This PDF file contains the front matter associated with SPIE Proceedings Volume 6864, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

It has been shown that locally resolved reflectance measurements can directly quantify scatter changes in tissues without the need for computationally expensive model-based reconstruction schemes. Imaging systems exploiting non-model based reconstruction schemes are faster compared to the conventional model based schemes and thus have the potential for imaging tissue pathologies in real-time. In this report, the scanning system is described in terms of the design, construction and testing for multi-wavelength reflectance imaging capable of measuring scatter changes with 100 micron resolution of tissue. Imaging fields of up to 256 by 256 pixels were used in this current system, with a design for a 100 micron spot to allow sampling of the local scatter values in this size of region. Tissue phantoms with varying scattering and absorption profiles within the region of interest were used to test the performance of this system. The results demonstrate the ability of the instrument to measure scatter changes independent of local absorber concentration. This new scanning system should allow visualization of tumor-associated scatter changes in situ, with full spectral resolution across the visible range.

A Stokes polarimetry imaging (SPI) system utilizes an algorithm developed to construct degree of polarization (DoP) image maps from linearly polarized light illumination. Partial-thickness tears of turkey tendons were imaged by the SPI system in order to examine the feasibility of the system to detect partial-thickness rotator cuff tear or general tendon pathology. The rotating incident polarization angle (IPA) for the linearly polarized light provides a way to analyze different tissue types which may be sensitive to IPA variations. Degree of linear polarization (DoLP) images revealed collagen fiber structure, related to partial-thickness tears, better than standard intensity images. DoLP images also revealed structural changes in tears that are related to the tendon load. DoLP images with red-wavelength-filtered incident light may show tears and related organization of collagen fiber structure at a greater depth from the tendon surface. Degree of circular polarization (DoCP) images exhibited well the horizontal fiber orientation that is not parallel to the vertically aligned collagen fibers of the tendon. The SPI system's DOLP images reveal alterations in tendons and ligaments, which have a tissue matrix consisting largely of collagen, better than intensity images. All polarized images showed modulated intensity as the IPA was varied. The optimal detection of the partial-thickness tendon tears at a certain IPA was observed. The SPI system with varying IPA and spectral information can improve the detection of partial-thickness rotator cuff tears by higher visibility of fiber orientations and thereby improve diagnosis and treatment of tendon related injuries.

Interferometric Synthetic Aperture Microscopy (ISAM)¹ is an optical microscopy computed-imaging technique for measuring the optical properties of three-dimensional structures and biological tissues. In this work, the principle of ISAM is reviewed, and its application to imaging tissue properties in various scanning geometries and instrument configurations is explored. The practicality of ISAM is demonstrated by imaging a rat heart and muscle using a real-time implementation of ISAM in conjunction with a clinical cart Optical Coherence Tomography instrument.

Establishing when the amount of recorded multiple scattered signal becomes dominant is important for various clinical applications that require optical coherence tomography imaging through a turbid environment such as blood. The profiles of detected signals obtained by compounding coherence tomography images of flowing blood-saline mixtures with various blood concentrations are analyzed. The scattering properties of the studied mixtures influence the corresponding profiles of the recorded signal. Monte Carlo simulations of light propagation through environments with various scattering coefficients are used to support and to explain the experimental data.

A well-established method of assessing structure is inverse light scattering analysis. With inverse light scattering analysis, the measured scattering properties of a scatterer(s) are associated with the most probable scattering distribution predicted by an appropriate light scattering model. One commonly used light scattering model is Mie theory, the electromagnetic theory of spherical scattering. Although Mie theory is a spherical scattering model, it has been used for deducing the geometry of spheroidal scatterers, which are important for studies of biological cell structure. The angle-resolved low coherence interferometry (a/LCI) technique is one method of Mie theory - based inverse light scattering analysis that has been used to evaluate biological structure both ex vivo and in vitro. In the present study, we examine the ability of a/LCI to assess structure, geometry, and cellular organization in ways that will further enable the study of function in biological materials.

