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- Light-Tissue Interaction II
- Light-Tissue Interaction I
- Tumor Diagnosis and Treatment I
- Light-Tissue Interaction I
- Instrumentation and Application
- Clinical Diagnosis and Treatment
- Optical Diagnosis and Spectroscopy I
- NIR Spectroscopy and Imaging I
- Optical Diagnosis and Spectroscopy II
- Optical Imaging
- NIR Spectroscopy and Imaging II
- Tumor Diagnosis and Treatment I
- Tumor Diagnosis and Treatment II
- Tumor Diagnosis and Treatment I
- Tumor Diagnosis and Treatment II
- OCT
- Poster Session
- NIR Spectroscopy and Imaging II
- Light-Tissue Interaction I
Light-Tissue Interaction II
Depolarization of light in turbid medium: effect of collection geometry
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Larger depolarization of incident polarized light has been reported for tissues compared to tissue phantoms with matched optical thickness (? =?s × d, ?s being the scattering coefficient and d the physical thickness). We show that this arises because for the sample with larger ?s more multiply scattered photons are detected in a narrow collection angle typically used in experiments. These results were verified by time resolved studies on transmitted light as well as by Monte Carlo simulation.
Theoretical study on light distribution in biological tissue with strong absorption
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Radiance in biological tissue with strong absorption is studied, by solving the steady-state Boltzmann transport equation in P3 approximation for an isotropy point source. We compare the diffusion solution to the total reflectance and the first two terms of the reflectance in P3 approximation respectively, and find that P3 approximation can improve the accuracy, especially in cases of strong absorption. Light radial distribution at the surface is also studied, it is shown that light centralizes in a small area as absorption tends strong. Through many calculations we have drawn a relation between radial width oflight distribution and the absorption coefficient.
Experimental research on depolarization property of layered biological tissues
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In this paper, depolarization property of light propagating through layered biological tissues is investigated by experiment. Intrialipid suspensions of different concentrations are chosen as liquid model of layered biological tissues. An experimental setup was established to measure the polarization state of light emitting from the Intrialipid suspensions. Under different polarization angle, light distributions transmitting through intrialipid suspensions of different concentration and thickness are measured by a Beam Profiler. The gray images obtained by the Beam Profile are used to analyze the polarization property of light emitting from biological tissue. According to the results, the relation of depolarization degree of emitting light from intrialipid suspensions with emitting position, concentration and thickness of intrialipid suspensions are discussed comprehensively.
Measurement of the refractive index of biotissue at four laser wavelengths
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Based on the principle of total internal reflection, a new experimental system , in which the sample is close sandwiched between two prisms, was designed to determine the refractive indices of biotissues and homogeneous medium. Some mammalian tissues have been determined at laser wavelengths ofO.488, 0.6328, 1.0795 and 1.3414?tm, respectively, and their dispersion equations have been obtained. And the absolute error between the n calculated from the dispersion equation and the measured is within 0.002. By utilizing these dispersion equations, the refractive indices of the tissues can be obtained at any wavelength within the waveband of O.488-1.3414?m. The method has great reliability and accuracy, and it can be used for measuring the refractive indices of biotissues and any other medium.
Angular spectrum distribution in biological tissues
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In order to describe angular intensity distribution of light in biological tissues, the concept of spatial angular spectrum is introduced in this paper. Light transmitting property in biological tissues can be described by radiative transfer theory, and discrete ordinates method is adopted in solving the radiative transfer equation. A differential equation group is obtained, which can describe the diffuse light field in biological tissues, and its general solutions are also presented in this paper. Based on the general solution, a computer program was designed to calculate the angular spectrum in different biological tissues. And numerical calculates are executed both for isotropic tissues and anisotropic tissues. The results of spatial angular spectrum in biological tissues are illustrated in the form of curves, which illustrates the effects of optical parameters on the angular spectrum in different biological tissues.
Light-Tissue Interaction I
Reflective angular spectrum of biological-tissue- embedded slab focus
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In this paper, we adopt normal tissue embedded a focus to simulate the local pathological changes tissue. Under the condition of thin beam irradiance, the model of local pathological changes tissue is simplified. Based on the simplified model, the adding method is used to analyze the reflective angular spectrum from the biological tissue. According to the calculations, the effective optical depths, where the focus can affect the reflective angular spectrum obviously are calculated and discussed in the different biological tissues. The effects ofthe geometrical parameters and the position of the focus on the reflective angular spectrum are also analyzed comprehensively.
Optical properties of porcine nasopharynx tissue in vitro
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Single integrating sphere technique was used to measure respectively total reflectance and transmittance of porcine nasopharynx tissue under the irradiation of He-Ne laser with the wavelength of 632.8nm, which has the advantage over conventional double-sphere techniques in that no corrections are required for sphere properties. In addition, with the measurement of unscattered transmission, the optical properties of porcine nasopharynx tissue in vitro have been determined by using Inverse Adding-Doubling Method. The optical properties of porcine nasopharynx tissue are characterized by low absorption (0.096mm-1) and high scatter (6.27mm-1). The scattered light is highly forward as demonstrated by the mean cosine of the scattering angle (0.92), and the optical penetration depth for porcine nasopharynx tissue at the wavelength of 632.8nm is about 2.4 1mm.
Two-photon excitation of hypocrellin A
Jian Liu,
Yuewei Zhao,
Jinquan Zhao,
et al.
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The two-photon excitation of hypocrellin A (HA) was examined at 800 nm. The two-photon excited fluorescence spectrum of HA was very similar to those obtained by one-photon excitation no matter whether or not the HA was dissolved in air-saturated or air-free solutions. The result showed that the two-photon induced photodynamic processes of HA will be almost the same as one-photon induced photodynamic processes. The two-photon excitation cross section of HA was measured at 800 nm as about 34.8 x 10-50 cm4s/photon .The large two-photon cross section of HA, suggested that the HA can be a potential two-photon phototherapeutic agent.
Tumor Diagnosis and Treatment I
Selective photothermal laser-tissue interaction with augmentation of immunoadjuvants in treatment of DMBA-4 metastatic mammary tumors in rats
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Induced anti-tumor immunity can be the most effective and long-term cure for cancers, particularly for metastatic tumors. Laser immunotherapy has been developed to induce such immunological responses in rats bearing DMBA-4 metastatic mammary tumors. It involves an intratumoral administration of a laserabsorbing dye (indocyanine green) and a specially formulated immunoadjuvant (glycated chitosan), followed by an irradiation of a near-infrared laser (805-nm diode laser). To understand the immunity induced in this tumor model, immunization using freeze-thaw cell lysates against the DMBA-4 tumors was performed, followed by the tumor challenge twenty-one days later. Also performed is the surgical removal of the primary tumors of the rats before the observation of metastatic tumors. The immunization only delayed the emergence of the primary and metastases in the rats but did not provide immunity against the tumor challenge. After surgical removal of the primary tumors, the tumors re-emerged at the primary sites and the metastases developed at multiple remote sites. In contrast, laser immunotherapy cured rats experienced tumor regression and eradication. Our research has provided strong support for the working mechanism of laser immunotherapy. The experimental results showed that selective photothermal laser-tissue interaction with a complementary use of immunoadjuvant could be a potential therapy for treatment of metastatic tumors by inducing a tumor-specific, long-lasting immunity.
Light-Tissue Interaction I
Detecting photoacoustic signals with a probing ultrasound beam
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A new method of measuring photoacoustic (PA) waves in situ is proposed. We make a probe ultrasonic beam to pass through the thick biotissue sample. Its focus point is used to tag the position of the PA signal overlapped by the PA interaction area in order to carry the PA information and take it out with the probe beam. When the detecting waves met the PA signal, a beating—wave is generated. Then it is received by a hydra-phone. After amplification and demodulation, a PA signal will be restored. In addition, the attenuation of PA signal in transmission could be decided by measuring the amplitude difference of probe ultrasound in front and behind the sample. It was helpful to simplify the reconstruction of the PA tomographic image and to increase SNR. The noise of the measurement system and background could be reduced when PA waveforms were discriminated. We measured the beating-wave produced by 532nm laser and 1 .4MHz probe ultrasonic beam in the thick biotissue and absorptive media, and reconstructed their PA signal waves with fine SNR.
Optical fiber fluorescent thermometry for electromagnetically induced heating in medicine treatment
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Heating induced by electromagnetic field, such as radio-frequency (RF) and microwave is often used in medical application. MW or RF heating is used in hypothermia and hyperthermia treatments. Hypothermia is a clinical condition in which the internal body temperature is lowered below 35 C . RF heating (at 13.56 MHz or 27. 13MHz) offers a fast, efficient and non-invasive method. Hyperthermia in cancer treatment involves heating ofmalignant tumors to 42.5-43CC for a extended period in an attempt to obtain remission. MW(at 2450MHz) is potentially a useful method for heating deep localized tumors. A serious problem with this heating modality involves the accuracy ofmonitoring and controlling the tissue temperature in the presence of a strong EM field. Conventional thermal sensors such as thermocouples and thermistors are all based on a metallic active element which cannot function in a strong EM field environment. Optical fiber fluorescent thermometry is a better technique to show this problem. In this paper we quantify the factors determining the performance ofthis method, some practical considerations also be described
Instrumentation and Application
Design of new type of reflectance pulse oximetry sensor
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The sensor is an important part of the oximetry. An ideal sensor can improve the quantity of the signal . After the analysis in theory, we get the optimal source-detector space, and design new type of pulse oximetry sensor, which makes the detecting signal have least dependence on changes in scattering properties of the tissue. The sensor in this paper consists of laser diode(LD) coupled with fiber in the center as light source and ring-like silicon electric cells with 660nm center wavelength at ?(0.4-0.8cm) and 940nm center wavelength at ?(0.8-1.2cm). The design has many advantages: (1) powerful photoelectricity signal and high Signal-to-Noise (SNR),(2) influence of unconscious movement reduces; (3) considering the skin tissue as homogenous media is more reasonable. The paper also discusses the light path length distribution, and makes revision to the formulation given by Lambert-Beer law.
