This PDF file contains the front matter associated with SPIE Proceedings Volume 6534, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

The current advances in fluorescence microscopy, coupled with the development of new fluorescent probes, make fluorescence resonance energy transfer (FRET) a powerful technique for studying molecular interactions inside living cells with improved spatial and temporal resolution, distance range, and sensitivity and a broader range of biological applications. In recent years, a large number of studies have been conducted aiming to understand the process of apoptosis during tumor therapy on a molecular basis. Here, we utilized a recombinant FRET Bid probe to determine the kinetics of Bid cleavage during Cisplatin-induced apoptosis in ASTC-a-1 cells. Cells treated with Cisplatin (20 μM) showed a cleavage of the Bid-FRET probe, occurring at about 4-5 h after onset of the Cisplatin exposure, and lasted about 1.5 h. Our data clearly showed the kinetics of Bid cleavage during Cisplatin-induced apoptosis. We also used FRET technique to measure the dynamics of caspase-3 activation during apoptosis induced by high fluence low-power laser irradiation (LPLI). The data showed that we can detect caspase-3 activation sensitively and effectively, by using the FRET probe SCAT3.

Homeostasis is a term that refers to constancy in a system. A cell in homeostasis normally functions. There are two kinds of processes in the internal environment and external environment of a cell, the pathogenic processes (PP) which disrupts the old homeostasis (OH), and the sanogenetic processes (SP) which restores OH or establishes a new homeostasis (NH). Photobiomodualtion (PBM), the cell-specific effects of low intensity monochromatic light or low intensity laser irradiation (LIL) on biological systems, is a kind of modulation on PP or SP so that there is no PBM on a cell in homeostasis. There are two kinds of pathways mediating PBM, the membrane endogenetic chromophores mediating pathways which often act through reactive oxygen species, and membrane proteins mediating pathways which often enhance cellular SP so that it might be called cellular rehabilitation. The cellular rehabilitation of PBM will be discussed in this paper. It is concluded that PBM might modulate the disruption of cellular homeostasis induced by pathogenic factors such as toxin until OH has been restored or NH has been established, but can not change homeostatic processes from one to another one.

Super-luminescent laser diodes (SLD) in 800 to 1300 nm wavelength windows have been widely used in optical coherence tomography (OCT) systems. The imaging resolution of OCT systems is proportional to the bandwidth of the SLD light source. Here we present a new design to achieve broad bandwidth (>100nm at 1310nm) in one chip by using two types of quantum wells. The bandwidth of an SLD with a single active region is determined by the material bandwidth, confinement factor, and the length of the active region. Neglecting spatial hole burning (SHB), the spectral density of amplified spontaneous emission (ASE) can be the function of cavity length and spectral density of spontaneous emission and net gain. The main factor that limits the ASE bandwidth is the net gain. The bandwidth of net gain has to be larger than 200 nm to obtain a 100 nm wide ASE spectrum if the ASE power is larger than several mW. SLDs usually work at very high pump current (>400mA) to achieve high output power. From simulations, we found the level of electron injection mainly determines the material gain. At the high injection level, large bandgap quantum wells can get high gain and dominate the spectrum if the improper design is used. So in our design, we put the small bandgap quantum wells at the N side to make the electron distribution in favor of long-wavelength material. Thus, and will be balanced at high current injection level (>550mA). Figure 7 shows the measured spectrum of such structure. The achieved spectral width is larger than 100nm and out put power is larger than 5 mW.

Diffuse optical tomography (DOT) is an appropriate tool for non-invasive exploration of human brain activation. The activation of sensorimotor cortex has been studied by several researchers since the first images of human brain were generated in 1995. However, high-quality images of sensorimotor cortex can not be obtained until the emerging of high-resolution DOT which uses a multi-centered geometry for arranging optical fibers. In this study, we did two experiments using our CW5 instrument (TechEn, USA). In the first experiment, the subject was asked to move his four fingers of right hand for 30 seconds, followed by 30 seconds of rest. Data collection lasted 420 seconds. In the second experiment, the subject was asked to tap his thumb against the other four fingers. Two conclusions can be reached from the experiments. Firstly, larger activated regions can be found on motor cortex in experiment 2 than in experiment 1. This indicates that high-resolution DOT can detect larger activated brain region when moving five fingers comparing to moving four fingers. Secondly, few activated regions can be found on sensory cortex in experiment 1, but it can be clearly found on sensory cortex in experiment 2. Up to our knowledge, it is the first time DOT has detected activated region on sensory cortex during motorial task.

A power-conserving wave-front division Fourier domain optical coherence tomography (WD FDOCT) has been successfully demonstrated. Unlike conventional Michelson-based FDOCT system, splitting ratio of WD FDOCT can be arbitrarily adjusted to enhance signal-to-noise ratio (SNR). Both theoretical and experimental SNR of this system are evaluated. WD FDOCT imaging of the anterior eye of a rat is also demonstrated.

Influence of source power on spatial-resolved diffuse reflectance in the region close to the source is studied experimentally. The fiber detector method is performed and the diffuse reflectances from 0.3mm-2.675mm source-detector separations are measured. The source is a 650nm diode laser and its maximum power is 10mw. The experimental result shows that the influence of source power on the diffuse reflectance from a tissue phantom at short source-detector separations is considerable. Also, this influence is found different from the effect of scattering coefficient (μ_s) and absorption coefficient (μ_a) on the diffuse reflectance. These results are important to measure the optical parameters of the tissue from the diffuse reflectance.

When optical coherence tomography (OCT) is used to image human retina, its lateral resolution is deteriorated by the aberrations of the human eye. To get over this disadvantage, a high-resolution imaging system combining OCT with adaptive optics (AO) is being developed. The AO system consists of a 61-element deformable mirror and a 16×16 array Shack-Hartmann wave front sensor. In this paper, the configuration of the AO/OCT system is described, and the simulation results and the static aberration analysis of AO/OCT systems are presented.

The work on laser varicose treatment carried out in CIOMP, CAS cooperating with The First Clinical Hospital, Jilin University is summarized. Dozens of animal experiments adopting dog and rabbit samples are made in a long time of several years. Different lasers are used, including long pulse frequency-doubled Nd:YAG(532nm) and semiconductor laser(808nm). Dozens of animal experiments show that laser has good efficacy to occlude the vein vessels. It has precise adjustability and relatively short treatment time only needing outpatient office setting with high cost and effect rate; It provides minimal invasion, often under local anesthesia and intravenous sedation thereby eliminating the need for general anesthesia, greatly shortens postoperative recovery term, and it is highly safe with no side effects and no serious complications.

Polarized light has been increasingly used in biomedical imaging to study the optical properties of biological tissues or enhance the imaging contrast by eliminating the scattered light. In this report, we combine polarization gating and Fourier gating to suppress interference by the diffusive photons and improve the quality of projection images. A Monte Carlo simulation is utilized to study the propagation of different polarized light through turbid media. Polarization of a photon is represented by a Stokes vector and the scattering matrix is calculated from Mie theory. By tracing the trajectory and the polarization of the photons, spatial distribution and polarization of photons transmitted through a spatial filter aperture are simulated. It is shown that polarization gating and Fourier gating can effectively reject the multiple scattered photons and improve the contrasts of the images. Differences between linearly and circularly polarized lights for scatterers of different size are compared. However, for large particles, effects of both gating techniques are limited.

Polarization gating has been an attractive technique for optical imaging in turbid media. In this study, we investigate the polarization difference projection image (PDPI) in turbid media with linearly and circularly polarized lights. An iris is placed at the focal spot of the imaging optics to examine the influence of spatial filtering on imaging contrast. Polystyrene microsphere suspensions in Rayleigh and Mie domains are used as the phantoms. Scattering coefficient μ_s and anisotropy factor g are varied independently to obtain the quantitative relation between the PDPI contrasts and the optical properties of the phantom. We also compare the PDPI contrast with the contrast of degree of polarization (DOP). Primary results show that the PDPI contrast is better than DOP image contrast either in Rayleigh or Mie scattering domain. In the Mie scattering domain, linear and circular PDPI contrasts are compared for different scattering coefficients. We also discussed how Fourier spatial gating improves the image contrast. The results are compared with Monte Carlo simulation.

We develop a fast scanning probe for forward-imaging optical coherence tomography (OCT). The probe is based on the resonant oscillation of a fiber cantilever which has two distinguished resonant frequencies intrinsic to its geometry. When actuated by piezoelectric bimorph with signals of mixed frequencies, various two-dimensional traversal scanning patterns are generated. Experiments on different probe parameters relating to the qualities of the final images- such as the density of the scanning coverage, frame rate are carried out. For correct image reconstruction, a micro two-dimensional position-sensitive detector (PSD) is also introduced to record the scanning pattern in real-time. Preliminary results of OCT imaging with this developed probe are presented.

A method for dispersion compensation in optical coherence tomography (OCT) by a double-grating based rapid scanning optical delay line (RSOD) is put forward. The added grating introducing an independent variable of the distance between gratings, along with the adjustable distance between grating and Fourier transform lens in a conventional RSOD can be used to compensate the group velocity dispersion (GVD) and the third order dispersion (TOD) of OCT system simultaneously. Theoretical development of the dispersion characteristics as well as the dispersion management scheme is given. Example of dispersion compensation in a typical OCT system is provided.

We have developed a noninvasive method to monitor the glucose concentration in tissue phantom used the OCT model which based on the extended Huygens-Fresnel (EHF) principle. The changes of the optical properties such as the scattering coefficient μ_s, the anisotropy factor g and the effective scattering coefficient μ_s with the increase of the glucose concentration in 10% Intralipid solution were obtained. The results showed that the scattering coefficient μ_s decreased when the glucose concentration increased in the solution, which is accorded with the conclusions by others. Contrarily, the factor g increased when the glucose concentration grown up. As a result, the coefficient μ_s is fall with the increased of the glucose concentration. Comparing with those previously reported in which only got the relative value of scattering coefficient μ_s, the most important advantage of our model is that we got the practical value of μ_s, g and μ_s. All of these reveal that the OCT EHF model is a promising method which is adapted to detect the glucose concentration in solution, and it will be applied in medical fields someday.

Accurate measurement of tissue optical properties becomes more and more important in biomedical applications such as diagnostic imaging for tissue pathology. Taking account of multiple scattering effects in OCT model, an algorithm is developed to extract depth-resolved tissue optical properties including scattering coefficient and anisotropy factor. By adding absorption coefficient as the third fitting parameter in the algorithm, it is possible to reduce fitting errors introduced by sample absorption. With an adapted algorithm based on the extended model, absorption coefficient can also be extracted. The validity of those algorithms is verified by sample model of solution of polyethylene sphere (PS).

