This PDF file contains the front matter associated with SPIE Proceedings Volume 10054, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

Blood plasma possesses the biomolecules released from cells/tissues after metabolism and reflects the pathological conditions of the subjects. The analysis of biofluids for disease diagnosis becomes very attractive in the diagnosis of cancers due to the ease in the collection of samples, easy to transport, multiple sampling for regular screening of the disease and being less invasive to the patients. Hence, the intention of this study was to apply near-infrared (NIR) Raman spectroscopy in the high wavenumber (HW) region (2500−3400 cm⁻¹) for the diagnosis of oral malignancy using blood plasma. From the Raman spectra it is observed that the biomolecules protein and lipid played a major role in the discrimination between groups. The diagnostic algorithms based on principal components analysis coupled with linear discriminant analysis (PCA-LDA) with the leave-one-patient-out cross-validation method on HW Raman spectra yielded a promising results in the identification of oral malignancy. The details of results will be discussed.

Mohs surgery is the current gold standard to treat large, aggressive or high-risk non-melanoma skin cancer (NMSC) cases. While Mohs surgery is an effective treatment, the procedure is time-consuming and expensive for physicians as well as burdensome for patients as they wait for frozen section histology. Our group has recently demonstrated high diagnostic accuracy using a noninvasive “spectral biopsy” (combination of diffuse reflectance (DRS), fluorescence (FS) and Raman spectroscopy (RS)) to classify NMSC vs. normal lesion in a screening setting of intact tissue. Here, we examine the sensitivity of spectral biopsy to pathology in excised Mohs sections. The system is designed with three modalities integrated into one fiber probe, which is utilized to measure DRS, FS, and RS of freshly excised skin from patients with various NMSC pathologies including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), where each measurement location is correlated to histopathology. The spectral biopsy provides complimentary physiological information including the reduced scattering coefficient, hemoglobin content and oxygen saturation from DRS, NADH and collagen contribution from FS and information regarding multiple proteins and lipids from RS. We then apply logistic regression model to the extracted physiological parameters to classify NMSC vs. normal tissue. The results on the excised tissue are generally consistent with in vivo measurements showing decreased scattering within the tumor and reduced fluorescence. Due to the high sensitivity of RS to lipids, subcutaneous fat often dominates the RS signal. This pilot study demonstrates the potential for a spectral biopsy to classify NMSC vs. normal tissue, indicating the opportunity to guide Mohs excisions.

Cervical cancer is the fourth most common malignancy in female worldwide; the present method for diagnosis is the biopsy, Pap smear, colposcopy etc. To overcome the drawbacks of diagnosis an alternative technique is required, optical spectroscopy is a new technique where the discrimination of normal and cancer subjects provides valuable potential information in the diagnostic oncology at an early stage. Raman peaks in the spectra suggest interesting differences in various bio molecules. In this regard, non invasive optical detection of cervical cancer using urine samples by Raman Spectroscopy combined with LDA diagnostic algorithm yields an accuracy of 100% for original and cross validated group respectively. As the results were appreciable it is necessary to carry out the analysis for more number of samples to explore the facts hidden at different stages during the development of cervical cancer.

Nerve-sparing surgery is essential to avoid functional deficits of the limbs and organs. Raman scattering, a label-free, minimally invasive, and accurate modality, is one of the best candidate technologies to detect nerves for nerve-sparing surgery. However, Raman scattering imaging is too time-consuming to be employed in surgery. Here we present a rapid and accurate nerve visualization method using a multipoint Raman imaging technique that has enabled simultaneous spectra measurement from different locations (n=32) of a sample. Five sec is sufficient for measuring n=32 spectra with good S/N from a given tissue. Principal component regression discriminant analysis discriminated spectra obtained from peripheral nerves (n=863 from n=161 myelinated nerves) and connective tissue (n=828 from n=121 tendons) with sensitivity and specificity of 88.3% and 94.8%, respectively. To compensate the spatial information of a multipoint-Raman-derived tissue discrimination image that is too sparse to visualize nerve arrangement, we used morphological information obtained from a bright-field image. When merged with the sparse tissue discrimination image, a morphological image of a sample shows what portion of Raman measurement points in arbitrary structure is determined as nerve. Setting a nerve detection criterion on the portion of “nerve” points in the structure as 40% or more, myelinated nerves (n=161) and tendons (n=121) were discriminated with sensitivity and specificity of 97.5%. The presented technique utilizing a sparse multipoint Raman image and a bright-field image has enabled rapid, safe, and accurate detection of peripheral nerves.

Osteoarthritis (OA) is very common joint disease in the aging population. Main symptom of OA is accompanied by degenerative changes of articular cartilage. Cartilage contains mostly type II collagen and proteoglycans, so it is difficult to access the quality and morphology of cartilage tissue in situ by conventional diagnostic tools (X-ray, MRI and echography) directly or indirectly. Raman spectroscopy is a label-free technique which enables to analyze molecular composition in degenerative cartilage. In this study, we generated an animal OA model surgically induced by knee joint instability, and the femurs were harvested at two weeks after the surgery. We performed Raman spectroscopic analysis for the articular cartilage of distal femurs in OA side and unaffected side in each mouse. In the result, there is no gross findings in the surface of the articular cartilage in OA. On the other hand, Raman spectral data of the articular cartilage showed drastic changes in comparison between OA and control side. The major finding of this study is that the relative intensity of phosphate band (960 cm^-1) increases in the degenerative cartilage. This may be the result of exposure of subchondral bone due to thinning of the cartilage layer. In conclusion, Raman spectroscopic technique is sufficient to characterize articular cartilage in OA as a pilot study for Raman application in cartilage degeneration and regeneration using animal models and human subjects.

