sub-100-micron spatial resolution were acquired in a longitudinal manner. This enabled the development of tumor-related vascular features, such as vessel tortuosity, feeding vessel recruitment, and necrosis to be visualized over time. The system was also used to study the temporal evolution of the response of the tumor vasculature following the administration of a therapeutic vascular disrupting agent (OXi4503). This revealed the well-known destruction and recovery phases associated with this agent. These studies illustrate the broader potential of this technology as an imaging tool for the preclinical and clinical study of tumors and other pathologies characterized by changes in the vasculature.  相似文献   

16.
We previously identified the gene metastasis-associated in colon cancer-1 (MACC1) and demonstrated its important role for metastasis prediction in colorectal cancer. MACC1 induces cell motility and proliferation in vitro as well as metastasis in several mouse models. Here we report non-invasive real time imaging of inhibition of colorectal tumor progression and metastasis in xenografted mice by MACC1 shRNA. First, we demonstrated reduction of tumors and liver metastases by endpoint imaging of mice transplanted with MACC1 endogenously high expressing colorectal cancer cells and treated with shRNAs acting on MACC1 or Met. Next, we generated a novel bicistronic IRES vector simultaneously expressing the reporter gene firefly luciferase and MACC1 to ensure a direct correlation of bioluminescence signal with MACC1 expression. We transfected MACC1 endogenously low expressing colorectal cancer cells with this luciferase-IRES-MACC1 construct, transplanted them intrasplenically, and monitored MACC1 induced tumor growth and metastasis by in vivo imaging over time. Transfection of an IRES construct harboring the firefly luciferase reporter gene together with MACC1 lacking the SH3-domain reduced tumor growth and metastasis. Finally, we counteracted the luciferase-IRES-MACC1 induced effects by shRNA targeting MACC1 and monitored reduced tumor growth and metastasis by in vivo imaging over weeks. In summary, the new bicistronic luciferase-IRES-MACC1 construct is suitable for in vivo imaging of tumor progression and metastasis, and moreover, for imaging of therapy response such as treatment with MACC1 shRNA. Thereby, we provide proof-of-concept for employment of this MACC1-based in vivo model for evaluating therapeutic intervention strategies aiming at inhibition of tumor growth and metastasis.  相似文献   

17.
The feasibility of air-coupled ultrasound transducers to detect laser-induced ultrasound from artificial blood vessels embedded in an optically scattering phantom is demonstrated. These air-coupled transducers allow new applications in biomedical photoacoustic imaging where contact with tissue is not preferred. One promising application of such transducers is the addition of photoacoustic imaging to the regular x-ray mammographic screening procedure.  相似文献   

18.
Cancer cells display heterogeneous genetic characteristics, depending on the tumor dynamic microenvironment. Abnormal tumor vasculature and poor tissue oxygenation generate a fraction of hypoxic tumor cells that have selective advantages in metastasis and invasion and often resist chemo- and radiation therapies. The genetic alterations acquired by tumors modify their biochemical pathways, which results in abnormal tumor metabolism. An elevation in glycolysis known as the "Warburg effect" and changes in lipid synthesis and oxidation occur. Magnetic resonance spectroscopy (MRS) has been used to study tumor metabolism in preclinical animal models and in clinical research on human breast, brain, and prostate cancers. This technique can identify specific genetic and metabolic changes that occur in malignant tumors. Therefore, the metabolic markers, detectable by MRS, not only provide information on biochemical changes but also define different metabolic tumor phenotypes. When combined with the contrast-enhanced Magnetic Resonance Imaging (MRI), which has a high sensitivity for cancer diagnosis, in vivo magnetic resonance spectroscopic imaging (MRSI) improves the diagnostic specificity of malignant human cancers and is becoming an important clinical tool for cancer management and care. This article reviews the MRSI techniques as molecular imaging methods to detect and quantify metabolic changes in various tumor tissue types, especially in extracranial tumor tissues that contain high concentrations of fat. MRI/MRSI methods have been used to characterize tumor microenvironments in terms of blood volume and vessel permeability. Measurements of tissue oxygenation and glycolytic rates by MRS also are described to illustrate the capability of the MR technology in probing molecular information non-invasively in tumor tissues and its important potential for studying molecular mechanisms of human cancers in physiological conditions.  相似文献   

19.
Optical-resolution photoacoustic microscopy (OR-PAM) is a novel imaging technology for visualizing optically absorbing superficial structures in vivo with lateral spatial resolution determined by optical focusing rather than acoustic detection. Since scanning of the illumination spot is required, OR-PAM imaging speed is limited by both scanning speed and laser pulse repetition rate. Unfortunately, lasers with high repetition rates and suitable pulse durations and energies are not widely available and can be cost-prohibitive and bulky. We are developing compact, passively Q-switched fiber and microchip laser sources for this application. The properties of these lasers are discussed, and pulse repetition rates up to 100 kHz are demonstrated. OR-PAM imaging was conducted using a previously developed photoacoustic probe, which enabled flexible scanning of the focused output of the lasers. Phantom studies demonstrate the ability to image with lateral spatial resolution of 7±2 μm with the microchip laser system and 15±5 μm with the fiber laser system. We believe that the high pulse repetition rates and the potentially compact and fiber-coupled nature of these lasers will prove important for clinical imaging applications where real-time imaging performance is essential.  相似文献   

20.
Because interleukin-10 (IL-10) has potent immunosuppressive and anti-inflammatory properties and is produced by some cancers, including melanoma, we hypothesized that its production by tumor cells may contribute to the escape from immune surveillance. To test this hypothesis, we transfected human A375P melanoma cells that do not express IL-10 with the murine IL-10 gene and subsequently analyzed for changes in tumor growth and metastasis in nude mice. Surprisingly, IL-10 gene transfer resulted in a loss of metastasis and significant inhibition of tumor growth. In addition, the growth of other murine or human melanoma cells was also inhibited when they were admixed with IL-10-transfected cells before injection into nude mice. We provide evidence that IL-10 exerts its antitumor and antimetastatic activity by inhibiting angiogenesis in vivo. The in vivo decrease in neovascularization found in IL-10-secreting tumors is most likely due to the ability of IL-10 to downregulate the synthesis of vascular endothelial growth factor (VEGF), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-6, and matrix metalloproteinase-9 (MMP-9) in tumor-associated macrophages. Other studies have shown that IL-10 inhibits tumor metastasis through a natural killer (NK) cell-dependent mechanism. The inhibitory effects of IL-10 on tumor growth and metastasis were also demonstrated in other tumor models, including breast cancers. Furthermore, administration of rIL-10 into mice resulted in inhibition of tumor metastasis. Because IL-10 has little toxicity when given systemically to human volunteers, its efficacy as an antimetastatic agent should be further explored, both as an independent and in combination with other inhibitors of neovascularization.  相似文献   

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