This PDF file contains the front matter associated with SPIE Proceedings Volume 6826, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

Optical Doppler tomography (ODT) combines Doppler principle with Optical coherence tomography (OCT) to image both the structure and the flow velocity of moving particles in highly scattering biological tissues. The flow velocity can be determined by measurement of the Doppler shift of the interference fringe frequency with a short-time Fourier transform (STFT) or a Hilbert transform. For STFT ODT, velocity resolution varies inversely with the Fourier transform window size at each pixel, while spatial resolution is proportional to the window size. Consequently, velocity resolution and spatial resolution are coupled. For phase-resolved ODT with Hilbert transform, high velocity resolution can be achieved while maintaining a high spatial resolution. However, the maximum determinable Doppler shift is limited by axial-line scanning speed. As a result, STFT ODT and phase-resolved ODT are applicable to measurement of high speed and low speed velocity, respectively. We use these two methods in the established ODT system. An in vitro model using a small circular glass tubule with flowing solution of polystyrene beads inside and an in vivo model of rat's cerebral arterioles are investigated, demonstrating the advantage and disadvantage of STFT ODT and phase-resolved ODT.

OCT is a powerful tool for detection of physiological functions of micro organs underneath the human skin surface, besides the clinical application to ophthalmology, as recently demonstrated by the authors' group. In particular, dynamics of peripheral vessels and eccrin sweat glands can be observed clearly in the time-sequential OCT images. The physiological functions of these micro organs, sweating and blood circulation, are controlled by the skin sympathetic nerve in response to externally applied stress. In this paper, we present microscopically analytical results based on the dynamic OCT of the micro organs in human fingers. In sweating dynamics, it is found that a spiral sweat duct is expanded by abrupt increase of sweat due to application of stress to a volunteer, resulting in remarkable increase of the reflection light intensity of the spiral duct in OCT. Mental-stress-induced sweating in each eccrin sweat gland, therefore, is analyzed quantitatively. Furthermore, dynamic OCT observation of peripheral vessels is interesting. A small vein of a human finger is observed clearly by the TD-OCT, where the vein expands and contracts repeatedly even in the resting state for temperature control on the fingertip. A change in the cross-sectional area of the vein exceeds 80 % for a young volunteer. The dynamic OCT will allow us to propose novel diagnoses of excessive sweating and diseases related to the sympathetic nerve.

The aim of this report is to establish a tongue inspection method based on OCT imaging for quantifying the tongue properties in traditional Chinese medical diagnosis. The measurement was performed in the model of rats suffering with Spleen-Stomach Dampness-Heat Syndrome using OCT equipment, OCT image and histology estimates of the glossal layer of microstructure were obtained, and the accurate thickness and moisture degree of the tongue coating were analyzed. These OCT image showed that tongue every layer matched the histology estimates of the glossal microstructure, and compared with normal control group the thickness of tongue coating increased in rats suffering with Spleen-Stomach Dampness-Heat Syndrome than normal control rats (P<0.01), yet the moisture degree of tongue body of model group decreased (P<0.01). Therefore, OCT image technique may be benefit and helpful as a tool to provide an objective diagnostic standard for study on tongue inspection in the clinical practice and research of TCM.

High-speed full-range complex Fourier domain optical coherence tomography (FDOCT) using sinusoidal phase-modulating interferometry is proposed. A high-rate two-dimensional (2-D) CCD camera is used to record time-sequential sinusoidally phase-modulated 2-D spectral interferograms, from which the complex 2-D spectral interferograms corresponding to each frame of the 2-D CCD camera are extracted by Fourier transform method. By taking inverse Fourier transform of the complex spectral interferograms, full-range B-scan images free of the complex conjugate ambiguity as well as dc and autocorrelation noises are obtained at intervals of the frame period of the 2-D CCD camera. Time-sequential cross-sectional imaging of human skin ex vivo with the proposed method is demonstrated.

Optical coherence tomography(OCT) is a new non-invasive, cross-sectional imaging technique that measures depth resolved reflectance of tissue by employing low-coherence interferometer. The acquisition of the signal may be achieved either in the time domain(TD) by altering the reference arm length of the interferometer, or in the frequency domain(FD) where the individual spectral frequency components of the interference signal are acquired.In this paper, the principle of FD OCT is presented and the main parameters which influence the quality of image are discussed in theory. A spectral domain OCT(SDOCT) system is introduced which can avoid scanning of the reference thus can reach very high acquisition speed. A design which combines the SOCT technique and endoscopy is put forward. We propose possible solutions to minimize the structure of rotating scanning which uses min-ultrasonic-motor to drive reflecting prism according to alimentary tract endoscopy's feature. Multi-layer cover-glasses (the thickness of every layer is 260.0μm) and onion-skin (1mm thick) are used as the object for imaging to prove that the system is successful. The lateral resolution is 15μm and the measuring range is 4.5mm. We obtain he measuring distance of two glass layers and the depth scan of an onion from the surface.

Point spread functions (PSF) of a given OCT system in both longitudinal and transversal directions often cause bluring in OCT images. A two-dimensional sharpening method is proposed to simultaneously deconvolve both the longitudinal and transversal PSFs. This is achieved through employing an artificial kernel formed by a two-dimensional matrix, incoroporating the product of the longitudinal and transversal PSFs. For comparison, both Wiener and Lucy-Richardson algorithms are used for the two dimensional deconvolution. The experimental results show that these two deconvolution algorithms can enhance the image sharpness effectively in both longitudinal and transversal directions.

Optical coherence tomography (OCT), which is a novel tomography method, is non-contact, noninvasive image of the vivo tomograms, and have characteristic of high resolution and high speed; therefore it becomes an important direction of biomedicine imaging. However, when the OCT system used in specimen, noise and distortion will appear, because the speed of the system is confined, therefore image needs the reconstruction. The article studies OCT 3-D reconstruction method. It cotains denoising, recovering and segmenting, these image preprocessing technology are necessary. This paper studies the high scattering medium, such as specimen of skin, using photons transmiting properties, researches the denoising and recovering algorithm with optical photons model of propagation in biological tissu to remove the speckle of skin image and 3-D reconstrut. It proposes a dynamic average background estimation algorithm based on time-domain estimation method. This method combines the estimation in time-domain with the filter in frequency-domain to remove the noises of image effectively. In addition, it constructs a noise-model for recovering image to avoid longitudinal direction distortion and deep's amplitude distortion and image blurring. By compareing and discussing, this method improves and optimizes algorithms to improve the quality of image. The article optimizes iterative reconstruction algorithm by improving convergent speed, and realizes OCT specimen data's 3-D reconstruction. It opened the door for further analysis and diagnosis of diseases.

We present a high-speed spectral domain optical coherence tomography (SD-OCT) system at 830 nm wavelength which is consisted of a fiber based Michelson interferometer and a custom-built spectrometer. The designed resolution of the spectrometer is about 67.4pm which limits the maximum detection depth 2.56mm in air. And the 35us exposure time of the high speed line scan CCD makes real-time imaging possible. Furthermore, a novel method of spectrometer calibration is put forward. The method can remove the influence of dispersion mismatch, thus accurately determine the distribution of wavelength on the line scan CCD, which leads to a precise interpolation and a subsequent better contrast image.

Laser-based photoacoustic imaging and microwave-based thermoacoustic imaging, combining the advantages of both the high image contrast that results from electromagnetic absorption and the high resolution of ultrasound imaging, could be the next successful generation imaging techniques in biomedical application. It can provide an effective approach of tissue structure and functional images to study the architectures, physiological and pathological properties and metabolisms of biological tissues. This paper is focused on photoacoustic and thermoacoustic imaging application in cancer early detection and treatment monitoring. A unique photoacoustic imaging system was used to detect tumors neovascularization associated with angiogenesis in a rat animal model. We also developed the imaging system to monitor the vascular damage during photodynamic therapy treatment. This method could be potentially used to guide PDT and other phototherapies using vascular changes during treatment to optimize treatment protocols, by choosing appropriate types and doses of photosensitizers, and doses of light. Potentially development of photoacoustic imaging and thermoacoustic imaging to employing in functional and molecular imaging also has been discussed. Especially, these imaging modalities can be further developed by using the contrast agents which modified with tumor-targeting antibodies to realize cancer early detection and cancer target treatment monitoring.

Photoacoustic imaging technique, which provided high ultrasonic resolution and high optical contrast tissue images, can overcome the disadvantages of pure optical imaging by measurement of laser-induced sound waves. The waves produced by tissue are high-frequency ultrasounds, meaning that they cannot be heard by human ear. However, it can be picked up with ultrasonic transducer and analyze them with a computer. The laser-induced ultrasonic signals from a biological sample can be used to reveal the tissues structure based on optical contrast. In current experiment system, an integrity multi-element synthetic aperture focusing (M-SAF) photoacoustic imaging system using real-time digital beamformer is developed. This system relies on pumping laser source to irradiate the biological tissue to produce photoacoustic signal, a linear ultrasonic transducer array is connected to a multichannel signal acquisition and real-time digital beam-formation system providing techniques of real-time dynamic receiving focus and dynamic receiving apodization to process the photoacoustic signal. Each element of the transducer array has a thin cylinder ultrasonic lens to select 2D image plane and suppress the out-of-plane signals to realize photoacoustic computed tomography. This method and system can provide a fast and reliable photoacoustic tomography approach that could be applied to noninvasive imaging and clinic diagnosis.