Ocular infection is a serious eye disease that could lead to blindness without prompt and proper treatment. In pathology, ocular infection is caused by microorganisms such as bacteria, fungi or viruses. The essential prerequisite for the optimal treatment of ocular infection is to identify the microorganism causing infection early as each type of microorganism requires a different therapeutic approach. The clinical procedure for identifying the microorganism species causing ocular infection includes Gram staining (for bacteria)/microscopy (for fungi) and the culture of corneal surface scraping, or aqueous and vitreous smear samples taken from the surface of infected eyes. The culture procedure is labor intensive and expensive. Moreover, culturing is time consuming, which usually takes a few days or even weeks. Such a long delay in diagnosis could result in the exacerbation of patients’ symptoms, the missing of the optimal time frame for initiating treatment and subsequently the rising cost for disease management. Raman spectroscopy has been shown highly effective for non-invasive identification of both fungi and bacteria qualitatively. In this study, we investigate the feasibility of identifying the microorganisms of ocular infection and quantifying the concentrations using Raman spectroscopy by measuring not only gram negative and gram positive bacteria but also infected cornea. By applying a modified orthogonal projection approach, the relative concentration of each bacteria species could be quantified. Our results indicate the great potential of Raman spectroscopy as an alternative tool for non-invasive diagnosis of ocular infection and could play a significantly role in future ophthalmology.

In-situ shifted excitation Raman difference spectroscopy (SERDS) experiments are presented using a portable sensor system. Key elements of this system are an in-house developed handheld probe with an implemented dual-wavelength diode laser at 785 nm. An optical power of 120 mW is achieved ex probe. Raman experiments are carried out in the laboratory for qualification using polystyrene as test sample. Here, a shot-noise limited signal-to-noise ratio (SNR) of 120 is achieved. Stability tests were performed and show a stable position of the Raman line under study within 0.1 cm^-1 and a stable Raman intensity better ± 2% mainly limited by shot noise interference. SERDS experiments are carried out in an apple orchard for demonstration. Green apple leafs are used as test samples. The Raman spectra show huge background interferences by fluorescence and ambient daylight which almost obscure Raman signals from green leafs. The selected excitation power is 50 mW and the exposure time is 0.2 s to avoid detector saturation. SERDS efficiently separates the Raman signals from fluorescence and daylight contributions and generates an 11-fold improvement of the signal-to-background noise with respect to the measured Raman signals. The results demonstrate the capability of the portable SERDS system and enable rapid in-situ and undisturbed Raman investigations under daylight conditions.

Raman spectroscopy has demonstrated great potential in biomedical applications. However, spectroscopic Raman imaging is not widely used because of slow data acquisition. Our previous studies have indicated that spectroscopic Raman imaging can be significantly sped up using the approach of narrow-band imaging followed by spectral reconstruction. A multi-channel system has been built to demonstrate the feasibility of fast wide-field Raman spectroscopic imaging based on simultaneous narrow-band image acquisition and spectral reconstruction based on Wiener estimation in phantoms. To further improve the accuracy of reconstructed Raman spectra, we propose a stepwise spectral reconstruction method in this study, which can be combined with the earlier developed sequential weighted Wiener estimation to improve the spectral reconstruction accuracy. The stepwise spectral reconstruction method first reconstructs the fluorescence background spectra from narrow-band measurements by sequential weighted Wiener estimation and then the pure Raman narrow-band measurements can be estimated by subtracting the estimated fluorescence background from the overall Raman measurements. Thereafter, pure Raman spectra can be reconstructed from estimated pure Raman narrow-band measurements. The result indicates that the stepwise spectral reconstruction method can improve the spectral reconstruction accuracy by more than 30% when combined with sequential weighted Wiener estimation, compared with traditional Wiener estimation. In addition, cell Raman imaging were realized by using a multi-channel wide field Raman spectroscopic imaging and the stepwise spectral reconstruction method. This method can potentially facilitate the use of spectroscopic Raman imaging to investigate fast changing phenomena in biological samples.

Neurological diseases are one of the leading causes of adult disability and they are estimated to cause more deaths than cancer in the elderly population by 2040. Stem cell therapy has shown great potential in treating neurological diseases. However, before cell therapy can be widely adopted in the long term, a number of challenges need to be addressed, including the fundamental research about cellular development of neural progenitor cells. To facilitate the fundamental research of neural progenitor cells, many methods have been developed to identify neural progenitor cells. Although great progress has been made, there is still lack of an effective method to achieve fast, label-free and noninvasive differentiation of neural progenitor cells and their lineages. As a fast, label-free and noninvasive technique, spontaneous Raman spectroscopy has been conducted to characterize many types of stem cells including neural stem cells. However, to our best knowledge, it has not been studied for the discrimination of neural progenitor cells from specific lineages. Here we report the differentiation of neural progenitor cell from their lineages including astrocytes, oligodendrocytes and neurons using spontaneous Raman spectroscopy. Moreover, we also evaluate the influence of system parameters during spectral acquisition on the quality of measured Raman spectra and the accuracy of classification using the spectra, which yield a set of optimal system parameters facilitating future studies.