The ability to separately measure the scattering coefficient (μ_s [cm^-1]) and the anisotropy (g) is difficult, especially when measuring an in vivo site that can not be excised for bench-top measurements. The scattering properties (μ_s and g) can characterize the ultrastructure of a biological tissue (nuclear size, mitochondra, cytoskeletion, collagen fibers, density of membranes) without needing an added contrast agent. This report describes the use of reflectance-mode confocal scanning laser microscopy (rCSLM) to measure optical properties. rCSLM is the same as optical coherence tomography (OCT) when the OCT is conducted in focus-tracking mode. The experimental measurement involves translating the depth of focus, z_f, of an objective lens, down into a tissue. As depth z increases, the reflected signal R decreases due to attenuation by the tissue scattering (and absorption, μ_a). The experimental data behaves as a simple exponential, R(z) = ρ exp(-μz_f) where ρ is the local reflectivity (dimensionless) and μ [cm^-1] is an attenuation coefficient. The relationship between (ρ,μ) and (μ_s,g) is: μ = (μ_s a(g) + μ_a) 2 G(g,NA) ρ = μ_s L_f b(g,NA) where a(g) is a factor that drops from 1 to 0 as g increases from 0 to 1 (determined by Monte Carlo simulations) allowing photons to reach the focus despite scattering, G is a geometry factor describing the average photon pathlength that depends on the numerical aperture (NA) of the lens and the anisotropy (g), L_f is the axial extent of the focus, and b(g,NA) is the fraction of scattered light that backscatters into the lens for detection.

Premalignant diseases of the gastrointestinal tract, such as Barrett's esophagus, long-standing ulcerative colitis, and adenomatous polyps, have a significantly increased risk for development of adenocarcinoma, most often through an intermediate stage of dysplasia. Adenocarcinoma of the colon is the second most common cancer in the United States. Because patients with colorectal cancer often present with advanced disease, the outcomes are associated with significant morbidity and mortality. Effective methods of early detection are essential. As non-polypoid dysplasia is not visible using conventional endoscopy, surveillance of patients with Barrett's esophagus and ulcerative colitis is performed via a system in which multiple random biopsies are obtained at prescribed intervals. Sampling error and missed diagnoses occur frequently and render current screening methods inadequate. Also, the examination of a tissue biopsy is time consuming and costly, and significant intra- and inter-observer variation may occur. The newer methods discussed herein demonstrate the potential to solve these problems by early detection of disease with high sensitivity and specificity. Conventional endoscopy is based on the observation of white light reflected off the tissue surface. Subtle changes in color and shadow reveal structural changes. New developments in optical imaging go beyond white light, exploiting other properties of light. Several promising methods will be discussed at this meeting and shall be briefly discussed below. However, few such imaging modalities have arrived at our clinical practice. Some much more practical methods to improve colorectal cancer screening are currently being evaluated for their clinical impact. These methods seek to overcome limitations other than those of detecting dysplasia not visible under white light endoscopy. The current standard practice of colorectal cancer screening utilizes colonoscopy, an uncomfortable, sometimes difficult medical procedure. Efforts to improve the practice of colonoscopy will be described. Another limitation of the current practice is the inability to detect polypoid neoplasia that is hidden from view under white light imaging by the natural folds that occur within the colon. A device to overcome this limitation will also be described. Efforts to improve colorectal cancer screening (and thereby decrease the death rate of this second leading cause of cancer death in the United States) are progressing in many arenas. The researcher, basic or clinical, should maintain an up to date overview of the field and how each new technological advance is likely to have a role in the screening and early detection of colorectal cancer.

Improved methods for detecting dysplasia, or pre-cancerous growth are a current clinical need, particularly in the esophagus. The currently accepted method of random biopsy and histological analysis provides only a limited examination of tissue in question while being coupled with a long time delay for diagnosis. Optical scattering spectroscopy, in contrast, allows for inspection of the cellular structure and organization of tissue in vivo. Fourierdomain angle-resolved low-coherence interferometry (a/LCI) is a novel scattering spectroscopy technique that provides quantitative depth-resolved morphological measurements of the size and optical density of the examined cell nuclei, which are characteristic biomarkers of dysplasia. Previously, the clinical viability of the a/LCI system was demonstrated by analysis of ex vivo human esophageal tissue in Barrett's esophagus patients using a portable a/LCI system. We present an adaptation of the portable a/LCI instrument that can be used in the accessory channel of a gastroscope, allowing for in vivo measurements to be taken. Modifications to the previous generation system include the use of an improved imaging spectrometer allowing for subsecond acquisition times and the redesign of the delivery fiber and imaging optics in order to fit in the accessory channel of a gastroscope. Accurate sizing of polystyrene microspheres and other preliminary results are presented, demonstrating promise as a clinically viable tool.

