This PDF file contains the front matter associated with SPIE Proceedings Volume 10470, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

Efficient mucociliary clearance is necessary to protect the respiratory tract from infection. Mucociliary dysfunction is common in respiratory diseases including asthma, chronic obstructive pulmonary disease, and cystic fibrosis. Rescuing mucociliary clearance by stimulating the metabolism of respiratory ciliated epithelia could offer new treatments for respiratory diseases. However, the coupling between cellular metabolism and mechanical output in respiratory ciliated epithelia is poorly understood. We propose to study this coupling with autofluorescence microscopy and optical coherence tomography (OCT), to measure cellular metabolism and ciliary motility, respectively. The autofluorescent metabolic co-enzymes NAD(P)H and FAD provide non-invasive measures of metabolism through the optical redox ratio (NAD(P)H intensity divided by FAD intensity), while OCT measures both the frequency of ciliary beating and cilia-driven fluid flow. Preliminary experiments were performed in ex vivo mouse trachea using an epifluorescence microscope and a spectral-domain OCT system. Cilia-driven fluid flow was quantified using 2D particle tracking velocimetry (PTV-OCT) and TrackMate, a particle-tracking tool. PTV-OCT was validated by manual particle tracking (within 4% agreement) and a calibrated flow phantom (r=0.998, p<0.001). Treatment of the trachea with cyanide, a complex IV inhibitor that reduces intracellular ATP levels, demonstrated that an increase in optical redox ratio (p<0.001) reflects a decrease in cilia-driven flow (p<0.05). Additional studies using human samples are underway to explore how pathologically altered metabolism affects ciliary motility. This optical imaging approach could provide a better understanding of respiratory disease pathogenesis, and new therapeutic targets. In the future, these technologies could also monitor intensive care patients through an endoscope.

To better understand bronchoconstriction in asthma, it is critical to dynamically visualize airway behavior in vivo. However, currently available imaging techniques do not have sufficient temporal and spatial resolution to investigate airway dynamics. We propose to use endobronchial Optical Coherence Tomography (OCT) to provide real-time cross-sectional images of airway dynamics with a high spatial resolution. Our aim was to study the structure and function of spatially distinct airways during tidal breathing (TB), breath-holds (BH) at end inspiration, and in a response to single deep inspiration (DI) and multiple DI (MDI) in a preclinical sheep asthma model. Anesthetized and mechanically ventilated sheep (n=3) were imaged with OCT in 4 dependent and 4 non-dependent airways at baseline and in methacholine constricted airways. We assessed airway morphology during TB, BH, DI and MDI maneuvers. The change in airway lumen area was found to be greater in the dependent airways compared to the non-dependent airways during TB (dependent: +14.9%, non-dependent: +6%) at baseline. Similarly, the dependent airways dilated more than the non-dependent airways in response to BH (dependent: +7.9%, non-dependent: +5.7%) in relaxed condition. Conversely, in the constricted lung, the DI and MDI maneuvers dilated the non-dependent airways (+13.6% DI, +44% MDI) more than the dependent airways (+6% DI, +15.5% MDI). Overall, dependent airways were more distensible than non-dependent airways during TB and BH, while this behavior was reversed following DI and MDI maneuvers in constricted airways possibly due to a greater local methacholine delivery due to gravitational dependencies on perfusion.

The understanding of alveolar mechanics is an essential step towards new and more protective ventilation strategies which are of dare need for the treatment of diseases of lung tissue and the airways. Such ailments become a major task for medical care and health care systems in modern industrial countries in the future. Besides the obvious importance as life-saving intervention, the mechanical strain and processes on the level of gas exchange are still insufficiently understood. Therefore, it is of great interest to characterize lung tissue and tissue dynamics during artificial ventilation at the alveolar level. 4D Optical coherence tomography (OCT) in combination with high-speed video microscopy (IVM) are promising tools for the investigation and characterization of lung tissue with a high spatial and temporal resolution in artificially ventilated rats. Optical access to the subpleural alveoli is achieved by removing the skin and tissue between the ribs. For IVM, a tunable focus lens is used to track axial motion and keep the tissue in focus and 4D OCT is performed using a gated scanning algorithm for image acquisition. The movement of alveolar tissue during uninterrupted ventilation was visualized during one ventilation cycle using these image acquisition techniques. The alveolar structures are clearly visible and can be segmented and measured regarding volume and volume changes. The measurement of three-dimensional volume changes during uninterrupted ventilation from OCT data and the comparison with two-dimensional information from IVM promote the understanding of alveolar mechanics and the effort for the development of more protective ventilation strategies.

Visualization of the airway smooth muscle (ASM) layer is crucial in understanding its role in normal and abnormal airway function. Increased thickness of the ASM layer is one of the pathological hallmarks of airway remodeling in asthma and chronic obstructive pulmonary disease (COPD). The thickness of the ASM layer cannot be measured using current imaging techniques such as CT. Recently, Adams et al. introduced a birefringence microscopy platform, based on polarization sensitive optical coherence tomography (OCT), that enabled identification of ASM by its optic axis orientation in humans and allowed investigation of ASM contractile force ex vivo. In this work, we implemented passive depth-encoded polarization multiplexing and polarization-diversity detection in a 1300-nm swept-source OCT system. Compared with the previous inter-A-line modulation, such a strategy offers a simpler, more noise-resistant measure of the full polarization response of the tissue captured from a single A-line. We also refined the reconstruction of the depth-resolved birefringence properties to obtain the local optic axis orientation, corrected for the effect of preceding tissue layers and system distortions. Human bronchial samples were measured ex vivo in benchtop configuration. ASM layers, featuring muscle bundles oriented roughly at 90 degrees to the long axis of the airway, were extracted from 3D volumes by careful mapping of depth-resolved optic-axis orientation. Comparison of OCT measurements with H&E stained histological sections was performed to assess the accuracy of ASM delineation.