Nucleic acid-based molecular diagnostics at the point-of-care (POC) and in resource-limited settings is still a challenge. We present a sensitive yet simple DNA detection method with single nucleotide polymorphism (SNP) identification capability. The detection scheme involves sandwich hybridization of magnetic beads conjugated with capture probes, target sequences, and ultrabright surface-enhanced Raman Scattering (SERS) nanorattles conjugated with reporter probes. Upon hybridization, the sandwich probes are concentrated at the detection focus controlled by a magnetic system for SERS measurements. The ultrabright SERS nanorattles, consisting of a core and a shell with resonance Raman reporters loaded in the gap space between the core and the shell, serve as SERS tags for ultrasensitive signal detection. Specific DNA sequences of the malaria parasite Plasmodium falciparum and dengue virus 1 (DENV1) were used as the model marker system. Detection limit of approximately 100 attomoles was achieved. Single nucleotide polymorphism (SNP) discrimination of wild type malaria DNA and mutant malaria DNA, which confers resistance to artemisinin drugs, was also demonstrated. The results demonstrate the molecular diagnostic potential of the nanorattle-based method to both detect and genotype infectious pathogens. The method's simplicity makes it a suitable candidate for molecular diagnosis at the POC and in resource-limited settings.

Standard endoscopic tools restrict clinicians to making subjective visual assessments of lesions detected in the bowel, with classification results depending strongly on experience level and training. Histological examination of resected tissue remains the diagnostic gold standard, meaning that all detected lesions are routinely removed. This subjects the patient to risk of polypectomy-related injury, and places significant workload and economic burdens on the hospital. An objective endoscopic classification method would allow hyperplastic polyps, with no malignant potential, to be left in situ, or low grade adenomas to be resected and discarded without histology. A miniature multimodal flexible endoscope is proposed to obtain hyperspectral reflectance and dual excitation autofluorescence information from polyps in vivo. This is placed inside the working channel of a conventional colonoscope, with the external scanning and detection optics on a bedside trolley. A blue and violet laser diode pair excite endogenous fluorophores in the respiration chain, while the colonoscope's xenon light source provides broadband white light for diffuse reflectance measurements. A push-broom HSI scanner collects the hypercube. System characterisation experiments are presented, defining resolution limits as well as acquisition settings for optimal spectral, spatial and temporal performance. The first in vivo results in human subjects are presented, demonstrating the clinical utility of the device. The optical properties (reflectance and autofluorescence) of imaged polyps are quantified and compared to the histologically-confirmed tissue type as well as the clinician’s visual assessment. Further clinical studies will allow construction of a full robust training dataset for development of classification schemes.

We are developing label-free hyperspectral imaging (HSI) for tumor margin assessment. HSI data, hypercube (x,y,λ), consists of a series of high-resolution images of the same field of view that are acquired at different wavelengths. Every pixel on the HSI image has an optical spectrum. We developed preprocessing and classification methods for HSI data. We used spectral features from HSI data for the classification of cancer and benign tissue. We collected surgical tissue specimens from 16 human patients who underwent head and neck (H&N) cancer surgery. We acquired both HSI, autofluorescence images, and fluorescence images with 2-NBDG and proflavine from the specimens. Digitized histologic slides were examined by an H&N pathologist. The hyperspectral imaging and classification method was able to distinguish between cancer and normal tissue from oral cavity with an average accuracy of 90±8%, sensitivity of 89±9%, and specificity of 91±6%. For tissue specimens from the thyroid, the method achieved an average accuracy of 94±6%, sensitivity of 94±6%, and specificity of 95±6%. Hyperspectral imaging outperformed autofluorescence imaging or fluorescence imaging with vital dye (2-NBDG or proflavine). This study suggests that label-free hyperspectral imaging has great potential for tumor margin assessment in surgical tissue specimens of H&N cancer patients. Further development of the hyperspectral imaging technology is warranted for its application in image-guided surgery.

Multi-Spectral Time-Resolved Fluorescence Spectroscopy (ms-TRFS) can provide label-free real-time feedback on tissue composition and pathology during surgical procedures by resolving the fluorescence decay dynamics of the tissue. Recently, an ms-TRFS system has been developed in our group, allowing for either point-spectroscopy fluorescence lifetime measurements or dynamic raster tissue scanning by merging a 450 nm aiming beam with the pulsed fluorescence excitation light in a single fiber collection. In order to facilitate an augmented real-time display of fluorescence decay parameters, the lifetime values are back projected to the white light video. The goal of this study is to develop a 3D real-time surface reconstruction aiming for a comprehensive visualization of the decay parameters and providing an enhanced navigation for the surgeon. Using a stereo camera setup, we use a combination of image feature matching and aiming beam stereo segmentation to establish a 3D surface model of the decay parameters. After camera calibration, texture-related features are extracted for both camera images and matched providing a rough estimation of the surface. During the raster scanning, the rough estimation is successively refined in real-time by tracking the aiming beam positions using an advanced segmentation algorithm. The method is evaluated for excised breast tissue specimens showing a high precision and running in real-time with approximately 20 frames per second. The proposed method shows promising potential for intraoperative navigation, i.e. tumor margin assessment. Furthermore, it provides the basis for registering the fluorescence lifetime maps to the tissue surface adapting it to possible tissue deformations.