Optical coherence tomography (OCT) is an emerging technology for high-resolution bio-medical imaging. The rapid scanning optical delay line (RSOD) has developed basically for depth scanning and dispersion compensation. If the pivot center of the galvamirror in RSOD is offset, phase modulation can be realized, providing a high carrier frequency required for heterodyne detection. However, the size of galvamirror should be increased, leading to lower response for its oscillation and hence a low scanning rate. In this paper we propose to apply a sinusoidal waveform (resonant scan) instead of a triangle waveform (linear scan) to the galvamirror. Numerical analysis on phase modulation by RSOD and successive envelop demodulation under different driving waveform is conducted. We demonstrate that it is possible to improve OCT frame rate by resonant scan without compromising the signal-to-noise performance if complete and accurate envelope demodulation and appropriate signal processing are adopted.

Maximal depth of non-distorted imaging is an important characteristic, which shows the efficiency of an application of a certain OCT setup for imaging the given object. This characteristic depends on the setup parameters and the properties of the studied object. The definition of the maximal depth of non-distorted imaging based on the classifications of photons contributing to the signal in dependence on the relations of their optical travel pathlength in the object and maximal reached depth was used in this work. We studied the effect of the coherence length and the detection angle on the formation of OCT signals and images from model biotissues as well as on the maximal depth of non-distorted imaging. The signals and images were obtained by implementing the Monte Carlo technique developed in our earlier works. The following single- and multilayer biotissue phantoms were considered as the studied objects: erythrocyte suspension at physiological hematocrit (35%), 2% intralipid solution reported to have optical properties close to those of skin in optical and NIR range, and multilayer human skin phantoms. For the simulations, the parameters of the OCT setup were chosen in accordance with real ones. The wavelengths of the light sources were chosen 820 and 910 nm. The conducted simulations show that a decrease in the detection angle and an increase in the coherence length increase the maximal probing depth in the studied objects due to smaller role of multiple scattering photons in the formation of the OCT signals. The obtained value of maximal depth of non-distorted imaging varies in the range from 50 to 600 μm depending on the values of the setup parameters.

Optical coherence tomography (OCT) is a recently developed high resolution biomedical imaging method. Fast scanning speed and miniature probe is benefit for clinical applications of OCT. In this paper we present a method to realize fast lateral scanning with two-dimensional (2D) resonant scanning pattern. By driving a fiber cantilever with a bimorph actuator near its resonance, the planar motion of the fiber cantilever may develop to an elliptical motion due to nonlinear coupling with longitudinal inertia. This effect can be exploited to form 2D scanning pattern. Basic principle relevant to realization of 2D scanning pattern of the fiber cantilever scanner by 1D actuator, as well as confirming experimental results are presented. Future work and system configuration on implementing this fiber cantilever scanner in the sample arm of a fiber-based OCT system is proposed.

A numerical simulation of the micro-explosion process during hard tissue ablation with infrared laser has been developed. This simulation investigates the explosion dynamics evolution of the water film in the Er:YAG and CO₂ laser irradiation and calculates the pressure and intensity of impulse on the hard tissue surface. The calculation results indicate that the micro-explosion has its special duration for different parameters. The pressure on the target surface caused by the explosion increases rapidly with the laser intensity increase and the maximal pressure value appeared for an adaptive water film thickness.

Functional near-infrared spectroscopy (fNIRS) has been used to investigate the changes in the concentration of oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin in brain issue during several cognitive tasks. In the present study, by means of multichannel dual wavelength light-emitting diode continuous-wave (CW) NIRS, we investigated the blood oxygenation changes of prefrontal cortex in 18 healthy subjects while performing a verbal n-back task (0-back and 2-back), which has been rarely investigated by fNIRS. Compared to the 0-back task (control task), we found a significant increase of O2Hb and total amount of hemoglobin (THb) in left and right ventrolateral prefrontal cortex (VLPFC) during the execution of the 2-back task compared to the 0-back task (p<0.05, FDR corrected). This result is consistent with the previous functional neuroimaging studies that have found the VLPFC activation related to verbal working memory. However, we found no significant hemisphere dominance. In addition, the effects of gender and its interaction with task performance on O2Hb concentration change were suggested in the present study. Our findings not only confirm that multichannel fNIRS is suitable to detect spatially specific activation during the performance of cognitive tasks; but also suggest that it should be cautious of gender-dependent difference in cerebral activation when interpreting the fNIRS data during cognitive tasks.

In neurosurgery, cortical warping is one of the significant sources of noises during optical imaging after the skull and the dura have been removed. The optical image sequence must be registered for further data analysis. The registration algorithms in widely used medical image tools, e.g. Automated Image Registration (AIR), Statistical Parametric Mapping (SPM), usually express the cortical warping as polynomials or terms of cosine basis. However, these nonlinear models do not faithfully fit the elastic warping of the cortexes, and thus can not achieve a satisfactory result. Based on the elastic model, i.e., the approximating thin-plate splines (aTPS), we propose herein an improved aTPS (iaTPS) algorithm to deal with the elasticity of the cortical warping. In the cost function of the original aTPS algorithm, landmarks with different localization uncertainties should be given different weights, however, due to the absence of a convincing method to specify these weights, a same weight value was manually set for all landmarks in practice. In our iaTPS algorithm, landmarks are categorized into several classes (usually 3~5) by their localization uncertainties, and the weights for each class are decided by an optimization process. The comparison experiment on the intraoperative optical data of human brain has shown that the new algorithm can offer better registration accuracy than the aTPS algorithm.

In original mammographic images obtained by X-ray radiography, only a small part of detected information is displayed to the human observer. A method aimed at minimizing image noise while optimizing contrast of mammographic image features is presented in this paper, for more accurate detection of microcalcification clusters. The method is based on the contourlet transform, which is a multiresolution, local and directional image representation. The difference from wavelet and other multiscale expansion lies in that the contourlet transform is constructed by using non-separable filter banks in discrete-domain, thus it can effectively capture important features of images. The enhancement procedure consists of two steps: noise filtering by the Stein's thresholding and denoised contourlet coefficients modification via a nonlinear mapping function. The experimental results have shown an improved visualization of significant mammographic features by the proposed method. A comparison with other enhancement algorithms is also discussed by employing a measure named target to background contrast ratio using variance.

The main goal of this work is the fast analysis of light scattered by a large optically soft spheroidal particle (size parameter ka > 20). In particular, these particles mimic single cells (e.g., red blood cells (RBC)) and their aggregates. Methodology of calculation of light scattering by arbitrarily oriented optically soft spheroidal particles in geometric optics approximation is presented. We show that the geometric optics approximation permits to quickly calculate the angular distributions of the intensities and phases of light scattered from optically soft particles, such as erythrocytes.

Although measurement of diffuse reflectance light can be used to determine the optical properties of tissue noninvasively, great effort should be firstly devoted to the development of the relation between the reflectance and optical properties of tissue in our opinion. In this paper, light diffuse reflectance by a tissue optical model with two-layered structure is discussed by use of Monte Carlo method. The distribution of diffuse reflectance vs. emitting angle at different optical properties of inner layer is calculated. In addition, the influence of the changing absorption coefficient, scattering coefficient of the inner layer on the light diffuse reflectance from the surface is investigated and analyzed. The simulation results show that the diffuse reflectance light is sensitive greatly to micro-change of optical properties (absorption coefficient and scattering coefficient) of the inner layer which has small value of optical properties. We believe that the results will be useful for the development of determination the optical parameters of bio-tissue in vivo.

The sensitivity expression of spatial-resolved diffuse reflectance to scattering parameter is deduced in the P₃ approximation model, and the influence of scattering parameter on the reflectance is analyzed using this expression. The results show that the sensitivity is distinct with that of the diffusion approximation in the region of about one transport mean free path, and optimum source-detector distance where the sensitivity to scattering parameter equals zero differs from the diffusion approximation's too.This optimum source-detector distance is found shortened when a medium has bigger scattering coefficient or bigger absorption coefficient. The research is very valuable for in vivo measurement based on the spatial-resolved diffuse reflectance.

The volatile halogenated methyl ethyl ether is used as anesthetic to inhibit actin-based dynamics directly or indirectly in animal cells. In plant cells, most intracellular movements are related with actin pathways too. We utilized isoflurane to study the dynamic choloroplast organization in unicellular baby and adult alga Acetabularia acetabulum. Fluorescence spectra were measured and choloroplast movements were recorded by confocal laser scanning microscope (CLSM) imaging in in Acetabularia acetabulum. Isoflurane was effective in the unicellular baby and adult organisms and showed time- dependent actin-inhibition patterns. Acetabularia acetabulum cells were treated for different times with isoflurane saturated solutions in artificial seawater (it was defined to be 100% isoflurane). The intensity of fluorescence at 680nm and 730nm were progressively decreased at 100% isoflurane. It was remarkable difference between fluorescence spectra of baby and adult Acetabularia were inhibited by isoflurance, adult Acetabularia cells showed more sensitive. Whereas the choloroplast in Acetabularia acetabulum was commendably imaged by CLSM at 20 and 40 zoom.

Spectroscopic optical coherence tomography (OCT), a functional extension of conventional structural OCT is developed based on previous fiber-based OCT system. Spectral information is obtained by carrying out Fourier transformation of the detected OCT signal without recurring to hardware. The developed system is applied to film reflectivity measurement and spectroscopic imaging of a finger from a human volunteer. The feasibility for spectroscopic extension of the developed system is confirmed by comparison curves of film reflectivity measured by the developed system with that obtained from a commercial spectrometer.

In this paper, a Monte Carlo (MC) based model of diffuse reflectance is introduced to retrieval the light absorption and scattering coefficients of multi-layered tissue. The absorption and transport scattering coefficients of biological tissues determine the radial dependence of the diffuse reflectance that is due to a point source. The MC model of diffuse reflectance consists of a forward part and an inverse one. The forward refers to a multi-layered MC simulation at a certain source detector separation, which results a time-resolved profile. The inverse one is a fitting procedure based on Levenberg-Marquardt algorithm using forward model in iteration, and the normalized intensity in each time bin is fitted. Tests with independent MC simulations show the errors in the deduced absorption and reduced scattering coefficients. Although a high amount of computation time is needed, compared with investigation methods using diffuse approximation to the transport equation, this model is valid for a wider range of optical properties and is easily adaptable to exiting probe geometries.

In this article, we briefly described a time-correlated single photon counting (TCSPC) system specifically designed for extracting the optical properties in turbid medium. This system was evaluated by use of two sets of liquid tissue-simulating phantoms containing different concentrations of Intralipid-10% as scatters and India ink as absorbers. With the distribution of times of flight (DTOF) of photons measured by the TCSPC system, some featured parameters, such as the mean time of flight and the variance of DTOF were calculated. Based on these parameters, we developed a simple and fast method to obtain the absorption coefficient μ_a and reduced scattering coefficient μ_s of the turbid medium. Furthermore, the accuracy of the method was validated using the Monte Carlo simulations. It was found that the optical properties could be extracted with this method, which was much faster than the conventional curve-fitting procedure. Our method could be useful in on-line monitoring of optical properties of biological tissue.