Simplified laser fluorescence scanner for proteomics studies and early cancer diagnosis
Byeoung C. Kim,
Jin H. Jeong,
Dong S. Jeong,
et al.
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A compact integral system was developed capable of quantitatively measuring analytes in biological fluids. This system uses the fluorescence as a reporter molecule to provide the information about the molecular density of the target molecule in the test sample. Developed for the purpose of providing an affordable means of fast point–of-care testing of marker molecules specifically arranged in the specimen, this system proved to be able to detect the presence of the marker agent at the level of 50 pg/ml in less than 15 minutes, with the actual measurement taking less than 1.5 minutes. The design concept for this unit is presented together with the result for a few representative samples.
In-vivo usable chemiluminescence probe carried by nanoparticles
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Chemiluminescence analysis technique is an important method in biology and medicine. Because the reaction between chemiluminescence reagent and high-energy molecule is instantaneous and short-lived, the present chemiluminescence analysis methods have difficulty in living body. In this paper, a novel chemiluminescence probe was designed and used, which was made of human serum albumin and chemiluminescence reagent 2-Methyl-6- (p-methoxyphenyl) -3,7- dihydroimidazo [1,2-a]pyrazin-3-one (MCLA); It can be used to detect the distribution of super oxide anion and singlet oxygen in living body. Electron microscope observation indicated that the diameter of nanoparticles was about 50~150nm and the diameter among 50~80nm can come to 80%. The results in vitro and in vivo showed that the nanoparticles could release MCLA slowly. In vivo experiment, injected the Hematoporphyrin Derivative (HpD) and nanoparticles in the denuded site of mice, stimulated by visible light, then can see distinct lurninesce at the injected site through detecting the two-dimensional image using a highly sensitive Intensified Charged-Coupled Device (ICCD) detector. The results of experiment proved that the time delay resulted from nanoparticles is obvious.
Rugged hollow fiber for the infrared and its use in laser lithotripsy
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A rugged hollow glass fiber is fabricated by all-liquid phase technique. A silica glass capillary is used as the substrate and a polymer film is firstly coated on the inside of the capillary to protect the glass tube from moisture. This protective coating keeps the thin-wall glass tube away from damage due to the following silver plating process. On the protective coating, a silver film is deposited by a conventional mirror plating technique. Subsequently, a polymer film is coated again on the silver film to reduce transmission loss by employing interference effect of the polymer film. The hollow fiber fabricated by the above process was tested for use in lithotripsy with Er:YAG laser light of 2.94 ?m-wavelength. In the test, the fiber is sealed with a silica glass cap and calculi in salt water were radiated by laser light with the pulse energy of 200 mJ. The calculi were broken after laser radiation of 30 minutes when the repetition rate was 10 Hz.
Analysis and basic designs of a cw 3- and 2-micron cascade Ho3+: ZBLAN fiber laser
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With cascade oscillation scheme from level 5I6,to 5I7, to 5I8 in Ho3+: ZBLAN fiber laser, it not only can produce cW 3- and 2- ?m laser beams simultaneously from one oscillator with appropriate pumping source, but also improves the output power and efficiency. In this paper, the operation principles of 3- and 2- ?m cascade Ho3+: ZBLAN fiber laser is analyzed. Both dynamic and steady state rate equations of this laser pumped with1.1-?m band laser are given for the first time. Basic designs of this laser pumped by Ytterbium-doped double clad fiber lasers (YDCFL) are given. Based on the theoretical analysis and designs, numerical computations of the steady state rate equations were performed. The numerical solutions agree well with the experimental results.
Clinical Diagnosis and Treatment
Highly sensitive chemiluminescence analysis system for medical radiation dose evaluation
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Chemiluminescence (CL) analysis technique is an important method in biological and medical diagnosis. In this research work, we present a novel system to detect and analyze the CL during the actinotheraphy to evaluate the radiation dose according to the principle of the cell stress response to ionizing radiation. The system consists of a sample chamber, a photomultiplier tube (PMT) detector, an amplifier, a discriminator, and a pulses counter. The PMT was cooled to reduce the thermal noise. With the single photon counting technique, high sensitivity, signal-to-noise ratio and stability was achieved. The sample chamber, which was driven by a step motor, has six sample cells for control experiments. A personal computer dominates the data acquisition and the control of the system through the newly implemented universal serial bus interface. There is also a peristaltic pump for auto-injecting the chemical reagent solution. The software developed on the LabVIEW platform makes the system with high automation. With the system, radiation dose could be quantified by the CL intensity from the cell stress response to ionizing radiation. Leukocytes, CCRF cell line and a CL probe MCLA were used to test the reliability ofthis system. The relationship between the 60Co irradiation doses and the intensity ofthe MCLA CL were obtained, which showed that this system could image the CL properly.
Rapid and sensitive immunomagnetic-electrochemiluminescent detection of P53 protein from human lung cancer cell
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In this work, we have designed an electrochemiluminescence (ECL) reaction system used to indicate P53 protein from human lung cancer cells. And we optimized the working electrode firstly in this experiment. The electrochemiluminescence magnetic immunoassay is quantitative, reproducible, and requires only minimal sample processing. A single photon counter was used to heighten the ECL detection limit. The homologous immunoassay format consisted of a double antibody sandwich in which a biotinylated capture antibody, pre-bound to streptavidin-coated magnetic beads, was used to bind antigen from test samples. A detector antibody, labeled with ruthenium( II ) tris-bipyridal chelate, was added and, when bounded to the bead immunocomplex, light was generated in the presence of an excess of tripropylamine. The light was detected and measured by the ECL reaction system we designed. High-sensitive, rapid and reproducible detection of tumor marker P53 protein was actualize with this detection system. The results showed that the electrode with many holes on it can enhance the ECL efficiency, so the detection limit of the system can be improved to 1/1000 fmol/L free labeled Ru(bpy)32+. Ru(bpy)32 + TPA(tripropylmine) ECL reaction system was used to indicate P53 protein from human lung cancer cells. This method could have potential applications in early-stage tumor diagnosis and environmental inspection.
Influence of low-level laser radiation on erythrocyte membranes
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The purpose of this research was to investigate the influence of low-level laser radiation on erythrocyte membranes. The method of seif-hemolysis test of erythrocyte was employed in the research. Blood is taken from the vein of a healthy human. The blood was diluted by physiological salt water. Samples ofthe blood are divided into laser groups and control groups. Each sample of the blood was of 2m1 in volume and was put in a test tube. Each test tube of laser groups was radiated by He-Ne laser for about 40 minutes. The output power of laser vary from 1 mW to 8mW for different test tubes. After the laser radiation, the sample of the blood in test tubes was kept in 37CC for 24 hours, and then was tested for the haemolytic ratio. The result of the research showed that the haemolytic ratio of erythrocyte of laser groups was slightly larger than that of the control groups, and the bigger of the laser power, the larger of the haemolytic ratio of erythrocyte. This result indicates that the low-level laser radiation on blood can influence the membranes of red blood cell. This influence can be a stimulation to red blood cells. It can improve the membranous property and functions of red blood cell under some conditions. This result would be helpful to understand the mechanisms of the Intravascular Low-Level Laser Irradiation Therapy (ILLLIT).
Active noncontact tonometer for glaucoma detection
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Glaucoma is an increasingly common cause of visual impairment, and in some cases causes blindness. The approach to develop a low cost and non-contact tonometer for the detection of glaucoma, to replace the Goldmann tonometer used worldwide, is presented in this paper. The new tonometer exploits the vibration property of the cornea - the resonance frequency of the cornea rises with increasing intra-ocular pressure (IOP). An audio frequency signal is used to vibrate the cornea of the eye, the vibration of the cornea is measured using a fibre optic lever probe, and then the IOP can be calculated from the detected resonance frequency of the cornea. The initial PC-version experiment system of the new tonometer has been demonstrated and preliminary testing has been performed, showing a suitable sensitivity in detecting the resonance frequency against the IOP using both the simulated-eye model and the pig’s eye. The initial system has been improved to be suitable for greater than 15mm detecting distance, and the measurement of vibrations of human cornea in-vivo has been carried out. Work is now focusing on increasing the sensitivity of the fibre probe, and reducing the measuring time to less than 1 second.
Optical Diagnosis and Spectroscopy I
Multiple diagnosis based on photoplethysmography: hematocrit, SpO2, pulse, and respiration
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Photo-plethysmography measure pulsatile blood flow in real-time and non-invasively.One of widely known application of PPG is a measurement of saturated oxygen in arterial blood (SpO2). In our work , using several wave length more than those used in a pulse oximeter, an algorithm and instrument have been developed to measure hematocrit, saturated oxygen pulse and respiratory rates simultaneously.To predict hemotocrit, a dedicated algorithm is developed based on scattering of RBC and a protocall for detecting outlier signal is used to increase accuracy and reliability.Digital filtering techniques are used to exart respiratory rate signal. Utilization of wave length under 1000nm and a multi-wavelength LED array chip and digital-oriented electronic enable us to make a compact device. Our preliminary clinical trails shown that the achived percent errors are±8.2% for hematocrit when tested with 594 person ,r2 for SpO fitting is 0.99985 when tested with a Bi-Tek pulse oximeter simulator and the SPO2 error for in vivo test is ±2.5% over the range of 75~100%. The error of pulse rates is less than ±5%. We obtained a positive predictive value of 96% for respiratory rates in qualitative analysis.
