This PDF file contains the front matter associated with SPIE Proceedings Volume 7169, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

A new diagnostic testing device is proposed for point of care (POC) applications. It consists of a microfluidic cartridge with a polymer biochip and an instrument for reading the biochip and controlling the microfluidics. This system allows a very easy determination of several parameters e.g. in patients blood automatically. The biochip is made of a thin polymer foil serving as waveguiding element and as carrier for the receptors on the biochip surface. A sensitive TIRF (total internal reflection fluorescence) readout is realised. Optical elements for incoupling and outcoupling of light are integrated into the foil. Beside the TIRF element, the disposable microfluidic cartridge integrates a sample inlet, several reservoirs for reagents, fluidic microchannels and electrochemical micropumps. Sandwich assays for the detection of clinically relevant parameters have been investigated. This hardware configuration forms the basis for a fully automated compact low cost device using cost efficient disposables.

A comparative study is reported regarding the use of two different surface plasmon resonance (SPR) biosensors, a homemade SPR grating biosensor and a reference prism coupled biosensor, to perform quantification of C-reactive protein (CRP) in human blood serum. Surface functionalization was conducted using anti-CRP fragments immobilized directly on gold. Adsorption time optimization for the antibody fragments monolayer, non-specific binding (NSB) resistance evaluation and CRP detection were conducted, with better results achieved by the grating biosensor on all topics, namely less functionalization time, higher resistance to NSB and wider CRP dynamic concentration range. A study regarding comparison between continuous flow and surface coating immobilization is also reported in this work. We have shown that surface coating immobilization achieves similar NSB resistance and CRP detection results, allowing a 75% assay cost reduction by lower solution volume requirement. Results suggest that the coating immobilization technique is the best suited to be used in further studies in order to obtain a viable immunosensor for CRP and other biomarkers detection in complex biological fluids.

A plastic biochip was developed for the detection of procalcitonin (PCT) and consists of a polymethylmethacrylate (PMMA) chip shaped in order to achieve several flow microchannels. A sandwich assay using a new antibody pairs is implemented with the capture antibody immobilized on the PMMA surface and the target antibody labelled with a fluorophore. A laser diode excites the fluorescent sensing layer. Thanks to the anisotropy of the fluorescence the emitted light travels along the thickness of the plastic material. The fluorescence coming out from the chip is collected by 1 mm plastic optical fibre and detected with a spectrum analyser.

Nitric oxide is a mediator in many physiological processes including vasodilatation of blood vessels, neurotransmission and prevention of platelet aggregation. It has also a role in the pathophysiology of sepsis, hemorrhagic shock, various traumatic events and critical conditions involved with circulatory abnormalities. The last one is accompanied by blood flow redistribution and is considered to be the putative cause of altered oxygen metabolism in various pathophysiological conditions. The present study tested the involvement of NO in the brain as a vital organ versus the small intestine, a less vital organ using the non-specific nitric oxide synthase inhibitor L-NAME and exogenous NO donor - nitrite. The parameters that were simultaneously monitored in both organs included mean arterial blood pressure (MAP), tissue blood flow (TBF), using laser Doppler flowmetery and NADH fluorescence using the fluorometric technique. Three groups were tested. Group 1 - L-NAME +nitrite, group 2 - control L-NAME and group 3 - control nitrite. Following LNAME, MAP significantly increased and remained elevated through the entire experiment. TBF decreased in both organs with full recovery in the brain and no recovery in the intestine, whereas NADH showed no significant changes. Nitrite alone had no significant effect on the parameters in any of the organs. In group 1 the infusion of nitrite decreased the level of elevated MAP earlier induced by L-NAME. Nitrite also recovered the reduced TBF in the brain whereas it had no beneficial effect on intestinal blood flow indicating for its regulatory role in the brain but not in the intestine.

Neonatal jaundice is a medical condition which occurs in newborns as a result of imbalance between the production and elimination of bilirubin. The excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. As the bilirubin levels rise in the blood stream, there is a continuous exchange between the extra vascular bilirubin and bilirubin in the blood stream and exposure to phototherapy also alters the process. Diffuse reflectance spectra from human skin contains physiological and structural information of human skin and nearby tissue. Blanching, a phenomenon in which a slight capillary closure pressure is applied to force the blood under the applied area. A diffuse reflectance spectrum has to be captured before and after blanching to isolate the intravascular and extra vascular bilirubin.A new mathematical model is proposed with extra vascular bilirubin concentration taken into consideration along with other optical parameters in defining the diffuse reflectance spectrum of human skin. Nonlinear Optimization and Genetic Algorithms have been adopted to extract the optical properties (bilirubin concentration) from reflectance spectrum of skin. Bilirubin components were extracted from simulated diffuse reflectance spectrum within an average error of 10%

