采用光二极管列阵技术的生物组织荧光光谱测量系统

我们报导一台采用光二极管列阵技术，微计算机控制的中型生物组织激光诱导测量系统，该系统的主要特点是操作简单，实时测量并可采用双波长激发。利用该系统，首次研究了光敏染料在琼脂凝胶状固体模式（模拟生物组织）中的荧光光谱。结果表明，该系统适用于临床上通过组织的自体或外源荧光光谱来鉴别正常组织和病变组织。     

荧光光谱技术在晚期糖基化终末产物中的应用

提出了一种把荧光光谱技术应用于检测晚期糖基化终末产物的方法,重点阐述了该荧光光谱检测系统的测量原理,设计了该荧光光谱检测系统.采用氙灯作为激发光源,利用该系统分别对发射波长为440 nm、445 nm、450 nm、455 nm进行激发光谱扫描测试,得出370 nm为最佳激发波长;采用370 nm的单色光作为激发光源,分别对正常人和糖尿病患者的皮肤组织进行荧光光谱检测,通过获得的荧光光谱分析可发现,两者在450 nm附近的荧光光谱存在明显差异.实验结果证明,该荧光光谱测量系统可应用于晚期糖基化终末产物的检测.     

人肺组织内源性显微荧光特性研究

采用新型显微荧光分光光度系统 ,实现激光诱导人肺组织内源性显微荧光光谱与图像的测量 ,获得不同组织层 (即上皮层 ,粘膜层和软骨层 )的荧光分布和荧光特性 ,为探索癌与正常组织自体荧光光谱特征差异的根源 ,揭示激光诱导自体荧光法诊断和定位早期肺癌的机理提供重要的实验依据     

基于Monte-Carlo模拟的光纤探头的设计以及探头在皮肤NADH荧光光谱测量中的应用

研发了一套血流介导皮肤荧光光谱(FMSF)检测系统,该系统可以非侵入性地检测人体皮肤内烟酰胺腺嘌呤二核苷酸(NADH)荧光光谱的动态变化;对该系统中的荧光探头进行了仿真设计,以提高NADH荧光的收集效率.首先构建人体7层皮肤结构模型,采用蒙特卡罗(Monte-Carlo)方法模拟组织中光子的传输规律;然后探究了收集光纤的纤芯直径、激发光纤与收集光纤的近边缘距离、光纤探头与皮肤之间的距离等对荧光光谱检测的影响;最后根据模拟结果研制了一套光纤探头,并将其应用于皮肤NADH荧光光谱检测系统中.结果 表明:采用该系统结合闭塞后反应性充血可以在体检测NADH荧光光谱,光谱强度呈现一种明显的动态变化.与现有技术相比,基于FMSF技术的皮肤NADH检测方法具有测量速度快、无创等优势,为研究线粒体能量代谢及糖尿病等相关疾病提供了先进的技术手段.     

基于粒子群优化算法的生物组织固有荧光光谱复原方法

为减少吸收和散射对生物组织荧光光谱的干扰,使用蒙特卡罗(MC)方法模拟不同光学参数下的生物组织荧光和漫反射光,提出基于组织漫反射光谱的荧光复原方法。将复原算法中的经验参数编码为解空间中的一个粒子,以组织荧光临床应用效果作为适应值,构建粒子群优化(PSO)算法实现经验参数优化。利用已建立的用于糖尿病无创筛查的组织光谱测量系统,收集327例受试者的皮肤组织荧光光谱和漫反射光谱,使用基于PSO的组织荧光复原算法进行光谱复原。以复原前、后的组织荧光光谱强度作为输入变量进行受试者工作特性(ROC)曲线分析,观察其在糖尿病筛查中的应用价值。结果显示,采用复原前的组织荧光光谱作为输入变量用于糖尿病筛查时,ROC曲线覆盖面积为0.54,最佳诊断点对应的敏感性为32%、特异性为76%;以复原后的组织荧光光谱作为输入变量时,ROC曲线覆盖面积为0.86,最佳诊断点对应的敏感性和特异性分别为72%、86%。上述结果表明,使用基于PSO的组织固有荧光光谱复原算法能有效提高组织荧光光谱的临床应用价值。     

微微秒时间分辨激光荧光光谱的测量

本文描述了一台用于测量时间分辨荧光光谱Ⅰ(λ,t)的时间相关单光子计数系统,使用微微秒激光脉冲作激发光源。系统的响应时间不大于50ps。可同步测量荧光寿命、时间积分光谱Ⅰ(λ)和两个时间门光谱Ⅰ(λ,t)。给出了从化合物的时间门光谱中获得各个荧光组份的光谱的方法。测量了激光染料溶液的上述参量,借助于这些溶液表证了该系统的特点。     