Near-infrared spectroscopy to measure milk constituents and its reliability design
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This paper presents a near-infrared spectroscopy method for measuring milk constituents based on AOTF technique. Some key problems encountered during study of spectrum stability, such as lower stability, parallel moving of the spectrum, were analyzed from the point of view of the system structure and the AOTF driver, The reliability designs, such as heat design, EMC design, and software allowance design, were performed. The capacities against interference and spectrum stability ofthe system have been improved accordingly, the coefficient of variation ofrepeatability within short time-scale has reached to 0.0002, and stability within long time-scale has reached to 0.001.
Emissive spectral analysis applied in 15N excretion test of Helicobacter pylori
Yayi Zhu,
Jicong Wu,
Zhenhua Zhang
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A new method for detecting the infection of Helicobacter pylon (HP), '5N-urea tracing and emissive optical spectroscopy method, is described in this paper. A group of 26 patients was tested. After '5N-urea was administered orally, urine specimen was collected from 30 to 120 minutes and its volume was measured. Then the concentration of ammonia in the urine specimen was determined. A special emissive optical spectrometer was applied to measure the '5N-abundance ofthe urine specimen, which was designed and manufactured by us and was an intelligent system. It contains a monochromator, a high frequency generator, a precise amplifier and a computer. The ratio (R) of the 15N amount of excretion in the urine to that of ingestion was found out. HP positive infection was predicated if R>0.3%. Taking the bacterial culture or (and) Gram stain as a reference standard, the specificity, sensitivity and positive predictability ofour test were 81%, 89% and 84% respectively. The new method is sensitive, noninvasive and useful for clinical practice. It is worth studying it further.
NIR Spectroscopy and Imaging I
Hemodynamic measurements in rat brain combining diffuse near-infrared absorption and correlation spectroscopies
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Measurement of concentration, oxygenation, and flow characteristics of blood cells can reveal information about tissue metabolism and functional heterogeneity. An instrument has been built that combines two near-infrared diffuse optical techniques to simultaneously monitor blood flow, blood volume and blood oxygen saturation. Diffuse correlation spectroscopy (DCS) monitors blood flow by measuring the optical phase shifts caused by moving blood cells, while diffuse photon density wave (DPDW) spectroscopy measured tissue absorption and scattering. The modularized design of the instrument provides the instrument great flexibility for trading off the temporal, spectral and spatial resolution by selecting the number of source-detector pairs and wavelengths. The frame acquisition rate of the current instrument is 0.2 Hz with 3? (wavelengths) × 15s (source positions) × 4d (detectors) for DPDW measurement in the frequency domain, and 1? × 3s × 9d for DCS. Higher frame acquisition rate could be achieved by reducing the spatial resolution, for example, 2 Hz with 3? × 1s × 4d for DPDW and 1? × 1s × 9d for DCS. The unique non-contact probe mounted on the back of a camera allows non-contact measurement that avoids potentially altering blood flow. We used this instrument to monitor in vivo the hemodynamic responses in rat brain during KCl induced cortical spreading depression (CSD).
Optical Diagnosis and Spectroscopy II
Autofluoresence spectroscopy for in-vivo diagnosis of human oral carcinogenesis
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An in vivo study of human oral cancer diagnosis by using autofluorescence spectroscopy is presented. A Xenon-lamp with a motor-controlled monochromator was adopted as the excitation light source. We chose the excitation wavelength of 330 nm, and the spectral measurement range was from 340 nm to 601 nm. A Y-type fiber bundle was used to guide the excitation light, and collect the autofluorescence of samples. The emitted light was detected by a motor-controlled monochromator and a PMT. After measurement, the measured sites were sectioned and sent for histological examination. In total 15 normal sites, 30 OSF (oral submucosa fibrosis) sites, 26 EH (epithelial hyperkratosis) sites, 13 ED (epithelial dysplasia) sites, and 13 SCC (squamous cell carcinoma) sites were measured. The discriminant algorithm was established by partial-least squares (PLS) method with cross-validation technique. By extracting the first two t-scores of each sample and make scattering plot, we found that the samples of different cancerous stages were in grouped distinct locations, except that samples of ED and EH were mixed together. It means that this algorithm can be used to classify normal, premalignant, and malignant tissues. We conclude that autofluorescence spectroscopy may be useful for in vivo detection of early stage oral cancer.
Research on a medical noncontact blood-sampling laser instrument
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The laser blood sampling is the last idea. The idea is based on focus laser beam to pierce the finger skin, and then we can get and analyze the blood sampling. Because there is not contact the method can wholly avoid the contact infection. In the paper, the core light source is a compact no water-cooled Er-doped YAG solid laser, researched and developed by ourselves. The erbium laser output wavelength is 2.94?m, which is accordance with water' s absorption peak. The water' s absorption in tissues is particularly great, so the erbium laser is suitable. Simultaneously we design the laser alignment system, the laser shaping system and the focal setting system. Depend on the theoretical analysis and experiments, we research and develop a medical blood—sampling instrument of laser, with the good application prospect.
Optical Imaging
Whole-body fluorescent imaging of tumor cells transfected with EGFP
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The green fluorescent protein (GFP), from the bioluminescent jellyfish Aequorea victoria, yields a bright green fluorescence when expressed in either eukaryotic or prokaryotic cells and illuminated by blue or UV light. The characteristic properties of GFP make this protein a good candidate for use as a molecular reporter to monitor pattems of protein localization, gene expression, and intracellular protein trafficking in living cells. In this study, human lung cancer cells (ASTC-a-l) were infected with EGFP plasmid vectors, and incubated in RPMI 1640 culture medium supplemented with 15% FCS and 800tg/ml G4l8. Five cell clones were observed strong fluorescence after several generations. The flow cytometry was used to determine the GFP expression stability, the results showed that there was significant difference between 2#(3#) and 4#(5#) (P<0.0l). The nude mouse, 6 weeks of age, was injected s.c. with a single dose of 3x 106 infected tumor cells. The GFP fluorescence was directly exited by 488nm argon ion laser and recorded by digital camera with 530nm long pass filter. This new metastatic model can play a critical role in the study of the mechanism in lung cancer and in screening of therapeutics that prevent or reverse this process. Key Words: GFP; Human lung cancer cells (ASTC-a-l); Flow cytometry; Nude mouse
Polarization-gated optical imaging: effect of size parameter of scatterer
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A theoretical treatment based on electromagnetic theory has been developed for the dependence of depolarization of linearly and circularly polarized light on size parameter of scatterer. The model reproduces the earlier results for the dependence of depolarization of circularly and linearly polarized light on scatterer size parameter. Further, the results obtained from this model show that for a given scatterer size parameter, a change in the value of ratio of refractive index of scatterer to that of the surrounding medium also significantly affects the degree of depolarization of both linearly and circularly polarized light. These results have been experimentally verified and can have important consequences for polarization gated optical imaging.
Novel optical imaging system for localization of early nasopharyngeal carcinoma
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By using a commercial nasal endoscope and laser-induced drug fluorescence technique, a novel optical imaging system as a localizer for nasopharyngeal carcinoma that coupled the excitation laser into the original white-light transmission system of endoscope was presented. The design approach of the imaging system and ultimate schematic diagram were also illustrated in detail. The design of optical imaging system mainly including the coupled technique with high efficiency between light source and optical fiber, and the directed coupled technique of two coaxial optical beam from different optical fiber without contact, as well as the technique for better clearness and contrast of displayed image of the optical imaging system. As a result, the fluorescence and reflection white light from the target tissue surface are alternately imaged by a nasal endoscope for respectively, which can be switched in real time for clinical examination of diagnosis and localizati on of early nasopharyngeal carcinoma.
Optical image quality improvement based on time-resolved Stokes vectors in filamentous tissues
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We first demonstrated the effectiveness of imaging in a tissue phantom with isotropic scattering by using polarization discrimination combined with the time gating method. In this situation with lean pork as targets and diluted milk as tissue phantom, the reduced scattering coefficient mapping manifests clear images. However, such an imaging technique became less effective in filamentous tissues, such as chicken breast tissues, because filamentous tissue had a deterministically anisotropic property. It led to coherent coupling between the two linear polarization components. In this situation, we employed the time-gated degree of polarization (DOP) imaging technique that based on the Stokes formalism. The results showed that the DOP measurement was quite effective in high-quality imaging of objects in filamentous tissues. The improvement of this method was attributed to the unchanged polarization part under the coupling processes ofvarious polarization components.
Signal compensation of photoacoustic tomography
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The results of theoretical and experimental investigations of pulsed optoacoustic (PA) method for tomography of biological objects in the requency range 1-10 MHZ at the depths up to 5 centimeters are presented. Some key problems of imaging are to reduce the effect of surface PA pulse and enhance the contrast of imaging. In this paper, we propose compensation methodology to restrain the noise signal of the surface, and apply the methodology to reconstruct PA tomography,
NIR Spectroscopy and Imaging II
Application of integral transform algorithms to high-resolution reconstruction of tissue inhomogeneities in medical diffuse optical tomography
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The applicability of the transform algorithms generally used in projection computed tomography is substantiated for the case of medical diffuse optical tomography (DOT). To reconstruct tissue optical inhomogeneities, a new method based on a concept of an average statistical trajectory for transfer of light energy (photon average trajectory, PAT) is proposed. By this method, the inverse problem of DOT is reduced to solution of integral equation with integration along a PAT. Within the internal zone of the object, remote well away from the boundaries, PATs tend to a straight line, and standard integral algorithms based on the inverse Radon transform may be used to restore diffuse optical images. To demonstrate the capabilities of the PAT method, a numerical experiment on cross-sectional reconstruction of cylindrical strongly scattering objects with absorbing inhomogeneities has been conducted. To solve the DOT inverse problem, two filtered backprojection algorithms (of Radon and of Vainberg) were used. The reconstruction results are compared with those obtained by a well-known software package for temporal optical absorption and scattering tomography, based on multiple solution of diffusion equation. It is shown that the PAT method using the Vainberg algorithm allows reconstruction of tissue optical structure with a 20%-gain in spatial resolution.