Differentiating radiation-induced necrosis from recurrent tumor in the brain remains a significant challenge to the neurosurgeon. Clinical imaging modalities are not able to reliably discriminate the two tissue types, making biopsy location selection and surgical management difficult. Label-free fluorescence lifetime techniques have previously been shown to be able to delineate human brain tumor from healthy tissues. Thus, fluorescence lifetime techniques represent a potential means to discriminate the two tissues in real-time during surgery. This study aims to characterize the endogenous fluorescence lifetime signatures from radiation induced brain necrosis in a tumor-free rat model. Fischer rats received a single fraction of 60 Gy of radiation to the right hemisphere using a linear accelerator. Animals underwent a terminal live surgery after gross necrosis had developed, as verified with MRI. During surgery, healthy and necrotic brain tissue was measured with a fiber optic needle connected to a multispectral fluorescence lifetime system. Measurements of the necrotic tissue showed a 48% decrease in intensity and 20% increase in lifetimes relative to healthy tissue. Using a support vector machine classifier and leave-one-out validation technique, the necrotic tissue was correctly classified with 94% sensitivity and 97% specificity. Spectral contribution analysis also confirmed that the primary source of fluorescence contrast lies within the redox and bound-unbound population shifts of nicotinamide adenine dinucleotide. A clinical trial is presently underway to measure these tissue types in humans. These results show for the first time that radiation-induced necrotic tissue in the brain contains significantly different metabolic signatures that are detectable with label-free fluorescence lifetime techniques.

Brain tumor surgeries are facing major challenges to improve patients’ quality of life. The extent of resection while preserving surrounding eloquent brain areas is necessary to equilibrate the onco-functional. A tool able to increase the accuracy of tissue analysis and to deliver an immediate diagnostic on tumor, could drastically improve actual surgeries and patient survival rates. To achieve such performances a complete optical study, ranging from ultraviolet to infrared, of biopsies has been started by our group. Four different contrasts were used: 1) spectral analysis covering the DUV to IR range, 2) two photon fluorescence lifetime imaging and one photon time domain measurement, 3) second harmonic generation imaging and 4) fluorescence imaging using DUV to IR, one and two photon excitation. All these measurements were done on the endogenous fluorescence of tissues to avoid any bias and further clinical complication due to the introduction of external markers. The different modalities are then crossed to build a matrix of criteria to discriminate tumorous tissues. The results of multimodal optical analysis on human biopsies were compared to the gold standard histopathology.

For neurosurgeries precise tumor resection is essential for the subsequent recovery of the patients since nearby healthy tissue that may be harmed has a huge impact on the life quality after the surgery. However, so far no satisfying methodology has been established to assist the surgeon during surgery to distinguish between healthy and tumor tissue. Optical Coherence Tomography (OCT) potentially enables non-contact in vivo image acquisition at penetration depths of 1-2 mm with a resolution of approximately 1-15 μm. To analyze the potential of OCT for distinction between brain tumors and healthy tissue, we used a commercially available Thorlabs Callisto system to measure healthy tissue and meningioma samples ex vivo. All samples were measured with the OCT system and three dimensional datasets were generated. Afterwards they were sent to the pathology for staining with hematoxylin and eosin and then investigated with a bright field microscope to verify the tissue type. This is the actual gold standard for ex vivo analysis. The images taken by the OCT system exhibit variations in the structure for different tissue types, but these variations may not be objectively evaluated from raw OCT images. Since an automated distinction between tumor and healthy tissue would be highly desirable to guide the surgeon, we applied Spectroscopic Optical Coherence Tomography to further enhance the differences between the tissue types. Pattern recognition and machine learning algorithms were applied to classify the derived spectroscopic information. Finally, the classification results are analyzed in comparison to the histological analysis of the samples.

Neurological cancer surgeries require specialized tools that enhance imaging for precise cutting and removal of tissue without damaging adjacent neurological structures. The novel combination of high-resolution fast optical coherence tomography (OCT) alongside short pulsed nanosecond thulium (Tm) lasers offers stark advantages utilizing the superior beam quality, high volumetric tissue removal rates of thulium lasers with minimal residual thermal footprint in the tissue and avoiding damage to delicate sub-surface structures (e.g., nerves and microvessels); which has not been showcased before. A bench-top system is constructed, using a 15W 1940nm nanosecond pulsed Tm fiber laser (500uJ pulse energy, 100ns pulse duration, 30kHz repetition rate) for removing tissue and a swept source laser (1310±70nm, 100kHz sweep rate) is utilized for OCT imaging, forming a combined Tm/OCT system – a smart laser knife. The OCT image-guidance informs the Tm laser for cutting/removal of targeted tissue structures. Tissue phantoms were constructed to demonstrate surgical incision with blood vessel avoidance on the surface where 2mm wide 600um deep cuts are executed around the vessel using OCT to guide the procedure. Cutting up to delicate subsurface blood vessels (2mm deep) is demonstrated while avoiding damage to their walls. A tissue removal rate of 5mm^3/sec is obtained from the bench-top system. We constructed a blow-off model to characterize Tm cut depths taking into account the absorption coefficients and beam delivery systems to compute Arrhenius damage integrals. The model is used to compare predicted tissue removal rate and residual thermal injury with experimental values in response to Tm laser-tissue modification.

Pancreatic cancer is one of the most feared cancer types due to high death rates and the difficulty to perform surgery. This cancer outcome could benefit from recent technological developments for diagnosis. We used a combination of standard Full Field OCT and Dynamic Full Field OCT to capture both morphological features and metabolic functions of rodents pancreas in normal and cancerous conditions with and without chemotherapy. Results were compared to histology to evaluate the performances and the specificities of the method. The comparison highlighted the importance of a number of endogenous markers like immune cells, fibrous development, architecture and more.