In a preclinical study, we demonstrated that blood flow and tissue oxygenation could be manipulated by focused ultrasound; the effects of such manipulation were interrogated via optical spectroscopy at wavelengths where oxy- and deoxy-hemoglobin display different extinction properties. We have designed a clinical breast scanner based on these noninvasive techniques. In addition to the focused ultrasound field intersecting with the volume of optical illumination and points of spectral collection, a diagnostic quality breast imaging probe is incorporated into the scanhead to achieve image guidance. Experimental confirmation of the system performance of the focused ultrasound field properties, diagnostic imaging capabilities and NIR spectroscopy subsystem has been carried out to demonstrate readiness for a clinical study involving 200 patients who are scheduled to undergo ultrasound-guided biopsy to rule out breast cancers.

We propose a new laser irradiation method for the treatment of cutaneous lesions in plastic surgery. In general, lasers with a spot size of 1 to 10 mm are used in irradiation on diseased skin. Although the target absorbs more light energy according to the theory of selective photothermolysis, the surrounding tissue, however, is still somewhat damaged. In proposed method, an f-theta lens, which is assembled by a shrink fitter, focuses the irradiation laser beam to a very fine spot with the size of 125 μm. Guided by the captured object-image, such laser beam is conducted by a pair of galvanometer-driven mirrors to irradiate only the desired tissue target without thermal damage to surrounding tissue. Moreover, an optical coherence tomography, whose probe is capable of wide field of view, can be used to provide the guidance information for the best treatment. The usefulness of the developed laser therapy apparatus was demonstrated by performing an experiment on the removal of tattoo pigment.

The goal of this study was an in vitro evaluation of one dimension dynamic ablation of hard bone tissue with pulse CO₂ laser. The tissue model was bovine shank bone which was put on a PC-controlled motorized linear drive stage and move repeatedly through the focused beam. Pulse CO₂ laser wavelength 10.6μm was focused down to a spot size of 510μm on the tissue sample surface. radiant exposure ranged from 5J/cm² to 45J/cm², repetition rates was 60Hz. After irradiation, the groove morphology produced by laser ablation were examined by optical coherent tomography (OCT) and light microscope following standard histological processing. Quantitative measurement of geometry and thermal damage of ablation groove was presented. It was shown that the width and depth of ablation groove and the zone of collateral thermal damage created in hard bone sample increased steadily with laser fluence. The results suggest that pulse CO₂ laser can be a suitable candidate to cut hard bone tissue, and laser radiant exposure has an important effect on ablation rate and collateral thermal damage.

The purpose of this article is to report long-term follow-up of improved external vulvuloplasty, intravenous laser photocoagulation and local sclerotherapy treatment of primary deep venous valvular insufficiency in eight hundred and seventy-two patients from Nov. 2000 to May 2006. Patients were evaluated clinically and with duplex ultrasound at 1, 3, and 12 months, and yearly thereafter until the fifth year to assess treatment efficacy and adverse reactions. Successful occlusion of the great saphenous vein and absence of deep vein reflux on color Doppler imaging, were noted in 956 limbs of 852 cases( 1 month follow-up), 946 limbs of 842 cases (6 month to 1 year follow-up), 717 of 626 (1~2 year follow-up), 501 of 417 (2~3 year follow-up), 352 of 296 (3~5year follow-up), 142 of 106 (5 year follow-up) after initial treatment. The cumulative total number of recurrence of reflux was fifteen cases. The respective competence rate was 95.18%, 96.23%, 94.23%, 95.25%, 94.23% and 94.12%. Of note, all recurrence occurred before 9 months, with the majority noted before 3 months. Bruising was noted in 0.7% of patients, tightness along the course of treated vein in 1.0% of limbs. There have been no paresthesia of cases, skin burns and deep vein thrombosis.

Low-power laser irradiation (LPLI) leads to photochemical reaction and then activates intracellular several signaling pathway. Reactive oxygen species (ROS) are considered to be the primary messengers produced by LPLI. Here, we studied the signaling pathway mediated by ROS upon the stimulation of LPLI. Src tyrosine kinases are well-known targets of ROS and can be activated by oxidative events. Using a Src reporter based on fluorescence resonance energy transfer (FRET) technique, we visualized the dynamic Src activation in Hela cells immediately after LPLI. Moreover, Src activity was enhanced by increasing the duration of LPLI. In addition, our results suggested that ROS were key mediators of Src activation, as ROS scavenger, vitamin C decreased and exogenous H₂O₂ increased the activity of Src. Meanwhile, Gö6983 loading did not block the effect of LPLI. CCK-8 experiments proved that cell vitality was prominently improved by LPLI with all the doses we applied in our experiments ranging from 3 to 25J/cm². The results indicated that LPLI/ROS/Src pathway may be involved in the LPLI biostimulation effects.

Usually biological tissue has complex geometry. In earlier works we used simple skin model with a number of horizontal layers. In this work we use the model that approximates complex objects. For example, cancerous growth consists of many layers which can be of different forms, for inter alia blood vessels. In this work we attempted to elaborate a mathematical model of thermal response of laser irradiated multilayered biological tissue. Every layer has its own optical and physical characteristics. We used Monte-Carlo simulation to calculate the propagation of light (laser beams) in tissue and receive the heat source function. As we usually have radial symmetric laser beams we use cylindrical coordinates. The solution of the 2D heat conduction equation is based on finite-element theory with the use a predefined number of finite elements. We simulated constant and pulse laser irradiation and as result there are temperature fields and the dynamics of heat conduction. Analysis of the results shows that heat is not localized on the surface, but is collected inside the tissue. By varying the boundary condition on the surface and type of laser irradiation (constant or pulse) we can reach high temperature inside the tissue without simultaneous formation of necrosis.

The adaptive optics (AO) retina imaging was performed with contrast enhancement by characterizing polarization parameters of the living retina. A removable pair of polarization state generating unit near the optical source and analysis unit near the CCD camera was incorporated into the basic 37-channle deformable mirror AO microscopic ophthalmoscope. Double-pass imaging polarimetry of the human eye was carried out, then incomplete Mueller matrix was calculated and analyzed to optimize the retina imaging condition using polarized light, which caused the subretinal structures with different polarization properties to emerge from the scattering light background, so the contrast of the image can be substantially enhanced. This method is demonstrated briefly and its validity was tested in the laboratory. The high-resolution images of ocular fundus are compared with 8-frame-averaging images we obtained prior to this method. The experiment results now show improved visualization of fundus structures to some extent without greatly sacrificing image resolution.

The mechanisms of light scattering from biological cells are investigated by using confocal microscopy and light scattering spectroscopy (LSS). The LSS system measures the light scattering in the visible wavelength range from 1.1° to 165.0°. The results provide evidence that the small-sized subcellular structures are the major contributors to the backscattering signals. A unified Mie and fractal model is proposed to interpret light scattering by biological cells. The results demonstrate that Mie scattering from bare cells and nuclei is dominant in small forward scattering angles. But Mie scattering from bare cells and nuclei is found not to be able to provide a satisfactory interpretation of scattering spectral signals in the large angles, which is determined by fractal scattering from the subcellular structures. The findings of the theoretical model are consistent with the results of experimental investigation on the light scattering from biological cells.

The photo-induced delayed luminescence (DL) of human serum and its dependence on exciting conditions, including exciting wavelength, exciting energy and exciting power, were studied in this paper. It was found that the DL of serum follows the law of hyperbolic decay rather than exponential decay, exhibiting coherent character. The exciting conditions had affinities with the activation as well as the active reactions of biological molecules, which were sensitive and active under UV-light excitation. Exciting energy mainly decides the activation. More sufficient activation leads to more drastic active reactions and stronger re-emission ability of bio-molecules after illumination, resulting in the more intensive photon emission and lower DL decay speed rate. On the other hand, exciting power also plays an important role in impacting the active reactions. Exciting light with higher power makes the active reactions more drastic, causing the higher photon counts. However, there are few correlations between exciting power and the re-emission ability of bio-molecules. These results may be useful for investigation and application of human serum.

An experimental protocol was established for noninvasively measuring the optical transport characteristics of skin tissue along human meridian direction over body surface including at acupuncture points. The diffuse remittance for 658 nm light radiation along the pericardium meridian and non-meridian directions were measured respectively. The influence of the chopped frequency of light on the detected light signal was investigated. It is shown that the optical transport characteristics of skin tissue accords with the Beer's exponential attenuation law along the meridian including at acupuncture points and non-median directions. However there is an obvious difference between the propagations along the meridian direction and non-meridian direction (P<0.05). Furthermore, the chopped frequency can affect the detected signal. The diffuse remittance signal decreased with the chopped frequency's increase and it was different between the meridian and non-meridian directions. These findings are important and meaningful for interpreting the human meridian phenomena by biomedical optics.