Reflectance spectrophotometry (RS), laser Doppler flowmetry (LDF) and transepidermal water loss (TEWL) techniques were simultaneously used to non-invasively monitor skin colour (SC), skin blood flow (SBF) and barrier function damage (BFD) in routinely patch-tested Japanese patients in dermatology clinic. The analytical quality, reliability and reproducibility of each technique were compared and analyzed in correlated to visual scoring patch test (PT) reactions as negative (-), doubtful (+?), weak (+) and strong (++/+++) at 48- and 72-hour monitoring. An attempt was made to quantify predominant in the clinic "+?"- and "+'"-PT-reactions. The relationship between 48 h and 72 h measurements in different reaction groups was poor for TEWL, LDF showed a tendency to decrease at 72 h, but good for RS. A correlation between visual scorings and instrumental mean values was poor for TEWL, good for LDF and excellent for RS. So, measurements by RS were the most statistically significant to non-invasively monitor and quantify doubtful, weak and strong PT reactions, accordingly providing continuous data grading of reaction intensity suitable in the clinic. Moreover, monitoring of SC changes was the most reliable parameter for the quantitative distinguishing of doubtful and weak reactions in pigmented skin.

Remote detection of airborne biological agents is a problem of contemporary interest. At issue is the discrimination of scatter from such harmful species and the scatter from naturally occurring particles such as hydrosols, pollen, and dust. The feature that our detection scheme attempts to exploit is that the species of interest typically have a characteristic size and shape that produce a unique signature in the depolarization of the scattered light. Through the use of T-matrix calculations we demonstrate the effect and show processing algorithms for quantifying and interpreting the measurements. Simulations suggest that it is possible to retrieve an estimate of the aspect ratio from a measurement of the spectral behavior of the linear depolarization in either the forward-scatter or back-scatter regime.

Functional ultra high resolution optical coherence tomography (fUHROCT) was used to non-invasively probe the functional response of retinal photoreceptors. Using this technique, time dependent changes in light reflectivity of the retinal photoreceptor layer were measured after external white light stimulation. The causes of the observed changes are currently not known. To better understand the observed reflectivity signals, we have developed a computational model based on the Finite-Difference Time-Domain method to simulate light scattering from retinal neurons. Preliminary simulation results suggest that cell dynamics and cell volume changes are the likely causes of the observed signals.

We propose an approach to adaptively adjust the spectral window size used to extract features from optical spectra. Previous studies have employed spectral features extracted by dividing the spectra into several spectral windows of a fixed width. However, the choice of spectral window size was arbitrary. We hypothesize that by adaptively adjusting the spectral window sizes, the trends in the data will be captured more accurately. Our method was tested on a diffuse reflectance spectroscopy dataset obtained in a study of oblique polarization reflectance spectroscopy of oral mucosa lesions. The diagnostic task is to classify lesions into one of four histopathology groups: normal, benign, mild dysplasia, or severe dysplasia (including carcinoma). Nine features were extracted from each of the spectral windows. We computed the area (AUC) under Receiver Operating Characteristic curve to select the most discriminatory wavelength intervals. We performed pairwise classifications using Linear Discriminant Analysis (LDA) with leave-one-out cross validation. The results showed that for discriminating benign lesions from mild or severe dysplasia, the adaptive spectral window size features achieved AUC of 0.84, while a fixed spectral window size of 20 nm had AUC of 0.71, and an AUC of 0.64 is achieved with a large window size containing all wavelengths. The AUCs of all feature combinations were also calculated. These results suggest that the new adaptive spectral window size method effectively extracts features that enable accurate classification of oral mucosa lesions.

We performed simultaneous measurement of light scattering and absorption due to reduction of cytochrome c oxidase as intrinsic optical signals that are related to morphological characteristics and energy metabolism, respectively, for rat brains after oxygen/glucose deprivation by saline infusion. To detect change in light scattering, we determined the wavelength that was the most insensitive to change in light absorption due to the reduction of cytochrome c oxidase on the basis of multiwavelength analysis of diffuse reflectance data set for each rat. Then the relationships between scattering signal and absorption signals related to the reductions of heme aa₃ (605 nm) and CuA (830 nm) in cytochrome c oxidase were examined. Measurements showed that after starting saline infusion, the reduction of heme aa₃ started first; thereafter triphasic, large scattering change occurred (200-300 s), during which the reduction of CuA started. Despite such complex behaviors of IOSs, almost linear correlations were seen between the scattering signal and the heme aa₃-related absorption signal, while a relatively large animal-to-animal variation was observed in the correlation between the scattering signal and CuA-related absorption signal. Transmission electron microscopic observation revealed that dendritic swelling and mitochondrial deformation occurred in the cortical surface tissue after the triphasic scattering change. These results suggest that mitochondrial energy failure accompanies morphological alteration in the brain tissue and results in change in light scattering; light scattering will become an important indicator of tissue viability in brain.