Tumor Diagnosis and Treatment I
Effect of anti-cancer medicament on the validity of a fluorescence-based technique for cancer diagnosis
Ronger Zheng,
Xiuzhen Guo,
Jing Wang,
et al.
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It is well known that the metabolizing of porphyrin is a normal physiological activity of animals, and one's illness would lead to the abnormality of the porphyrin metabolism in his body. Based on the extensive studies of the serum fluorescence, a diagnostic technique of cancers in human body has been developed with high sensitivity and specificity. From its clinical investigations, however, it was found that the characteristic of the serum fluorescence would varied since some medicine's taking, hence highly affected the validity of the cancer diagnosis with the serum fluorescence. In this paper, the excitation and fluorescence spectra of common used photo-sensitizes, anti-cancer drugs, antibiotics and hormones were taken to investigate how the medicament affect the monitoring the fluorescence of blood serum for cancer diagnosis. From the spectral analysis, it was found those drugs would affect the fluorescence monitoring of carotenoid and porphyrin in the human blood serum in four ways. The mechanisms of each way have been discussed. The detected limit for each drug investigated was determined to be 1x10-7g/ml to 1x10-3g/ml. It is concluded that once the dose exceeds 500mg, the medicament would affect the diagnosis. For the medicine of Fluorouracilum, Methotrexate, Aspirin and Diethylstilbestrol, the diagnosis would be interfered seriously even with the dose just above 10mg. It is strongly suggested that to achieve high accuracy of diagnosis, the person to be tested should not take medicine during the 3 days before the test proceeding.
Tumor Diagnosis and Treatment II
Spectral and photobleaching properties of hematoporphyrin monomethyl ether
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The absorption spectrum, fluorescence excitation and emission spectrum of new photosensitive drug Hematoporphyrin Monomethyl Ether (HMME) in physiological saline with 10 percent human serum were obtained. Experimental results show that the maximum absorption peaks for HMME in physiological saline with 10 percent serum appear at 400nm in the soret region. There are two major peaks, at 620nm and at 685nm in fluorescence emission spectrum of HMME when excited by light with the wavelength of 41 3. mm. Furthermore, the photobleaching properties of HMME in tissue phantom irradiated by J( laser were determined from the intensity fluctuations of the collected fluorescence. The photobleaching time of HMME increased with the increasing of HMME concentration, while the photobleaching time of HMME decreased with the increasing of irradiated laser power. When the power of irradiation and the concentration of HMME equal to 12mW and 3ig/ml, respectively, the photobleaching time of HMME is approximately 190 second. All of these results provide the implications for the clinical application and dosimetry of HMJ\4E in the photodynamic diagnosis of cancers.
Rapid imaging of oxygen free radicals produced in PDT using FCLA chemiluminescence probe
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In this paper, we report a rapid imaging method for oxygen free radicals produced in photodynamic therapy (PDT) in vivo using chemiluminescence probe. The mechanism for PDT involves singlet oxygen (102)generated by energy transfer from photosensitizers. '02 can react with FCLA, which is a specific chemiluminescence probe for detecting 102 and superoxide (02). The reaction of FCLA (Fluoresceinyl Cypridina Luminescent Analog) and 102can give emission with peak wavelength at about 532 nm. In the present study, FCLA was chosen as an optical reporter of 102produced from photosensitization reaction of Hematoporphyrin Derivative (HpD) in model solution and in nude mice with transplanted mammary cancer. Photosensitized chemiluminescence from the reaction of FCLA with 102was detected by a highly sensitive Intensified Charge-Coupled Device (ICCD) detector. The chemiluminescence was markedly inhibited by the addition of 10 mmol/L sodium azide (NaN3) to the model solution and minor effects were observed at the addition of 1 0 imol/L superoxide dismutase (SOD), 20 mmol/L mannitol and I 00 tg/mL catalase, respectively, thus indicating that '02 generation from photosensitization reaction mainly results in the light emission. Experiments in vivo with tumor-bearing mouse showed a clear chemiluminescence image of tumor.
Tumor Diagnosis and Treatment I
Improvement of tumor response to photodynamic therapy by manipulation of tumor oxygenation in an in-vivo model system
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Photodynamic therapy (PDT) requires molecular oxygen during light irradiation in order to generate reactive oxygen species. Tumor hypoxia, either pre-existing or induced by PDT, can severely hamper the effectiveness of PDT treatment. Lowering the light irradiation dose rate or fractionating a light dose may improve cell kill of PDT induced hypoxic cells, but will have no effect on pre-existing hypoxic cells. In this study, hyper-oxygenation technique was used during PDT to overcome hypoxia. C3H mice with transplanted mammary carcinoma tumors were injected with 12.5 mg/kg Photofrmn and irradiated with 630 nm laser light 24 hours later. Tumor oxygenation was manipulated by subjecting the animals to 3 alp hyperbaric oxygen or normobanc oxygen during PDT light irradiation. The results show a significant improvement in tumor response when PDT was delivered during hyper-oxygenation. With hyper-oxygenation, up to 80% of treated tumors showed no re-growth after 60 days. In comparison, only 20% of tumors treated while animals breathed room air did not re-grow. To explore the effect of hyperoxygenation on tumor oxygenation, tumor PO2 was measured with microelectrodes positioned in pre-existing hypoxic regions before and during the PDT. The results show that hyperoxygenation may oxygenate pre-existing hypoxic cells and compensate for oxygen depletion induced by PDT light irradiation. In conclusion, hyper-oxygenation may provide effective ways to improve PDT treatment efficiency by oxygenating both pre-existing and treatment induced cell hypoxia.
Tumor Diagnosis and Treatment II
Chemiluminescence from human serum albumin oxidation by singlet oxygen
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Irradiating the mixture of 5 ?M human serum albumin (HSA) with 10?M hematoporphyrin (HP) in 0.01 M phosphate buffered saline (PBS, pH 7.2) solution with visible light resulted in a peak chemiluminescence (CL) followed by rapid decay, which could be detected by a highly sensitive intensified charge coupled device (ICCD). The CL decays almost double-exponentially with a lifetime of about I 80 s. Experiments of bubbling air indicate that resolved oxygen molecules play a critical role to the CL, and the CL intensity depends on concentrations ofHP and HSA in PBS solution. The substitution of D20 for H20 increased the CL intensity and the CL intensity was reduced at the addition of the singlet oxygen (102) quencher of4O mM sodium azide (NaN3). Fluorescence-quenching experiments ofHSA at 330 nm during a 40-mm irradiation show aromatic amino acids such as tryptophan (Trp) were destroyed along with the decrease of CL intensity during the course of photosensitization of HP. These results suggest that 102 formation from the photosensitization of HP results in the oxidation of aromatic amino acids in HSA and the CL is a result of the decay to ground level ofexcited species generated from the oxidation ofaromatic amino acids.
New photoacoustic technique for detection of breast cancer
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Photoacoustic (PA) technique is a very important and promising biomedical diagnosis and imaging method, which can afford abundant information to analyze the pathological part of the tissue and image it. This paper proposes a new method to detect the PA wave. A focused probe ultrasonic beam was used to tag the position of PA signal and simultaneously overlapped with the PA signal, which in fact is carried out by the probe ultrasound. The overlapped signal is received by the transducer and will be further processed such as amplification and digitization. At last a compute analyzes and processes the digitized signal and the original PA signal can be restored by Fourier filtering. Furthermore, the noise of the measurement system and background could be reduced after filtering. On the basis of this method, we designed a novel setup to detect breast cancer tumor and the performance of this setup was evaluated in breast tissue-like phantom. The experiment results demonstrate the practicability of this technique.
OCT
Tissue clearing of biotissues for optical coherence tomography
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The high scattering nature of non-transparent human tissue limits the imaging depth of optical coherence tomography (OCT) to 1-2 millimeters. By using the longer wavelength of the light source, the penetration depth is improved; the imaging contrast is however decreased largely due to the reduced backscattering in microscopic scale and the reduced refractive heterogeneity in macroscopic scale. For more effective diagnosis using OCT, a concurrent improvement of penetration depth and imaging contrast are often needed. We report in this paper that the OCT imaging depth and contrast can be enhanced concurrently by the use of osmotic agents. We demonstrate experimentally, by examples, that the topical applications of glycerol and propylene glycol, two common biocompatible and osmotically active solutions, onto the tissue surfaces could significantly improve the OCT imaging contrast and depth capability. The biotissues demonstrated include the rat skin, human oesophageal and gastric tissues.
Analysis of speckle in optical coherence tomography
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An analysis has been developed based on former theory analysis and a new deduction about the forming of speckles is given. The popular theories believe that the speckle of OCT image comes from the multiple scattering effect, which distorts the wave-front of light then the speckle induced. By the principle of scattering, least-scattered light still maintains coherent, whereas multiply scattered light will lose coherence for the reason ofdepolarization, phase shift and dispersion. So mostly the least scattered light contributes the amplitude of the detected coherence envelope. The speckle comes from the superposition of several coherence envelopes.
Image quality improvement with dispersion compensation and retrieval algorithms in optical coherence tomography
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We proposed and demonstrated a novel technique of improving the spatial resolution of an optical coherence tomography (OCT) system given a certain light source spectrum. By using dispersive materials in the reference arm of the OCT system, the resultant dispersion compensation led to a FWHM of interference fringe envelope smaller than the Fourier transform limited value, at the expense of significant tails. The effects of the tails, which would blur the OCT images, were tremendously reduced with retrieval algorithms. Simulation results and processed OCT scanning images have shown the capability of the proposed technique. Two retrieval algorithms were proposed and compared.