Intense pulsed light system in combination with contact cooling is a useful tool for treating photodamaged skin. It can emit broadband light, and target different kind of pigment in skin. But the pressure on skin often influences the temperature field distribution inside the skin when the treatment head contacts skin. In this paper, we assumed the pressure on skin would cause the changes of thermal diffusivity and optical absorption coefficient. Under these assumptions, the temperatures inside skin induced by intense pulsed light system with contact cooling were modeled using Monte Carlo method and explicit finite difference bioheat conduction equation. The results suggest that pressure imposed on skin surface should be taken into account when using pulsed light system with contact cooling to treat lesions inside the skin.

A three-dimension comprehensive thermal model of breast is developed to understand the influence of the tumor on the surface temperature. Finite element analysis method is used to solve the heat diffusion equation. The simulated results show that the surface temperature distribution of the breast is directly related to the position and size of the tumor embedded in it. It is also found that our numerical results could capture the change in the position of tumor. Furthermore, the numerical results are compared with the thermography. Our study shows that the temperature distribution over breasts can be well simulated with this comprehensive thermal model, which seems to be a powerful adjuvant tool to help the clinician in the interpretation of thermograms.

Conventional polarization coherent anti-Stokes Raman scattering (P-CARS) microscopy always suffers from serious signal attenuation in imaging cells and tissue. We develop a novel heterodyne-detection method for P-CARS imaging with an ability of high imaging vibrational contrast and signal strength. We demonstrate this method by imaging 4.69-μm polystyrene beads immersed in water.

We report a post-growth microwave heating implementation to improve on the surface-enhanced Raman scattering (SERS) performance of a metal-polymer substrate. This technique generates SERS-active nanostructures on the gold film deposited on hierarchical polystyrene (PS) beads. A significant improvement in SERS signals of bioanalyte (saliva) is achieved, demonstrating its potential to enhance SERS activities in metal-polymer substrates for biomedical applications.

Near-infrared (NIR) Raman spectroscopy has shown promise to detect cancer and precancer in human through measuring the biomolecular and biochemical changes of tissue associated with diseases transformation. Most of studies of NIR Raman spectroscopy on tissue diagnosis are concentrated on the so-called fingerprint region (800-1800 cm^-1), there are only very limited work for tissue diagnosis using the high wavenumber (2800-3700 cm^-1) spectral features. The purpose of this study is to explore the ability of NIR Raman spectroscopy in high wavenumber region for the in vivo detection of cervical precancer. A rapid NIR Raman spectroscopy system associated with a fiber-optic Raman probe was used for the in vivo spectroscopic measurements. Multivariate statistical techniques including principal components analysis (PCA) and linear discriminant analysis (LDA) were employed to develop the diagnostic algorithm based on the spectral data from 2800-3700 cm^-1. Classification result based on PCA-LDA showed that high wavenumber NIR Raman spectroscopy can achieve the diagnostic sensitivity of 93.5% and specificity of 95.7% for precancer classification.

Fluorescence microscopies with nanometer-distance resolution to locate the position and track individual single molecules were developed and applied. We focused on quantitatively study of the motion of lipid-anchor green fluorescent proteins with an oblique illumination mode of the microscope. A protein dynamics was analyzed using a photon statistics. In addition, fluorescence resonance energy transfer (FRET) microscopy and surface enhance Ranman spectroscopy (SERS) studies etc. were also introduced in this report .

Cytotoxic chemotherapy agents are the foundation of current leukemia therapy. For a large number of adult and elderly patients, however, treatment options are poor. These patients may suffer from disease that is resistant to conventional chemotherapy or may not be candidates for curative therapies because of advanced age or poor medical conditions. To control disease in these patients, new therapies must be developed that are selectively targeted to unique characteristics of leukemic cell growth and metastasis. A large body of elegant work in the field of immunology has demonstrated the mechanisms whereby leukocytes traffic to specific sites within the body. Vascular cell adhesion molecules and chemicalattractants combine to direct white blood cells to appropriate environments. Although it has been hypothesized that leukemic white blood cells home to hematopoietic organs using mechanisms similar to those of their benign leukocyte counterparts, detailed study of leukemic cell transit through bone marrow has yet to be undertaken. We develop the "in vivo microscopy" to study the mechanisms that govern leukemic cell spread through the bone marrow microenvironment in vivo in real-time confocal infrared fluorescence imaging. A recently developed "in vivo flow cytometer" and optical imaging are used to assess leukemic cell spreading and the circulation kinetics of leukemic cells. A real- time quantitative monitoring of circulating leukemic cells by the in vivo flow cytometer will be useful to assess the effectiveness of the potential therapeutic interventions.

In this paper, we present our investigation on the identification of endogenous fluorophores in photoreceptors using autofluorescence spectroscopy, which is performed with an inverted laser scanning confocal microscope equipped with an Argon ion laser and a GreNe laser. In our experiments, individual cones and rods are clearly resolved even in freshly prepared retina samples, without slicing or labeling. The experiment results show that autofluorescence spectrum of the photoreceptors has three peaks approximately at 525nm, 585nm and 665nm. Furthermore, the brightest autofluorescence originates from the photoreceptor outer segments. We can, therefore, come to a conclusion that the peaks at 525nm, 585nm are corresponding to FAD and A2-PE, respectively, which are distributed in the photoreceptor outer segments.

In this paper, we present a novel wide-field fluorescence sectioning microscopy using dynamic speckle illumination that provides depth discrimination. Some simple modifications are made to a conventional wide field fluorescence microscope, which allows for the illumination of the sample using dynamic speckle patterns and the acquisition of a sequence of independent wide-field fluorescence images. The full-field fluorescence image of the sample at a particular depth is obtained using specific digital image processing algorithms. Compared with conventional confocal scanning fluorescence microscopy, this novel imaging modality is capable of providing a reasonably high sectioning performance with a compact and cost-effective system. The experimental results show that the wide-field fluorescence sectioning microscopy can provide high contrast imaging even in scattering biological media, therefore has wide potential applications in biomedical research and clinics.

Noninvasive and minimally invasive blood glucose sensing is one of most interesting research fields. For the noninvasive measurement using near-infrared spectroscopy, the optical signal was impaired by the uncertain physiological noise and systematical drift. A floating reference method by differentially processing two signals from reference point and measuring point was used to deal with these uncertain noises. For the minimally invasive measurement, interstitial fluid extracted by ultrasound and vacuum is investigated. Low-frequency ultrasound was applied to enhance the skin permeability to interstitial fluid by disrupting the stratum corneum lipid bilayers. In this paper, a kind of protein absorbing the glucose specifically called D-galactose/D-glucose Binding Protein (GGBP) was introduced to construct a novel surface plasmon resonance (SPR) measuring system. By immobilizing GGBP onto the surface of the SPR sensor, a new detecting system for glucose testing in mixed solution was developed. The experimental result indicated that, the SPR system succeeded in distinguishing glucose resolution of 0. 1 mg/L, and had linear relationship between 0.5 mg/L and 5 mg/L.

Quality and parameters of probing optical beams are extremely important in biomedical imaging systems both for image quality and light coupling efficiency considerations. For example, the shape, size, focal position, and focal range of such beams could have a great impact on the lateral resolution, penetration depth, and signal-to-noise ratio of the image in optical coherence tomography. We present a design, construction and characterization of different variations of GRIN and ball fiber lenses, which were recently proposed for ultra-small biomedical imaging probes. Those fiber lens modules are made of a single mode fiber and a GRIN or ball fiber lens with or without a fiber spacer between them. The lens diameters are smaller than 0.3 mm. We discuss design methods, fabrication techniques, and measured performance compared with modeling results.

Alpha-fetoprotein (AFP) detection by using a localized surface plasmon coupled fluorescence (LSPCF) fiber-optic biosensor is setup and experimentally demonstrated. It is based on gold nanoparticle (GNP) and coupled with localized surface plasmon wave on the surface of GNP. In this experiment, the fluorophores are labeled on anti-AFP which are bound to protein A conjugated GNP. Thus, LSPCF is excited with high efficiency in the near field of localized surface plasmon wave. Therefore, not only the sensitivity of LSPCF biosensor is enhanced but also the specific selectivity of AFP is improved. Experimentally, the ability of real time measurement in the range of AFP concentration from 0.1ng/ml to 100ng/ml was detected. To compare with conventional methods such as enzyme-linked immunosorbent assay (ELISA) or radioimmunoassay (RIA), the LSPCF fiber-optic biosensor performs higher or comparable detection sensitivity, respectively.