In optical coherence tomography (OCT), broad-bandwidth optical sources are required to achieve high axial resolution. Introducing a variable phase shift achromatically between the probe and reference beams is required for phase-shifting algorithms implemented to extract the coherence signal. We propose a full-field OCT using an achromatic phase shifter based on wave plates. The phase shifter that is almost independent of the wavelength over a range of 240 nm, can provide a phase shift of eight times the rotating angle of the half-wave plate. The system is based on a Michelson interferometer, illuminated by a white light source, and has several advantages compared with previous implementation of full-field OCT based an achromatic phase shifter. Numerical simulation on phase shift error and amplitude ratio between orthogonal polarization components at nominal phase shifts required for two typical phase-stepping algorithms is conducted. Approach for extracting OCT signal by the revised Carre algorithm is presented.

With the model of harmonic oscillator in quantum mechanics, we derive the interaction equations between laser and molecule bonds. We conclude that Laser- irradiated process can lower molecule energy level, improve the biological activity, shorten the period of mature according to the investigation on the seed of "Sangjiao sticky rice". The technique of Raman spectroscopy also is used to analysis the sample groups and contrast groups.

The microscopic mechanism of the electricity and thermology effects of interaction of laser with plasmalemma are researched by electromagnetics, quantum mechanics and quantum statistics. We derived the formulas on the polarigalion effects and "temperatue-rising effect" of laser-plasmalemma interaction. The results of our theory recherch can explain some experiments.

In the first place, the coherent collective vibration models of the living biological molecule system (e.g. DNA and protion) are analyzed in this paper. Then we have analyzed yet order-disordering variance due to resonance effect and the nonlinear behavior of terahertz radialion(THR)-biological system interaction. The analytic results show that the interaction between the living biological system and THR can produce resonance excitation effect, and so the system can be produced under further action of the laser. In addition, we have analyzed the nonlinear properties of the THR bio-molecule interaction and explained the mutagenesis effects of THR. The theoretic analysis is consistent with the results of THR biological test.

Experiments were carried out using the tomato (Lycopersicon esculentum) stored at 28°C and 4°C , at the same time, the spontaneous ultra-weak photon emission (UPE), delayed luminescence (DL), ethylene releasing, respiratory intensity, chroma main wavelength and chlorophyll content were detected. It was found that: The curve of the spontaneous UPE is just consists with respiratory intensity at 28°C and relate to chlorophyll content variation. The experiment data were given guide line to noninvasive test maturity, DL data were dealt with curve fitting and compared with coherent theory.

A 16-channel near-infrared spectroscopy (NIRS) was used to measure concentration changes of oxygenated and deoxygenated hemoglobin (oxy-HB and deoxy-HB) in prefrontal area while the subjects were performing mental works. Thirty healthy college participants were administered two mental arithmetic tasks while the changes of concentration on oxy-HB and deoxy-HB were measured. Oxy-HB increased during the mental works, and the increases of oxy-HB were greater in male subjects than in female subjects during the difficult task. These results suggest that NIRS is sensitive to evaluate the oxy-HB activity of prefrontal cortex during mental works.

The objectives of the study were to establish relationships between the nondestructive near-infrared (NIR) spectral measurements and the major internal quality indices of pear ('Fengshui', Jiangxi) fruit, and to evaluate the use of NIR spectrometry in measuring the internal quality indices of pear fruit. Intact pear fruit were measured by reflectance NIR in 350-1800 nm range. In this study, Calibration models relating NIR spectra to soluble solids content (SSC), and firmness were developed based on multi-linear regression (MLR), Principal component analysis (PCA) and partial least square (PLS) regression with respect to the logarithms of the reflectance reciprocal log (1/R), its first derivative D₁log (1/R)and second derivative D₂log (1/R). The best combination, based on the prediction results, was MLR models with respect to D₁log (1/R) at equatorial position of pear fruit. Prediction with MLR models resulted correlation coefficients (R_p) of 0.9151 and 0.8125, and root mean standard error of prediction (RMSEP) of 0.6834 and 1.3778 for SSC and firmness, respectively. The preliminary results of the built models indicated that NIR spectroscopy could provide an accurate, reliable and nondestructive method for assessing the internal quality indices of pear fruit.

The research for optical transmission in biomedicine has been studied for many years at domestic and abroad, but the applicative research for nondestructive measuring in fruit internal qualities has not been found nowadays. Therefore, the transmission mechanism and the research methods of optical transmission in biomedicine can be applied in fruit internal qualities analysis. It will give a chance to improve measuring precision in fruit internal qualities. In this paper, the optical transmission mechanism in fruit tissue, the optical property parameters of fruit tissue, the models of optical transmission in fruit tissue and the measurement methods of optical parameters in fruit tissue have been researched respectively. Meanwhile, an important measurement method, namely integrating sphere technology, is presented. It will provide the theoretical foundation for the research for nondestructive measuring in fruit internal qualities.

The objective measurement of skin erythema is of much importance in clinical dermatological diagnosis and new dermatological drug tests. The measurements that used currently are facing a main problem that all the measurements are deeply influenced by the melanin in the epidermis and the incident intensity. Basing on the skin optical model, a new parameter is introduced in order to describe the change of erythema. The new parameter is defined by the difference of the logarithm of the diffuse reflected light intensity between normal skin and erythema skin. The theoretical analysis shows that this new parameter can reflect directly the deviation of the concentration of haemoglobin from the normal range under the assumption of keeping the concentration of melanin constant and the illuminating light uniform. In addition, the experimental study also shows that this method is hardly influenced by the illuminating light intensity, and can be effectively applied in the clinical diagnosis.

Background and Objectives. Laser-induced autofluorescence (LIAF) is a promising tool for cancer diagnosis. This method is based on the differences in autofluorescence spectra between normal and cancerous tissues, but the underlined mechanisms are not well understood. The objective of this research is to study the microscopic origins and intrinsic fluorescence properties of basal cell carcinoma (BCC) for better understanding of the mechanism of in vivo fluorescence detection and margin delineation of BCCs on skin patients. A home-made micro- spectrophotometer (MSP) system was used to image the fluorophore distribution and to measure the fluorescence spectra of various microscopic structures and regions on frozen tissue sections. Materials and Methods. BCC tissue samples were obtained from 14 patients undergoing surgical resections. After surgical removal, each tissue sample was immediately embedded in OCT medium and snap-frozen in liquid nitrogen. The frozen tissue block was then cut into 16-&mgr;m thickness sections using a cryostat microtome and placed on microscopic glass slides. The sections for fluorescence study were kept unstained and unfixed, and then analyzed by the MSP system. The adjacent tissue sections were H&E stained for histopathological examination and also served to help identify various microstructures on the adjacent unstained sections. The MSP system has all the functions of a conventional microscope, plus the ability of performing spectral analysis on selected micro-areas of a microscopic sample. For tissue fluorescence analysis, 442nm He-Cd laser light is used to illuminate and excite the unstained tissue sections. A 473-nm long pass filter was inserted behind the microscope objective to block the transmitted laser light while passing longer wavelength fluorescence signal. The fluorescence image of the sample can be viewed through the eyepieces and also recorded by a CCD camera. An optical fiber is mounted onto the image plane of the photograph port of the microscope to collect light from a specific micro area of the sample. The collected light is transmitted via the fiber to a disperserve type CCD spectrometer for spectral analysis. Results. The measurement results showed significant spectral differences between normal and cancerous tissues. For normal tissue regions, the spectral results agreed with our previous findings on autofluorescence of normal skin sections. For the cancerous regions, the epidermis showed very weak fluorescence signal, while the stratum corneum exhibited fluorescence emissions peaking at about 510 nm. In the dermis, the basal cell island and a band of surrounding areas showed very weak fluorescence signal, while distal dermis above and below the basal cell island showed greater fluorescence signal but with different spectral shapes. The very weak autofluorescence from the basal cell island and its surrounding area may be attributed to their degenerative properties that limited the production of collagens. Conclusions. The obtained microscopic results very well explain the in vivo fluorescence properties of BCC lesions in that they have decreased fluorescence intensity compared to the surrounding normal skin. The intrinsic spectra of various microstructures and the microscopic fluorescence images (corresponding fluorophore distribution in tissue) obtained in this study will be used for further theoretical modeling of in vivo fluorescence spectroscopy and imaging of skin cancers.

In biological scientific research, separating biological macromolecules or cells in liquid is always a challenging job. Optical tweezers have been a valuable research tool since their invention in the 1980s. One of the most important developments in optical tweezers in recent years has been the creation of two-dimensional arrays of optical traps. In this paper, a method based on interference is discussed to form the gradient laser fields, which may cause spatial modulation of the concentration of particles. The parameters related with the optical tweezers array are discussed in detail and simulated by Matlab software to show the impact factor of the important parameters for the concentration distribution of the particles. The spatial redistribution of particles in a laser interference field could be also predicted according the theoretical analysis.

A single tapered fiber optical tweezers is demonstrated experimentally based on a fused tapered fiber probe. Yeast cells immersed in water were trapped at the tip of the fiber probe and moved in 3 dimensions at a certain velocity. The trapping force, both axial and transverse, can only be attributed to the force effect of the optical field emerging from the end of the fiber probe. The output optical field was numerically simulated by using a BPM (beam propagation method) method. It is qualitatively discussed that such optical field own the ability to form a 3-D optical trap.

Near Infrared Imager (NIRI) has been widely used to access the brain functional activity non-invasively. We use a portable, multi-channel and continuous-wave NIR topography instrument to measure the concentration changes of each hemoglobin species and map cerebral cortex functional activation. By extracting some essential features from the BOLD signals, optical tomography is able to be a new way of neuropsychological studies. Fourier spectral analysis provides a common framework for examining the distribution of global energy in the frequency domain. However, this method assumes that the signal should be stationary, which limits its application in non-stationary system. The hemoglobin species concentration changes are of such kind. In this work we develop a new signal processing method using Hilbert-Huang transform to perform spectral analysis of the functional NIRI signals. Compared with wavelet based multi-resolution analysis (MRA), we demonstrated the extraction of task related signal for observation of activation in the prefrontal cortex (PFC) in vision stimulation experiment. This method provides a new analysis tool for functional NIRI signals. Our experimental results show that the proposed approach provides the unique method for reconstructing target signal without losing original information and enables us to understand the episode of functional NIRI more precisely.