Deep vein thrombosis (DVT) is of serious mortality and morbidity, which often happens in inpatients and especially with the postoperative population [1]. The golden standard to diagnose DVT is venography, which relies on complicated imaging modalities requiring to be injected in a vein below the clot invasively and ionizing procedures that employing xray imaging to show where and how the DVT blocks. The near-infrared spectroscopy (NIRS) is recently found to be an intriguing and potential method detecting DVT in clinics. It has been reported recently that employing NIRS to diagnose DVT. Arteriosclerosis obliterans (ASO), local extremities manifestations of systemic atherosclerosis, usually cause thrombosis and the reduction of distal blood flow. Thrombolytic therapy is to use exogenous activator to activate the dissolution system, which can dissolve intracoronary thrombus. Here we attempt to monitor the DVT and ASO patients during the whole procedure of thrombolytic treatment, then compare the data with those DVT and ASO patients did not take treatments and normal population. 8 DVT and 9 ASO patients and 12 normal subjects were recruited to take the measurements of concentration variation of oxy- and deoxy-hemoglobins (Δ[HbO2] and Δ[Hb]) by NIRS-based thrombosis monitor. Thereinto, 5 DVT and 6 ASO patients has taken the thrombolytic treatment, and the data for the periods before treatment, during treatment, and after treatment were extracted for analysis. We found that Δ[HbO2] fluctuates and even decreases in DVT and ASO patients. After the thrombolytic therapy, Δ[HbO2] increases about 45% and converge to the curves of normal subjects. And the Δ[Hb] emerges the similar trends, except for the rising trend in the beginning and the downtrend after thrombolytic therapy. The findings indicated NIRS has big potential in clinical monitoring of DVT and ASO patients and offering reliable and quantitative evaluation of thrombolytic therapy outcomes.

A complication of intraventricular hemorrhage among preterm neonates is post-hemorrhagic ventricle dilation (PHVD), which is associated with a greater risk of life-long neurological disability. Clinical evidence, including suppressed EEG patterns, suggests that cerebral perfusion and oxygenation is impaired in these patients, likely due to elevated intracranial pressure (ICP). Cerebral blood flow (CBF) and the cerebral metabolic rate of oxygen (CMRO2) can be quantified by dynamic contrast-enhanced NIRS; however, PHVD poses a unique challenge to NIRS since the cerebral mantle can be compressed to 1 cm or less. The objectives of this work were to develop a finite-slab model for the analysis of NIRS spectra, incorporating depth measurements from ultrasound images, and to assess the magnitude of error when using the standard semi-infinite model. CBF, tissue saturation (StO2) and CMRO2 were measured in 9 patients receiving ventricle taps to reduce ICP. Monte Carlo simulations indicated that errors in StO2 could be greater than 20% if the cerebral mantle was reduced to 1 cm. Using the finite-slab model, basal CBF and CMRO2 in the PHVD patients were not significantly different from a control group of preterm infants (14.6 ± 4.2 ml/100 g/min and 1.0 ± 0.4 ml O2/100 g/min), but StO2 was significantly lower (PDA 70.5 ± 9%, PHVD 58.9 ± 12%). Additionally, ventricle tapping improved CBF by 15.6 ± 22%. This work indicates that applying NIRS to PHVD patients is prone to error; however, this issue can be overcome with the appropriate model and using readily available ultrasound images.

In Canada, 8% of births occur prematurely. Preterm infants weighing less than 1500g are at a high risk of neurodevelopmental impairment: 5-10% develop major disabilities such as cerebral palsy and 40-50% show other cognitive and behavioural deficits. The brain is vulnerable to periods of low cerebral blood flow (CBF) that can impair energy metabolism and cause tissue damage. There is, therefore, a need for an efficient neuromonitoring system to alert the neonatal intensive care team to clinically significant changes in CBF and metabolism, before injury occurs. Optical technologies offer safe, non-invasive, and cost-effective methods for neuromonitoring. Cerebral oxygen saturation (ScO2) can be measured by exploiting the absorption properties of hemoglobin though Near-Infrared Spectroscopy (NIRS), and Diffuse Correlation Spectroscopy (DCS) can monitor CBF by tracking red blood cells. These measures can be combined to describe metabolism, a key indicator of tissue viability. In this study we present the development and testing of a hybrid broadband NIRS/DCS neuromonitor. This system is novel in its ability to simultaneously acquire broadband NIRS and DCS signals, providing a truly real-time measure of metabolism. Narrow bandpass and notch filters have been incorporated to diminish light contamination between the two modalities, preferentially filtering out each source from the opposing detector, allowing for an accurate measure of ScO2, CBF, and metabolism. With a broadband NIRS/DCS system, a real-time measure of CBF and metabolism within the developing brain can aid clinicians in monitoring events that precede brain injury, ultimately leading to better clinical outcomes.

Primary lymphedema and lymphatic malformations in the pediatric population remains poorly diagnosed and misunderstood due to a lack of information on the underlying anatomy and function of the lymphatic system. Diagnostics for the lymphatic vasculature are limited, consisting of lymphoscintigraphy or invasive lymphangiography, both of which require sedation that can restrict use in infants and children. As a result, therapeutic protocols for pediatric patients with lymphatic disorders remain sparse and with little evidence to support them. Because near-infrared fluorescence (NIRF) imaging enables image acquisition on the order of tenths of seconds with trace administration of fluorescent dye, sedation is not necessary. The lack of harmful radiation and radioactive contrast agents further facilitates imaging. Herein we summarize our experiences in imaging infants and children who are suspected to have disorders of the lymphatic vascular system using indocyanine green (ICG) and who have developed chylothorax following surgery for congenital heart defects. The results show both anatomical as well as functional lymphatic deficits in children with congenital disease. In the future, NIRF lymphatic imaging could provide new opportunities to tailor effective therapies and monitor responses. The opportunity to use expand NIRF imaging for pediatric diagnostics beyond the lymphatic vasculature is also afforded by the rapid acquisition following trace administration of NIRF contrast agent.