This paper presents a study on non-invasive detection of two common epithelial cancers (skin and esophagus) based on oblique incidence diffuse reflectance spectroscopy (OIDRS). An OIDRS measurement system, which combines fiber optics and MEMS technologies, was developed. In our pilot studies, a total number of 137 cases have been measured in-vivo for skin cancer detection and a total number of 20 biopsy samples have been measured ex-vivo for esophageal cancer detection. To automatically differentiate the cancerous cases from benign ones, a statistical software classification program was also developed. An overall classification accuracy of 90% and 100% has been achieved for skin and esophageal cancer classification, respectively.

Fast Fourier transform spectroscopy has proved to be a powerful method for study of the secondary structure of proteins since peak positions and their relative amplitude are affected by the number of hydrogen bridges that sustain this secondary structure. However, to our best knowledge, the method has not been used yet for identification of proteins within a complex matrix like a blood sample. The principal reason is the apparent similarity of protein infrared spectra with actual differences usually masked by the solvent contribution and other interactions. In this paper, we propose a novel machine learning based method that uses protein spectra for classification and identification of such proteins within a given sample. The proposed method uses principal component analysis (PCA) to identify most important linear combinations of original spectral components and then employs support vector machine (SVM) classification model applied on such identified combinations to categorize proteins into one of given groups. Our experiments have been performed on the set of four different proteins, namely: Bovine Serum Albumin, Leptin, Insulin-like Growth Factor 2 and Osteopontin. Our proposed method of applying principal component analysis along with support vector machines exhibits excellent classification accuracy when identifying proteins using their infrared spectra.

The purpose of this study was to investigate the feasibility of applying a rapid near-infrared (NIR) Raman endoscopy system coupled with narrow band imaging technique for distinguishing dysplasia from normal gastric mucosa tissue during clinical gastroscopy.

Nonlinear Raman microspectroscopy is a powerful tool for minimally invasive chemical analysis of cells and tissues. In this report we evaluate the state-of-the-art of this technology with an eye on potential clinical applications.

Estimating the distribution of myocardial fibrosis after myocardial infarct is important for appropriate therapeutic planning. Here, we applied a Raman confocal microscope equipped with slit scanner for molecular tissue imaging of rat infarcted hearts. Raman spectra of the cytoplasm of cardiomyocytes included the resonance Raman bands at 751, 1130 and 1582 cm-1 arising mainly from reduced b- and c- type cytochromes. Raman spectra of fibrotic tissues at the borderzone of old myocardial infarct were highly consistent with that of collagen type I. Based on these findings, we successfully obtained Raman tissue images of a cardiomyocyte and surrounding collagen at the cellular level.

Urinary tract infection diagnosis and antibiogram require a 48 hour waiting period using conventional methods. This results in ineffective treatments, increased costs and most importantly in increased resistance to antibiotics. In this work, a novel method for classifying bacteria and determining their sensitivity to an antibiotic using Raman spectroscopy is described. Raman spectra of three species of gram negative Enterobacteria, most commonly responsible for urinary tract infections, were collected. The study included 25 samples each of E.coli, Klebsiella p. and Proteus spp. A novel algorithm based on spectral ratios followed by discriminant analysis resulted in classification with over 94% accuracy. Sensitivity and specificity for the three types of bacteria ranged from 88-100%. For the development of an antibiogram, bacterial samples were treated with the antibiotic ciprofloxacin to which they were all sensitive. Sensitivity to the antibiotic was evident after analysis of the Raman signatures of bacteria treated or not treated with this antibiotic as early as two hours after exposure. This technique can lead to the development of new technology for urinary tract infection diagnosis and antibiogram with same day results, bypassing urine cultures and avoiding all undesirable consequences of current practice.

A hyperspectral imaging system using a liquid-crystal tunable filter (LCTF) was constructed for the purpose of in vivo optical imaging of oral neoplasia. The system operates in fluorescence mode and has the dual capability of capturing high quality widefield images and detecting fluorescence emission spectra from arbitrary locations within the captured field of view (FOV). The system was calibrated and evaluated for spectral resolution and accuracy. In vivo hyperspectral images were obtained from two normal volunteers and two patients with confirmed oral malignancy. Normal volunteer measurements revealed differences in intensity and lineshape of spectra between different anatomic locations, but intensity and lineshape were similar between different measurement sites from the same anatomic location. Measurements from normal and neoplastic areas of two patients with previously confirmed oral neoplasia showed differences in intensity, lineshape, and location of peak intensity. We have demonstrated that this system can provide both high quality widefield images, and spectral information at chosen locations within the field of view.