A novel flat-faced thin fiber optic tweezers is proposed. It was fabricated by heating and drawing method under the condition of laying aside the conventional focusing method. With this fiber optic probe, the single fiber optic tweezers realized trapping a yeast cell in water. The experiment results were in good agreement with the simulated results which were carried out using FDTD method.

Fluorescence spectroscopy diagnostics on epithelium tissues requires being able to obtain depth resolved measurements. We study here an optical probe combining a ball lens, a flat tip excitation fiber and a bevel collection fiber. Varying the angle of the bevel collection fiber is seen to be a way of changing the depth of the fluorescence collected signal. Fixing the excitation-collection distance, we observe that large bevel angles of the collection fiber tip allows to augment the fluorescence collected signal of the stroma, whereas small angles improve the signal from the epithelial layer.

A novel two-core optical fiber probe is proposed and fabricated by grinding method. The distribution of the optical field emerging from the probe was simulated using BPM method. With the probe, a single fiber optic tweezers system was constructed and successfully used to trap and rotate microscopic particles. The structure of this system is simple and compact. With the merit of easily controlling and adjusting, this novel system can adapt to the optical micromanipulation need of more biological cells and molecular.

A series of novel near-infrared fluorescent compounds containing both desferrioxamine (DFO) and multi-RGD peptides, i.e. DFO-Cypate-(RGD)_n-NH₂ (1), were designed and synthesized based on a dicarboxylic acid-containing near-infrared fluorescent carbocyanine (Cypate) scaffold. The trimeric 1 (n=3) showed the strongest cellular internalization into A549 cells in vitro among the four analogs of 1 (n=1, 2, 3, 4), suggesting that such a linear array of three RGD peptide motifs might be optimal for synergistic effects on cellular internalization. The four analogs showed higher internalization than an integrin α_vβ₃-targeting cyclic RGD peptide analog DFO-cypate-[RGDfK(~)] (2) after 1h of incubation, indicating that the linear arrays of multi-RGD peptides might be different from the cyclic RGD peptide analog in the internalization kinetics and mechanism of receptor targeting. Confocal microscopy showed that 1 (n=4) could localize at least in part to the mitochondria. Noteworthy, the two compounds 1 (n=2, 3) resulted in a 1.5 to 2 fold increase in fluorescence of the calcium indicator fluo4 after 30 min of incubation. These results suggest the possible effects of these compounds on the cellular function by internalization. Such a type of near-infrared fluorescent cypate analogs containing both DFO and multi-RGD peptides could provide a platform for discovering and developing novel multifunctional optical contrast agents for integrin receptor targeting as well as related tumor imaging and therapy.

Core-shell semiconductor quantum dot (QD) has been attracting more and more extensive attentions and interests in biomedicine photonics due to its good stability and high fluorescence quantum efficiency. In this paper, we reported that the photoluminescence of core-multishell CdSe QDs performed a two-photon action under a femtosecond laser excitation in wide incident power range. The two-photon absorption cross sections of such QDs were measured by the intensity-dependent transmittance method and the results demonstrated a very strong two-photon absorption capacity of QDs. The fluorescent spectra of QDs with an amphiphilic polymer showed that the fluorescent peak wavelength appeared blue shift obviously and the full width at half maximum (FWHM) broadened to 40 nm. Furthermore, the intracellular distribution of the QDs probes in cancer cells had been observed under two-photon excitation. The experimental results indicated that the QDs mainly distribute at cell membrane and selectively gathered on cytoplasm of cancer cells. The QDs which permeated into cancer cells quickly were very steady binding with cancer cells. Under long time laser irradiation, the QDs hardly took place photobleaching, which demonstrated a very steady photochemical performance of these QDs..

Optical probes are now routinely used in a remarkable number of imaging applications in the life sciences and medicine. We report the design, synthesis and characterization of a novel nanoprobe for biological applications based on surface enhanced Raman scattering (SERS). Specifically, the nanoprobe consists of magnetic Fe₃O₄ nanoparticles immobilized with silver nanoparticles and SERS tags. An efficient cellular uptake has been confirmed with confocal laser scanning microscopy. The nanoprobe retains its excellent SERS signals when incorporated into a cell. Besides, the probe also delivers spatially localized chemical information from its biological environments. The multi-functional probe is likely to be useful to develop new tools for targeted molecular probing of cells and provide a new way to monitor the complex changes at cellular level.

Polymeric micelles, self-assemblies of block copolymers, are emerging as attractive drug delivery systems for hydrophobic photodynamic sensitizers. Recent advances in the formulation of photosensitizers for photodynamic therapy (PDT) with diblock copolymers are presented. This paper reviews the main characteristics of existing drug-loading micelles with diblock copolymers, including loading efficiency, particle size and morphology, stability, cellular uptake, subcellular distribution and therapeutic efficiency. The results indicate that diblock polymeric micelles are potentially useful for the delivery and release of hydrophobic photosensitizers in PDT. While significant progress has been achieved, many challenges remain in elucidating the detailed internalization mechanisms of the micelles and resulting mechanisms for enhanced photocytotoxicity. Some critical issues for diblock copolymers to deliver hydrophobic photosensitizers for PDT are highlighted.

Photodynamic diagnosis (PDD) is of increasing interest for diagnosis in oncology. It is based on the selective accumulation of photosensitizers in tumours, such as porphyrin and phthalocyanine. In the present study, novel dihydroxy phosphorus tetrabenzotriazacorrole derivates have been synthesized. And photophysical properties of these derivates have been studied. Dihydroxy phosphorus tetrabenzotriazacorrole derivates display a fluorescence which is from the higher S₂ electronic state. With excitation at 614 nm, the fluorescence maximum is at 668 nm for dihydroxy phosphorus(V)-2,9,16,23-tetranitrotetrabenzotriazacorrole {P(OH)₂TBC(NO₂)₄} in N,N-dimethylformamide (DMF). But with excitation at 310 nm for P(OH)₂TBC(NO₂)₄ in DMF, in addition to S₁ fluorescence a new fluorescence peak appears at 490 nm, which is attributed to S₂-state fluorescence. It indicates that the dihydroxy phosphorus tetrabenzotriazacorrole derivates might have a potential application as a dual fluorescent marker for photodynamic diagnosis.

Introduction: As it is always difficult to find the optimal combination of photosensitizer and of laser wavelength to achieve selective vascular damage in PWS-PDT, the selective vascular effects of HMME (Hematoporphyrin monomethyl ether) mediated PDT with 413 nm and with 532 nm were compared by mathematical simulation in this study. Materials & Methods: Firstly, distribution of 413 nm, 532 nm light in PWS tissue was simulated by Monte Carlo model. Two energy density groups were set, one is 80mW/cm²x40min for both 413 nm and 532 nm, the other is 80mW/cm²x40min for 532 nm while 80mW/cm²x20min in for 413 nm. Secondly, the productivity of reactive oxygen species (ROS) in target vessels and normal tissue were simulated using a simulation system for PDT of PWS established in our lab, which considering the amount of light and photosensitizer in tissue, the molar extinction coefficient of photosensitizer, and quantum yield of ROS. Concentration of HMME for each wavelength were same. Finally, the productivity of ROS n in target vessels and normal tissue were compared between 413 nm PDT and 532 nm PDT under different energy density. Result: Under the same energy density, ROS productivity in target vessels of 413 nm PDT was significantly higher than that of 532 nm PDT. Moreover, it was still higher at low energy density than that of 532nm PDT with high energy density. Conclusion: HMME mediated PDT using 413 nm has the potential to increase the selective vascular effect of PDT for PWS by shortening treatment time.

Photodynamic therapy (PDT) induces cell apoptosis mainly by the mitochondrial pathway. The Bcl-2 family proteins play an important role in this pathway. However, the detailed mechanism is not elucidated. The current study was aimed to determine whether Bim, a BH3-only protein of Bcl-2 family, was involved during Photofrin-PDT-induced apoptosis in ASTC-a-1 and MCF-7 cell lines. The data show that massive reactive oxygen species (ROS) were generated firstly after Photofrin-PDT treatment, leading to the disappearance of the mitochondrial membrane potential. Furthermore, the activation of Bim and Bax were dynamically observed. Confocal imaging of the cells transfected with GFP-BimL demonstrated that BimL translocate to mitochondria occurred about 12 min after PDT treatment. Bax activation occurred about 15 min after PDT treatment. These results suggest that Bim, as an effectors, was involved in Photofrin-PDT-induced apoptosis.

To analyse the effect of oxygen on the photobleaching of HMME, photobleaching rates of HMME when bubbled with oxygen or argon, added with singlet oxygen quenchers or hydroxyl radical quencher were compared. According to the solvents in which HMME was dissolved, four groups were set, HMME-DMSO, HMME-PBS, HMME-Albumin buffer, HMME-Cells suspension. Each group was divided into four subgroups, bubbled with oxygen or argon, added with singlet oxygen quenchers or hydroxyl radical quencher respectively. Spectra measurement was performed at 10min intervals for a period of 40 min before and after laser irradiation, photobleaching rates under different condition were compared. Photobleaching was the fastest when bubbled with oxygen, apparentely inhibited when bubbled with argon or added with singlet oxygen quenchers. Hydroxyl radical quencher can inhibit photopleaching of HMME slightly, but its inhibition was gentler than that of singlet oxygen quenchers and argon. Oxygen plays an inportant role in thre photobleaching of HMME, and the process is singlet oxygen mediated self-sensitized photooxidation.