Single-molecule/particle tracking technology is becoming a powerful tool to the noninvasive study of membrane property and membrane molecular processes. Here, we used total internal reflection fluorescence microscopy combined with oblique illumination fluorescence microscopy to investigate green fluorescence protein within living cell. Total internal reflection illumination allowed the observation of molecules in the cell membrane of living cell since the penetrate depth is adjusted to about 100nm, and oblique illumination is allowed the observation of molecules/particles both in the cytoplasm and apical membrane, which suggested this combination would be promising to investigate protein dynamics through the whole cell. Not only individual protein molecule/particle tracks have been analyzed quantitatively to reveal the motion of protein, but also statistical analysis has been done to substantiate the observation of protein dynamics. Our data that involved up to 700 trajectories in several hundreds cells are indicated that at least four modes of motion are presented, that is directed motion, normal diffusion (random walk), binding motion and corralled motion. Detailed analysis as well as statistical analysis is presented in the paper.

Fluorescence resonance energy transfer (FRET) has found wide use in structural biology, biochemistry, and cell biology for measuring intra- and inter-molecular distances in the 1-10 nm range and for obtaining quantitative spatial and temporal information about the interaction of proteins, lipids, and DNA. The measurements of distances and interactions are based on the calculation of the fluorescence transfer efficiency using some algorithms to process the acquired images from several different filter sets. However, FRET measurements can suffer from several sources of distortion because of cross talk between donor and acceptor fluorophores. In this paper, we measured the FRET efficiency on glass coverslips using microarray technology and described an algorithm to analyze the FRET data obtained, which is corrected for the cross talk due to spectral overlap of donor and acceptor molecules. Measurement of the interaction of the donor and acceptor, which are mixed together or coupled to the respective 3'-end and 5'-end of a single-strand DNA are shown to document the accuracy of the approach, and allow one to estimate cross talk between the different filter units and to reveal the relationship of the FRET efficiencies of these two samples relative to the donor and acceptor concentrations.

Surface plasmon resonance (SPR) technique is based on an optical measurement approach that is highly sensitive to the refractive index unit (RIU) of the sample on its analysis surface. Here, we demonstrate the direct detection of proteins and small molecules using an advanced SPR technology with a sensitivity that is as good as Fourier transform infrared (FTIR) spectroscopy. Some quantitative results are reported in this paper.

Total internal reflection fluorescence microscopy (TIRFM) was used to image single molecules with evanescent waves. The molecules were excited by an evanescent wave with different intensities. Single molecules were imaged on low-noise high-quantum-yield charge-coupled device (CCD) cameras. Two-step photobleaching behavior was observed. Duration from fluorescent spots appearing to disappearing was counted. The duration was decided by the speed of photobleaching. Peak intensity was counted as exciting intensity change. The proportion relationship between the reciprocal of duration and exciting intensity was obtained. The emitted intensity and duration of fluorescein were compared with GFP. A single molecules emit the same number photons was proved.

Tumor necrosis factor-α (TNF-α) elicits a wide range of biological responses, including neuronal apoptosis and neuroprotection, and this functional pleiotropy is essentially determined by the individual molecular orchestration. Two main pathways lead to apoptosis - the 'extrinsic' or death receptor-initiated pathway, and the 'intrinsic' or mitochondrial pathway. In this study we firstly examine the signaling pathways involved in TNF-α induced apoptosis in living PC12 cells by optical imaging. Our results show that the cleavage of BID has been monitored in real time using fluorescence resonance energy transfer (FRET) technique after PC12 cells treated with TNF-α. Then we observe BAX can't translocation to mitochondria during PC12 cells apoptosis induced by TNF-α, and that there is no any evidence of cytochrome C release into cytosol during cell apoptosis. Our data support that TNF-α mediated PC12 cells apoptosis is extrinsic apoptotic pathway which independent of mitochondria.

Low-power laser irradiation (LPLI) has been shown to promote cell proliferation in various cell types, yet the mechanism of which has not been fully clarified. Studying the signaling pathways involved in the laser irradiation is important for understanding these processes. The Ras/Raf/MEK/ERK (extracellular-signal-regulated kinase) signaling pathway is a network that governs proliferation, differentiation and cell survival. Recent studies suggest that Ras/Raf signaling pathway is involved in the LPLI-induced cell proliferation, but the dynamic activation of Ras in living cells induced by LPLI has not been reported. In present study, to monitor the dynamic activation of H-Ras after LPLI treatment in living cells in real time, Raichu-Ras reporter was utilized, which was constructed based on fluorescence resonance energy transfer (FRET) technique. Our results show that the dynamic activation of H-Ras at the cell edges of the plasma membrane is monitored during cell proliferation induced by LPLI (0.8 J/cm²) in serum-starved COS-7 cells expressing Raichu-Ras reporter using FRET imaging on laser scanning confocal microscope, and that LPLI causes the redistribution of H-Ras from the cytoplasm to plasma membrane. The same results are observed in EGF treated COS-7 cells. Taken together, LPLI induces the COS-7 cells proliferation by activated Ras.

It is well known that plant and animal viruses had widely spread the whole of world, and made a big loss in farming and husbandry. It is necessary that a highly efficient and accurate virus's detection method was developed. This research combines reverse transcription polymerase chain reaction (RT-PCR) technique with electrochemiluminescence method, to detect plant RNA viruses for the first time. Biotin-probe hybridizes with PCR product to specific select the target for detection, thus can avoid pseudo-positive result. TBR-probe hybridizes with PCR product to emit light for ECL detection. Specific nucleic acid sequences (20bp) were added to 5' terminal all of the primers, which can improve the chance of hybridization between TBR-probe and PCR product. At the same time, one of the PCR product chain can hybridize two Ru-probes, the ECL signal is intensified. The method was used to detect Odntoglossum ringspot virus ORSV, Sugarcane mosaic virus ScMV, Sorghum mosaic virus SrMV, and Maize dwarf mosaic virus MDMV, the experiment results show that this method could reliably identity virus infected plant samples. In a word, this method has higher sensitivity and lower cost than others. It can effectively detect the plant viruses with simplicity, stability, and high sensitivity.

Apoptosis is an important cellular event that plays a key role in pathogeny and therapy of many diseases. The mechanisms of the initiation and regulation of PDT-induced apoptosis are complex. Some PDT-associated apoptosis pathways involved plasma membrane death receptors, mitochondria, lysosomes and endoplasmic reticulum (ER). In order to determine the apoptosis pathway induced by Photofrin-PDT, we used fluorescence resonance energy transfer (FRET) technique and probe SCAT3 to monitor the dynamics of caspase-3 activation after PDT treatment and also measured caspase-8 activity. With laser scanning confocal microscopy, we found that Photofrin were localized primarily in mitochondria, the primary targets of Photofrin-PDT. Formation of mitochondrial reactive oxygen species (ROS) was detected within minutes after PDT treatment. This was followed by mitochondrial membrane potential (ΔΨm), cytochrome c release, caspase-9 activity, caspase-3 activity and apoptosis. After PDT treatment, caspase-3 was activated rapidly while caspase-8 remained inactivated. Our results indicated that PDT-induced apoptosis was initiated from mitochondria pathway and independent of caspase-8 activation. The activation of caspase-3 by PDT started 20 minutes after treatment and completed in about 15 minutes. PDT-induced apoptosis is directly initiated from mitochondria pathway and not involved in the death receptors-dependent pathway. Our results demonstrated that FRET could be an effective tool to determine PDT-induced apoptosis and other cell death mechanism.

Heat shock protein70 (HSP70) is expressed plentifully in tumor cells, and it could regulate tumor immunity. Recent studies show that PDT induces cell surface expression and release HSPs from the treated cells. HSPs have critical role in the PDT-induced immune responses, but the dynamic of HSP70 in living cells induced by PDT has not been reported. In present study, YFP-HSP70 was used to monitor the dynamic distribution of HSP70 in living cells in real time. With confocal laser scanning microscope, we detected the dynamic distribution of HSP70 after PDT treatment. The results show that HSP70 most localize in the cytoplasm of tumor cells, but few localize on cell surface, and that the cytoplasmic HSP70 immediately translocated to the cell surface after Photofrin-PDT treatment. In addition, the surface-expressed HSP70 remain unchanged and did not release from tumor cells during apoptotic process. Our data suggest that HSP70, expressing on the cell surface after PDT treatment , may serves as a surface targets for immune cells and induced immune responses to regulate the efficacy of PDT.

Taxol is known to inhibit cell growth and triggers significant apoptosis in various cancer cells, and activation of proliferation factor NF-κB during Taxol-induced apoptosis is regarded as a main reason resulting in tumor cells resistance to Taxol. It has been found that ursorlic acid can inhibit the activation of NF-κB. In order to study whether ursorlic acid can enhance the Taxol-induced apoptosis, we use fluorescence resonance energy transfer (FRET) technique and probe SCAT3 to compare the difference of caspase-3 activation between Taxol alone and Taxol combined ursorlic acid. With laser scanning confocal microscopy, we find that ursorlic acid, a nontoxic food component, sensitizes ASTC-a-1 cells more efficiently to Taxol-induced apoptosis by advanced activation of caspase 3. The result also suggests that there would be a synergistic effect between Taxol and ursorlic acid, and the more detailed mechanism of synergistic effect needs to be clarified further, such as the correlations among NF-κB, Akt, caspase 8, which leads to the advanced activation of caspase 3 during combined treatment of Taxol and ursorlic acid. Moreover, this may be a new way to improve Taxol-dependent tumor therapy.

Apoptosis is a very important cellular event that plays a key role in pathogeny and therapy of many diseases. One of the important modes cell death by photodynamic therapy (PDT) is apoptosis. The translocation of Bax from the cytosol into the mitochondrial outer membrane is a central event during apoptosis. In this study, we detected the kinetics of Bax activation in the cells with different photosensitizers treatments. Using laser scanning confocal microscopy, we found that Photofrin were localized primarily in mitochondria and N-aspartyl chlorine e6 (NPe6) preferentially localized to lysosomes. The results showed Bax can be activated and translocated from the cytosol to mitochondria by Photofrin-PDT treatment but not by NPe6-PDT treatment in ASTC-a-1 cells. The activation of Bax started 15 minutes after Photofrin- PDT treatment and the process of activation completed within 45 minutes. These results indicated that the initiation and process of Bax activation are different corresponding to different sublocalization photosensitizers treatments. Our data suggests that different sublocalization photosensitizers in PDT treatments photodamaged different organelles and will trigger various apoptotic pathways in PDT treatment.

UV irradiation is a DNA-damage agent that triggers apoptosis through both the membrane death receptor and the mitochondrial apoptotic signaling pathways. Bid and Bax are two important proapoptotic members of the Bcl-2 family, localize largely in the cytoplasm and redistribute to mitochondria in response to most apoptotic stimuli. Cells deficient in Bax are resistant to UV-induced apoptosis, cells deficient in Bid are less susceptible than normal cells in response to DNA damage. Thus, studying characteristics of Bid and Bax translocation by UV irradiation is very important for us to understand the cellular signaling mechanisms mediating UV-induced apoptosis. In this study, to investigate Bid and Bax translocation in real time in a single cell by UV irradiation, we transfected Bid-CFP, YFP-Bax and DsRed-Mit into human lung adenocarcinoma cells (ASTC-a-1), then observed temporal and spatial characteristics of Bid and Bax translocation by laser confocal scanning microscope imaging technique. Our results showed that Bax translocation was earlier than Bid translocation and the average duration of Bax translocation was about 20-30 min during UV-induced apoptosis.