An optical biopsy system which equips miniaturized Raman probes, a miniaturized endoscope and a fluorescent image probe has been developed for in vivo studies of live experimental animals. The present report describes basic optical properties of the system and its application studies for in vivo cancer model animals and ex vivo human cancer tissues. It was developed two types of miniaturized Raman probes, micro Raman probe (MRP) made of optical fibers and ball lens hollow optical fiber Raman probe (BHRP) made of single hollow optical fiber (HOF) with a ball lens. The former has rather large working distance (WD), up to one millimeter. The latter has small WD (~300μm) which depends on the focal length of the ball lens. Use of multiple probes with different WD allows one to obtain detailed information of subsurface tissues in the totally noninvasive manner. The probe is enough narrow to be inserted into a biopsy needle (~19G), for observations of the lesion at deeper inside bodies. The miniaturized endoscope has been applied to observe progression of a stomach cancer in the same rat lesion. It was succeeded to visualize structure of non-stained cancer tissue in live model animals by the fluorescent image technique. The system was also applied to ex vivo studies of human breast and stomach cancers.

Both Confocal Microscopy and Raman Spectroscopy have shown potential for diagnosis and differentiation of cancerous and normal skin. Many current studies utilizing these techniques use large bench-top microscopes, and are not suited for in-vivo diagnosis in a clinical setting. We have developed a microscope which combines confocal reflectance imaging with Raman spectroscopy into a compact handheld probe, allowing images and Raman spectra to be taken in-vivo. The compact design of this handheld unit is largely due to the use of a MEMS mirror which scans the illumination laser light in two dimensions to produce the confocal reflectance image of the skin. An integrated CCD camera provides a large area view of the skin surface which helps to guide the location of the confocal reflectance image area. Using this probe, in-vivo confocal reflectance images and Raman spectra of normal skin have been obtained with axial resolutions of 4 μm for the confocal channel and 10 μm for the Raman channel. This paper presents the instrument design and optical characteristics, including representative in-vivo images and Raman data from normal skin tissue.

Optical coherence tomography (OCT) provides high-resolution, cross-sectional imaging of tissue microstructure in situ and in real-time, while fluorescence molecular imaging (FMI) enables the visualization of basic molecular processes. There are great interests in combining these two modalities so that the tissue's structural and molecular information can be obtained simultaneously. This could greatly benefit biomedical applications such as detecting early diseases and monitoring therapeutic interventions. In this research, a new optical system that combines OCT and FMI was developed. The system demonstrated that it could co-register en face OCT and FMI images with a 2.4 x 2.4 mm field of view. The transverse resolutions of OCT and FMI of the system are both 10 μm. Capillary tubes filled with Cy 5.5 fluorescent dye in different concentrations (750nM to 24μM) under a scattering medium (1% - 2% intralipid) are used as the phantom. En face OCT images of the phantoms were obtained and successfully co-registered with FMI images that were acquired simultaneously. A linear relationship between FMI intensity and dye concentration was observed. The relationship between FMI intensity and target fluorescence tube depth measured by OCT images was also observed and compared with theoretical modeling. This relationship could help in correcting reconstructed dye concentration. Imaging of colon polyps of APC^min mouse model is presented as an example of biological applications of this co-registered OCT/FMI system. In conclusion, a co-registering OCT and FMI imaging system has been demonstrated. The system enables simultaneous visualization of tissue morphology and molecular information at high resolutions over a 2-3 mm field-of-view.

We present a preliminary study that combines functional electrical stimulation and time-domain near infrared spectroscopy for a quantitative measurement of the local muscular metabolism during rehabilitation of post-acute stroke patients. Seven healthy subjects and nine post-acute stroke patients underwent a protocol of knee flex-extension of the quadriceps induced by functional electrical stimulation. During the protocol time-domain near infrared spectroscopy measurement were performed on both left and right muscle. Hemodynamic parameters (concentration of oxy- and deoxy-genated hemoglobin) during baseline did not show any significant differences between healthy subject and patients, while functional performances (knee angle amplitude) were distinctly different. Nevertheless, even if their clinical histories were noticeably different, there was no differentiation among functional performances of patients. On the basis of the hemodynamic parameters measured during the recovery phase, instead, it was possible to identify two classes of patients showing a metabolic trend similar or very different to the one obtained by healthy subjects. The presented results suggest that the combination of functional and metabolic information can give an additional tool to the clinicians in the evaluation of the rehabilitation in post-acute stroke patients.