To study the risk of thermal injury in photodynamic therapy for choroidal neovascularization by calculating the retinal temperature of rabbits, a mathematical model for laser induced thermal effect on retina was developed. Homogeneous layer retinal models of different pigmented rabbits were presented to analyze the light distribution. The finite element method realized by Matlab software was used to solve classical bio-heat transfer model - Pennis equation, in which heat loss due to choroidal blood flow was considered. The retinal temperature was calculated with different laser parameters, including different wavelengths (532nm, 578nm and 690nm), power density (200~1600 mW/cm²), spot diameter (1mm, 2mm and 3mm) and different pigmented eye fundi. The prediction results showed the retinal temperature increased first, then reached maximum in a few seconds and kept constant during laser irradiation. Once laser exposure ended, the temperature decreased quickly to normal. With the increase of laser power density and spot size, the retinal temperature raised too. The temperature reduced exponentially with the distance from laser spot increased. The maximum temperature of non-pigmented rabbits was lower than that of pigmented rabbits. The temperature induced by 578nm laser irradiation was highest, the next was by 532nm laser and the lowest was by 690nm laser. For current parameters used to treat choroidal neovascularization (690nm, 600mW, 2mm, 83sec), the maximum retinal temperature calculated was less than 45 °C, which indicating no thermal damage induced.

In this study, the early apoptotic events of mTHPC-medicated photodynamic therapy (PDT) was explored in two human nasopharyngeal carcinoma (NPC) cell lines - NPC/HK1 cells and NPC/CNE2 cells. Cells (5 x 10³) were incubated with mTHPC (0.8 μg/ml) in chamber slides for 20 h and subjected to light irradiation at 2 J/cm² (LD₈₀). Morphologic changes of treated cells were examined at 0- 4 h after the light irradiation by a light microscopy. The early stage of apoptosis was detected by fluorescein-conjugated Annexin V (Annexin V-FITC) assay. Mitochondrial membrane damage and cytochrome c release were determined by flowcytometric analysis. The Bcl-2 expression was measured by Western blot analysis. One hour after mTHPC-mediated PDT, membrane blebbing and cell shrinkage appeared in both HK1 and CNE2 cells. Annexin V-FITC assay showed that a considerable number of HK1 and CNE2 cells became apoptotic at 1 h after PDT. Flowcytometric analysis showed that the cytochrome c was released at 1 h after PDT. The Bcl-2 expression also declined significantly in both cell lines compared to the control groups. mTHPC-mediated PDT can effectively induce apoptotic responses in NPC cells which might be modulated by mitochondrial damage and Bcl-2 inhibition.

It has been proven that photodynamic therapy (PDT) is effective in treating various malignant and non-malignant diseases. In the treatment of certain non-malignant vascular diseases, such as wet age-related macular degeneration (AMD) and port wine stains (PWS), unlike in the treatment of malignant solid tumors, light irradiation usually starts immediately after the intravenous (IV) injection of photosensitizers while the photosensitizers is mainly circulating inside blood vessels. Under such vascular-targeting action mode, photoreactions between photosensitizers and light can selectively destruct the vascular tissues. Light distribution is complex so that it is important to understand the optical properties of targeted vessels and surrounding tissues. To better determine the optical properties of vascular tissues, we developed a tissue-simulating phantom and adopted frequency-domain measurement of phase difference. Absorption and reduced scattering coefficients in blood vessels were estimated and light distribution was simulated by the Monte Carlo method. These determinations are essential for the implication of better light dosimetry models in clinical photodynamic therapy and vascular-targeting PDT, in particular.

Mitochondrial apoptosis inducing factor (AIF) on activation can translocate to the nucleus and induce cell death via caspase-independent pathway in cisplatin-induced apoptosis. Yet the precise signal transduction pathway(s) which regulates AIF-induced apoptotic pathway still remains poorly understood. In this study, we investigated the molecular mechanism of AIF release and redistribution in cisplatin-induced apoptosis in living ASTC-a-1 cells, as assessed by real-time anlysis. Herein, We report that during cisplatin-induced apoptosis, calpain activation, as measured in intact cells by a fluorescent substrates, is an early event, taking place well before AIF release and caspase-3 activation. Confocal imaging of the cells transfected with AIF-GFP demonstrated that AIF release occurred about 9 h after cisplatin treatment. The event proceeded progressively over time, coinciding with a nuclear translocation and lasting for more than 2 hours. AIF release and redistribution were effectively inhibited in samples co-treated with calpeptin and PD150606, two selective calpain inhibitors. Therefore, our results clearly show the kinetics of AIF release and redistribution in cisplatin-induced apoptosis in living ASTC-a-1 cells, and calpain played a crucial role in these events.

Endoscopic optical coherence tomography (OCT) allowing high-resolution imaging of internal tissue is attractive for medical imaging. Fibre, fibre bundle or GRIN lens rod acting as endoscopic probe is placed in the sample arm of a Michelson interferometer in current endoscopic OCT systems, this arrangement has to be carefully configured to avoid dispersion and polarization fading. In this study, a common path OCT system with outside path length compensation is presented. The system based on Fizeau configuration requires a Michelson interferometer to compensate the optical path difference between the reference and signal light in the Fizeau sensing interferometer. Experiments of path length compensation and vibration are conducted, and the results demonstrate that this outside compensation method is feasible and the system is immune to the vibration which occurs at the Fizeau sensing interferometer. This OCT imaging approach is very suitable for endoscopic imaging and detailed endoscopic OCT system is also presented. Several samples were imaged to demonstrate the performance of the proposed OCT system.

As the first barrier exposed to carcinogens, the bronchus is prone to early pathologic alterations. The assessment of these early changes is of key significance in the physiological studies and disease diagnosis of bronchus. Here, we demonstrate nonlinear optical microscopy (NOLM) to image mouse bronchial wall microstructure based on intrinsic nonlinear optical contrast. Our results show that NOLM is effective for imaging the bronchial intact microstructural components, providing quantitatively information on the biomorphology and biochemistry of tissue. With the advent of the clinical portability of typical nonlinear optical endoscopy, the NOLM technique has the potential to be applied in vivo the clinical diagnosis and monitoring of bronchial disease.

Wavelength-encoded imaging uses wavelength division multiplexing to produce cross-sectional images without mechanical scanning, and could be of a great interest in endoscope applications. In this paper, a scheme for wavelength-encoded imaging using time-encoded Frequency-domain optical coherence tomography (swept-source optical coherence tomography, SS-OCT) is presented. This approach implements swept broadband source with narrow instantaneous spectral width and low dispersion diffraction grating to simultaneously produce depth-lateral imaging of the sample. Compared to previous spectral-domain wavelength-encoded endoscope, the proposed method enables high-speed and high dynamic range detection. System design such as image resolvable points, imaging resolution as well as theoretical analysis of the interference signal pattern are developed.

As a novel hybrid imaging modality, photoacoustic (PA) imaging combines the merits of high optical contrast, good ultrasonic resolution and sufficient imaging depth, which may be of great benefit to noninvasively detect and monitor the pathological changes of subcutaneous vasculature, e.g., congenital vascular tumor and vascular malformation. In this paper, we apply a set of photoacoustic imaging system to image a sample of subcutaneous blood vessels, which is used to simulate the location of human's subcutaneous vasculature. Furthermore, an image of subcutaneous vasculature of the abdomen in a mouse is acquired in vivo. Laser pulses at a wavelength of 532 nm from a Q-switched Nd:YAG laser are employed as light source to generate PA signals in the experiments, because the optical absorption of whole blood is much stronger than that of other tissues at this wavelength. A needle polyvinylidene fluoride (PVDF) hydrophone with a diameter of 1mm is used to capture PA signals through a circular scan. The experimental results show that detailed structural information of subcutaneous vasculature, such as the shape and position of the blood vessels and the vessel branching, is clearly revealed by the PA imaging system. The spatial resolution of the PA imaging system reaches 80μm. Moreover, the reconstructed image of a mouse's abdomen in vivo demonstrates that this technique is suitable for noninvasive subcutaneous vasculature imaging. All of the results prove that the PA imaging can be used as a helpful tool for monitoring the pathological changes of subcutaneous vasculature.

The technologies based on Differential Interference Contrast microscopy (DIC), Laser Scanning Confocal Microscopy (LSCM), Two Photon Emission Laser Scanning Microscopy (TPELSM) and Optical Coherent Tomography (OCT) were used to study the changes of mouse skin after irradiated by Intense Pulse Light (IPL). The experimental results were compared and analyzed by different microscopic observation tools. The relations of the epithelial or dermal interaction with IPL in different energy density were given, and the morphologic changes of mouse skin were observed before and after days irradiated respectively. The function of dermal collagen during the renovating of the tissue and the key factors were presented.