Fluorescence labeled liposome nanoparticles were prepared by dispersion of film method. The size of nanoparticles was around 50 nm. DPPE-FITC synthesized in our lab was used to label the liposome nanoparticles. Anti-cytokeratins 19 antibody was connected to the surface of the fluorescence liposome nanoparticles. After incubation with MGC cells and COS-7 cells for 30 min, MGC cells were selectively recognized by anti-cytokeratins 19 antibody modified liposome nanoparticles and well imaged under laser confocal microscope. This fluorescence labeled liposome nanoparticles is expected to have good applications in cell recognition and tumor diagnosis.

In this paper, a novel method for the differentiation of the retinal pigment epithelium (RPE) cells after light-induced damage by two-photon excitation is presented. Fresh samples of RPE cells of pig eyes are obtained from local slaughterhouse. Light-induced damage is produced by the output from Ti: sapphire laser which is focused onto the RPE layer. We study the change of the autofluorescence properties of RPE after two-photon excitation with the same wavelength. Preliminary results show that after two-photon excitation, there are two clear changes in the emission spectrum. The first change is the blue-shift of the emission peak. The emission peak of the intact RPE is located at 592nm, and after excitation, it shifts to 540nm. It is supposed that the excitation has led to the increased autofluorescence of flavin whose emission peak is located at 540nm. The second change is the increased intensity of the emission peak, which might be caused by the accelerated aging because the autofluorescence of RPE would increase during aging process. Experimental results indicate that two-photon excitation could not only lead to the damage of the RPE cells in multiphoton RPE imaging, but also provide an evaluation of the light-induced damage.

The spectral resolved imaging technique has a typical characteristic that it allows simultaneous recording of real-color RGB image representation and corresponding spectra. In this paper, we present a nonlinear spectral resolved imaging approach based on two-photon excited autofluorescence and second harmonic generation of biological tissues to elucidate microstructure and spectroscopic features of unstained rabbit arterial wall. Coupled to the image-guided spectral analysis method, we use a series of recorded nonlinear spectral resolved images excited by a broad range of laser wavelengths (730-910nm) to identify five components in unstained rabbit arterial wall including in NADH, elastin, flavin, porphyrin derivatives and collagen. Using the combination of a nonlinear spectral resolved imaging approach and two-channel synchronized detection, we obtained high contrast 2-D and 3-D images of collagen and elastic fiber in the arterial wall. Our results demonstrate that simultaneously linking a nonlinear spectral resolved imaging approach with the image-guided spectral analysis method and multi-channel synchronized detection technique is a very useful method because it can in tandem acquire the structural modifications of different tissue components and quantitatively record the change of corresponding emission signal. This method has the potential to provide more comprehensive diagnostic information for determining tissue pathology which associated with mechanical properties of aorta wall and pharmacodynamical studies of vessels.

Transplantation technique of retinal pigment epithelium has been noticeable in recent years and gradually put into clinical practice in treatment of retinal degenerative diseases. Generally, immunological, histochemical, and physical methods are used to study the iris pigment epithelium (IPE) and retinal pigment epithelium (RPE) cells, which need complex sample preparation. In this paper, we provided a simple autofluorescence microscopy to investigate the fresh porcine IPE and RPE cells without any pretreatment. The results showed that the morphology and size of both were similar, round and about 15 μm. The main flourophore in both cells was similar, i.e. lipofuscin. In additional, the autofluorescence spectrum of RPE shifted blue after light-induced damage by laser illuminating. Because it was easier for IPE to be damaged by laser than for RPE, and the power of one scanning operation to get a full image was strong enough to damage IPE sample, we hadn't get any satisfied autofluorescence spectrum of IPE.

In this paper, we measured and analyzed the characteristic of endogenous fluorophores in porcine layered retina by using advanced fluorescence spectroscopy and microscopy imaging technology. It was found that there were obvious contrasts corresponding to the different layers of retina, which may be important for fundus disease diagnosis. The retinal pigment epithelium cells exhibited strong autofluorescence with as emission peak of 600±10nm when excited with 860-nm light. The emission peak of photoreceptors was at 652±5nm, and the emission peak of retinal vessels layer was weak and at 640~700nm, when excited with 488-nm light. Autofluorescence images of three layers of retina were obtained using the same setup. We concluded that the main endogenous fluorophore in PRE was lipofuscin and that in retinal vessels was porphyrin. What's more, the FMHW (full width at half. maximum) of retinal fluorescence spectrum was broad, which suggested that there wasn't only one endogenous fluorophores of tissues excited.

The real-time and quantitative detection assay is important for the gene detection. With the TaqMan probes for the detection based polymerase chain reaction (PCR), four targets could be checked in a single process in solution assay. A new method is developed to immobilize the TaqMan probes on a microarray, which could be used to the multi-target gene fragment quantitative detection with PCR. A new type microarray scanner is designed for the assay. A thermocycler system was built into the scanner platform. A new type of the vessel sealed with the gene amplification solution which could perform the thermo-cycling and scanning. To decrease the background intensity a confocal system was used as the fluorescent intensity detection in the scanner. To calculate the gene quantity, a standard liner graph was draw with the fluorescent intensity versus the cycles. From the standard liner, the quantity of the original gene fragment could be calculated in time with the cycles. This scanner offers the great advantage of real-time quantitative detection of DNA targets in a microarray.

We present a novel 5-dimensional (5-D) MMM system that is based on a microlens array for producing discrete excitation spots array, a prism for 2-dimensional (2-D) spectral dispersion and a specially designed picosecond streak camera for providing simultaneous temporal and spectral resolutions, which enables the acquisition of fluorescence lifetime information of any spectrum within the whole spectra in only one measurement. The near-infrared light from a mode-locked titanium: sapphire femtosecond laser is split into an array of beams that are transformed into an array of high-aperture foci at the sample. A time- and spectrum-resolved image of 3×3 foci on the sample can be obtained with a snapshot. By translating the sample stage laterally and axially and implementing a dedicated image reconstruction algorithm in the control system, 5-D data sets that combine temporal and spectral resolutions and 3-dimensional (3-D) spatial coordinates can be obtained. The spectrum-resolved and depth-resolved fluorescence lifetime microscopic images are demonstrated. Preliminary results indicate that the system has high temporal, spectral and spatial resolutions and holds potential for providing high image acquisition rate.

By integrating two-photon excited fluorescence (TPEF) technique into confocal optical system, TPEF images of zygote spindles of ICR (Internal Control Region) rats have been obtained in high resolution for the first time. Experimental results demonstrate the validity of TPEF as an efficient probe in investigating cell spindles at early embryonic developmental stage.

A Simultaneous Time- and Spectrum-Resolved Multifocal Multiphoton Microscopy (STSR-MMM) system has been developed for the acquisition of fluorescence lifetime information of any spectrum of the biological samples in only one measurement. The near-infrared light from mode-locked titanium: sapphire femtosecond laser is split with a microlens array into an array of beams that are transformed into an array of high-aperture foci at the sample for parallel multiphoton excitation. The Gaussian shape of the excitation beam results in non-uniformity and asymmetry of the excitation foci array and also of the reconstructed fluorescence image. A coefficient matrix has been presented for the correction of the non-uniformity and asymmetry in the fluorescence image. Data acquisition and image processing methods have also been investigated to increase the image acquisition speed and improve the reconstruction of time- and spectrum-resolved fluorescence image. The methods for obtaining fluorescence intensity image, spectrally resolved intensity image and spectrally resolved lifetime image are also presented.

In this present paper, the microalgae irradiated by Nd:YAP laser are observed using Laser Confocal Scan microscope, and the auto fluorescence of microalgae cells is analyzed with quantitative analysis system, so as to investigate the effect of auto fluorescence alteration on growth of irradiated microalgae. Method: Platymonas subcordiformis, Phaeodactylum tricormutum and Isochyrsis zhanjiangensis are irradiated by Nd:YAP laser with 10w at 1341nm, irradiating time:12s, 30s, 35s and 55s. On Lambda Scan mode, the auto fluorescence images and fluorescence spectra of algae cells are obtained by the excitation 488nm (Ar⁺ laser). Result: there are two summit peaks, 489.8nm and 680.9nm, for Platymonas subcordiformis, Phaeodactylum tricormutum and Isochyrsis zhanjiangensis fluorescence spectrum. Contrast to the CK, the peak positions of fluorescence of irradiated algae cells is similar to the whole while the peak light intensity alters. On irradiation of promoting dose, however, the auto fluorescence intensity is enhanced more than control, with different type of microalgae, the different fluorescence intensity are shown in the analysis, and all of the microalgae pigment bodies change can be seen also. Conclusion: Physiological incentive effect of irradiated microalgae can be given expression on fluorescence characteristics and fluorescence intensity alteration of cells.

In this paper, we developed a full-field OCT system using thermal light as the low-coherence light source. A well-known Linnik interferometer configuration was used. Broad spectral width of the thermal light 450-650nm was used to achieve high axial resolution of 1.1&mgr;m in biological sample for OCT imaging. Two water immersion objectives of 0.5N.A were used to balance the dispersion and a transverse resolution of 0.7μm was obtained. With a fast machine-coding algorithm, system sensitivity of more than 80dB and imaging rate as high as 18frame/s with 500x500 pixels per frame could be achieved. Mouse embryos were imaged in vivo with full-field OCT at different depth for the developmental study. Useful information for pre-implementation genetic diagnosis (PGD) was obtained by image analysis and segmentation. As far as known, for the fist time, 3D images of mammalian embryos were obtained with full-field OCT without the need of dye labeling.

Inspection of tongue is an age-old technique used by Traditional Chinese Medicine (TCM) practitioners to determine a patient's health status. Because tongue examination is a subjective and inaccurate diagnostic method, a scientific tool which can provide objective and accurate information is needed to assist the TCM practitioners in their practice. The purpose of the study was to examine the feasibility of developing a glossoscopy from an optical coherence tomography (OCT) imaging system. In the present study, an OCT system was used to examine the tongue of the rat. After examination, the tongue was surgically removed, sectioned by a microtome and put on a glass slide for histological examination. The slides were examined under a bright-field microscope. Results of the OCT imaging studies showed that the OCT system was capable of showing the images of three distinct regions of the tongue: the tongue coating layers, the interface between the tongue coating and the tongue body, and the tongue body. It was also possible to assign an index number to each of the coating layers. When the tongue tissue was examined under a microscope, three separate regions of the tongue also were visible. Results of this pilot study shows that the OCT potentially can be developed into a glossoscopy for clinical application in TCM practice.