High spatiotemporal resolution imaging is desirable for better understanding of dynamic information processing in the retina. Optical recording of stimulus-evoked neural activity can offer high spatial resolution with parallel monitor of many retinal neurons working together. We have recently demonstrated near infrared light imaging of fast intrinsic optical responses (FIORs) in activated amphibian retinas. High spatiotemporal resolution imaging of FIORs disclosed transient optical changes associated with electrophysiological responses. These FIORs were typically initiated from the center of the retinal area covered by the visible stimulus light pattern, and rapidly spread to surrounding area. Dynamic changes, i.e. amplitudes, polarities, and spreading patterns, of FIORs were dependent on the stimulus light intensity and delivery duration. In the retinal area covered by the visible light stimulus pattern, low strength stimuli evoked FIORs dominated by positive signals, but strengthened stimuli elicited negative-going responses. However, positive responses were consistently observed in surrounding area, beyond the edge of the stimulus light pattern at least 50 μm. Our experimental study and physiological analysis suggest that the negative FIORs are associated with the phototransduction of activated photoreceptors, and the positive FIORs result primarily from dynamic changes of second- and third-order neurons during retinal activation. Dynamic patterns and spreading waves of fast neural activity may reflect involvements of the feedback mechanisms, e.g. light adaptation and center-surround antagonism, of the retina.

NIR light scattering from ex vivo porcine cardiac tissue was investigated to understand how imaging or point measurement approaches may assist development of methods for tissue depth assessment. Our results indicate an increase of average image intensity as thickness increases up to approximately 2 mm. In a dual fiber spectroscopy configuration, sensitivity up to approximately 3 mm with an increase to 6 mm when spectral ratio between selected wavelengths was obtained. Preliminary Monte Carlo results provided reasonable fit to the experimental data.

Fourier Domain Low Coherence Interferometry (fLCI) is a promising technique which combines the depth resolution of low coherence interferometry with the sensitivity of light scattering spectroscopy for probing the health of epithelial tissue layers. Our new fLCI system configuration utilizes a white light Xe arc lamp source and a 4-f interferometer which re-images light scattered from the sample onto the detection plane. The system employs an imaging spectrometer at the detection plane to acquire depth resolved profiles from 252 adjacent spatial points without the need for any scanning. The limited spatial coherence of the light source requires the resolution of adjacent spatial points for the generation of depth information. Depth-resolved spectral information is recovered by performing a short-time Fourier transform on the detected spectra, similar to spectroscopic optical coherence tomography. Wavelength dependent variations in scattering intensity are analyzed as a function of depth to obtain information about the neoplastic transformation of the probed cells. Previous studies have demonstrated fLCI as an excellent technique for probing the scatterer morphology of simple phantoms and of in vitro cancer cell monolayers. We now seek to assess the ability of the new fLCI system to measure the health of subsurface tissue layers using the hamster cheek pouch model. Seven hamsters will have one cheek pouch treated with the known carcinogen DMBA. At the conclusion of the 24 week treatment period the animals will be anesthetized and the cheek pouches will be extracted. We will use the fLCI optical system to measure the neoplastic transformation of the in situ subsurface tissue layers in both the normal and DMBA-treated cheek pouches. Traditional histological analysis will be used to verify the fLCI measurements. We expect our results to establish the feasibility of fLCI to distinguish between healthy and dysplastic epithelial tissues in the hamster cheek pouch.

The formation of bacterial colonies and biofilms requires coordinated gene expression, regulated cell differentiation, autoaggregation, and intercellular communication. Therefore colonies of bacteria have been recognized as multicellular organisms or "superorganisms." It has consequently been postulated that the phenotype of colonies formed by microorganisms can be automatically recognized and classified using optical systems capable of collecting information related to cellular pattern formation and morphology of colonies. Recently we have reported a first practical implementation of such a system, capable of noninvasive, label-free classification and recognition of pathogenic Listeria species. The design employed computer-vision and pattern-recognition techniques to classify scatter patterns produced by bacterial colonies irradiated with laser light. Herein we report our efforts to extend this system to other genera of bacteria such as Salmonella, Vibrio, Staphylococcus, and E. coli. Application of orthogonal moments, as well as texture descriptors for image feature extraction, provides high robustness in the presence of noise. An improved pattern classification scheme based on an SVM algorithm provides better results than the previously employed neural network system. Low error rates determined by cross-validation, reproducibility of the measurements, and overall robustness of the recognition system prove that the proposed technology can be implemented in automated devices for bacterial detection.