Optical Coherence Tomography (OCT) is a non-destructive imaging modality that has proven to be a useful tool for making quantitative measurements in a variety of applications. One area where non-destructive quantitative measurement is important is contact lens metrology, specifically prism. Prism is defined as the difference between the largest and smallest thickness measured at a fixed distance from the contact lens edge. We developed and tested an algorithm that automatically analyzes OCT images to accurately measure contact lens thickness. Images were obtained with the Thorlabs OCT930SR spectral radar OCT system. An automated rotation stage was used to precisely rotate the OCT probe 360 degrees in small increments to acquire OCT images along the entire outer edge of the contact lens. The algorithm was able to successfully analyze hundreds of OCT images. For comparison, measurements were taken by physically slicing contact lenses and manually measuring their thickness using a microscope. The error between the two measurements had a mean of -1.268 um and a range of 9.041 um. Thickness measurements were repeatable with a maximum range of 1.8 μm. The success of the algorithm has demonstrated the possibility of using OCT images for performing non-destructive contact lens metrology.

Microbicide gels are topical products that have recently been developed to combat sexually transmitted diseases including HIV/AIDS. The extent of gel coverage, thickness, and structure are crucial factors in gel effectiveness. It is necessary to be able to monitor gel distribution and behavior under various circumstances, such as coatis, and over an extended time scale in vivo. We have developed a multiplexed, Fourier-domain low coherence interferometry (LCI) system as a practical method of measuring microbicide gel distribution, with precision and accuracy comparable to currently used fluorometric techniques techniques. The multiplexed system achieved a broad scanning area without the need for a mechanical scanning device, typical of OCT systems, by utilizing six parallel channels with simultaneous data collection. We now propose an imaging module which will allow the integration of the multiplexed LCI system into the current fluorescence system in conjunction with an endoscope. The LCI imaging module will meet several key criteria in order to be compatible with the current system. The fluorescent system features a 4-mm diameter rigid endsoscope enclosed in a 27-mm diameter polycarbonate tube, with a water immersion tip. Therefore, the LCI module must be low-profile as well as water-resistant to fit inside the current design. It also must fulfill its primary function of delivering light from each of the six channels to the gel and collecting backscattered light. The performance of the imaging module will be characterized by scanning a calibration socket which contains grooves of known depths, and comparing these measurements to the fluorometric results.

Ovarian cancer is the fourth leading cause of cancer-related death among women. If diagnosed at early stages, 5-year survival rate is 94%, but drops to 68% for regional disease and 29% for distant metastasis; only 19% of cases are diagnosed at early, localized stages. Optical coherence tomography is a recently emerging non-destructive imaging technology, achieving high axial resolutions (10-20 µm) at imaging depths up to 2 mm. Previously, we studied OCT in normal and diseased human ovary ex vivo. Changes in collagen were suggested with several images that correlated with changes in collagen seen in malignancy. Areas of necrosis and blood vessels were also visualized using OCT, indicative of an underlying tissue abnormality. We recently developed a custom side-firing laparoscopic OCT (LOCT) probe fabricated for in vivo imaging. The LOCT probe, consisting of a 38 mm diameter handpiece terminated in a 280 mm long, 4.6 mm diameter tip for insertion into the laparoscopic trocar, is capable of obtaining up to 9.5 mm image lengths at 10 µm axial resolution. In this pilot study, we utilize the LOCT probe to image one or both ovaries of 17 patients undergoing laparotomy or transabdominal endoscopy and oophorectomy to determine if OCT is capable of differentiating normal and neoplastic ovary. We have laparoscopically imaged the ovaries of seventeen patients with no known complications. Initial data evaluation reveals qualitative distinguishability between the features of undiseased post-menopausal ovary and the cystic, non-homogenous appearance of neoplastic ovary such as serous cystadenoma and endometroid adenocarcinoma.

In vivo reflectance confocal microscopy shows promise for the early detection of malignant melanoma (MM). Two hallmarks of MM have been identified: the presence of pagetoid melanocytes in the epidermis and the breakdown of the dermal papillae. For detection of MM, these features must be identified qualitatively by the clinician and qualitatively through automated pattern recognition. A machine vision algorithm was developed for automated detection. The algorithm detected pagetoid melanocytes and breakdown of the dermal/epidermal junction in a pre-selected set of five MMs and five benign nevi for correct diagnosis.