With the limitation of the depth of focus in microscope, especially in high-power objectives, different areas in the field of view have different focal planes and therefore only sharp focused images in a small part of the view can be obtained. A three-dimension micro-image fusion algorithm is introduced based on wavelet transform (WT) in microscope auto-focusing system. The step motor is driven continuously moving across the vicinity of the focal plane to obtain the micro image information of the relevant position. With real-time multi-focused images acquired and saved, the image fusion algorithm is applied to finally get a complete and sharp three-dimension image. This can be used to extend the depth of focus in microscope and in three-dimension reconstruction in biologic slice, rock specimen, and so on. The particularity brought by the image fusion of a real-time system is mainly studied as well as the algorithm based on this condition. Here we emphasize the multi-focus fusion algorithm based on WT. Images acquired from the digital camera are transformed from spatial domain to wavelet domain. All the details from different images are extracted and processed from the wavelet coefficients and then are recombined to form the new coefficient of the resulting image. By taking an inverse WT, we finally get the final three-dimension image. This system has two main advantages: real-time processing and accurate fusion result.

The azimuthally polarized beam always keeps a zero intensity at the center of the doughnut shaped pulse. As a result, it can be utilized to overcome the problem of not perfect zero in STED microscopy to exhibit a high resolution. This paper examines the utilization of this beam as the stimulated emission depletion pulse in STED microscopy and the results are compared with the effects of using a doughnut model generated by the linearly polarized lights with inserting the phase plates in lights. The calculations show that the azimuthally polarized beam has a great potential in the STED microscopy.

Surface plasmon resonance has become a strong tool in the bio-interaction analysis since the first introduction by BIACore in 1990. Most research work have been carried out by employing angle interrogation, which is well known as angle scanning SPR system. Wavelength interrogation SPR is another method to trace the bio-interaction in real time. Due to the broad band excitation, it owns great potentials in photonic studies. In this paper, the sandwich structure of prism/gold/sample is studied by a home-made simulation program based on matrix of Fresnel reflection coefficients. The structure of 3 layers to 5 layers are studied in detail.

Raman spectroscopy is a molecular vibrational spectroscopic technique that is capable of optically probing the biomolecular changes associated with diseased transformation. The purpose of this study was to explore near-infrared (NIR) Raman spectroscopy for identifying precancer (dysplasia) from normal gastric mucosa tissues. High-quality Raman spectra in the range of 800-1800 cm^-1 can be acquired from gastric tissue within 5 seconds. Raman spectra showed significant differences between normal and dysplastic tissue, particularly in the spectral ranges of 850-900, 1,200-1,290 and 1,500-1,800 cm^-1 which contained signals related to hydroxyproline, amide III and amide I of proteins, and C=C stretching of lipids, respectively. The ratio of Raman intensities at 875 to 1,450 cm^-1 provided good differentiation between normal and dysplastic gastric tissue (unpaired Students' t-test, p<0.001), indicating that NIR Raman spectroscopy has a great potential for the non-invasive diagnosis of dysplasia in the stomach.

In the sensing of blood glucose by the near-infrared spectroscopy, building a robust and effective model is the precondition to obtain an accurate and reasonable prediction result of glucose concentration. In the chemometrics analysis, training set should be representative, reasonable distribution and cover the scope of prediction set. So the experiment designs became one of most difficult challenges for the noninvasive glucose sensing, especially for the in vivo experiments. In this paper, the oral glucose tolerance tests of two diabetics were carried out. The transcutaneous diffuse reflectance spectra were collected by a custom-build spectrometer and the glucose reference were measured by an invasive portable glucose meter. Then the influence of different experiment designs including the error in the references, the time delay between glucose in blood and interstitial fluid, the change in physiological temperature and different validation methods were analyzed. The result showed that, the error induced by the uncertainty in the reference was lower than that by the time delay, which could be up to 15.4%. And the proportion of error induced by temperature change is more than 50%, which is the most significant. Furthermore, the prediction error was restricted by the validation set selection and the way to change the blood glucose concentration.

Nasopharyngeal carcinoma (NPC) is one of the malignant tumors threatening people's health and life which is mostly found in South China; early diagnosis is crucial to improve the effective treatment and higher survival rates. In this work, preliminary study on Raman spectra of nasopharyngeal carcinoma in vitro is reported. Spectra were obtained from normal and cancerous nasopharyngeal tissue which had undergone biopsy for high risk nasopharyngeal carcinoma. Factors effecting Raman spectra were also studied including sample storage time, spectral accumulation time. The results show that sample storage time has a negative effect on the measurement while increasing accumulation time does not appear to improve the spectra quality significantly. Consistent spectral differences appear to exist between normal and cancerous tissues, mainly in several bands. The results demonstrate Raman spectroscopy has the potential ability to detect and diagnose cancerous tissues. Future studies will advance toward true in vivo, real time and non-invasively.

This paper demonstrates the potential of an elaborately devised near-infrared Raman system in analysis of urine. The broad band in the long-wavelength region of the electronic absorption spectra of the sol with added adsorbent at certain concentrations has been explained in terms of the aggregation of the colloidal silver particles. We have reported the surface-enhanced Raman (SERS) spectra of urine, and studied the silver solution enhanced effects on the urine Raman scattering. The Raman bands of human's urine was assigned to certain molecule vibrations. We have found that different donators have dissimilar SERS of urine in different physiological condition. Comparatively few studies have explored the ability of Raman spectroscopy for the analysis of urine acid. In the present report, we investigated the ability of surface enhanced Raman spectroscopy to measure uric acid in the human urine. The results suggested that the present Raman system holds considerable promise for practical use. Practical applications such as the quantitative medical examination of urine metabolites may also be feasible in the near future.

Light transport model has great potential in medical diagnosis and therapy because of the non-invasive nature of light and the selectively poisonous effect to tumors of photodynamic treatment Light transport model must be understudied for basic research and clinical application of biomedical optics., many investigators only study the diffusion equation of matched medium, they take the tissue as the same refractive index. In fact, A tissue is multi-layered mismatched medium, In order to understand the light transport in tissue,The frequency domain analytical solutions of the diffusion equation for photon migration through highly scattering a n-layered mismatched medium have been obtained. The effect of the refractive-index mismatch is taken into account, and the extrapolated boundary condition has been considered. At the same time, the phase in different situation is calculate use the model.

The light propagation model of finite size flat beam in biological tissue is set up. Gaussian beams and circularly flat beams were compared. The model is simulated with Monte Carlo method, and the influence of parameters of biological tissue and properties is analyzed. The potential application of the model is demonstrate by estimating the absorption and transport-corrected scattering coefficients from reflectance measured from intact tissue.

A method is proposed for adaptively choosing local regularization parameter based on gray scale difference estimation, and used to three-dimensional (3D) biological microscopic image restoration MPMAP algorithm. Every optical-sectioning image of 3D microscopic image with noise is decomposed in wavelet domain, and then its high frequency images of horizontal , vertical and diagonal direction are reconstructed. Then the images are convoluted respectively with corresponding direction operator, and the local gray scale differences of high frequency images before and after convolution are calculated. The minimum of corresponding local gray scale differences in the high frequency images is selected as local gray scale difference estimations of the optical-sectioning image, then the local regularization parameter of the optical-sectioning image is chosen by mapping local gray scale difference estimation. The local regularization parameter of the 3D microscopic image is made of the local regularization parameters of every optical-sectioning image. The test results show that the local regularization parameter based on gray scale difference estimation can describe more accurately intensity and position of noises than noise variance estimation. The local regularization parameter is used to 3D biological microscopic image regularization restoration with MPMAP algorithm. Experimental results show that better super-resolution effect is reached than whole regularization parameter MPMAP.

In this work, we have studied the propagation of ultrasound modulation scattering signal in multi-layer scattering media. The relations to the modulation light intensity and its modulation depth contributed by the thickness, absorption coefficient and scattering coefficient of two- and three- layered scattering media are figured out. The results of Monte Carlo simulation and experiments show that the modulated depth of the modulated light is only dependent on optical and ultrasonic properties of scattering media within the ultrasound zoom, and doesn't change in the propagation in multi-layer scattering media. And the modulated depth is a key factor in ultrasound-modulated optical tomography.

This research proposes a new method for skin diagnose using near infrared as the light source (750nm~1300nm). Compared to UV and visible light, near infrared might penetrate relatively deep into biological soft tissue in some cases although NIR absorption property of tissue is not a constant for water, fat, and collagen etc. In the research, NIR absorption and scattering properties for skin are discussed firstly using the theory of molecule vibration from Quantum physics and Solid State Physics; secondly the practical model for various NIR absorption spectrum to skin tissue are done by optical simulation for human skin. Finally, experiments are done for further identification of proposed model for human skin and its reaction to near infrared. Results show success with identification from both theory and experiments.