Confocal light absorption and scattering spectroscopic (CLASS) microscopy is a novel optical technique for observing submicron intracellular structures in living cells. It allows monitoring nondestructively cell function and cell dynamics in vivo and in real time. CLASS microscopy, having accuracy well beyond the diffraction limit, does not require cell fixation as the electron microscopy. In addition, it provides not only size information but also information about the biochemical and physical properties of the cell. CLASS microscopy can also visualize multiple compartments inside of living cell without employing exogenous molecular markers which are required by fluorescence microscopy and which can affect normal cell functioning. Recently we improved our CLASS microscope by utilizing the full power output of the supercontinuum laser and used it to study apoptosis in live cells.

We describe the development of a compact time-resolved system for the measurement of the optical properties of highly scattering media over a bandwidth of 600-1100 nm. The instrument is based on a fiber laser generating supercontinuum radiation, that is spectrally dispersed and used to sequentially illuminate the sample. A single photon avalanche photo-diode in combination with time correlated single-photon counting is used to recover the time-dispersion curve at each wavelength. The calibration of the system and in-vivo applications are shown.

We used a unified Mie and fractal model to analyze elastic light spectroscopy of cell suspensions to obtain the size distributions of cells and nuclei, their refractive indices, and the background refractive index fluctuation inside the cell, for different types of cells, including human cervical squamous carcinoma epithelial (SiHa) cells, androgen-independent malignant rat prostate carcinoma epithelial (AT3.1) cells, non-tumorigenic fibroblast (Rat1p) cells in the plateau phase of growth, and tumorigenic fibroblast (Rat1-T1E) cells in the exponential phase of growth. Signal sources contributing to the scattering (μs) and reduced scattering (μ^'s) coefficients for these cells of various types or at different growth stages are compared. It is shown that the contribution to μ_s from the nucleus is much more important than that from the background refractive index fluctuation. This trend is more significant with increase of the probing wavelength. On the other hand, the background refractive index fluctuation overtakes the nucleus and may even dominate in the contribution to reduced scattering. The implications of the above findings on biomedical light scattering techniques are discussed.

An investigation of the normal incidence of an infinite plane wave on a slab of uniformly scattering media is undertaken using the P_N-method. We demonstrate the computational competitiveness of the P_N-method, not only in its ability to provide timely solutions even for strongly anisotropic scattering (g > 0.9), but also in its ability to simultaneously treat various theories of scattering such as the Henyey- Greenstein model, the Fokker-Planck forward scattering approximation using the Laplace-Beltrami operator, and the Leakeas-Larsen rational approximation. We also discuss the extendibility of the method to the study of backscatter and transmission due to normally incident collimated pencil beam illumination.

Cardiovascular devices such as heart-lung machine generate un-physiological level of shear stress to damage red blood cells, leading to hemolysis. The diagnostic techniques of cell damages, however, have not yet been established. In this study, the time-resolved optical spectroscopy was applied to quantify red blood cell (RBC) damages caused by the extracorporeal circulation system. Experimentally, the fresh porcine blood was subjected to varying degrees of shear stress in the rotary blood pump, followed with measurement of the time-resolved transmission characteristics using the pico-second pulses at 651 nm. The propagated optical energy through the blood specimen was detected using a streak camera. The data were analyzed in terms of the mean cell volume (MCV) and mean cell hemoglobin concentration (MCHC) measured separately versus the energy and propagation time of the light pulses. The results showed that as the circulation time increased, the MCV increased with decrease in MCHC. It was speculated that the older RBCs with smaller size and fragile membrane properties had been selectively destroyed by the shear stress. The time-resolved optical spectroscopy is a useful technique in quantifying the RBCs' damages by measuring the energy and propagation time of the ultra-short light pulses through the blood.

Method of rapid detection of bacterial cells by light scattering is described. Determination of quantitative changes of bacteria is the given method based on the changes of their size distributing in the process of cultivation. Liquid medial are diluted and analyzed by the proposed technology to determine presence of bacteria. A method includes sounding of flow suspended bacterial cells by monochromatic coherent light, registration of signals of co-operation of sounding radiation with the explored microbiological objects by detects amplitudes and durations of scattered light impulses. Distribution of particles by sizes is determined from the measured functional dependence of number of registered particles from amplitude and duration of the proper electric impulses on the output photoreceiver. Detection is done for a range of particle size from 0.1 to 10 mkm, and thus particle's size distribution is determined. The results of studying of rapid detection of Escherichia coli by light scattering are described.