Biomedical application of OCT technology
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Optical coherence tomography (OCT) is a novel technique with high resolution for rapid, noninvasive imaging in living biological tissues (human body). With this technique, a thin "optical section" within a thick biological specimen can be obtained. This technique not only has higher axial resolution but also has higher longitudinal resolution than ordinary optical microscopy. In this paper a low-coherence optical tomography system including a fiber-optical Michelson interferometer and a confocal scanning microscope is described, and theoretical analysis is given to this high-precision microscopic imaging system based on optics, mechanics, electronics and computer. Meanwhile, various kinds of potential applications of OCT system in clinical medicine are described in details, such as in ophthalmology, dermatology, cerebrum, dentistry and internal medicine, etc. The characteristics of OCT technology and limitations of OCT application are also investigated, and some schemes are studied to make OCT technology more practical. The future of OCT technology in medical application is predicted. The research of this paper can provide a new, effective technique method of high-speed, high-resolution and noninvasive detection for clinical medicine, and this is very important in deepen and widen the field of OCT study.
High-speed scanning optical coherence tomography
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In biomedical imaging high speed axial scanning is very important for obtaining the cross-sectional images of tissue microstructures. For this purpose our optical coherence tomography (OCT) system incorporated a scanning optical delay line (RSOD) that uses Fourier-transform pulse shaping technique. In this technique axial scanning in the time domain is implemented by a linear phase ramp in the frequency domain. By combining the axial scanning (Z-axis) in the reference arm and lateral scanning (X-axis) in the sample arm using a lateral scanning galvanometer, the system could image samples with a size of 400×800 pixels (Z-X image) at the speed of 6 frames per second. Some imaging results are presented in this paper.
Poster Session
Formulation of beam propagating through the organized tissues withpolarization-sensitive OCT
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It is known that the collagen-rich and well-organized biological tissues have birefringent characteristics when presented to the light. Determination of collagen fiber organization in tissue is of paramount importance in clinical diagnosis. With the precise control of the polarization state of incident and reflected light, polarization sensitive optical coherence tomography (PSOCT) could be used to visualize the tissue birefringence. To understand this better, the mathematical treatment relying on rigorous polarization optics would be needed. This paper is primarily for this purpose. The emphasis is placed on the discussions of light reflected from within a sample using a point source beam and analytical derivations of the polarization properties of tissue based on quasi-Stokes parameters (I, Q, U, V) and Jones matrix formalism.
Optical properties of skin
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This paper describes the light intensity and polarization characteristics of the regular reflectance and the backscattered light, which were generated by putting the linear polarized light into the surface of skin. We come to the following conclusions: (1) when incidence light is linear polarized light, its regular reflectance is polarized light with the same polarization state of the incident light, while the backscattered light will lose almost all its polarization; (2) when the incidence light, whose optical vector's direction is parallel with the incidence plane, enters the skin with the Brewster's angle, the regular reflectance almost vanishes. At the same time, receive the light energy where the regular reflectance occurs. The backscattered light, which enters the tissue, covers 97% ofthe received total energy.
Influence of medium parameters on the transmitted intensity and shape of ultrashort laser pulses
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Based on the diffusion approximation theory, this paper researched quantitatively the influence of the thickness, the absorption coefficient, the scattering coefficient, and the anisotropy coefficient on the ultrashort laser pulse transmitted through turbid biological tissues. After transmitting through the turbid media, several picoseconds laser pulse will be widened by the diffusive scattering. The various medium parameters have much different influences on the intensity and shape of the transmitting ultrashort laser pulse. The paper concluded that the basic optical parameters of tissues can be acquired by analysing the pulse shape, and that the change of the pulse shape is mainly influenced by the scattering other than absorption. The research results can be used in optical diagnostics.
Propagation characteristics of autofluorescence in tissue
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This paper studied the LIAF transportation mechanism in tissue by a series of Monte-Carlo simulations, and investigated the effects of boundary condition, optical properties, structure, and the quantum yield of tissue chromophores on LIAF spectra. According to the layered structure of gastrointestinal tract and the penetration depth of laser beam, a bi-layer tissue model was set up for simulating the distribution of LIAF spectra obtained from normal tissue and adenoma. The results showed that an index-mismatched boundary reduced both the amount of excitation and emission that are remitted from the medium surface. In addition, the origin of fluorescence in normal and cancerous tissues was discussed. We found out that the cancerous mucosa has significant lower fluorescence efficiency compared to normal tissues. The reason is two-fold: firstly, the fluorescence quantum efficiency ofcancerous mucosa, which is the percentage of fluorescence of the cancerous tissues that get excited, is lower than that of normal mucosa., secondly, due to the higher absorption coefficient of cancerous mucosa, the amount of excitation light reaching submucosa layer is reduced, resulting in significantly lower remitted fluorescence from submucosa layer.
Development and application of a new diode laser therapy apparatus
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Using the Y type fiber, high efficiency fiber coupler and A1GaInP diode laser has developed a new diode laser therapy apparatus with the wavelength of 650nm. The output laser power from the fiber of the apparatus can reach more than 100mW. The fiber localizer of the apparatus is easy for orientation during the therapy and the output laser power is very stable and reliable. The apparatus has been widely used in about 20 hospitals, and has successfully cured more than 50,000 patients who suffered from various diseases, which mainly including cervical spondylosis, traumatic infection, skin bruise, sudden deafness, tympanitis, tinnitus, infantile rhinallergosis, rheumatism, rheumatoism, scapulohumeral periarthritis, asthma, temporomandibular joint disturbance, ulcer, eczema ani, postoperative crissal edema, and so on. The apparatus has also well performed in the application of haematococcus pluvialis's laser mutagenesis breeding.
Application of the laser instrument in biomedicine
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The laser possesses the features of monochromaticity, directivity, high brightness and heat, pressure and electromagnetic effect on tissue. A variety of laser instruments is used in medical fields. The laser instrument is not only an apparatus of medical research, but also used in diagnose and treatment ofdisease. The good effect ofapplication makes it an important means in defeating the disease.
Optical manipulation of microscopic particles and biological cells by laser microbeams
Yan Li,
Jinghua Liu,
Xiangwang Meng,
et al.
Show abstract
The paper introduces to construct a laser micro-beam system for cell manipulation. This system consists of an optical tweezers with optical kinetic effect, and an optical scissor, which is a Nd:YAG laser beam with synthetical effect of sound pressure, thermal expansion and bounce-back pressure. The system can manipulate, deflect, rotate, and punch cells, and so on after we couple two laser beams into microscope. We construct a laser micro-beam system and gained anticipated experiment results. We can successfully manipulate cells in suspension, concise chromosome and punch a hole in cells or organelles on the basis of the system.
Stereoscopic imaging technology for medical video endoscope
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With the development of the minimally invasive surgeries (MIS), the quality of information provided to surgeons becomes more and more important. Consequently it has been a trend that stereoscope replaces the traditional monocular endoscopes. This 3D video endoscope system acquires separate left and right images by a pair of stereo-objective lenses replicating human binocular vision. The system employs time multiplexing technique accomplished by images processor. The separate left and right images will been seen with an active matrix liquid crystal screen and a circular polarized eyewear at different moments at the same time. The clinical evaluation shows that when the system is adopted to perform the MIS, the procedure is safer, more effective, and less invasive.
Application of logarithmic analog operator with high-accuracy ratio in biochemical analyzer
Jingfeng Wang,
Zhihua Liu,
Jiaxin Xiong,
et al.
Show abstract
A new analog logarithmic(Log.) operating method based on lambert-Bill's law in a biochemical analyzer is researched in this paper. We use the relationship ofthe voltage across the capacitor Log. to the time of discharging when the capacitor is discharged, change the relationship of transmittance and the concentration of a solution to the relationship of the voltage across the capacitor and the time of discharging, the concentration of the solution is gotten easily. This operator exists between pure analog and pure logic Log. operator, which avoids theory error produced by logic Log. operator fully, absorbs the merits of low cost and fast working speed of analog Log. operator, uses a large dynamic program controlled gain amplifier to improve adaptation range of input signal. thus a high operating accuracy and speed are obtained . At the same time correlate measuring experiments are done and error analyzing are produced.
Novel microarray scanner
Wenkui Wang,
Min Liu,
Qiquan Hu
Show abstract
A novel scanner is developed for detecting the laser induced fluorescence signal emitted from a microarray slide. The scanner uses a line array CCD as detector instead of PMT. In this scanner, a laser line generator is used to generate a laser line to excite the fluorescence. The scanner has high resolution and high sensitivity due to the high sensitive and resolution line array CCD detector and reasonable objective optics system. The microarray slide is driven by a step motor in one direction, which is controlled by PC. Hence a large scanning area can be realized with this scanner. The preliminary experiment results of this novel scanner system are presented in this paper. In this scanner, the sensitivity of the line array CCD is similar to that of PMT, It takes this scanner less than 5 minutes to scan a standard slide (1" x 3"), a different resolution can be achieved, for example, 5 microns, 10 microns, or 14 microns.
Semiconductor laser cure instrument for brain blood oxygen
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In this paper, based on the principle oflaser cure, using the semiconductor laser with Wavelength 650 nm, we developed a laser cure instrument for brain blood-oxygen. The arterial part of a nose can be directly irradiated by a laser head, and the laser beams affect directly on the blood of a circulation system. It can decrease the blood viscosity, increase the quantity of blood oxygen and deformation ability ofred blood cell. Simultaneously, both the temples of a brain are also irradiated to dilate the blood vessel and just a neural system. Clinical examination shows that the instrument has not only the function of health protection, but also the therapeutic function for brain arteriosclerosis, and also can cure other illnesses, such as neurasthenic, insomnia.
