光学成像在疾病诊断中的应用

当前，医生们利用各种成像技术与疾病进行斗争，其中光学成像技术是获得高分辨率图像的新方法，其原理是每种生物介质具有各自特有的光谱特性，可赖以区分病变组织和正常组织，或对潜在问题准确定位。而光学相干层析则是最精确的光学成像技术，可提供１０～２０μｍ量级的高分辨率及比迄今为止任何其他技术都高的灵敏度。本文着重讨论光学相干层析术的基本原理及目前发展状况     

A permissible region strategy for fluorescence molecular tomography

Optical Review - A large-scale fluorescence measurement captured by non-contact fluorescence molecular tomography imaging system is utilized to reconstruct the three-dimensional distribution of...     

超声分子成像进展

超声分子成像在超声医学成像的基础上,利用靶向超声造影剂为分子探针,以可视化和定量获取活体组织细胞的分子信息为目标的影像术。它不用进行手术活检,不仅可以给出病灶的空间信息,而且能确定它的性质,进行针对性的治疗和对疗效进行评估。本文对现有的核医学分子成像,磁共振分子成像,光学分子成像和光声分子成像技术作了简单介绍,着重讨论了超声分子成像技术和应用的进展。     

Endoscopic, rapid near-infrared optical tomography

This is believed to be the first demonstration of near-infrared (NIR) optical tomography employed at the endoscope scale and at a rapid sampling speed that allows translation to in vivo use. A spread-spectral-encoding technique based on a broadband light source and linear-to-circular fiber bundling was used to provide endoscopic probing of many source-detector fibers for tomography as well as parallel sampling of all source-detector pairs for rapid imaging. Endoscopic NIR tomography at an 8 Hz frame rate was achieved in phantoms and tissue specimens with a 12 mm probe housing eight sources and eight detectors. This novel approach provides the key feasibility studies to allow this blood-based contrast imaging technology to be attempted in detection of cancer in internal organs via endoscopic interrogation.     

Imaging needle for optical coherence tomography

We describe a miniature optical coherence tomography (OCT) imaging needle that can be inserted into solid tissues and organs to permit interstitial imaging of their internal microstructures with micrometer scale resolution and minimal trauma. A novel rotational coupler with a glass capillary tube is also presented that couples light from a rotating single-mode fiber to a stationary one. A prototype needle with a 27-gauge (~410-mum) outer diameter has been developed and is demonstrated for in vivo imaging. The OCT needle can be integrated with standard excisional biopsy devices and used for OCT-guided biopsy.     

Recent advances in bioluminescence tomography: methodology and system as well as application

Optical molecular imaging has been rapidly developed to noninvasively visualize in vivo physiological and pathological processes involved in normal and suffering organisms at the cellular and molecular levels, in which advanced optical imaging technology and modern molecular biology are being combined to provide a state‐of‐the‐art tool for preclinical biomedical research. Among optical molecular imaging modalities, bioluminescence tomography (BLT) has experienced considerable growth and attracted much attention in recent years for its excellent performance, unique advantages, and high cost‐effectiveness. This article focuses on the genesis and development of BLT, especially for its computational methodology, imaging system, and biomedical application. An overview of the advantages and challenges of the conventional planar bioluminescence imaging technique is first described in comparison with currently available molecular imaging modalities. The imaging algorithms for inverse source reconstruction are classified and summarized according to different a priori knowledge, followed by a simple depiction of the uniqueness theorems of BLT solution. Diverse imaging systems for obtaining three‐dimensional quantitative information of internal bioluminescent sources are then reviewed. The latest application examples of BLT in tumor study and drug discovery are introduced and compared with other mature imaging technologies. Finally, the paper is concluded and an attractive prospect for BLT is predicted.     