Mohs surgery, for the precise removal of basal cell carcinomas (BCCs), consists of a series of excisions guided by the surgeon's examination of the frozen histology of the previous excision. The histology reveals atypical nuclear morphology, identifying cancer. The preparation of frozen histology is accurate but labor-intensive and slow. Nuclear pathology can be achieved by staining with acridine orange (1 mM, 20 s) BCCs in Mohs surgical skin excisions within 5-9 minutes, compared to 20-45 for frozen histology. For clinical utility, images must have high contrast and high resolution. We report tumor contrast of 10-100 fold over the background dermis and submicron (diffraction limited) resolution over a cm field of view. BCCs were detected with an overall sensitivity of 96.6%, specificity of 89.2%, positive predictive value of 93.0% and negative predictive value of 94.7%. The technique was therefore accurate for normal tissue as well as tumor. We conclude that fluorescence confocal mosaicing serves as a sensitive and rapid pathological tool. Beyond Mohs surgery, this technology may be extended to suit other pathological needs with the development of new contrast agents. The technique reported here accurately detects all subtypes of BCC in skin excisions, including the large nodular, small micronodular, and tiny sclerodermaform tumors. However, this technique may be applicable to imaging tissue that is larger, more irregular and of various mechanical compliances with further engineering of the tissue mounting and staging mechanisms.

Human neural stem were cultivated and characterized using infrared spectroscopic imaging. A classification algorithm based on linear discriminate analysis was developed to distinguish the differentiation of the stem cells to neurons, astrocytes and stem cells without labeling. The classification is based upon spectral features which mainly arise from proteins, nucleic acids. A spectral training set was formed with spectra from cells which were identified by a subsequently staining according to a standard histological protocol. Differentiated cells could be classified with a high accuracy whereas not differentiated stem cells did exhibit some misclassifications

Gold nanoshells (GNS) are a new class of nanoparticles that can be optically tuned to scatter or absorb light from the near-ultraviolet to near-infrared (NIR) region by varying the core (dielectric silica) /shell (gold) ratio. In addition to spectral tunability, GNS are inert and bioconjugatable making them potential labels for in vivo imaging and therapy of tumors. We report the use of GNS as exogenous contrast agents for enhanced visualization of tumors using narrow band imaging (NBI). NBI takes advantage of the strong NIR absorption of GNS to distinguish between blood and nanoshells in the tumor by imaging in narrow wavelength bands in the visible and NIR, respectively. Using tissue-simulating phantoms, we determined the optimum wavelengths to enhance contrast between blood and GNS. We then used the optimum wavelengths for ex-vivo imaging of tumors extracted from human colon cancer xenograft bearing mice injected with GNS. Systemically delivered GNS accumulated passively in tumor xenografts by the enhanced permeability and retention (EPR) effect. Ex-vivo NBI of tumor xenografts demonstrated tumor specific heterogeneous distribution of GNS with a clear distinction from the tumor vasculature. The results of this study demonstrate the feasibility of using GNS as contrast agents to visualize tumors using NBI.

Several hand-held based optical imaging devices have been developed towards breast imaging, which are portable, patient-comfortable, and use non-ionizing radiation. The devices developed to date are limited in that they have flat probe faces and are incapable of real-time coregistration (as needed for 3-D tomographic imaging). A hand-held based optical imager has been developed in our lab, which has unique features of (i) simultaneous over sequential source illumination, which enables rapid data acquisition, (ii) a flexible probe face, which enables it to contour to any tissue curvature, and (iii) self coregistration facilities towards 3-D tomographic imaging. Real-time coregistration is demonstrated using the imager via fluorescence-enhanced studies in the continuous-wave mode, performed on slab phantoms (filled with 1% Liposyn solution) and in vitro samples (chicken breast). Additionally, preliminary studies were conducted using curved phantoms. In all cases, a 0.45-cc target filled with 1 μM Indocyanine green was used to represent a tumor. Real-time 2-D surface images of the phantom were obtained via multiple scans at different target depths. Preliminary surface imaging studies demonstrated that the summation of multiple scans distinctly differentiated the target from artifacts (up to 3 cm deep), which was not possible from individual scans.