A linear generalized pulse spectrum technique for image reconstruction of fluorescence molecular tomography is proposed. The algorithm employs a finite element method solution to the Laplace-transformed coupled diffusion equations and can simultaneously reconstruct both fluorescent yield and lifetime images of fluorophores. The proposed algorithm was validated using simulated data for 3D phantoms. We investigated the ability of the algorithm to reconstruct the fluorescent yield and lifetime at different region, contrasted the imaging quality of different target lifetime and proved the noise-robustness by using noisy data with different signal-to-noise ratio. The results show that the approach accurately retrieves the position and shape of the target and prove the effectiveness of the methodology.

It is known that plasma is very important in the diagnosis and therapy of disease so that more and more scientific workers attach importance to the plasma storage life or storage environment. We research plasma disintegration with the increases of storage time based on the fluorescence spectroscopy. Based on the experimental researches and theoretical analysis, we find that their plasma fluorescence intensity is increasing within about 10 hours, and but is decreasing gradually and is nearly a straight line after this. It is indicated that plasma proteins have begun to disintegrate so as to make the fluorescence quenching after storage time beyond 10 hours. And the disintegration speed of plasma in the case of different concentration is different, the concentration is higher and the speed is lower in them, and but they are almost same after about 35 hours. Therefore, we think that plasma under higher concentration is deposited easier. These research consequences may order a theoretical and experimental reference to know the changes of plasma in structure in different disintegration time. It may make sense for understand the plasma disintegrative mechanism and distinguishing the fine plasma with faulty.

Phenylketonuria is a genetic disease, which causes the metabolization disorder of phenylalanine, this disorder would damage the neural system of infants as a result of the accumulation of phenylalanine in blood. Therefore, it is of great importance to diagnose and treat phenylketonuria as early as possible for newborns. The aim of this paper is to develop a fluorescence detection system to measure blood phenylalanine concentration of new-born infants. In this design, a high luminance ultraviolet LED is used for excitation source, and a kind of bifurcated optical fiber assembly is applied for conduction of light. The excitation source is filtered and coupled into quartz fibers of the bifurcated fiber assembly for conduction of light to excite the fluorescence of phenylalanine in blood sample. The collected fluorescence is transmitted along the glass fibers of the assemblies and coupled to a photomultiplier tube. The fluorescence is filtered with 470~500 nm band-pass filter to subdue scattered excitation light and to limit the spectral width of the detected fluorescence. By the comparison with a standard instrument, the new system with low power consumption, low cost and small size is also proven sensitive and accurate, which meets the demand of clinical phenylketonuria screening.

A laser induced fluorescence imaging system for localization of Nasopharyngeal Carcinoma is developed. In this fluorescence imaging system, the fluorescence intensity with information of detected objection is gained by an image intensifier, which makes color information of the fluorescence image eliminated and the result is a monochrome image of the fluorescence with thermally induced noise. The monochrome fluorescence image is sent to a CCD and captured by an image board, which is controlled by a computer. Image processing is carried out to improve the image quality and therefore improve the system's ability to differentiate carcinomas from normal tissue. Gaussian smoothing is implemented in order to reduce the noise. Image binarizing process is realized to obtain an optimal threshold of the image. Image pixels with grey value below this threshold are assigned as diseased and those above are normal. A pseudo color processing is then accomplished to get better visual perception and understanding of the image, greatly increasing the detail resolution of the grey image. The processed image is then displayed on the screen of the computer in real time. The real time laser induced fluorescence imaging system with the image processing methods developed is efficient for localization of the nasopharyngeal carcinoma.

An optical system for measurement of the intracellular pH (pHi) in a single living cell by using the fluorescent probe, 5(6)-carboxyfluorescein diacetate (CFDA) and fiber optic nanoprobe was demonstrated in this work. The CFDA probe is used to determine pHi in the yeast, Saccharomyces cerevisiae 97 while fiber optic nanoprobe is used to guide excitation light and receive emission light within a single cell. Experimental results showed that our system had higher detection sensitivity than other standard spectrometer, which is important to single-cell analysis, especially for the microanalysis in a single-cell.

Ovarian cancer has the highest mortality rate among the gynecologic cancers, and it goes undetected because adequate technology does not exist to detect preinvasive or early stage disease. Fluorescence spectroscopy of urine may provide a cost-effective tool to improve precancer detection. This study describes initial investigation of the potential of intrinsic urine fluorescence spectra for detecting early ovarian cancer. Using the Xenon arc lamp to irradiate the urine from ovarian cancer, cervical carcinoma groups and healthy donors, we obtained fluorescence emission spectra. The three groups of samples show different emission spectra peak and fluorescence intensity. Ovarian cancer group has the largest displacement of maximum spectra peak at 380-400nm excitation wavelength. And the fluorescence intensity from ovarian cancer group is significantly higher with the healthy donors and cervical carcinoma group in comparison at the short wave excitation region of 320-360nm, while cervical carcinoma group has higher fluorescence intensity than ovarian cancer group at 380-500nm excitation. Characteristic fluorescence mechanism was studied through comparison of fluorescence spectra and software fitting image. Fluorescence spectra at 440nm excitation is found to be perfectly lorentzian fitted by three characteristic fluorescence peaks, which are originated form coproporphyrin, riboflavin and p-hydroxyphenol derivatives existing in the urine.

Objective: Auto-fluorescence micro-imaging of microalgae are observed by using of laser scanning confocal microscopy (LSCM) and fluorescence microscopy, so as to investigate the effect of auto fluorescence alteration on growth of irradiated microalgae irradiated, meanwhile, the method of microalgae cells stained also to be studied. Methods: Platymonas subcordiformis, Phaeodactylum tricormutum and Isochyrsis zhanjiangensis cells are stained with acridine orange, and observed by fluorescence microscopy; the three types microalgae mentioned above are irradiated by Nd:YAP laser with 10w at 1341nm, irradiating time:12s, 30s, 35s and 55s, than to be cultured 6 days, and the auto fluorescence images and fluorescence spectra of algae cells are obtained by LSCM on lambda scan mode, at excitation 488nm (Ar⁺ laser). Results: It is showed that the shapes and the structural features of microalgae cells stained can be seen clearly, and the cytoplasm and nucleus also can be observed. The chloroplasts in cell is bigger on promoting effects, conversely, it is to be mutilated, deformation and shrink. Contrast to the CK, the peak positions of fluorescence of algae cells irradiated 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. Conclusions: The method of cell stained can be used to observed genetic material in microalgae. There are obvious effects for laser irradiating to chloroplasts in cells, the bigger chloroplasts the greater fluorescence intensity. Physiological incentive effects of microalgae irradiated can be given expression on fluorescence characteristics and fluorescence intensity alteration of cells.

The fluorescence spectral characteristic of tumor blood was studied by laser-induced fluorescence technology, and compared with the fluorescence spectra of the same type healthy mice blood, the differences between them are distinct. When the whole blood solutions were induced by 407nm laser, they radiate fluorescence band from 420nm to 750 nm, which spectral peak located at 620nm. In high concentration solutions (blood concentration is higher than 4%), the fluorescence intensity are lower than normal blood, but in those low concentration solutions (blood concentration is lower than 2%) the fluorescence intensity of the tumor blood are higher than the normal ones. It is analyzed that the change of the fluorescence characteristic between the tumor blood and the normal is caused by the concentration difference of the tumor identification-porphyrin. The experimental results showed that the obvious difference of the fluorescence spectral characteristic between the forepart tumor and normal blood can offer some value assistance to clinical diagnosis on cancer.

Blood spectrum examination has many superiorities, however , its spectrum signals often include the noise. The wavelet transformation method has good partial analysis ability on the signal. In this paper, the author chooses the normal person's blood serum and the high blood fat serum, carries them on the absorption spectrum examination. The author takes the wavelet theory as the foundation, uses it in human body blood serum absorption spectrum signal processing .Finally , it can smooth the noise well and make more useful information stand out . The normal person blood serum renewedly structural spectrum signal appears 8 absorptions peaks at 207nm, 215nm,223nm, 230.5nm, 240nm, 267.5nm, 277nm and 284.5nm place, the high blood fat blood serum renewedly structural spectrum signal appears 9 absorption speaks at 203.5nm, 211.5nm, 219.5nm, 236nm,243.5nm, 267.5nm, 275nm, 282nm and 289nm place. From above, the information of renewedly structural blood serum spectrum signal using the wavelet transformation method in the wave length 200nm~300nm section increases obviously. The high blood fat blood serum sample spectrum's two peaks positions gap between 219.5nm and the 236nm is obviously wider than the two peaks positions' gap of normal person blood serum sample in this spectrum section. Not only so, the former owns a peak at 289nm place but the latter not.