组织固有荧光光谱复原算法及其在糖尿病筛查中的应用研究

通过设计不同光学参数的组织仿体,研究吸收、散射对组织荧光光谱及组织漫反射光谱的影响规律,优化经验复原算法,以校正吸收、散射的影响,获得组织的固有荧光光谱。结果显示:使用优化的经验复原算法(经验参数kx和km分别为0.9和-0.8)能够有效降低吸收、散射对荧光强度的影响,且荧光强度与荧光成分的浓度线性相关。在基于皮肤组织荧光光谱法筛查糖尿病的应用研究中应用上述光谱复原算法,结果显示:与原始荧光光谱相比,采用复原后的固有荧光光谱进行糖尿病筛查时,受试者工作特征(ROC)曲线覆盖面积由0.54增加至0.81,在特异性同为70.6%时,敏感性由38.6%增至77.6%。采用组织仿体优化生物组织固有荧光光谱经验复原算法能有效提高荧光光谱的临床应用价值。     

测量随机信号形状的宽波段系统

这些仪器预定用于记录在很宽的持续时间范围内一次信号和多重信号的形状。在光谱荧光测量时．在无线电物理学、生物物理学和医学中，在激光定位和光学探测，在无线电测量和计算系统的电子学零件的生产和检测时可以采用这些仪器。     

血流介导组织荧光光谱测量系统及仿体验证

基于血流介导组织还原型辅酶Ⅰ(NADH)荧光光谱检测技术的微循环功能评估对心血管病的早期预警具有重要价值,然而血流介导过程中氧饱和度的变化会干扰荧光信号的测量。本课题组搭建了集成有组织漫反射率测量模块的血流介导组织荧光光谱测量系统,并引入生理参数提取和荧光光谱复原算法,以排除干扰。不同光学参数的组织仿体试验结果表明,复原算法可以有效降低吸收、散射的影响,复原后的NADH的荧光强度与其浓度呈线性相关(拟合优度R²=0.99);血液血氧仿体试验结果显示,组织氧饱和度的变化会干扰荧光的检测,经过校正的NADH的固有荧光光谱与氧饱和度的变化无关。4位受试者的在体试验结果显示,经过光谱复原后,荧光闭塞响应值和恢复响应值的平均值分别下降了22.8%和22.1%,这可以解释为氧饱和度的变化对实测NADH荧光的干扰。本研究结果预期能够有效提升血流介导组织荧光光谱测量系统的检测准确性。     

双通道分光式表面色显微测量方法研究

提出了一种用于颜色产品微面积精细颜色测量、采用双通道测色分光系统的软硬件模型，给出了测量原理、实验装置和测量结果。该系统结构简单、色分辨率高，测量光谱范围为可见区，光谱分辨率为10nm，能进行较暗物体和荧光物体的微面积精细颜色测量，并能给出各种标准照明体和各种色度系统下的色度参数。     

Multispectral system for medical fluorescence imaging

The principles of a powerful multicolor imaging system for tissue fluorescence diagnostics are discussed. Four individually spectrally filtered images are formed on a matrix detector by means of a split-mirror arrangement. The four images are processed in a computer, pixel by pixel, by means of mathematical operations, leading to an optimized contrast image, which enhances a selected feature. The system is being developed primarily for medical fluorescence imaging, but has wide applications in fluorescence, reflectance, and transmission monitoring related to a wide range of industrial and environmental problems. The system operation is described for the case of linear imaging on a diode array detector. Laser-induced fluorescence is used for cancer tumor and atherosclerotic plaque demarcation using the contrast enhancement capabilities of this imaging system. Further examples of applications include fluorescing minerals and flames.     

生物组织标本尺寸对自体荧光法检测结果的影响

利用激发波长和发射波长处的蒙特卡罗模拟作为研究手段，对一系列不同边长胃肠壁组织的立方形标本模型进行检测，分析标本的上、下表面以及侧面的逸出荧光，最终确定适合作离体检测的胃肠壁组织标本尺寸的边长不小于3mm。     

Morphological model of human colon tissue fluorescence

Fluorescence spectroscopy of tissue is a promising technique for early detection of precancerous changes in the human body. Investigation of the microscopic origin of the clinically observed tissue fluorescence can provide valuable information about the tissue's histology. The objective of this study was the development of a morphological model of colon tissue fluorescence which connects the clinically observed spectra with their underlying microscopic origins. Clinical colon tissue fluorescence spectra were modeled by measuring the intrinsic fluorescence properties of colon tissue on a microscopic level and by simulating light propagation in tissue using the Monte-Carlo method. The computed spectra were in good agreement with the clinical spectra acquired during colonoscopy, and exhibited the characteristic spectral features of the in vivo collected spectra. The authors' analysis quantitated these spectral features in terms of the intrinsic fluorescence properties of tissue and its general histological characteristics. The fluorescence intensity difference between normal and adenoma observed in vivo was found to be due to the increased hemoglobin absorption, the reduced mucosal fluorescence intensity, and the absence of submucosal fluorescence in adenomatous polyps. The increased red fluorescence in adenoma was found to be associated with the dysplastic crypt cell fluorescence     

In Vivo Cardiac Muscle Perfusion: A New Measurement Method

A nonradioactive tracer technique for the evaluation of heart disease is presented. A microprocessor controlled scanning system is used to position a germanium detector such that it interrogates an isolated segment of myocardial tissue. Iodine based contrast agent in intravenously injected while irradiating the tissue segment with a low energy X-ray spot beam. X-ray induced iodine fluorescence of the passing contrast agent is then used to monitor the local tissue perfusion.     