Novel methods that can help in the diagnosis and monitoring of joint disease are essential for efficient use of novel arthritis therapies that are currently emerging. Building on previous studies that involved continuous wave imaging systems we present here first clinical data obtained with a new frequency-domain imaging system. Three-dimensional tomographic data sets of absorption and scattering coefficients were generated for 107 fingers. The data were analyzed using ANOVA, MANOVA, Discriminant Analysis DA, and a machine-learning algorithm that is based on self-organizing mapping (SOM) for clustering data in 2-dimensional parameter spaces. Overall we found that the SOM algorithm outperforms the more traditional analysis methods in terms of correctly classifying finger joints. Using SOM, healthy and affected joints can now be separated with a sensitivity of 0.97 and specificity of 0.91. Furthermore, preliminary results suggest that if a combination of multiple image properties is used, statistical significant differences can be found between RA-affected finger joints that show different clinical features (e.g. effusion, synovitis or erosion).

Autonomic Dysreflexia (AD) is an uncontrolled response of sympathetic output occurring in individuals with an injury at the sixth thoracic (T6) neurologic level. Any noxious stimulus below the injury level can trigger an AD episode. Progression of an AD attack can result in severe vasoconstriction below the injury level. Skin oxygenation can decrease up to 40% during an AD event. We present a quantitative and non-invasive method of assessing the progression of an AD event by measuring patient's skin oxygen levels and blood flow using a fiber optic based system.

A CMOS camera-based imaging photoplethysmography (PPG) system has been previously demonstrated for the contactless measurement of skin blood perfusion over a wide tissue area. An improved system with a more sensitive CCD camera and a multi-wavelength RCLED ring light source was developed to measure blood perfusion from the human face. The signals acquired by the PPG imaging system were compared to signals captured concurrently from a conventional PPG finger probe. Experimental results from eight subjects demonstrate that the camera-based PPG imaging technique is able to measure pulse rate and blood perfusion.

A practical system to visualize vessels underneath the skin has been developed, based on near-infrared (NIR) transillumination. A study in the clinical setting proved the system to be useful as a support in blood withdrawal in young children. During clinical application it was found that performance varied depending on vessel size, depth of vessels and surrounding lighting conditions. To gain more insight on the different variables that determine functioning of the system, we performed phantom studies. A combined liquid/solid phantom was fabricated with similar optical properties as the tissue layers of skin reported in literature at 850 nm. This phantom was used to estimate the depth of visibility in the relation to vessel size and darkness of the skin. Vessel contrast was determined analytically from images and evaluated by 3 independent observers. The knowledge gained from these experiments will be helpful to improve the imaging system and develop a solid phantom to be used as a gold standard to test the system under various clinical lighting conditions. The working range of the system was found to be appropriate to visualize the vessels used for the most procedures, such as blood withdrawal and placement of intravenous lines.

To assess vascular responses of the human hand to inspiratory gasps and hand cooling, two imaging "remote sensing" instruments were utilized: 1) a high-resolution infrared (IR) imaging camera and 2) a full-field laser perfusion imager (FLPI). Data analysis was performed on the data sets collected simultaneously from both instruments. A non-localized drop of both FLPI and IR signals was observed at ~0.5-2.0 min after gasp onset. Spontaneous oscillations, much below the human cardiac and respiratory frequencies, were observed with both imagers. The dominant oscillations for both imaging modalities centered around 0.01Hz. Spectral frequencies, their power, and the duration of temperature oscillations (bursts) for different hand areas changed in time and were spatially heterogeneous. The highest spatial correlation between the two data sets was found between the mean IR derivative image and the mean original FLPI image for the baseline conditions. Heterogeneous images of the human hand were consistently detected non-invasively by both instruments. After cooling, a temperature elevation of ~0.5ºC was seen as a spotted pattern mainly in the thenar and hypothenar areas. A generalized increase in perfusion over the same areas was observed in FLPI images. Both IR and FLPI imagers sensitively identify vasoconstrictor responses induced by inspiratory gasp and hand cooling maneuvers. The specificity to physiological changes and high imaging rate for both instruments, coupled with the current ease of use of optical cameras in clinical settings, make the described combination of two instruments an ideal imaging approach to studying the dynamics of thermal and perfusion heterogeneity in human skin.

Reflective terahertz (THz) imaging may potentially become a valuable tool in determining skin hydration due to its non-ionizing photon energy, high sensitivity to water concentration and ability to penetrate through clothing. The high absorption coefficient of water in the THz range is responsible for contrast between substances with lesser or higher degrees of water saturation. Water content, as well as collagen fiber arrangement, varies between different layers of skin. This study sought to determine whether the high THz absorption in water could be exploited to distinguish between these layers. Porcine skin specimens were sectioned into samples of increasing thickness, with the undersides corresponding to different layers in skin. The undersides of the samples were scanned using a THz imaging system operating at a center frequency of 0.5 THz with 0.125 THz of noise-equivalent bandwidth at a standoff of 4 cm and a spot size of 13 mm. Collagen solutions of varying hydrations were also prepared and raster scanned with the same system. The reflectivity of the deeper layers of skin was found to be higher than that of the upper layers, indicating that the deeper layers are more hydrated. The collagen solutions with higher hydration also had higher THz reflectivity. These results suggested that THz is able to distinguish between different layers of skin based on water content and the nature of its association with components in skin.