OCT技术在发育生物学中的应用

基于光学低相干反射测量而发展起来的光学相干层析技术（ Optica1 Coherence Tomography,OCT）是一种新型的成像技术，它可以对强散射介质如生物组织实施非侵入性的快速活体成像。与传统的组织切片相比,OTC可以大大减少对发育形态成像所需的时间、复杂程度及成本。非接触和非侵入式的成像方式有助于研究个体发育中由基因变异所引起的形态和功能变化，因而在发育生物学的研究当中有着广阔的应用前景。概述了OCT技术在发育生物学当中诸方面的应用情况。     

Dual-modal photoacoustic/CT imaging system

Photoacoustic(PA) tomography(PAT) breaks the barrier for high-resolution optical imaging in a strong lightscattering medium, having a great potential for both clinical implementation and small animal studies. However,many organs and tissues lack enough PA contrast or even hinder the propagation of PA waves. Therefore, it is challenging to interpret pure PAT images, especially three-dimensional(3 D) PA images for deep tissues, without enough structural information. To overcome this limitation, in this study, we integrated PAT with X-ray computed tomography(CT) in a standalone system. PAT provides optical contrast and CT gives anatomical information. We performed agar, tissue phantom, and animal studies, and the results demonstrated that PAT/CT imaging systems can provide accurate spatial registration of important complementary contrasts.     

免疫光子学进展

光学分子成像是在复杂生物体中同时描述多种分子和细胞功能的最佳手段.作为机体发挥防御、监视和自稳功能的免疫系统,研究者们正面临着如何将其作为一个真正的系统来研究的挑战.免疫光子学是指基于光子学原理和方法的活体免疫光学成像和免疫光子治疗.以多光子激发显微成像和光声层析成像为代表的高时空分辨活体成像技术,以荧光蛋白为代表的活...     

Noninvasive photoacoustic angiography of animal brains in vivo with near-infrared light and an optical contrast agent

Optical contrast agents have been widely applied to enhance the sensitivity and specificity of optical imaging with near-infrared (NIR) light. However, because of the overwhelming scattering of light in biological tissues, the spatial resolution of traditional optical imaging degrades drastically as the imaging depth increases. Here, for the first time to our knowledge, we present noninvasive photoacoustic angiography of animal brains in vivo with NIR light and an optical contrast agent. When indocyanine green polyethylene glycol, a novel absorption dye with prolonged clearance, is injected into the circulatory system of a rat, it obviously enhances the absorption contrast between the blood vessels and the background tissues. Because NIR light can penetrate deep into the brain tissues through the skin and skull, we are able to successfully reconstruct the vascular distribution in the rat brain from the photoacoustic signals. On the basis of differential optical absorption with and without contrast enhancement, a photoacoustic angiograph of a rat brain is acquired that matches the anatomical photograph well and exhibits high spatial resolution and a much-reduced background. This new technology demonstrates the potential for dynamic and molecular biomedical imaging.     

衍射增强成像方法在计算机断层成像中的应用

衍射增强成像是X射线相位衬度成像方法之一，这种方法具有较高的衬度和空间分辨率. 利用它对由轻元素组成的生物、医学样品成像可以观察到常规吸收成像无法观察到的内部微细结构. 这种方法在生物、医学、材料科学等无损检测领域中的应用研究，已成为当前国际上X射线成像领域中的研究热点. 讨论衍射增强成像方法和该方法在计算机断层成像中的应用. 实验结果表明，使用衍射增强成像方法获得的数据源能够重建出微米级的生物组织结构，这些组织结构信息在常规X射线断层成像中是难以得到的. 关键词： 衍射增强成像 CT重建 同步辐射 微细结构     

Applying LED in full-field optical coherence tomography for gastrointestinal endoscopy

Optical coherence tomography (OCT) has become an important medical imaging technology due to its non-invasiveness and high resolution. Full-field optical coherence tomography (FF-OCT) is a scanning scheme especially suitable for en face imaging as it employs a CMOS/CCD device for parallel pixels processing. FF-OCT can also be applied to high-speed endoscopic imaging. Applying cylindrical scanning and a right-angle prism, we successfully obtained a 360° tomography of the inner wall of an intestinal cavity through an FF-OCT system with an LED source. The 10-μm scale resolution enables the early detection of gastrointestinal lesions, which can increase detection rates for esophageal, stomach, or vaginal cancer. All devices used in this system can be integrated by MOEMS technology to contribute to the studies of gastrointestinal medicine and advanced endoscopy technology.     

Dual-path handheld system for cornea and retina imaging using optical coherence tomography

Optical Review - A dual-path handheld system is proposed for cornea and retina imaging using spectral domain optical coherence tomography. The handheld sample arm is designed to acquire two images...     