Smart medical catheters face a connectivity challenge. An example is found in ultrasound imaging where the supply of power at the distal end and the signal transmission requires many thin and fragile wires in order to keep the catheter thin and flexible and this leads to a relatively high cost of production. We have built a fully functional benchtop demonstrator that is immediately scalable to catheter dimensions, in which all electrical wires are replaced by just two optical fibers. We show signal transfer of synthetic aperture ultrasound images as well as photovoltaic conversion to supply all electronics. The absence of conductors provides excellent galvanic isolation as well as RF and MRI compatibility and the simple design utilizing off the shelf components holds a promise of cost effectiveness all of which may help translation of these advanced devices into the clinic. We show photovoltaic conversion of 405 nm light to 45 V and 1.8 V by two blue LEDs as well as 200 MHz broad-band signal transfer using modulated 850 nm VCSEL light. Synthetic aperture ultrasound images are acquired at a frequency of 12 MHz with a collapse-mode capacitive-micromachined ultrasonic transducer. Bandwidth, noise level and dynamic range are nearly identical as shown in comparison of the images acquired with the optical link and its electrical equivalent. In conclusion, we have successfully demonstrated low-cost and scalable optical signal and power transmission for an ultrasound imaging system enjoying intrinsic RF / MRI compatibility and galvanic isolation.

We report on a novel monolithic high-power diode pumped Tm:YAG laser at 2.02 μm. The pulsed laser generates average output power and pulse energy of beyond 90W and 900mJ in 400 μs pulses, respectively. This wavelength allows usage of standard fused silica fibers and optics, a price competitive solution for minimally-invasive endoscopic surgery. Recent developments in double-clad fiber combiners enable a rugged delivery system for the laser and the OCT ideal for a seeing laser scalpel. This gives the possibility to detect in-depth underlying tissue not yet ablated by the laser in a 2D or 3D fashion with micrometer resolution.

We present the design, development, and bench-top verification of an innovative compact clinical system including a miniaturized handheld optoelectronic sensor. The integrated sensor was microfabricated with die-level light-emitting diodes and photodiodes and fits into a 19G hollow needle (internal diameter: 0.75 mm) for optical sensing applications in solid tissues. Bench-top studies on tissue-simulating phantoms have verified system performance relative to a fiberoptic based tissue spectroscopy system. With dramatically reduced system size and cost, the technology affords spatially configurable designs for optoelectronic light sources and detectors, thereby enabling customized sensing configurations that would be impossible to achieve with needle-based fiber-optic probes.

It is difficult to obtain quantitative measurements as to surface areas and volumes from standard photos of the body parts of patients which is highly desirable for objective follow up of treatments in e.g. dermatology. plastic, aesthetic and reconstructive surgery. Recently, 3-D scanners have become available to provide quantification.

Phantoms (3-D printed hand, nose and ear, colored bread sculpture) were developed to compare a range from low-cost (Sense), medium (HP Sprout) to high end (Artec Spider, Vectra M3) scanners using different 3D imaging technologies, as to resolution, working range, surface color representation, user friendliness. The 3D scans files (STL, OBJ) were processed with Artec studio and GOM software as to deviation compared to the high resolution Artec Spider scanner taken as ‘golden’ standard. The HP Spout, which uses a fringe projection, proved to be nearly as good as the Artec, however, needs to be converted for clinical use. Photogrammetry as used by the Vectra M3 scanner is limited to provide sufficient data points for accurate surface mapping however provides good color/structure representation. The low performance of the Sense is not recommended for clinical use. The Artec scanner was successfully used to measure the structure/volume changes in the face after hormone treatment in transgender patients.

3D scanners can greatly improve quantitative measurements of surfaces and volumes as objective follow up in clinical studies performed by various clinical specialisms (dermatology, aesthetic and reconstructive surgery). New scanning technologies, like fringe projection, are promising for development of low-cost, high precision scanners.

The human gastrointestinal tract or ‘gut’ is one of the body’s largest functional systems spanning up to 8 metres in length from beginning to end. It is formed of a series of physiologically different sections that perform the various functions required for the digestion of food, absorption of nutrients and water, and the removal of waste products. To enable the gut to perform correctly it must be able to transport digesta through each section at the appropriate rate, and any breakdown or malfunction of this transport mechanism can have severe consequences to on-going good health.

Monitoring motor function deep within the gut is challenging due to the need to monitor over extended lengths with high spatial resolution. Fiber Bragg grating (FBG) manometry catheters provide a near ideal method of monitoring physiologically significant lengths of the gut in a minimally invasive fashion. Following the development by our group of the first viable FBG based manometry catheter we have undertaken a series of clinical investigations in the human esophagus, colon, stomach and small bowel. Each region presents its own technological challenge and has required a range of modifications to the basic catheter design. We present the design of these catheters and clinical results from over 100 in-vivo studies.

Volume measurement of the leg is important in the evaluation of leg edema. Recently, method for measurement by using a depth camera is proposed. However, many depth cameras are expensive. Therefore, we propose a method using Microsoft Kinect. We obtain a point cloud of the leg by Kinect Fusion technique and calculate the volume. We measured the volume of leg for three healthy students during three days. In each measurement, the increase of volume was confirmed from morning to evening. It is known that the volume of leg is increased in doing office work. Our experimental results meet this expectation.