The requirements for diagnostic and surgical lighting have remained largely unchanged over the past several years-illumination level, glare, shadow and tissue heating reduction are the dominant factors in choosing a lighting system. Since human visual perception remains the key tool in clinical diagnostics and surgery, it is worth exploring ways to heighten visual contrast between areas of interest with respect to surrounding tissues. A simulation program for predicting test illuminant spectral distribution that would enhance contrast between standard color patches typical of tissue color is used. Data images of the color patches under the predicted test illuminant as realized using a spectrally tunable source are collected. Details of the simulation program, the equipment used for this test and results of the test will be discussed.

A relationship has been reported by several research groups [1 - 4] between the density and shapes of nerve fibers in the cornea and the existence and severity of peripheral neuropathy. Peripheral neuropathy is a complication of several prevalent diseases or conditions, which include diabetes, HIV, prolonged alcohol overconsumption and aging. A common clinical technique for confirming the condition is intramuscular electromyography (EMG), which is invasive, so a noninvasive technique like the one proposed here carries important potential advantages for the physician and patient. A software program that automatically detects the nerve fibers, counts them and measures their shapes is being developed and tested. Tests were carried out with a database of subjects with levels of severity of diabetic neuropathy as determined by EMG testing. Results from this testing, that include a linear regression analysis are shown.

Processing large images files or real-time video streams requires intense computational power. Driven by the gaming industry, the processing power of graphic process units (GPUs) has increased significantly. With the pixel shader model 4.0 the GPU can be used for image processing 10x faster than the CPU. Dedicated software was developed to deform 3D MR and CT image sets for real-time brain shift correction during navigated neurosurgery using landmarks or cortical surface traces defined by the navigation pointer. Feedback was given using orthogonal slices and an interactively raytraced 3D brain image. GPU based programming enables real-time processing of high definition image datasets and various applications can be developed in medicine, optics and image sciences.

Colonoscopy is the most widely prescribed colonic imaging method for the clinical surveillance of colorectal cancer for the detection of adenomatous polyps. However, some adenomas appear diminutive and flat, making them difficult to discriminate from non-neoplastic tissue even for the most experienced colonoscopists. We report here an optical system for performing excitation resolved visible and near-infrared autofluorescence imaging and hyperspectral imaging for the accurate distinction between neoplastic and non-neoplastic tissue. This is demonstrated on ex vivo colorectal tissues using our multimodal imaging system, which has potential applications for the in vivo endoscopic imaging and diagnosis of colorectal cancer tissue.

To enhance foveal fixation detection while bypassing the deleterious effects of corneal birefringence in retinal birefringence scanning (RBS), we developed a new RBS design introducing a double-pass spinning half wave plate (HWP) and a fixed double-pass retarder into the optical system. Utilizing the measured corneal birefringence from a data set of 300 human eyes, an algorithm and a related computer program, based on Mueller-Stokes matrix calculus, were developed in MATLAB for optimizing the properties of both wave plates. Foveal fixation detection was optimized with the HWP spun 9/16 as fast as the circular scan, with the fixed retarder having a retardance of 45° and fast axis at 90°. With this new RBS design, a significant statistical improvement of 7.3 times in signal strength, i.e. FFT power, was achieved for the available data set compared with the previous RBS design. The computer-model-optimized RBS design has the potential not only for eye alignment screening, but also for remote fixation sensing and eye tracking applications.

Colorectal carcinoma is one of the most frequent and deadliest tumors in the western world. The visualization of cancer-specific enzymatic activities could possibly improve sensitivity and specificity as compared to classical white-light endoscopy. DNase X, which is typically found in early lesions, and TKTL1, which identifies aggressive carcinomas with a high metastatic potential, could potentially constitute such cancer-specific enzymes. Here, fluorescent dyes have been developed in order to specifically detect these enzymatic activities. A fiber-based system was developed for the detection of small concentrations of fluorescent dyes in scattering and absorbing media. With the use of the reflectance spectrum and a theoretical model for the light distribution, the intrinsic fluorescence is assessed from the raw fluorescence. The resulting intrinsic spectrum shows only a weak dependence on the optical properties of the sample and its intensity correlates with the fluorophore concentration. Thus, small concentrations and small variations in the concentrations of the fluorescent dye can be measured. In conclusion, the presented fluorescence diagnostic system in combination with new fluorescent probes has the potential to distinguish between cancerous tissue samples with high enzymatic activity and non-cancerous tissue samples with lower enzymatic activity.