In vivo bidirectional color Doppler flow imaging of picoliter blood volumes using optical coherence tomography

We describe a novel optical system for bidirectional color Doppler imaging of flow in biological tissues with micrometer-scale resolution and demonstrate its use for in vivo imaging of blood flow in an animal model. Our technique, color Doppler optical coherence tomography (CDOCT), performs spatially localized optical Doppler velocimetry by use of scanning low-coherence interferometry. CDOCT is an extension of optical coherence tomography (OCT), employing coherent signal-acquisition electronics and joint time-frequency analysis algorithms to perform flow imaging simultaneous with conventional OCT imaging. Cross-sectional maps of blood flow velocity with <50-microm spatial resolution and <0.6-mm/s velocity precision were obtained through intact skin in living hamster subdermal tissue. This technology has several potential medical applications.     

光学相干层析术用于鲜红斑痣诊断

光学相干层析术(optical coherence tomography,简称OCT)具有非侵入性,高分辨及高速成像的优点,特别适合于生物医学领域。但由于大部分生物组织具高散射系数,通常仅能对表层组织下数毫米深度内进行成像。穿透深度不足限制了OCT在皮肤科等领域应用。作为常见多发病的鲜红斑痣具有病变组织浅,血管增生明显等特点,所以OCT非常适于鲜红斑痣的检测。通过选择皮肤穿透性好的中心波长为1310nm超辐射二极管,合理优化样品臂和参考臂光强比例及偏振控制,实现了对鲜红斑痣在体成像研究,采集了清晰的OCT图像,得到其关键特征参数,如表皮层厚度,血管直径等,对鲜红斑痣的诊断及制定合理治疗方案具有重要意义。     

An efficient lattice Boltzmann method for fluorescent diffuse optical tomography on GPUs

Optical Review - Fluorescent diffuse optical tomography (FDOT) is an emerging imaging modality, with great prospects in areas such as biology and medicine. However, current FDOT encounters...     

光纤型光学相干层析成像系统的研制

光学相干层析(OCT)成像技术是一新近发展的高分辨力生物医学成像手段,能非侵入性地对活体内部的结构与生理功能进行可视化观察。采用宽带近红外光源,基于迈克耳孙干涉原理和外差探测方法,建立了单模光纤型光学相干层析成像系统,相干地提取从生物体内部返回的深度分辨的弹性散射光信息,并依此构筑了自然状态下活体组织的二维光学相干层析成像图像和三维光学相干层析成像图像。光纤化设计的光学相干层析成像系统紧凑、灵活,便于与光纤导管、内窥镜和其它成像装置的有机结合,以拓展其观察范围和应用领域。     

Combined multi-spectrum and orthogonal Laplacianfaces for fast CB-XLCT imaging with single-view data

Optical Review - Cone-beam X-ray luminescence computed tomography (CB-XLCT) is an attractive hybrid imaging modality, which has the potential of monitoring the metabolic processes of...     

Magnetic resonance imaging of the penis: normal anatomy

This study was undertaken to investigate the magnetic resonance anatomy of the normal penis, by means of the use of a new designed surface coil specific for the study of male external genital organs. The combined evaluation of T1- and T2-weighted images obtained by choosing different repetition and echo time values together with an appropriate selection of scanning planes oriented according to various angles of incidence strongly contributed to perform a complete morphological analysis of the penis and constantly revealed fine anatomical details of diagnostic and clinical significance. Among these, the magnetic resonance examination (data referred to a 0.5 T apparatus) allowed a precise morphological differentiation of the penile covering tissues, such as outer skin, dartos tunica and hypodermal connective; the vascular characterization of cavernous tissue, belonging to corpora cavernosa and spongiosum urethrae, of deep arteries and superficial dorsal vein(s); the resolution of the albuginea and the identification of the urethral lumen. Such a capability of magnetic resonance imaging in providing accurate demonstration of penile structures without technical artifacts and use of ionizing radiations makes the actual technology able to cooperate efficaciously with computerized tomography and diagnostic sonography for an efficient clinical assessment of penis diseases.     

Fiber-optic-bundle-based optical coherence tomography

A fiber-optic-bundle-based optical coherence tomography (OCT) probe method is presented. The experimental results demonstrate this multimode optical fiber-bundle-based OCT system can achieve a lateral resolution of 12 microm and an axial resolution of 10 microm with a superluminescent diode source. This novel OCT imaging approach eliminates any moving parts in the probe and has a primary advantage for use in extremely compact and safe OCT endoscopes for imaging internal organs and great potential to be combined with confocal endoscopic microscopy.