Because the view angle of the endoscope is narrow, it is difficult to get the whole image of the digestive tract at once. If there are more than two lesions in the digestive tract, it is hard to understand the 3D positional relationship among the lesions. Virtual endoscopy using CT is a present standard method to get the whole view of the digestive tract. Because the virtual endoscopy is designed to detect the irregularity of the surface, it cannot detect lesions that lack irregularity including early cancer. In this study, we propose a method of endoscopic entire 3D image acquisition of the digestive tract using a stereo endoscope. The method is as follows: 1) capture sequential images of the digestive tract by moving the endoscope, 2) reconstruct 3D surface pattern for each frame by stereo images, 3) estimate the position of the endoscope by image analysis, 4) reconstitute the entire image of the digestive tract by combining the 3D surface pattern. To confirm the validity of this method, we experimented with a straight tube inside of which circles were allocated at equal distance of 20 mm. We captured sequential images and the reconstituted image of the tube revealed that the distance between each circle was 20.2 ± 0.3 mm (n=7). The results suggest that this method of endoscopic entire 3D image acquisition may help us understand 3D positional relationship among the lesions such as early esophageal cancer that cannot be detected by virtual endoscopy using CT.

In reconstructive surgery, tissue perfusion/vessel patency is critical to the success of microvascular free tissue flaps. Early detection of flap failure secondary to compromise of vascular perfusion would significantly increase the chances of flap salvage. We have developed a compact, clinically-compatible monitoring system to enable automated, minimally-invasive, continuous, and quantitative assessment of flap viability/perfusion. We tested the system’s continuous monitoring capability during extended non-recovery surgery using an in vivo porcine free flap model. Initial results indicated that the system could assess flap viability/perfusion in a quantitative and continuous manner. With proven performance, the compact form constructed with cost-effective components would make this system suitable for clinical translation.

As many as 80,000 patients a year in the US undergo thyroidectomies or parathyroidectomies for diseased glands. About 21% of these surgeries result in disruption of blood supply to health parathyroid glands, which, if unaddressed, may result in long-term hypocalcemia. Surgeons need to know as soon as possible whether or not the blood supply to a parathyroid gland has been disrupted, as this informs their decision on whether or not to excise and reimplant the gland. There is a non-trivial failure rate involved in this transplantation process, and in the absence of an objective gold-standard surgeons often rely on subjective visual inspection in making this decision. Here we present Laser Speckle Imaging as a real-time objective method to assess parathyroid viability. Our device consists of a 785 nm laser source and a near-infrared camera with a zoom lens, positioned above the surgical field with an articulated arm. With the laser diffusing light onto the tissue, the camera acquires images which are processed in real-time and displayed on a monitor. These speckle contrast images are then averaged and the relative difference in speckle contrast between the parathyroid gland and surrounding thyroid tissue is calculated and correlated with the surgeon’s assessment of viability. Preliminary findings from in vivo measurement of 9 diseased glands show 100% agreement with the surgeon when taking a greater than 5% relative difference to indicate devascularization. This device has the potential to be used as an intraoperative tool for assessing parathyroid viability.

Surgeons have been increasingly relying on minimally invasive surgical guidance techniques not only to reduce surgical trauma but also to achieve accurate and objective surgical risk evaluations. A typical minimally invasive surgical guidance system provides visual assistance in two-dimensional anatomy and pathology of internal organ within a limited field of view. In this work, we propose and implement a structure illumination endoscope to provide a simple, inexpensive 3D endoscopic imaging to conduct high resolution 3D imagery for use in surgical guidance system. The system is calibrated and validated for quantitative depth measurement in both calibrated target and human subject. The system exhibits a depth of field of 20 mm, depth resolution of 0.2mm and a relative accuracy of 0.1%. The demonstrated setup affirms the feasibility of using the structured illumination endoscope for depth quantization and assisting medical diagnostic assessments

Nephrotic disease is a group of debilitating and sometimes lethal diseases affecting kidney function, specifically the loss of ability to retain vital proteins in the blood while smaller molecules are removed through filtration into the urine. Treatment routes are often dictated by microscopic analysis of kidney biopsies. Podocytes within the glomeruli of the kidney have many interdigitating projections (foot processes), which form the main filtration system. Nephrotic disease is characterised by the loss of this tightly interdigitating substructure and its observation by electron microscopy (EM) is necessitated as these structures are typically 250􀀀500nm wide, with 40nm spacing. Diagnosis by EM is both expensive and time consuming; it can take up to one week to complete the preparation, imaging, and analysis of a single sample. We propose structured illumination microscopy (SIM) as an alternative, optical diagnostic tool. Our results show that SIM can resolve the structure of fluorescent probes tagged to podocin, a protein localised to the periphery of the podocyte foot processes. Three-dimensional podocin maps were acquired in healthy tissue and tissue from patients diagnosed with two different nephrotic disease states; minimal change disease and membranous nephropathy. These structures correlated well with EM images of the same structure. Preparation, imaging, and analysis could be achieved in several hours. Additionally, the volumetric information of the SIM images revealed morphological changes in disease states not observed by EM. This evidence supports the use of SIM as a diagnostic tool for nephrotic disease and can potentially reduce the time and cost per diagnosis.