Protein profiles of tissue homogenates were recorded using HPLC separation and LIF detection method. The samples were collected from volunteers with clinically normal or cervical cancer conditions. It is shown that the protein profile can be classified as belonging to malignant or normal state by using hard and Fuzzy clustering methods. The study was performed to test the utility of the HPLC-LIF protein profiling method for classification of tissue samples as well as to establish a complementary method for histopathology for clinical diagnosis of the tissue as normal or malignant.

Visible and near-infrared dyes are largely used in diagnostics and sensing. For this reason, it is very important to study their time-resolved fluorescence in presence or in absence of proper scattering medium in order to simulate the optical characteristics of biological tissues. Moreover, if one- or two-photon excitation processes are available also visible dyes will be employed taking advantages from using exciting sources in the diagnostic window (red and near IR) of the electromagnetic spectrum, where the photons are rarely absorbed and more often scattered. Visible and near IR fluorescent samples (Indocyanine Green and Rhodamine 6G) in absence and in presence of scattering agents (different Intralipid concentrations) and one- and two- photon time-resolved experiments have been performed. As expected, the presence of scattering agents modified time-resolved spectra and the related lifetime components. The experimental results have been used to preliminarly test different theoretical approaches describing the propagation of fluorescence signals in scattering media.

We present an advanced three-dimensional tomographic imaging system using the optical coherence gating based on stroboscopic illumination. The proposed system is based on a wide-field optical coherence tomography (WF-OCT) that is capable of en-face tomographic imaging through whole-field illumination and parallel detection technique. The scheme enables achievement of a three-dimensional volumetric image in real time only with a single axial continuous scanning. The axial scanning of the OCT system generates interferometric signal with a beat (or Doppler) frequency. The time-varying interfergams are usually detected in series with a CCD camera for the WF-OCT case. However, because the camera response is much slower than the Doppler frequency, the interference signal is averaged out for most cases. To avoid the averaging out problem of the beat signal, the input light is optically switched on and off at the same rate as the Doppler frequency generated by the axial scan. When the constructive interference components in the signal are synchronized with the stroboscopic illumination of the light source, the envelope signal of the sample can be detected by the slow camera. Compensated adaptive optic system was combined with the OCT instrument to avoid decrease of the interference signal by nonlinearity of scan motion. With the implemented WF-OCM, a lithium battery volume image of 6×4.5×0.005 (X×Y×Z) mm³ was obtained in 82 ms with axial scanning speed of 0.63 mm/s and visualized in volume rendering.

Ultra Wide Band (UWB) radar is a promising emerging technology for breast cancer detection that makes use of the dielectric contrast between normal and tumour tissues at microwave frequencies. An important consideration in UWB imaging system design is the configuration of the antenna array. Two antenna configurations have been previously proposed to image the breast: the planar and the circular distributions. The planar configuration involves a 2D array of antennas placed on the naturally flattened breast with the patient lying in the supine position. Conversely, the circular configuration involves the patient lying in the prone position, with the breast surrounded by a circular array of antennas. In this paper, the two different configurations are compared using various metrics, including the minimum number of antennas needed to successfully detect the presence and location of tumours of different sizes in the breast. In order to effectively test both supine and prone imaging approaches, two 2D Finite-Difference Time-Domain (FDTD) models of the breast are created. The backscattered signals recorded from each antenna configuration are passed through a simple delay and sum beamformer and images of the backscattered energy are created. The images obtained using both antenna configurations are compared and the performance of each imaging approach is evaluated by quantitative methods and visual inspection, for a number of test conditions.

Three one-dimensional (1D) optical transducers are known to be effective in determining the spatial coordinates of a target (marker) with higher speed and accuracy compared to the two-dimensional (2D) optical transducers system. But one disadvantage is that it can only position one marker at a time and couldn't solve the correspondence problem when two or more markers are lighted simultaneously, for which reason this tracking system necessitates a markers controlling system and is inconvenient in some applications. This paper proposes an approach to solve the correspondence problem by adding a fourth linear transducer to the current three ones. The geometric model of this system is presented and the constraint for correspondence is deduced. An analysis of the constraint degeneration is given and simulation experiments are conducted under both ideal and error conditions. Experiments show that this approach enables 1D transducers system to perform both active and passive tracking, and its high tracking accuracy is further improved.