Brightfield Laser Scanning Imaging (BLSI) is available on Laser Scanning Cytometers (LSCs) from CompuCyte Corporation. Briefly, digitation of photodetector outputs is coordinated with the combined motions of a small diameter (typically 2 to 10 microns) laser beam scanning a specimen in the Y direction (directed by a galvanometer-driven scanning mirror) and the microscope stage motion in the X direction. The output measurements are assembled into a two-dimensional array to provide a "non-real" digital image, where each pixel value reports the amount of laser-scattered light that is obtained when the laser beam is centered on that location. Depending on the detector positions, these images are analogous to Differential Interference Contrast or Phase Contrast microscopy. We report the incorporation of the new laser scattering capabilities into the workflow of a high-volume clinical cytology laboratory at University Health Network, Toronto, Canada. The laboratory has been employing LSC technology since 2003 for immunophenotypic fluorescence analysis of approximately 1200 cytological specimens per year, using the Clatch methodology. The new BLSI component allows visualization of cellular morphology at higher resolution levels than is possible with standard brightfield microscopic evaluation of unstained cells. BLSI is incorporated into the triage phase, where evaluation of unstained samples is combined with fluorescence evaluation to obtain specimen background levels. Technical details of the imaging methodology will be presented, as well as illustrative examples from current studies and comparisons to detailed, but obscure, historical studies of cytology specimens based on phase contrast microscopy.

We attempted to selectively determine the absorption coefficient (μ_a) of bottom regions in two- and four-layered models with time-domain near infrared measurement. The difference curve in the time-resolved reflectance between a target and a reference medium was divided into segments, and a slope of each segment was calculated to determine depth-dependent μ_a (μ_a^seg). The deviation of μ_a^seg in later time segments from the real μ_a of the bottom layer was μ_a^seg in an earlier time segment to that in a later one. Using this function, we could determine μ_a in the bottom layer for various target media with different conditions.

Diffuse optical tomography (DOT) is an emerging technique for biomedical imaging. The imaging quality of the DOT strongly depends on the reconstruction algorithm. In this paper, four inhomogeneities with various shapes of absorption distributions are simulated by a continues-wave DOT system. The DOT images are obtained based on the simultaneous iterative reconstruction technique (SIRT) method. To solve the trade-off problem between time consumption of reconstruction process and accuracy of reconstructed image, the iteration process needs a optimization criterion in algorithm. In this paper, the comparison between the root mean square error (RMSE) and the convergence rate (CR) in SIRT algorithm are demonstrated. From the simulation results, the CR reveals the information of global minimum in the iteration process. Based on the CR calculation, the SIRT can offer higher efficient image reconstructing in DOT system.

Diffuse optical tomography (DOT) is a technique to assess the spatial variation in absorption and scattering properties of the biological tissues. DOT provides the measurement of changes in concentrations of oxy-hemoglobin and deoxy-hemoglobin. The oxygenation images are reconstructed by the measured optical signals with nearest-neighbor pairs of sources and detectors. In our study, a portable DOT system is built with optode design on a flexible print circuit board (FPCB). In experiments, the hemodynamics temporal evolution of exercises and vessel occlusions are observed with in vivo measurements form normal subjects and some patients in intensive care unit.

Raman spectroscopy and Multivariate methods were used to study serum blood samples of control and breast cancer patients. Blood samples were obtained from 11 patients and 12 controls from the central region of Mexico. Our results show that principal component analysis is able to discriminate serum sample of breast cancer patients from those of control group, also the loading vectors of PCA plotted as a function of Raman shift shown which bands permitted to make the maximum discrimination between both groups of samples.

Mueller matrix has a vast application regarding information of any scattering (turbid) media such as fog, sea water, and biological tissues. It can extract information from scattering properties of the medium. Recently, information from Mueller images and their interpretation are being used for diagnostic purposes in biological tissues. Polar decomposition of Mueller matrices for scattering medium have also been developed, which could be a very powerful and sensitive tool for mapping the morphology of human tissue sections. On the basis of such decomposition, we report here the variation of diattenuation, depolarization and retardance from normal to dysplasia state in cervix tissue.