The paper compared the response of HL60 cells with peripheral blood mononuclear cell (PBMC) after 5-ALA PDT for different periods of time and then followed by irradiating with different wavebands for different fluences. The results of parameter experiments were obtained: 1 × 10⁵/mL HL60 cell was incubated with 1 mmol/L ALA in dark for 4 h and the maximum fluorescence of PpIX level appeared; then irradiated with 410 nm (4 mW/cm²) for 14.4 J/cm² and maximum photodamage to membrane and mitochondrial function of HL60 cell resulted. Analyzed the experimental results of references, we got that the effect of photodynamic purging of leukemia cells may be modulated by the leukemia cell type; the photosensitizer's type, dose, and its location point; the incubation time and condition; the light wavelength and its dosage. If the light is delivered at a high rate, significant heating of a molecule and its surrounding may take place. A too low dosage has no effect at all or will result in high relapse rate due to the presence of cancer cells. The wavelength and intensity of light required to carry out photopurging is determined by the absorption properties of the photosensitizer. The light dose actually received by the photosensitizer and tissue may be higher or lower depending on the manner of irradiation.

The effectiveness of Nd:YAG laser treatment on in vitro acid resistance of human enamel was studied. After surface polishing, enamel blocks irradiated by different power laser and control group were put into 5ml of lactate buffer solution (0.1mol/L), which was in water of 37°C for 72 hours. The hardness and morphology of enamel surface were investigated by microhardness meter and scanning electron microscopy. Compared with control, the group with 0.3W laser treatment has the least caries lesion (p<0.001). At the same time, the mechanism of caries prevention and acid resistance by laser was discussed in detail. We drew a conclusion that the change of contents in enamel and crystal orientations and partial decomposition of the organic matrix might be the main reason for enhancing acid resistance. And best caries inhibition could be achieved when the temperature rising of enamel surface was in the range of 300~400°C by laser parameters being controlled suitably.

Alcohol, which is ubiquitous today, is a major health concern. Its use was already relatively high among the youngest respondents, peaked among young adults, and declined in older age groups. Alcohol is causally related to more than 60 different medical conditions. Overall, 4% of the global burden of disease is attributable to alcohol, which accounts for about as much death and disability globally as tobacco and hypertension. Alcohol also promotes the generation of reactive oxygen species (ROS) and/or interferes with the body's normal defense mechanisms against these compounds through numerous processes, particularly in the liver. Photobiomodulation (PBM) is a cell-specific effect of low intensity monochromatic light or low intensity laser irradiation (LIL) on biological systems. The cellular effects of both alcohol and LIL are ligand-independent so that PBM might rehabilitate alcohol induced dysfunction. The PBM on alcohol induced human neutrophil dysfunction and rat chronic atrophic gastritis, the laser acupuncture on alcohol addiction, and intravascular PBM on alcoholic coma of patients and rats have been observed. The endonasal PBM (EPBM) mediated by Yangming channel, autonomic nervous systems and blood cells is suggested to treat alcohol induced dysfunction in terms of EPBM phenomena, the mechanism of alcohol induced dysfunction and our biological information model of PBM. In our opinion, the therapeutic effects of PBM might also be achieved on alcoholic myopathy.

Hematoporphyrin monomethyl ether (HMME) is a novel and promising porphyrin-related photosensitizer for photodynamic therapy (PDT). We use the human breast cancer MCF-7 cells to investigate the photodamage effect of HMME and reactive oxygen species (ROS) generation in HMME-PDT. Methods: The growth rates of MCF-7 cells at 24h after irradiation by 532nm laser with HMME of 5~20μg/ml and light dose of 0.3~4.8J/cm² were determined by CCK-8 assays. Hoechst33342 staining was used to investigate the morphological change of the tumor cell. Flow cytometry combined with dual Annexin V/PI staining was used to identify the death mode of the cells following PDT. The changes of ROS labeled by DCFH-DA were observed by Laser Scanning Confocal Microscopy (LSCM). Our results show that HMME-based PDT induced significant cell death, and the photocytotoxity to MCF-7 cells is dose-dependent at the range of HMME concentration 5~20μg/ml and the light dose 0.3~4.8J/cm². The nucleolus underwent apoptosis and/or necrosis observed by LSCM with Hoechst33342 staining. The necrosis and apoptosis rate were 16.0% and 12.4% respectively by FCM, showing the number of necrosic cells was more than that of apoptosis. There was an intense increase of fluorescence intensity standing for ROS generation within 30min post-PDT, and the peak was at about 10min after PDT. Our results suggest that HMME-PDT could inhibit the proliferation of MCF-7 cells remarkably. Because the MCF-7 cells lack procaspase-3, the apoptosis rate is lower. ROS played an important role in the photodamage with HMME.

Photoselective laser vaporization of the prostate (PVP) is the most promising method for the treatment of benign prostatic hyperplasia (BPH), but KTP lasers used in PVP with lamp-pumped are low efficient .To increase the efficiency , we develop a 80-W, 400kHz, linearly polarized green laser based on a frequency-doubled fiber laser. A polarization-maintaining large-mode area (LMA) fiber amplifier generate polarized 1064nm fundamental wave by amplifying the seed signal from a composite Cr⁴⁺:YAG-Nd³⁺:YAG crystal fiber laser. The fundamental wave is injected into a KTP crystal with confined temperature management to achieve second harmonic generation (SHG). The overall electrical efficiency to the green portion of the spectrum is 10%.80-W maintenance-free long-lifetime KTP laser obtained can well satisfy the need of PVP.

Based on the lateral photo effect of the semiconductor photoelectric position sensitive device, Developing a new kind of photo-electro position sensitive detector as the receiver of the laser beam, taking the laser as the launcher, and using optical lens, light filter .etc, we have designed a new kind of 3D non-contact optical measurement system with high accuracy and high resolution. The characteristics of this system are demonstrated as: very high response speed; very high position resolution; the position output has nothing to do with the intensity of the light spot as well as the size of it, only if the center of gravity of it is related; And it can detect the intensity and the position of the incident light spot at the same time, etc. On the basis of the ruled lines of the Cartesian axes located on the object that is measured, it can produce the contour of the object, which provides a optical detecting method that can measure the marginal date accurately for detecting irregular shape and early surgical analysis and diagnosis. This measurement system has very high application value for the clinical diagnosis. Finally, it has analyzed the factors affecting system precision and causes of the system errors, and has provided the experimental result and several important conclusions.

A new generation of Up-converting phosphor technology-based biosensors (UPT-based biosensor) has been developed for immunoassay, where a kind of novel Up-converting phosphor (UCP) particle serves as the biological marker. Its control system is based on a micro-computer control unit instead of a personal computer, which results in low power consumption, high reliability and portability for field detection. By detecting the content of the UCP on the test strip, the system figures out the concentration of the biological molecular of interest, which can be used in field examination of biological analytes. In this paper, a series concentration of standard samples have been tested by the biosensor, which is proved to have higher sensitivity (~ng/ml), higher stability (CV<3~5%), better linear relationship and an excellent correlation (R²≥0.95). The UPT-based biosensor has stable, reliable and sensitive performances. It can meet the need of various rapid bioassay applications.

Matrix Metalloproteinase (MMP) plays an active role in remodeling cartilage in osteoarthritic cartilage. To find an effective method of prevention of osteoclasia, this in vitro study focuses on the expression of MMP-3 and MMP-13 in the SW1353 cells by LED irradiation. The human chondrosarcoma cell line SW1353 were stimulated with the proinflammatory cytokine IL-1beta or tumor necrosis factor-alpha (TNF-alpha), and were received the irradiation of LED (632nm, 4mW/cm²). The cell count was assessed over a 96-hour period by using Trypan blue dye exclusion assay, and the cell activity was evaluated with a Cell Counting Kit-8 Assays. The subsequent expression of MMP-3 and MMP-13 was quantified. Results of this experiment showed that the cultural cell activity was decreased, and the expression of MMP-3 and MMP-13 was increased by being stimulated with IL-1beta or TNF-alpha. After received LED irradiation, the death rate of cultural cell was increased and the expression of MMP-3 and MMP-13 was decreased significantly. The present study concluded that particular LED irradiation stimulates SW1353 cell proliferation activity and inhibit the MMP-3 and MMP-13 enzymatic activity. These findings might be clinically relevant, indicating that the low power laser irradiation treatment is likely to achieve the repair of articular cartilage in clinic.

To assess modulation of laser on erythrocyte permeability and deformability via cell morphology changes, healthy human echinocytes with shrinking size and high plasmic viscosity due to cellular dehydration were treated with 1 mW, 2 mW, 3 mW, and 5 mW laser power exposure respectively. Image analyzing system on single intact erythrocyte was applied for measuring comprehensive cell morphological parameters (surface area, external membrane perimeter, circle index and elongation index) that were determined by the modulation of erythrocyte water permeability and deformability to detect relationship between erythrocyte water permeability alteration and deformability. Our preliminary experiment showed that exposure under light dose of 5 mW for 5 min could induce more active erythrocyte swelling and deformation. water channel aquaporin-1(AQP-1) was inhibited by the incubation of HgCl₂ in the presence and absence of 5 mW laser irradiation. The result suggested that osmotic water permeability is a primary factor in the procedure of erythrocyte deformability. In addition, no modulation of laser(5mW) on erythrocyte deformability had been found when the echinocytes were cultured with GDP-β-S (G protein inhibitor).

Absorption spectrum of CPD₃ is determined. There are two absorption bands all in absorption spectrum, the maximal absorption of band B is at 395nm in 0.9% NaCl solution and TE buffer solution, the band Q is locating at 677nm and 651nm respectively in solvents above. The order of magnitude of extinction coefficient is 10⁴ in both solvents. the absorption peak of CPD₃-DNA mix solution have 6nm and 23nm red shift for band B and band Q respectively compared with pure CPD₃ in 0.9% NaCl solution, this indicates that interaction between photosensitizer and DNA occurring. Time series data of absorption for CPD₃-DNA mix solution supports the interaction viewpoint further, and the full action time is about 90mins. The type of interaction needs a further investigating. Stronger absorption in red region and the interaction with DNA suggests that CPD₃ will have a bright future in photodynamic therapy.

This study is focused on the determination of the real and imaginary parts of the complex refractive index of oxyhemoglobin and deoxyhemoglobin solutions (1.6 g/l) at different concentrations of glucose (from 0 to 1000 mg/dl with a step of 100 mg/dl) from a few hours to over one week of incubation. The real part was measured using Abbe refractometer. Theoretical values of real part of refractive index were calculated supposing non-interacting hemoglobin and glucose molecules. The imaginary part was determined using transmittance measurements at the wavelength range from 500 nm to 1000 nm. It is shown that the real and imaginary parts of the complex refractive index measurements have a potential for the evaluation of glycated hemoglobin amount.