Breast-conserving surgery is a well-accepted breast cancer treatment. However, it is still challenging for the surgeon to accurately localize the tumor during the surgery. Also, the guidance provided by current methods is 1 dimensional distance information, which is indirect and not intuitive. Therefore, it creates problems on a large re-excision rate, and a prolonged surgical time. To solve these problems, we have developed a fiber-delivered optoacoustic guide (OG), which mimics the traditional localization guide wire and is preoperatively placed into tumor mass, and an augmented reality (AR) system to provide real-time visualization on the location of the tumor with sub-millimeter variance. By a nano-composite light diffusion sphere and light absorbing layer formed on the tip of an optical fiber, the OG creates an omnidirectional acoustic source inside tumor mass under pulsed laser excitation. The optoacoustic signal generated has a high dynamic range (~ 58dB) and spreads in a large apex angle of 320 degrees. Then, an acoustic radar with three ultrasound transducers is attached to the breast skin, and triangulates the location of the OG tip. With an AR system to sense the location of the acoustic radar, the relative position of the OG tip inside the tumor to the AR display is calculated and rendered. This provides direct visual feedback of the tumor location to surgeons, which will greatly ease the surgical planning during the operation and save surgical time. A proof-of-concept experiment using a tablet and a stereo-vision camera is demonstrated and 0.25 mm tracking variance is achieved.

Brain death, the irreversible and permanent loss of the brain and brainstem functions, is hard to be judged precisely for some clinical reasons. The traditional diagnostic methods are time consuming, expensive and some are even dangerous. Functional near infrared spectroscopy (FNIRS), using the good scattering properties of major component of blood to NIR, is capable of noninvasive monitoring cerebral hemodynamic responses. Here, we attempt to use portable FNIRS under patients’ natural state for brain death diagnosis. Ten brain death patients and seven normal subjects participated in FNIRS measurements. All of them were provided different fractional concentration of inspired oxygen (FIO₂) in different time periods. We found that the concentration variation of deoxyhemoglobin concentration (Δ[Hb]) presents the trend of decrease in the both brain death patients and normal subjects with the raise of the FIO₂, however, the data in the normal subjects is more significant. And the concentration variation of oxyhemoglobins concentration (Δ[HbO₂]) emerges the opposite trends. Thus Δ[HbO₂]/Δ[Hb] in brain death patients is significantly higher than normal subjects, and emerges the rising trend as time went on. The findings indicated the potential of FNIRS-measured hemodynamic index in diagnosing brain death.

Intraoperative guidance is often used during procedures to provide surgeons with information linking the current surgical scene to some preoperative plan or model. This allows surgeons to visualize structures or targets of interest that are not visible in the intraoperative imaging modality. A common method to enable this type of technology is the use of fiducials that can be located both preoperatively and intraoperatively. In this work, we focus on the registration of preoperative computed tomography with intraoperative three-dimensional ultrasound. We examine the use of titanium fiducials activated intraoperatively by the photoacoustic effect. The photoacoustic effect is generated when the metal fiducials are illuminated by laser light, resulting in an acoustic signal at each fiducial that can be observed by a conventional ultrasound transducer. A transrectal ultrasound transducer is translated to generate a three-dimensional ultrasound volume. The set of fiducial points are segmented from the three-dimensional ultrasound volume and registered with the corresponding set of fiducial points segmented from the computed tomography volume. The target registration error metric is used to validate the registration between these two coordinate systems. The resulting target registration error was 1.55 ± 0.62mm. It was observed in this experiment that there were certain acoustic reverberation and refraction artifacts that occurred at distances coinciding with the size of the fiducial. Further work with different shapes and sizes of fiducials may be necessary to quantify and analyze how they affect the generation of a photoacoustic signal.

The peripheral nervous system plays an important role in motility, sensory, and autonomic functions of the human body. Preservation of peripheral nerves in surgery, namely nerve-sparing surgery, is now promising technique to avoid functional deficits of the limbs and organs following surgery as an aspect of the improvement of quality of life of patients. Detection of peripheral nerves including myelinated and unmyelinated nerves is required for the nerve-sparing surgery; however, conventional nerve identification scheme is sometimes difficult to identify peripheral nerves due to similarity of shape and color to non-nerve tissues or its limited application to only motor peripheral nerves. To overcome these issues, we proposed a label-free detection technique of peripheral nerves by means of Raman spectroscopy. We found several fingerprints of peripheral myelinated and unmyelinated nerves by employing a modified principal component analysis of typical spectra including myelinated nerve, unmyelinated nerve, and adjacent tissues. We finally realized the sensitivity of 94.2% and the selectivity of 92.0% for peripheral nerves including myelinated and unmyelinated nerves against adjacent tissues. Although further development of an intraoperative Raman spectroscopy system is required for clinical use, our proposed approach will serve as a unique and powerful tool for peripheral nerve detection for nerve-sparing surgery in the future.

In India oral cancer ranks the top due to the habitual usage of tobacco in its various forms and remains the major burden. Hence priority is given for early diagnosis as it is the better solution for cure or to improve the survival rate. For the past three decades, optical spectroscopic techniques have shown its capacity in the discrimination of normal and malignant samples. Many research works have conventional Raman in the effective detection of cancer using the variations in bond vibrations of the molecules. However in addition polarized Raman provides the orientation and symmetry of biomolecules. If so can polarized Raman be the better choice than the conventional Raman in the detection of cancer? The present study aimed to found the answer for the above query. The conventional and polarized Raman spectra were acquired for the same set of blood plasma samples of normal subjects and oral malignant (OSCC) patients. Thus, obtained Raman spectral data were compared using linear discriminant analysis coupled with artificial neural network (LDA-ANN). The depolarization ratio of biomolecules such as antioxidant, amino acid, protein and nucleic acid bases present in blood plasma was proven to be the best attributes in the categorization of the groups. The polarized Raman results were promising in discriminating oral cancer blood plasma from that of normal blood plasma with improved efficiency. The results will be discussed in detail.