Life sciences is an important field of scientific research nowadays .On this important subject to the human blood measure, this paper puts forward applying infrared spectrum analysis technology to this research subject less likely to be set foot of diagnosis on disease. This paper gives infrared spectrums of cholesterol serums of normal and abnormal bloods sample within the range of certain frequency spectrum. By comparing the characteristic of the spectrums, we can measure and judge whether the serum sample is normal or not. Results indicate the differences on the absorption rate, position of absorption peak between normal and abnormal blood sample. A new method of medical diagnosis and analyses is presented. Compared with the other existed blood measures methods, it is convenient and easy to popularize for the serum infrared spectrum characteristic analysis method presented in this paper, meanwhile it has the merit of analyses simple fast.

Fluorescence correlation spectroscopy (FCS) is a new kind of real-time, high-speed and single-molecule technique. It is used to detect the kinetic characteristics of fluorescent dye such as diffusion coefficient in the aqueous solution. Combined with confocal microscope optics, it has been now widely applied in cell biological research. Through a time correlation analysis of spontaneous intensity fluctuations, this technique with EGFP as a probe is capable of determining viscosity of fluids according to Stokes-Einstein equation. Nucleoplasmic viscosity is an important physical parameter to quantify the rheological characteristics of the nucleoplasm. Investigation on nucleoplasmic viscosity plays an important role in further understanding intranuclear environment. In this paper, FCS is introduced to noninvasively investigate nucleoplasmic viscosity of living cells. The results show that nucleoplasmic viscosity of lung adenocarcinoma (ASTC-a-1) cells is 2.55±0.61 cP and nucleoplasmic viscosity is larger than cytoplasmic viscosity at 37 °C (pH 7.4). In addition, significant changes in nucleoplasmic viscosity are detected by FCS when cells are exposed to hyper or hypotonic medium. Our study suggests that FCS can be used to detect the kinetic characteristics of biomolecules in living cells and thus helps to investigate the dynamic changes of the microenvironment in the cell.

In this paper, the fluorescence spectrum of serum and neural network theory was combined and used to analyze the blood cholesterol concentration. Studies show that there is fluorescence spectrum in the wave band 425 to 600 nm with a peak near 460nm when the excitation wavelength is 410nm; the shape of curves keeps almost consistent with cholesterol concentration; there is no significant correlation between fluorescence intensity at 460nm and cholesterol concentration, but random, which indicates that there are other fluorescence emission at 460nm . Based on the evident correlation between serum fluorescence intensity and cholesterol concentration in the wave band of 450 to 470nm , a neural network model was built to determine the cholesterol concentration. It provides a new spectral test method of cholesterol

Background and Objective: Hypertrophic scar is a pathological scar that grows aberrantly by excessive deposition of collagens in the dermis. It is known that photodynamic therapy (PDT) contributes to a variety of diseases, however, the use of inhibiting scar formation has not been fully explored. The purpose of this study is to investigate the effect of HMME-PDT (Photodynamic therapy induced by Hematoporphyrin Monomethyl Ether) with different parameters on hypertrophic scar in rabbit ear. Materials and Methods: After the placement of 7-mm diameter dermal wounds on each ear, the acute model of dermal hypertrophic scar in the New Zealand white rabbits was established. Scar wounds were randomly separated into 2 groups: the experimental group received HMME-PDT with different parameters, and the control group received no special treatment. Specimens were harvested from scar wounds on postoperative day 28. Scar and hypertrophic index (HI) were observed by haematoxylin-eosin staining. Results: Compared with the control group, scar formation was inhibited by HMME-PDT in the experimental group with parameters as follows: photosensitizer dose 10mg/kg, power density 20mw/cm², fluence 5J/cm², meanwhile, HI was decreased significantly. Conclusion: HMME-PDT may play a role in inhibiting hypertrophic scarring in rabbit ear. The biological effect is determined by the dose of photosensitizer, interval between the injection of photosensitizer and irradiation, power density and energy fluence.

Measurement of excitation-emission matrices (EEMs) for nasopharyngeal carcinoma (NPC) and normal nasopharyngeal tissues in vitro was employed to determine the optimal excitation wavelengths that contain the most diagnostic information for optical diagnosis. Pathologically confirmed normal nasopharyngeal and NPC tissues(n=47) were obtained from 25 patients undergoing surgical biopsy. The autofluorescence EEMs of tissue biopsies were recorded with a TCSPC spectrofluorimeter. Fluorescence excitation wavelengths varied from 260 to 500 nm, and the corresponding fluorescence emission spectra were recorded from a range starting 20 nm above the excitation wavelength and extending to 700 nm. The calibration for different EEMs measurements was performed for quantitative comparison. As a result, we find that the excitation-emission pair of 340-380 nm yields the best performance for discrimination of NPC tissues with the sensitivity and specificity of 77.2% and 88.0%, respectively

Caspase-2 is important for the engagement of the mitochondrial apoptotic pathway, in the presence of DNA-damaging agents, such as cisplatin; however, the mechanism by which caspase-2 executes apoptosis remains obscure. In this study, we carried out the measurements of the dynamics of caspase-2 activation in a single living cell by a FRET (fluorescence resonance energy transfer) probe. A FRET probe was constructed that encoded a CRS (caspase-2 recognition site) fused with a cyan fluorescent protein (CFP) and a red fluorescent protein (DsRed) (CFP-CRS-DsRed). Using this probe, we found that during TRAIL-induced apoptosis, caspase-2 was not activated, and caspase-2 activation occurred in etoposide and cisplatin treated cells. However, during cisplatin-induced apoptosis caspase-2 activation was initiated much earlier than that of etoposide. Cisplatin and etoposide is one of the most broadly used drugs in the Clinical applications of cancer chemotherapy, and TRAIL, which belongs to the TNF family proteins, can selectively induce apoptosis in many transformed cells but not in normal cells. Most of anticancer drugs can induce apoptosis mediated by the activation of caspase pathway. Thus, the perfect synergistic effect group of multi-drug can be selected by using our FRET probe.

Objective to simulate and model the cells proliferation of Platymonas subcordiformis irradiated by laser, so as to obtain the quantitative relationship between laser parameters and the effects of mircoalgae irradiated. Methods : Platymonas subcordiform is irradiated by Nd:YAP(1341 , 10w , 45s--90s);LD(670nm , 800mw , 20min,30min ),Ar⁺ (532nm,80mw,50Min-65Min) , with 14 dose treatment groups, each 3 samples, and the cells proliferation to be observed in delay phase of mircoalgae growth, as a data source, and according to the characteristics of growth and reproduction of single-cell alga in cultured process, Gaussian growth curves are constructed, to fit the samples growth curve with least squares regression ,and to predict mircoalgae growth trends; on building the linear twin objective programming model and analyzing by stepwise regression , the laser parameters which is larger correlation with the numbers of cells proliferation and the rates are screened from all, and a optimal strategy given by model optimization software (Lingo).Results: By constructing growth curve function, in delay phase, with mircoalgae cells proliferation accelerating , a single peak Gaussian curve is showed; with inhibited growth the cell numbers trend to reduced, and after sub-cultivation the numbers significantly upward, then the growth curves meet double-Gaussian function category. There are goodness of fitting for SSE: 2.383e-005; R-square: 0.9997. It is showed that the parameters of Nd:YAP(1341nm , 10w,45s) is relatively suitable to accelerate cells proliferation. Conclusions: On mathematical model constructed, in delay phase of Platymonas subcordiformis, the quantitative relationship is obtained between laser irradiation parameters and the growing effects to stimulate or to inhibit.

In this paper, a feature extracting method based on wavelets for horizontal attenuated total reflectance Fourier transform infrared spectroscopy (HATR-FTIR) cancer data analysis and classification using artificial neural network trained with back-propagation algorithm is presented. 168 Spectra were collected from 84 pairs of fresh normal and abnormal lung tissue's samples. After preprocessing, 12 features were extracted with continuous wavelet analysis. Based on BPNN classification, all spectra were classified into two categories : normal or abnormal. The accuracy of identifying normal, early carcinoma, and advanced carcinoma were 100%, 90% and 100% respectively. This result indicated that FTIR with continuous wavelet transform (CWT) and the back-propagation neural network (BPNN) could effectively and easily diagnose lung cancer in its early stages.

We present a simultaneous time- and spectrum-resolved multifocal multiphoton microscopy (MMM) system using a novel field of view (FOV) zoom scanning protocol. The system employs a microlens array for producing discrete excitation spot array, a dispersive prism and a high repetition rate streak camera for simultaneous temporal and spectral resolutions. By combining a pair of galvo mirrors and a sample stage for fine and coarse scanning respectively, the resolution and FOV of the system can be changed without changing any optical elements. The system can be operated not only in low resolution and large FOV, but also in high resolution and small FOV applications, without compromising the performances of the optical elements in the system. By implementing a special system control protocol and image reconstruction algorithm, fluorescence images in different FOVs and resolutions can be obtained. This FOV zoom scanning protocol is demonstrated with two-photon excitation fluorescence imaging of a fluorescence resolution test target.