Plants senescence is a phase of plants ontogeny marked by declining photosynthetic activity that is paralleled by a decline in chloroplast function. The photosystem II ( PSII ) in a plant is considered the primary site where light-induced delayed fluorescence (DF) is produced. With the leaves of Catharanthus roseus (Catharanthus roseus (L.) G.Don) as testing models, we have studied the effects of plants senescence induced by dark and/or exogenous hormones treatments on characteristics of DF by using a home-made portable DF detection system, which can enable various DF parameters, such as DF decay kinetic curve and DF intensity, to be rapidly produced for the plants in a short time. The results show that the changes in DF intensity of green plants can truly reflect the changes in photosynthetic capacity and chlorophyll content. Therefore, DF may be used an important means of evaluating in vivo plants senescence physiology. The changes in DF intensity may provide a new approach for the rapid and early detection of plants senescence caused by age or other senescence-related factors. DF technique could be potential useful for high throughput screening and less time-consuming and automated identifying the interesting mutants with genetic modifications that change plants senescence progress.

We present the luminescence properties of CdS nanoparticles conjugated with active DNA molecules. Having the action of activators, CdS nanoparticles combine with DNA molecules easily and tightly. The fluorescence from CdS nanoparticles is characteristics of bright spots under dark optical microscopy, indicating that CdS nanopaticles can be used labeling DNA molecules. Strong photoluminescence emission of A-DNA-CdS keeps relatively steady at room temperature in terms of the time behavior of optical bleaching, showing that CdS nanoparticles are suitable to long time biological analysis and detection.

Employing a luminescence spectrometer the usefulness of light-induced delayed luminescence (DL) for the detection of aflatoxinB1 (AfB1) contamination in whole rice was studied. Rice was artificially contaminated with Aspergillus flavus (7.5×10⁵ conidia/ml) and incubated for 0 - 72 h. The DL spectra of contaminated rice were obtained by a luminescence spectrometer. The correlation between the spectra and contamination levels was established. The DL intensity has a negative correlation with the AfB1 concentration. The results suggested that the DL technique might be useful for the rapid and non-invasive evaluation of AfB1 contamination levels in whole rice.

X-ray phase contrast imaging is a promising new technology today, but the requirements of a digital detector with large area, high spatial resolution and high sensitivity bring forward a large challenge to researchers. This paper is related to the design and theoretical investigation of an x-ray direct conversion digital detector based on mercuric iodide photoconductive layer with the latent charge image readout by photoinduced discharge (PID). Mercuric iodide has been verified having a good imaging performance (high sensitivity, low dark current, low voltage operation and good lag characteristics) compared with the other competitive materials (α-Se,PbI₂,CdTe,CdZnTe) and can be easily deposited on large substrates in the manner of polycrystalline. By use of line scanning laser beam and parallel multi-electrode readout make the system have high spatial resolution and fast readout speed suitable for instant general radiography and even rapid sequence radiography.

Laser technology has succeeded in medical application. High power 532nm laser has applied in prostate ablation and other clinic application. To understand optical property of bio-tissue at 532nm wavelength, a method of monitoring surface temperature was used to measure absorption coefficient of gall-stone, porcine liver and canine prostate. The absorption coefficient of gall-stone is about 62cm^-1 at 532nm wavelength, and those of porcine liver and canine prostate are about 13cm^-1 and 5.4cm^-1, respectively. These results help to understand the optical property of bio-tissue and offer theoretic reference for optical dosimetry in clinic application.

Photorejuvenation is a promising technique for esthetics. But evaluating approach for efficacy of photorejuvenation is relatively behind demand. In this study, after discussion of current techniques, a novel evaluating method for photorejuvenation which combines reflectance and fluorescence spectroscopy is proposed. Laser induced autofluorescence spectroscopy can be used to detect biochemical information from depth of skin. Tristimulus values which reflect the color of skin can be obtained by diffuse reflectance spectroscopy. So combination of the reflectance and fluorescence spectrum is expected to be a promising tool for evaluating efficacy of photorejuvenation.

C-C bond is the most common kind of interactions in biological molecules. For example, the molecules of cholesterol and fibrinogen are connected with C-C bonds. We analysis the effect of Laser onto C-C bond in medical cure case by the method of Intra-vascular Laser Irradiation on blood (ILIB), and in theory a new model of "Laser-(C-C)" inharmonic oscillator is constructed on the base of quantum mechanics. Furthermore, we investigate the helpful influence of ILIB through sixty-two cases of brain-thrombus.

One of the popular methods for measurement of intracellular free calcium ([Ca²⁺]_i) is ratiometric fluorescence technique. R_max and R_min play an important role in the calibration of [Ca²⁺]_i measurement. The purpose of this study was to analyze influencing factors in the [Ca2+]_i measurement. R_max and R_min deduced from theory had a hyperbolic relation with the ratio of C_f and C_b (C_f: free indicator concentration; C_b: Ca²⁺-bound indicator concentration). In experiments, using radiometric fluorescence imaging system, they were measured separately in two types of cell lines in concentration gradient (2×10⁵cells/ml, 5×10⁵cells/ml, 1×10⁶cells/ml and 2×10⁶cells/ml). By Triton method, R_max and R_min of K562 cells were 1.21 and 0.20, respectively, and that of Hepa1-6 cells were 2.02 and 1. These results indicated that R_max and R_min were not influenced by concentration gradient in a certain range of cell concentration, but they were different in various types of cell lines.

Hepa1-6 cells were irradiated with UV and incubated for varying periods of time. [Ca²⁺]_i (intracellular calcium concentration) of UV-irradiated cell was measured by ratio fluorescence imaging system. The comet assay was used to determine DNA damage. During the UVB-irradiation, [Ca²⁺]_i had an ascending tendency from 0.88 J/m² to 92.4J/m². Comet assay instant test indicated that when the irradiation dosage was above 0.88J/m², DNA damage was observed. Even after approximate 2 h of incubation, DNA damage was still not detected by 0.88J/m² of UVB irradiation. During UVA-irradiation, the elevation of [Ca²⁺]_i was not dose-dependent in a range of 1200 J/m²-6000J/m² and DNA damage was not observed by comet assay. These results suggested that several intracellular UV receptors might induce [Ca²⁺]_i rising by absorption of the UV energy. Just [Ca²⁺]_i rising can't induce DNA damage certainly, it is very likely that the breakdown of calcium steady state induces DNA damage.u

Photodynamic therapy (PDT) is a promising new treatment modality for several diseases, most notably cancer. In PDT, light, O2, and photosensitizer are combined to produce a selective therapeutic effect. Chlorophyll derivative photosensitizer(CPD) is the class of new photosensitizers for photodynamic therapy ( PDT) . And to date, little is known about the interaction between the photosensitizer and the inner parts of tumor cell in PDT. A fluorescent microscopy and imaging study on CPD was performed. To observe the dynamic process of how the photosensitizer (CPD) enters the tumor cell and intracellular distribution of CPD in tumor cells, we used confocal laser scan microscopy(CLSM) under one-photon excitation induced by a 488nm Ar+ laser. We also obtained the fluorescence photobleaching of CPD in cells with varied intensity of excitation laser(488nm). By means of CLSM, we found most of the photosensitize CPD distribute in on nuclear membrane but few in nuclear.

Photodynamic therapy (PDT) is an important method to treat tumor. It is known that singlet oxygen (¹O₂) is the main factor mediating cytotoxicity in PDT. The effectiveness of a PDT treatment is directly linked to the ¹O₂ produced in the target. So to control the dose of ¹O₂ is very important. Although the luminescence from ¹O₂ can be detected and is suggested as an indicator for evaluating photodynamic therapy, the inherited disadvantages limit its potential for in vivo applications. We have previously reported that chemiluminescence (CL) can be used to detect ¹O₂ production in PDT and linked the signal to the cytotoxicity, but the irradiation of laser decrease the sensitivity of the detection in vivo. During PDT the high sensitivity probe, Fluoresceinyl Cypridina Luciferin Analog (FCLA), is used to monitor ¹O₂. In order to avoid the infection of irradiation light, the delayed CL of FCLA is used to indicate ¹O₂. After recording the delayed CL during PDT and scoring the skin of mice after PDT, the statistic analysis was done. The data shows a remarkable relationship between the score and the CL. the result suggests that the CL can be used as a dose metric in vivo in PDT.

Since microscope was invented in 17 century, optical instruments have continued to be an important tool for advanced investigations in biology and medicine. The step by step development of optical technology has also preceded the realization of macroscopic and microscopic biology, providing new advances that help better understanding of these fields. Even today it is necessary to build new optical devices to foster the advancement of frontier biological research, and for new applications in medical research. Here in this paper, we describe two new advanced optical systems for biological detection, which are already used in a series of new instrument products, such as the confocal scanner, the digital imaging scanning system.

A LED array is used as PDT light source in a photo-reaction chamber. The LED array is alterable in wavelength by replacing different LEDs, stable in output power, adjustable in power value and spot size; the geometry of the LED array is flat shape. Based on the experiment of ALA-PDT, we measured and analyzed the spectrum characteristics and output power of some different purple LEDs, selected one as PDT light source whose emission peak is near the absorption peak of the ALA. The experiment on HL60 tumor cells in vitro demonstrates our photo-reaction chamber has visible photodynamic effect on ALA-PDT.

Medical image 3D reconstruction is an important research and application areas. A comprehensive survey is given in four aspects: the general process of medical image 3D reconstruction, image fusion, image segmentation, and 3D reconstruction algorithm.

In clinic, surrounding density of breast abnormalities is an important cue for radiologists to distinguish between benign and malignant abnormalities on mammogram. It may also be an important feature to be used in computer-aided diagnosis (CAD) system. The purpose of our work is to analyze the density distribution surrounding benign or malignant mass. The cases used in this study are selected from the Digital Database for Screening Mammography (DDSM) provided by the University of South Florida. For each case, the mass boundaries marked by experienced radiologists are used and 30 3-pixel-wide bands, one outside another, surrounding each mass are considered. A few density features including the average gray level and the distribution skewness of the gray levels on every surrounding band were calculated. For every feature in each corresponding band, average values were calculated for 10 benign cases and 10 malignant cases, respectively. The preliminary analysis results show that the intensities surrounding benign masses tend to be higher than those surrounding malignant masses. They also show that the standard deviation of intensities surrounding benign masses tend to be larger than those surrounding malignant masses. Similar analysis was also carried out with mass boundaries automatically identified by computer and the results corroborate the analysis with mass boundaries marked by radiologists.