Monte Carlo simulation of measuring capillary blood flow with diffused light correlation
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The velocity of capillary blood flow is an important parameter to diagnose some diseases. In this paper, a model was set up to non-invasively measure the capillary blood flow using diffusing temporal light auto-correlation. This method is independent of the direction of blood flow. The distance between the light source and the detector was discussed in order to obtain high SNR (signal to noise ratio). The influences of the Brownian motion and the random flow of scatterers on the auto-correlation of diffusing light were analyzed with Monte Carlo simulation. The simulation results show that the characteristic correlation time exponentially decays as the mean-squared velocity of capillary blood flow increases, which is useful for medical diagnosis.
Double-wavelength laser equipment for cosmetic skin resurfacing and treatment
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The paper analyses the overall performance parameters, operation principle, and general structure of a double wavelength (1064nm and 532nm) laser device for Laser skin resurfacing and treatment. The instrument uses solid state Laser with the energy ofper pulse 400mJ or 200Mj, the width ofpulse of 8-iOns and the density of light spot of 12. 8J/cm2 or 6.4J/cm2. Discussion is made carefully for the design of solid laser power supply, and fundamental intelligent controlling systems. Reliability and security design is also analyzed particularly.
Design of touchscreen control unit for medical Q-switched ruby laser system
Xiaoqiang Wen,
Zhisheng Ye,
Zhenji Jin
Show abstract
The paper describes the structure of the touchscreen control unit for medical Q-switched ruby laser system, then analyzes the produced mechanism and the transmitted ways of the electromagnetic interference (EMI) noises in ruby laser system, and gives the specific methods for the EMI problems, synthetically. The analyses and methods are verified by the ultimate results of our experimentations. The conclusions and methods of the paper are useful for the design of control units in other medical and industrial lasers.
Experimental study on skin surface character utilizing laser Doppler effect
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In this paper, the study on roughness of skin surface utilizing laser Doppler effect is put forward. Theoretically speaking, the roughness can be regard as the synthesis of longitudinal and transverse displacement of a point on epidermis. In the paper, the fundamentals and method of displacement measurement utilizing laser Doppler effect are introduced, and the theoretical system of skin surface cognition utilizing laser Doppler effect is established. The system design of skin surface character testing is extracted, a new reference optical system is put forward to achieve the roughness detection, an optical grating is used for frequency mixing and getting high SNR signals in this measurement. The factors influencing the measurement accuracy are expounded. Moreover, the theory analysis and experiment-based methods are offered to improve the accuracy. The measurement technique utilizing laser Doppler effect has many advantages, such as high precision, quickly response speed, large measurement range and non-touch measurement, so this study can be applied in analyzing the profile and distortion of skin surface, which is very important in theory and practice for the non-invasive detection fields ofbiology and iatrology.
Design of a high-power semiconductor medical laser based on microprocessor control
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This paper introduces the design of optics, power driver and control system of a high power semiconductor medical laser. The instrument adopts 980nm laser with maximum power output of 2W as therapeutic beam and 670nm laser of 3mW as aiming beam. The laser beams, after being collimated , can either be transmitted directly or be coupled through an optical fiber. In the driver of therapeutic laser, there exist current supply, protection circuit , temperature controller and light power feedback loop. The whole system is controlled by a microprocessor. With appropriate hardware and software, we've achieved , in our driver ,a variety of protection features including the ability to suppress transients and reduce noise, relay shorting protection , soft turn-on , current limit and overvoltage shut-off ,which keep the laser diode from damage. Meanwhile, we've also obtained a continuously adjustable optical power output with high accuracy and stability , both of which are vital to a safe and reliable
Reflectivity of the human cornea and its influence on the selection of a suitable light source for a low-cost tonometer
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This article introduces an experiment designed to investigate which wavelength of light is best reflected by the cornea. Results indicate that the human cornea reflects near-infrared or violet light more efficiently than it does bright visible light. Further, results indicate that at a wavelength of 580nm, the reflectivity of the cornea decreases to a minimum value of 37% given light incident on the cornea at an angle of 45°. A light source suitable for the detection of glaucoma has been selected based on these results, also taking into account the spectral response of a suitable photo-detector.
Low-cost multibeam optical tweezers with Laguerre-Gaussian mode and its manipulation of cells
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Optical tweezers are useful tools for use as non-contact micromanipulators of biological cells and organisms. Conventionally, a Gaussian laser mode is used as the trapping beam. In this paper, the authors describe a detailed recipe for construction of a low cost dual optical tweezers. The system is based on a conventional optical microscope and high-order Laguerre-Gaussian beam lasers. The authors studied both Laguerre-Gaussian beam trap and Gaussian beam trap's characteristics. It has been found that the high-order Laguerre-Gaussian beam trap has many significant advantages: the high-order Laguerre-Gaussian beam trap can hold larger particles more stable than Gaussian beam trap; a single Laguerre-Gaussian beam trap is able to catch free cells and hold them together simultaneously, but traditionally only the multi-Gaussian beam optical traps can fulfill the work; the high-order Laguerre-Gaussian beam trap is safer than the Gaussian beam trap. In addition, the high-order mode laser is inexpensive and the low cost system will make this technique more widely accessible to researchers.
Application of DWDM-OADM employed in a railway-area communication network
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We have proposed a physical bus and logical star DWDM-OADM architecture optical transport network in the Railway Communication Company's area communication. The OADM optical nodes architecture was illustrated, the logical dual-star architecture 's self-healing fUnction was described. We have demonstrated the logical single-star architecture network transmission performance.
Clinical study on the treatment of anal eczema by semiconductor laser accompanied with traditional Chinese medicine steam washing
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36 cases with anal eczema in treatment group were treated with 650nm semiconductor laser accompanied with traditional Chinese medicine steam-washing, of whom 25 cases were cured, and 11 cases improved. 36 cases with anal eczema in control group 1 were treated only with 650nm semiconductor laser. 36 cases with anal eczema in control group 2 were treated only with traditional Chinese medicine steam-washing. The treatment group was compared with the control groups. The results showed that the therapeutic effect of the treatment group was superior to the 2 control groups.
Diode laser irradiation treatment of thromboangitis obliterans
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The optical parameters for the treatment of thromboangitis obliterans were presented. The penetration characteristics of 650nm laser diode interaction with human vessel and blood were also studied respectively. The extra-vascular irradiation instrumentation using 650nm diode laser was developed based on the above investigation, and it can be applied for the treatment of thromboangitis obliterans and other diseases. In clinical application, out of the 10 patients, including 7 males and 3 females that suffered from thromboangitis obliterans were treated with the extra-vascular irradiation instrumentation. 2 patients were suffered from upper limb, while the others were suffered from lower limb. Patient received 10 times treatment as a course, and the laser power for the first half-course was 20mW and ranged from 40mW to 80mW for the successively half-course. The total effective rate was 70 percent. A male patient in the third stage vasculitis of right foot without any improvement after treatment with traditional therapy but cured with diode laser irradiation after a course of treatment. The treatment mechanism of thromboangitis obliterans with diode laser was also briefly discussed.
Feasibility of laser and electromagnetism combined therapy in prostatitis
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The current therapy methods for prostatitis, and its advantages and disadvantages were discussed in this paper. Two kinds of noninvasive therapy method were presented based on the combination of diode laser technique with traditional Chinese acupuncture and the interaction between low energy laser and biotissue. Firstly, dual-wavelength diode laser with the wavelength of 650nm and 810nm, respectively, were used to irradiate the acupoints. Diode laser with the wavelength of 650nm has remarkable biological stimulation effect, while 8lOnm diode laser mainly has thermal effect. Secondly, a low frequency pulse electromagnetic field is also applied when the targets are irradiated by the diode laser in the application of laser-electromagnetism therapy. Finally, the laser and electromagnetism parameters, as well as therapy methods and instrumental design are also presented in detail.
Mechanism study of intravascular low-level laser irradiation therapy
Yuqiang Jiang,
Chang-yong Li,
Xiaobo Wang,
et al.
Show abstract
Intravascular low level laser irradiation (ILLLI) therapy has been applied in clinic widely since Mester et a!. reported the beneficial effects of low-level laser treatment on wound healing in the early 1980s. Clinical reports show that is an effective measure. But the mechanism of ILLLI is not very clear yet. In this article, it will be discussed why the oxygen content in the blood increases after irradiated by He-Ne laser and how does it influence the functions of body. It will be proved that the ability of blood carrying oxygen acts as a key role in the ILLLI.
Chinese medicine photosensitizer stimulated by violet ray for early-stage cancer diagnosis
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A novel technique and equipment for the diagnosis and treatment ofthe gastric cancer using violet laser to stimulate the traditional Chinese medicine photosensitizer are proposed. The photosensitizer's feature that it can gather together selectively inside the tumor tissues is utilized to test and treat the early-stage gastric cancer. The characteristic absorption spectrum and fluorescence emission spectrum of the traditional Chinese medicine photosensitizer are measured, and two violet light sources matching with the spectrums are proposed as well. One is "Hg-Xe" lamp with a special configuration at 433nm at the peak power, and the other is violet LD with a wavelength 405nm at the peak power, which exactly matches the absorption peak ofthe traditional Chinese medicine photosensitizer.
Q-switched Er:YAG radiation transmission through an oxide glass fiber for medical applications
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In the last few years, there has been an increasing interest for the 3 m laser radiation in various medical applications, as this wavelength is strongly absorbed by the water and the other components of soft and hard tissue. An intensive development effort is going on throughout the world, in order to develop reliable lasers emitting in the 3 m wavelength range. Our laser development effort with the Q-switched Er:YAG laser is briefly described in this article. Additionally for medical applications there is a great demand for good flexible delivery systems, in the mid-IR wavelength region. In this work the radiation transmission of a Q-switched Er:YAG laser, emitting at 2.94 m, through high power (HP) oxide glass fibers of 450 ?m core diameter was studied. Attenuation measurements were obtained as a function of the laser energy input and as a function of curvature, at 90o, 180o and 360o bending angle. The output beam quality was studied using a beam profiler. Experiments with the same delivery system transmitting free-running Er:YAG laser radiation, were performed for comparison. The results are promising for the delivery of Q-switched Er:YAG laser radiation, as the fibers exhibited attenuation of 0.7 dB/m, and no damage of them was observed.