用漫反射光谱校正组织自体荧光光谱的研究

利用漫反射光谱所含信息来消除组织对自体荧光散射和吸收的影响，从而提取出组织的固有荧光光谱。利用蒙特卡罗（MC）方法分析组织的荧光失真因数曲线和漫反射光谱之间的关系，发现两者的曲线形状基本相同，并以胃肠正常和癌变组织的漫反射光谱来校正实验获得的自体荧光（LIAF）光谱。最终得到的固有荧光光谱体出了组织的生化信息变化。     

Fluorescence lifetime imaging using a diode-pumped all-solid-statelaser system

A whole-field fluorescence lifetime imaging system is presented which is based, for the first time, on an all-solid-state diode-pumped oscillator/amplifier system. Fluorescence lifetime imaging of unstained biological tissue in vitro using this instrument demonstrated contrast between different tissue constituents     

Quantifying spatial localization of optical mapping using Monte Carlo simulations

Optical mapping techniques used to study spatial distributions of cardiac activity can be divided into two categories. 1) Broad-field excitation method, in which hearts stained with voltage or calcium sensitive dyes are illuminated with broad-field excitation light and fluorescence is collected by image or photodiode arrays. 2) Laser scanning method, in which illumination uses a scanning laser and fluorescence is collected with a photomultiplier tube. The spatial localization of the fluorescence signal for these two methods is unknown and may depend upon light absorption and scattering at both excitation and emission wavelengths. We measured the absorption coefficients (micro a), scattering coefficients (micro s), and scattering anisotropy coefficients (g) at representative excitation and emission wavelengths in rabbit heart tissue stained with di-4-ANEPPS or co-stained with both Rh237 and Oregon Green 488 BAPTA 1. Monte Carlo models were then used to simulate absorption and scattering of excitation light and fluorescence emission light for both broad-field and laser methods in three-dimensional tissue. Contributions of local emissions throughout the tissue to fluorescence collected from the tissue surface were determined for both methods. Our results show that spatial localization depends on the light absorption and scattering in tissue and on the optical mapping method that is used. A tissue region larger than the laser beam or collecting area of the array element contributes to the optical recordings.     

大鼠早期急性心肌缺血的双光子荧光成像及分析

双光子荧光显微成像技术具有较低的光漂白与光损伤、较佳的成像对比度、较深的穿透深度等优点。采用结扎大鼠冠状动脉左前降支的方法建立急性心肌缺血模型,通过双光子荧光显微成像技术获得不同结扎时间下大鼠左心室前壁心肌组织的双光子荧光图像。从中分析了不同结扎时间下心肌组织的形态学变化,实现对心肌组织损伤范围的确定;并对双光子荧光图像进行快速傅里叶变换(FFT),使用方向指数这一参数对心肌缺血的程度进行初步的量化评估。结果表明,双光子荧光显微成像技术结合FFT分析技术,有望在心肌缺血性疾病的诊断和治疗中实时、快速、准确地判断心肌缺血的范围和评估其损伤程度。     

Hybrid small animal imaging system combining magnetic resonance imaging with fluorescence tomography using single photon avalanche diode detectors

The high sensitivity of fluorescence imaging enables the detection of molecular processes in living organisms. However, diffuse light propagation in tissue prevents accurate recovery of tomographic information on fluorophore distribution for structures embedded deeper than 0.5 mm. Combining optical with magnetic resonance imaging (MRI) provides an accurate anatomical reference for fluorescence imaging data and thereby enables the correlation of molecular with high quality structural/functional information. We describe an integrated system for small animal imaging incorporating a noncontact fluorescence molecular tomography (FMT) system into an MRI detector. By adopting a free laser beam design geometrical constraints imposed by the use of optical fibers could be avoided allowing for flexible fluorescence excitation schemes. Photon detection based on a single-photon avalanche diode array enabled simultaneous FMT/MRI measurements without interference between modalities. In vitro characterization revealed good spatial accuracy of FMT data and accurate quantification of dye concentrations. Feasibility of FMT/MRI was demonstrated in vivo by simultaneous assessment of protease activity and tumor morphology in murine colon cancer xenografts.