In order to provide comprehensive information and improve the accuracy of clinical diagnoses and surgical therapies, medical image fusion is becoming a new hot topic. As the basic and key issue medical image registration has very important meaning. This paper offers a solution to medical image registration based on maximization of mutual information (MI) and particle swarm optimization (PSO). First, the rigid transformation with translational and rotational parameters is applied to the floating image. As an increasingly popular matching criterion for image registration, MI is adopted in this method. Theoretically, the maximization of MI is obtained if the transformed image and the reference image are geometrically aligned. Then an improved PSO algorithm is used to search the registration parameters. The experimental results demonstrate the effectiveness of the proposed registration scheme.

In this paper, we have developed a model-based approach to match two X-ray angiograms from different views. Under the guidance of the prior knowledge of anatomic structure of human coronary vessels, this method can build a node attribute table and assign unique anatomic labels to coronary arteries in X-ray angiograms automatically by the father-son relationship of the nodes, which is essential in reconstruction of vessels.

Electrorotation (ROT) is widely used for the investigation of the dielectric properties of biological cells. Traditionally the tedious measurements of the rotational rates of the cells are handled manually. In this paper, a ROT chip detection platform equipped with computer-aided measuring system is presented. The rotational motions of the cells are captured by CCD camera and an algorithm is implemented to automatically estimate the rotational rates by analyzing the captured image. The acquired data is verified by a comparison with manual stop-watch measurements. The experimental results are accurate and robust against variations in illumination and cellular deformation within maximum 5% deviation from the manual measurements. Thus the platform as a whole can be employed to detect changes in the cellular membrane dielectric properties caused by external stimulation, or those occurring naturally.

This paper introduced a newly developed method to acquire three-dimensional data from serial two-dimensional images of a dental cast. The system consists of a computer and a set of data acquiring device. The data acquiring device is used to take serial pictures of the a dental cast; an artificial neural network works to translate two-dimensional pictures to three-dimensional data; then three-dimensional image can reconstruct by the computer. The three-dimensional data acquiring of dental casts is the foundation of computer-aided diagnosis and treatment planning in orthodontics.

We present a parallel Fourier domain optical coherence tomography (FD-OCT) system using Xenon flash lamp. Parallel configuration is implemented by one dimensional illumination and two dimensional detection with a CCD camera. The imaging axial resolution is 2.6μm in air with maximum depth range of ~650μm. The dynamic range is ~70DB with exposure time less than 1ms for a 1000*512 pixel image.

In this presentation, several ultrasound-modulated optical phenomena in a tissue phantom were observed by a pulsed ultrasound transducer. Some factors affected the modulated signal value were studied including the changing of the experimental conditions such as the distance between the focused volume of ultrasound beam and the detector as well as the frequency of ultrasound transducer. The experimental results and the analysis suggest that a compositive parameter concerning the intensity of the modulated signal, namely the modulation depth which is a key parameter to measure the scattering property even as a sensor to indicate the glucose concentration.

Dual-wavelength optical low-coherent interferometry is proposed in this paper to measure the oxygen saturation in human retinal blood vessel. Wavelength consideration is made from the standpoint of eye safety and system sensitivity. Principle of oxygen saturation measurement based on dual-wavelength low-coherence interferometer is thoroughly developed. Numerical simulation on interference signal versus oxygen saturation corresponding to the oxygen sensitive wavelength and the isobestic wavelength is conducted.

Axial resolution is a key factor in optical coherence tomography (OCT). Biomedical applications will benefit from improved resolution and quality that ultrahigh resolution OCT can provide. Existing approaches to improve axial resolution of OCT mostly depend on new broadband light sources, which are always costly and inconvenient in instrumentation. In this paper we adopt an alternative method to enhance the axial resolution of OCT by combining coherence gate with optical superresolution. A three-zone phase pupil filter is designed and inserted into the sample arm of OCT. The depth responses measured demonstrate that an improvement of more than 15% in axial resolution is achieved in the proposed OCT system.

Projected index computed tomography (PICT) is an emerging noninvasive imaging technique that can provide tomographic mapping of sample's refractive index. In this paper, we report a PICT system developed on the basis of a fiber-optic OCT system. The tomographic mapping is reconstructed with convolution back projection algorithm using a series of angular projection data collected by optical coherence tomography (OCT) at sequential orientations. Measurement of refractive index distribution of a glass tube is carried out. The result shows that the developed system has high resolution and sensitivity to discriminate tube boundaries. With index information involved, the reconstructed PICT image is free of distortions, which are inherent artifacts of conventional OCT image.

The customary methods for localizing the foreign body in human body present several disadvantages, radioscopy has significant radiation exposure, MRI can not work with the metal, and also they are expensive and neither is portable. Microwave-induced thermoacoustic imaging which shares similar mechanism with photoacoustic imaging can achieve high ultrasound resolution and good microwave absorption contrast. Besides, microwave can reach deeply hidden sample in biological tissue because of its long wavelength, hence, this new imaging modality can be potentially applied to detect the foreign body hidden in human body. Our detecting methods were validated by imaging simulated foreign body embedded in biological tissue at different depths, the unknown samples embedded deeply were discernible and the signal to noise ratio was good. By employing the multi-element linear transducer array and phase-controlled focus algorithm, a circular scan of thermoacoustic signals at 20 angles needs no more than 2 minutes. Our established thermoacoustic imaging system has potential to supply a novel and fast method for surgical localization of an unknown foreign body.

Image edge recognition is a crucial aspect of biomedical image processing. In this paper, a rapid gradient segmentation method based on the depth-first traverse of images is presented. This method defines the data structure for the pixel firstly, estimate and catch gradient from four pixels around the arbitrary point coming from an arbitrary pixel of image. If the pixel satisfies the feature of edge, the edge perpendicular to the directions of gradient is processed by depth-first traverse, the pixels are marked at the same time. It will withdraw when no pixels satisfy the feature in the directions, then depth-first traverse from the next direction with gradient, mark the pixel as corner, and traverse the image completely. The segmentation method has been applied to edge recognition of color biomedical image and other images. The experimental results showed that edges and corners of biomedical image can be segmented obviously, and be easy to identify.

This study is to evaluate cardiac systolic and diastolic function of Chinese male canoeists during heavy load exercise training by Doppler echocardiography. Eighteen young male volunteer canoeists were tested, and trained five weeks. Then the change of cardiac systolic and diastolic function of the tester was examined by the Doppler echocardiography method.The results showed that there were no significant differences of LVEF and Δ%D, but the E/A ratio of elite canoeists reduced (p<0.05) after the heavy load exercise training. Moreover, the ratio of E/A less than 1 was found in two elite canoeists. The further research is required to understand the mechanism of the change. These results showed that monitoring of diastolic function was more meaningful than monitoring of systolic function during the heavy load exercise training, especially not neglected the cardiac function of elite canoeists.

Positron emission tomography (PET) is becoming increasingly important in the field of medicine and biology. The maximum-likelihood expectation-maximization (ML-EM) algorithm is becoming more important than filtered back-projection (FBP) algorithm which can incorporate various physical models into image reconstruction scheme. However, ML-EM converges slowly. In this paper, we propose a new algorithm named AC-ML-EM (accelerated and convergent maximum likelihood expectation maximization) by introducing gradually decreasing correction factor into ML-EM. AC-ML-EM has a higher speed of convergence. Through the experiments of computer simulated phantom data and real phantom data, AC-ML-EM is shown faster and better quantitatively than conventional ML-EM algorithm.

Cerebrovascular disease is one of the leading causes of death, and approximately 50% of survivors have a residual neurologic deficit and greater than 25% require chronic care. Cerebrovascular reserve capacity (CVRC) describes how far cerebral perfusion can increase from a baseline value after stimulation. High blood pressure is the most important independent risk factor for stroke and other vascular diseases. The incidence of stroke in the hypertensive is six times higher than in the patient with normal blood pressure. CVRC in the hypertensive was even lower than in control patients. MR perfusion weighted imaging (MR PWI) with the well-established acetazolamide (ACZ) stimulation test has been used for assessing brain function. The aim of this work is to assess the cerebrovascular reserve capacity by MR PWI with "ACZ" tolerance test in spontaneous hypertensive rat (SHR) and to identify its value in evaluating the CVRC. Experimental animal including 3 groups: Wistar-Kyoto rats (WKY) (12-week-old) as control group, SHR (12-week-old and 20-week-old) as experimental group. MR PWI was performed respectively before and after acetazolamide administrated orally in 3 groups on a clinical 1.5 Tesla GE Signa MR fx/i whole-body MR system. The ROI was chosen in the bilateral frontal lobe to measure the value of rCBV, rCBF and MTT. The results showed that before ACZ-test, there was statistic differences between the WKY and SHR(12-week-old), and between SHR(12-week-old) and SHR(20-week-old) in the values of rCBV and rCBF (P>0.05), and after ACZ-test, there were statistic differences between WKY and SHR (20-week-old), and between SHR(12-week-old) and SHR(20-week-old) in the rCBV value (P<0.05). It is concluded that the method of MRI PWI combined with the "ACZ stress test" can provide more qualitative and half-quantitative information on the cerebral perfusion to evaluate the CVRC in SHR.

The high contrast and high resolution photoacoustic tomography was used to image the gold nanoshell clearance in rat brain in vivo. With our current imaging system, the acquisition of photoacoustic signals is realized through a circular scan of a single-element transducer. Therefore, the data acquisition is slow. In this case, an improved simultaneous iterative reconstruction algorithm was developed to reduce the acquisition time by using limited data in the experiments. This algorithm is based on the least square principle; it can be used to reconstruct high quality images from the limited data containing much noise. Furthermore, it is always convergent. So it can improve the imaging quality comparison with conventional filter back-projection algorithm (FBP) and algebraic reconstruction algorithm (ART). Here we accurately mapped rat brain structures with gold nanoshell contrast agents. We also imaged the clearance of gold nanoshell in the rat brain. It provides an accurate non-invasive monitoring method for fluid pathways in biological tissues, which makes photoacoustic tomography as a powerful method for imaging pathologic tumor vessels, delineating neovascularization, and studying global and regional hemodynamic activities in the brain.

In this paper, we have developed a limited-view scanning microwave-induced thermoacoustic computed tomography (CT) system based on the multi-element phase-controlled focus technique. A 320-element linear transducer array was relatively rotated to capture thermoacoustic signals within limited detection views, which effectively eliminated the problem that the focused ultrasonic transducer can but receive finite signal from boundaries of tissues which are nearly perpendicular to the axis of the transducer. Using phase-controlled focus technique to collect thermoacoustic signals, the data need not be averaged because of a high signal-to-noise ratio, resulting in a data acquisition time of less than 5 s in each view. The collected limited-view data was utilized to reconstruct the geometrical details based on limited-field-filtered back-projection algorithm. The system may provide a reliable approach to thermoacoustic imaging, which can potentially be developed as a powerful diagnostic tool for early-stage breast caners.