Biophoton emission from the right and left hands
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Spontaneous ultraweak photon (biophoton) emissions from hands are measured for healthy subjects. The data provide basic reference information for diagnostic application of biophoton emission. The overall average of biophoton emissions from the hands is 226.4 ± 14.3 counts per second. The asymmetry of the biophoton emission rates between the left and the right hands could be significant for both western and oriental diagnosis.
[Ca2+]i and MCLA-enhanced ultraweak chemiluminescence of macrophages irradiated with low-intensity He-Ne laser
Show abstract
Low intensity He-Ne laser therapy (eg: intravascular laser irradiation on blood, ILIB) has been wildly used to treat with some illness in clinic but the mechanism remain obscure. Laser power, the irradiation time and the irradiation dose were changed. Laser scanning confocal microscope (LSCM) was used to real-time research the effort of low intensity irradiation on {Ca2+}I in mouse marcophage and single photon counter device (SPC) was used to detect the MCLA enhanced chemiluminescence of macrophage irradiation with low intensity He-Ne laser. Proper dose of low intensity He-Ne laser irradiation can increase the [Ca2+]I of the macrophage and immunocompetence of macrophage effectively. Laser power of 0.16mw is more effect to increase the [Ca2+]i than laser power of 0.40mw. The [Ca2+]i is markedly different even the irradiation dose or the irradiation time is same. Both the irradiation dose and laser power are key factor for the change of [Ca2+]i and immunocopetance of macrophage. Activating ammuno-system of body is one of the very important mechanisms of Low-intensity He-Ne laser therapy.
Construction of tissue autofluorescence spectra by Monte-Carlo simulation
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This study investigated a bilayer gastrointestinal normal tissue (including mucosa and submucosa layers) and a cancerous tissue model (including adenoma and submucosa layers), and reconstructed their Laser-Induced Autofluorescence (LIAF) spectra by Monte-Carlo simulation. The good correlation between the reconstructed spectra and experimental spectra suggested that Monte-Carlo simulation can accurately describe the generation and transportation of fluorescence in tissue and therefore can detect cancerous tissue by revealing the real biophysical and biochemical information of tissue.
Correction of tissue autofluorescence by reflectance spectrum
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This paper focuses on obtaining the intrinsic Laser-Induced Autofluorescence (LIAF) spectra by using reflectance spectra to minimize the effect of the absorption and scattering of tissue. The correlation between fluorescence distortion coefficient (J) and reflectance spectra (R) has been studied by Monte-Carlo simulation. The results show that R represents a very good approximation of f for tissue fluorescence spectra correction. Corrected fluorescence spectra were calculated by dividing the measured LIAF spectra by the diffuse reflectance (R). The corrected fluorescence spectra for normal tissue exhibit two emission peaks at wavelength 420 nm and 475 nm, respectively, while one emission peak at 425 nm was recorded for the corrected spectra of the cancerous tissue. We proposed that the difference between spectra from normal tissue and adenoma was caused by the less NADH concentration in adenoma than that in normal tissue.
Experimental investigation of the fluorescent spectra of human blood and its components
Yuqiang Jiang,
Chang-yong Li,
Xiaobo Wang,
et al.
Show abstract
It has been discussed that the increasing of oxygen content in the blood acts as a key role during the intravascular low level laser irradiation (ILLLI) therapy. In this article, it was investigated why the content of oxygen in the blood would increase after He-Ne laser radiation via measuring the fluorescent spectra of blood and its components. The fluorescent spectra of human blood and its components (plasma, red blood cell) were measured before and after the samples were irradiated by He-Ne laser for 10 minutes, and the changes of spectra were investigated. The fluorescent spectra of human whole blood and components are different. The spectra of whole blood have peaks at 490nm and 614nm; plasma sends strong fluorescence between 410nm and 600nm; the spectra of red blood cell (RBC) have a strong peak at ôI4nm. After irradiated by He-Ne laser for 10 minutes, it was found that there are changes in the spectra of RBC and whole blood. Such a conclusion can be drawn that He-Ne laser inadiation can affect the hemoglobin's energy levels structure and improve the ability of blood carrying oxygen. It is significant to the application of ILLLI.
Noninvasive intracranial pressure measurement using near-infrared light
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Increases in intracranial pressure (ICP) may occur in patients of cerebral edema, brain tumors, encephalitis, brain injury etc. The care of these patients has been improved with continuous ICP monitoring. However, all the present clinical ICP monitors are invasive. Non-invasive ICP monitor is greatly expected. In this paper, a new method for ICP non-invasive monitoring using near-infrared light is proposed. Both theoretical and experimental studies have shown that correlation analysis applied to ICP, cerebrospinal fluid (CSF) and near-infrared diffuse reflection light from the brain tissue provides a possibility for non-invasive ICP detection. First, the correlation between the reflected light and the thickness of CSF is studied with Monte-Carlo simulations. It is concluded that the intensity of the reflected light changes significantly with the thickness of CSF, suggesting the feasibility to detect ICP by measuring the diffuse reflection near-infrared light from the brain tissue because the thickness of CSF changes with ICP. Secondly, the correlation of the diffuse reflection light and ICP is studied based on the experimental data acquired with helps of volunteers. It has been proved very promising to determine ICP non-invasively using near-infrared light.
New advancement of noninvasive measurement of blood glucose by near-infrared spectroscopy
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Noninvasive blood glucose measurement with near-infrared spectroscopy suitable for home use would allow a more accuracy and frequent determination of glucose level, along with reducing the long-term health care costs of diabetic patients due to no reagents. The fundamental research results of noninvasive blood glucose sensing of our research group are introduced in this paper. They are involving the aspects as followed, the prediction results of the fundamental experiments by PLS calibration method and artificial neural networks respectively; the wavelength selection by genetic algorithm; the quantitative relation among prediction accuracy, instrumental precision and regression algorithms; and the determination of measuring mode according to the measuring wavelength range, and so on. The experiments that done with the samples from simple ones to complex ones have proved the feasibility of noninvasive blood glucose measurement methodology by near-infrared spectroscopy. In addition, the further research subjects of the fundamental problems involving human body measurement are proposed.
Determination of instrumental precision requirement for expected glucose prediction accuracy
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Noninvasive measurement of blood glucose is a focal topic in the biomedical engineering field, but no success has been achieved completely as yet. The necessary instrumental precision (i.e., instrumental repeatability signal-to-noise ratio) is prerequisite for the desired prediction accuracy, which have not been investigated systematically. The mathematic relations regarding instrumental precision, regression method and prediction accuracy are put forward. They are tested and analyzed through the determination of glucose concentration in an aqueous solution with near-infrared (NIR) spectroscopy and chemometrics. The results show that the mathematic relations provide a estimate method of prediction accuracy for spectroscopic measurement. In addition, they can determine the necessary instrumental requirement for the expected prediction accuracy when certain regression method is used. This provides theoretic guides to the measuring methods design and references to the prediction accuracy analysis of the noninvasive glucose measurement and even the near-infrared spectroscopy.
In vivo determination of the absorbance spectra of human skin
Queyu Li,
Yang Wang,
Yong-Lin Zhang
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This is a pilot study about optical properties of the yellow race skin on the base of the theory of Kubelka-Munk. The physical model of light-transfer in skin tissue is analyzed, then a formula of light-absorption ratio of human skin is derived. Not only a method of the detection of optical absorption of skin in vivo based on Virtual Instrument and spectrum technique is established, but also a detection platform is built accordingly. It is the first time to realize the in vivo determination of the absorption spectrum of human skin.
Laser-induced fluorescence detection system for microfluidic chip
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Microfluidic chip is used for the biochemical analyses such as DNA sequencing and the separation of the protein or single cell. It has been shown to offer more advantages than the conventional capillary electrophoresis (CE): less reagent, miniaturization, high efficiency and sensitivity. In this paper, a laser induced fluorescence (LIF) detection system based on a 488nm argon ion laser and FITC fluorescent dye, is described for use with the microfluidic chip. The optical path of transmission type is adopted in our experiment. The pinhole is also applied to improve the performance of the whole detection system. There are some factors that influence the signal-to-noise ratio (SNR) of the detection system such as objective lens, the laser intensity and the pinhole. The pinhole plays a vital role in the confocal system and its performance is discussed in detail in our paper. The experimental data are presented and explained to show the relationships of these factors.
Conditions and methods of high-precision measurement of blood glucose concentration using mid-IR ATR spectroscopy
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This paper involves conditions and methods of high precision measurement of blood glucose concentration using Mid-IR ATR spectroscopy: (1) Comparing the spectra of saline solution, plasma, and whole blood to which adding glucose respectively, we find that in these three backgrounds with different complexity, the absorption peaks of glucose are at the same wavelengths in the band of 1200 to 900 cm' . (2) Analyzing experimental results of concentration gradient built by adding glucose to a series of plasma, we obtained a high correlation (greater than 0.98) between glucose concentration and absorbance in the band of 1200 to 900 cm-2, it provides us the feasibility of building calibration model of glucose concentration in this specific band. (3) In the process of building calibration model for glucose concentration of 40 whole blood samples (blood glucose concentration varied from 73 to 167 mg/dL, mean was 94.46 mg/dL, standard error was 17.68 mg/dL) by utilizing PLS method optimized with full cross validation, we applied genetic algorithms to the selection of optimal subsets of wavelengths, the number of wavelengths for calibration was decreased to 14 and the precision of the model was improved considerably, RMSEP was 10.56 mgldL. This proves that high precision measurement of blood glucose concentration can be achieved in narrow-band width (1200-900cm-1) when few wavelengths are selected.
Preliminary investigation of simultaneous measurement of multicomponents in human plasma by near-infrared spectroscopy
Xueling Zhao,
Lu Zhang,
Yan Wang,
et al.
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The feasibility of simultaneous measurement of multi-components in human blood is studied with near-infrared (NIR) transmission spectroscopy. First, how to reduce the prediction error is studied by improving the stability of measurement conditions. Second, wavelength selection is studied with model optimizing method. The results show that NIR spectroscopy can be valid for simultaneous measurement of multi-components in human blood, and that it can be successfully used to simultaneous determination of glucose, total protein, albumin, globulin protein, urea, creatinine, triglycerides, total bilirubin, uric acid, and cholesterol in human blood instead of clinical and biochemical measurements.
Noninvasive hemoglobin-measurement-based pulse oximetry
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This paper is presented the investigation of a medical instrument known as a pulse oximetry. The development of such an instrument for the non-invasive hemoglobin saturation is described. The software control is used to realize the measurement to be a practical non-invasive sense. Results obtained from the tested samples in the local hospital have shown that the detected signals from this instrument can be used to process the data interpretation for medical diagnosis purpose.
Real-time image capture and display system based on PCI bus for medical electronic endoscope
Zheng Sun,
Daoyin Yu,
Jie Jiang
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This paper introduces the study and implementation of the real-time CCD image acquisition and displaying system for medical electronic endoscope. To achieve real-time video acquisition the image capturing system of endoscope is combined with computer technology in which the popular PCI local bus interface is utilized and an FPGA is used as the kernel controller. The image capturing frequency ofthe system can reach 33MHz and displaying speed can be up to 50 frames per second (fps) at 640 X 480 pixels.
Computer analysis method for determining protein relative molecular weight in gel electrophoresis images
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The technology of computer analysis for gel electrophoresis images is based on the computer image analysis and gel electrophoresis. Particle in complex mixture have different molecular weight and with different charge. Migration distances of sample zones are compared with the position of standards and the molecular size of unknowns is determined. By this way, biology particle and molecule with different compound can be separated from other. Digital camera can acquire image and process digital transact, then based on the digital image to realize automatic identification, sign, molecular weight calculate. For the convenient of observe and acquire, sample pre band on ethidium bromide stained agarose gels. The instrument is mainly made up of UV light source, digital camera and camera obscura etc. Formulas for calculate of protein's molecular weight and mobility in polyacrylamide gel is connected with standard curve and the relative mobility of band. After many experiments the conclusion can be deduced that the change of electrophoresis start point and front edge (m, n, r's value) will result in the change of K and b. Unknown samples' molecular weight only have relation with the standard sample's molecular weight and the value of r1, r2 and r3.
Conformation and structure of extrusion polymer by the computed digital tomography image
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A novel image measurement with computed digital tomography was developed for the conformation and structure of polymer material during extrusion in the paper. It is difficult to measure the configuration and structure of polymer material during extrusion. On the basis of the relation of polymer free volume and the temperature, pressure and viscosity during extrusion, the method synthetically utilizes the knowledge of nuclear physics, photo-electricity, mechanism, computer technology and mathematics, the dynamic configuration and flow behavior of polymer can be visually obtained by the interaction of the atom of polymer or polymer chain and the photon beam to come from gamma ray, in which the photoemission, Compton effect and electron pair effect will be generated. The experimental result indicates the method can not only measure the dynamic conformation and structure of extrusion polymer in the way of non-open, non-destroy and on-line, but also deduce the relationship between the mechanical properties and the conformation of extrusion polymer.
Real-time imaging spectrometry for microscope
Liming Li,
Katsuo Aizawa,
Fumihiko Ichikawa
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Significant research attention has focused on the photodynamic diagnosis (PDD) technique, which uses imaging spectrometry to analyze the image and spectra. Up to now, the fluorescence spectrum at only one point in the image can be measured by imaging spectrometry, but it is not enough for diagnosis. The problem is how to obtain the relationship between the exact position and its respective spectrum. In this paper, we demonstrated a novel imaging spectrometry, which can accurately measure the whole surface of tissue instead of a single point. Using this apparatus, we measured the microscope spectrometry image of the hematoxylin-eosin stained tumorous tissue of mice. From the pseudo RGB images of the spectra, tumorous tissues were very clear. In this image, the spectra at arbitrary positions could be taken instantly as well as the transmission and absorption band based on the background spectrum. The spectral intensity distribution images were also obtained at selected wavelengths (for example 425 nm, 505 nm, 535 nm, 600 nm) to get the area distribution of the stained tumorous tissue. In our experiments, we obtained clear spectrometry imaging from weakly illuminated objects. It took 30 seconds to measure a static image of a sample. Moreover, this apparatus is suitable for real-time measurements of living tissue if using laser illumination, a high-speed CCD camera, a fiber, an endoscope and photosensitizer. In the near future, this novel technique can be used in tumor photodynamic diagnosis.
Novel computer-based processing techniques for quantitative measurement of skin structures
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Measuring skin structures quantitatively has many applications in dermatology and cosmetology. The purpose of this research was to extend from previous image processing and counting techniques to overcome challenges in time efficiency, customization for each image, and staining differences between images. Performances of the new techniques are then compared with traditional methods. The application of interest is the analysis of structural changes in skin responding to repetitive mechanical stress. The image processing and analysis methods for quantitative measurement of skin structures described in this paper represent an advancement over previous computer processing methods in terms of data management and automation. Results showed significant differences in cellular density in the papillary dermis and collagen density in the reticular dermis for skin subjected to combined shear/compression or tension compared with an unstressed control. The computer method took longer to conduct than the traditional method, though with recent advances in computer hardware this time difference would be eliminated. Keywords: Optical microscope, computerized morphometry, quantitative morphology, image processing, skin
DSP-based data acquisition and processing system for OCT
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Optical Coherence Tomography (OCT) is a novel optical imaging technology that provides high-resolution cross-sectional views of subsurface microstructure of biological tissues. It features high sensitivity, noninvasiveness, high resolution of micron scale, probing depth of 2cm for transparent tissue and 1~2mm for highly scattering tissue, and etc. OCT has shown a promising future to become a complement to the conventional imaging techniques in the fields of medicine and biology. But there are still a number of problems should be solved before OCT technology can be applied to practical usage. One of those is the limited imaging speed. In this paper, a high-speed data acquisition and processing (DAP) system for OCT is presented. Built around the high-powered Digital signal Processor (DSP) TMS32OVC5410A, the system is designed to cooperate with a PC to realize the image-scanning control, signal acquisition, data processing, transmission, image reconstruction and display. Superior to conventional data acquisition systems (DAQs), this system implants pre-processing of raw data into DSP, thus reduces the image acquisition time by carrying out the large amount of computation in the DSP, rather than in the PC. In addition, it can present two images with different information at per 2-D scans. And the system can be extended to future diverse applications by loading flexible digital signal processing schemes.
High-speed optical coherence tomography based on line scanning
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Optical coherence tomography (OCT) based on the theory of Michelson interferometer is a novel imaging technique with high resolution and performs non-invasive. The images of traditional OCT system can be obtained through pointscanning which its scanning speed is slow, and this limits the real time measurement of the system. This paper introduces a new imaging technique of OCT system with high speed, using line-scanning method instead of pointscanning method. The new method can increase the scanning speed and can realize real time measurement, which provide a fundamental technique for the high-speed imaging.
NIR Spectroscopy and Imaging II
Application of LED imager for breast cancer diagnosis
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This paper focuses on breast cancer diagnosis using the newly developed low-noise threewavelength (?=730nm, 805nm and 850nm) NIR light emitting diode (LED) continuous-wave (CW) imager. The NIR CW imager has its advantage of simplicity, and potential for a portable instrument. The imaging rate is 5 frame/second. The signal to noise ratio is larger than 2000 when measuring at a breast model ( ?a=0.04/cm, ?'= 8/cm), which corresponds to 4x 10-4 optical density (OD) error. Phantom test was carried out, and indicated good localization of heterogeneity. It was known that cancer has more blood concentration and de-oxygenation than normal tissue, which is the principle of breast cancer detection using NIR spectroscopy. Clinical results of breast cancer studies will be presented. Keywords: LED, Breast Cancer Imaging, CW
Phase cancellation system for tumor imaging using targeted fluorescent contrast agents
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Recent developments in receptor specific targeting fluorescent contrast agents can give tumor/tissue contrasts in the excess of 10, and are capable of selectively labeling various pre-cancer/cancer signatures to enhance the sensitivity and specificity of cancer detection [reference: Weissleder et al, Achilefu et al]. We have developed a novel imaging system for fast and accurate localization of fluorescent contrast agent labeled tumor embedded several centimeters inside the highly scattering medium mimicking breast tissue using the phased cancellation configuration (00 and 1800 source-pair) with a goniometric probe. Phantom tests and intratumor injection of fluorescent dye, Indocyanine Green (ICG), have demonstrated the capability of twodimensional localization of tumor labeled with fluorescent contrast agents about 3.0 cm deep within several millimeters enor range. The accuracy of the localization suggests that this system would be helpful to guide the clinical fine-needle biopsy for early detection of breast cancer.
Light-Tissue Interaction I
Tissue structure analysis at optical immersion
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This paper presents structural and optical models of tissues with basic multiple scattering, which is transformed to low scattering. It is shown that reflection, transmission, light scattering, and state of polarization of the scattered light by a tissue can be effectively controlled by changes of refractive index of tissue components. Method of matching of the refractive indices of scatterers and ground matter by means of administration of chemical agents is discussed in the framework of control of optical properties of tissues. The possibility of usage of optical immersion method for diagnostic purposes based on contrasting of tumor and other abnormalities, in-depth profiling of tissue and blood, and on monitoring of endogenous and exogenous matter diffusion within tissue is demonstrated.