Chronic Lung Allograft Dysfunction (CLAD) remains a significant cause of morbidity and mortality following lung transplantation. Bronchiolitis obliterans Syndrome (BOS) is a predominant phenotype of CLAD primarily affecting the small and subsequently the large airways leading eventually to graft failure. In addition, the allograft airways are also involved in other types of CLAD such as Restrictive Allograft Syndrome (RAS). Freedom from BOS at five years post-transplant is only approximately 50 % among lung transplant recipients. The diagnosis of CLAD is primarily based on pulmonary function testing and radiographic findings on CT scan. Transbronchial biopsies have a low diagnostic yield due to the multifocal nature of CLAD and the frequent lack of bronchioles in the biopsy specimen. Thus, CLAD is often diagnosed after significant disease progression. We performed endoscopic OCT as a minimally invasive method to identify early CLAD biomarkers. During 65 routine surveillance and event-initiated bronchoscopies of lung transplant recipients at Vancouver General Hospital, OCT imaging was performed prior to acquiring biopsy samples, with multiple 3D volumetric scans taken at locations as close as possible to those biopsied. OCT has the potential to be advantageous over biopsy because multiple airways in the lung can be quickly surveyed. As a first step towards clinical utility we present our methods for quantifying observable biomarkers including luminal size and alveolar density. Ranges of values are established and correlated with airway generation, time since transplant, and infection status.

Transthoracic core-needle biopsy under imaging guidance is a common procedure in lung cancer diagnosis. It is performed in order to extract material for histology from a nodule that has previously been detected with radiography or computed tomography in the patient’s chest. In order to avoid recalling for non-diagnostic material, the radiologists are used to performing several biopsies so that the chance of resection of relevant material is increased. The use of a real-time tool for lung biopsy assessment during biopsy procedure would be valuable to decrease the number of biopsies thus decreasing the risk of complications. As an answer to this need, LLTech develops an optical imaging device for real time biopsy assessment at cellular level. Based on full-field optical coherence tomography, the system performs micron resolution optical virtual slices in the sample depth within a few minutes. In addition, benefiting from its high-speed acquisition capability, the system quickly records the evolution of this optical slice over time, thus highlighting intracellular residual movements of freshly excised tissue. Both the tissue architecture and the intracellular activity are imaged and combined in an exhaustive analysis that favors the pathologists reading. LLTech presents the images obtained on dozens of lung biopsies in collaboration with Cochin Hospital radiology and pathology departments to evaluate the potential of dynamic cell imaging on lung cancer assessment.

Development of effective rescue countermeasures for toxic inhaled industrial chemicals such as methyl isocyanate (MIC) has been an emerging interest. The conducting airways are especially sensitive to such chemicals, and their inhalation can cause severe airway and lung damage. In an attempt to develop an effective therapeutic agent for MIC, animal models have been evaluated with molecular diagnostics, histological examination, and arterial blood gases. However, direct measurement of the airway structure has not been performed. Our group previously demonstrated anatomical OCT scanning of human proximal airways with endoscopic probes. However, a smaller probe with diameter of less than half a millimeter is required for scanning the MIC-exposed rat trachea. In this study, we acquired volumetric scanning of MIC-exposed rat trachea using a miniature endoscopic probe and performed automated segmentation to reconstruct a 3-D structure of the intraluminal surface. Our miniature probe is 0.4 mm in diameter and based on a fully fiberoptic design. In this design, three optical fibers with core sizes of 9, 12, and 20 um replace the lens, and the angle-polished fiber at the distal end reflects the beam at a perpendicular angle and replaces the mirror. Using automated segmentation, we reconstructed the three-dimensional structure of intraluminal space in MIC-exposed rat trachea. Compared to the non-exposed rat trachea, which had a hollow tubular structure with a relatively uniform cross-section area, the MIC-exposed rat trachea showed significant airway narrowing as a result of epithelial detachment and extravascular coagulation within the airway. This technique could potentially be applied to high-throughput drug screening of animal models.

Airway inhalation injuries are present in up to a third of all major burns patients and are the leading cause of mortality among this population. Understanding the mechanism of injury could minimise oedema (swelling) and airway damage. In this study, we present an anatomical OCT (aOCT) imaging system, based on a 1300-nm wavelength, high-speed, long-range MEMS-VCSEL swept laser source, for real-time volumetric imaging and assessment of inhalation injuries in airways up to 3 cm in diameter. A custom fibre-optic probe with GRIN lens and micro prism is inserted though the nasal passage. Airway cross-sectional images acquired are used to assess airway diameter and lumen area, as well as to visualize the airway in three dimensions. Preliminary scans of healthy human subjects are presented. The effect of the supine position and fluid intake on airway geometry is quantified to better understand how these factors may contribute to the treatment outcomes of burns patients.

Infectious pneumonia is a major cause of morbidity/mortality, mainly due to the increasing rate of microorganisms resistant to antibiotics. Photodynamic Inactivation (PDI) is emerging as a promising treatment option, which effects are based on oxidative stress, targeting several biomolecules and probably preventing potential resistant strains. In previous studies, the in vitro inactivation of Streptococcus pneumoniae using indocyanine green (ICG) and infrared (IR) light source (780 nm) was successful, and achieving satisfactory reduction of colony-forming units (CFU/mL). In the present study, a proof-of-principle protocol was designed to treat lung infections by PDI using extracorporeal irradiation with a 780 nm laser device and nebulized ICG as photosensitizer. Balb/c mice were infected with S. pneumoniae and PDI was performed two days after infection using 800 μM of nebulized ICG and extracorporeal irradiation. Our results indicate that IR-extracorporeal PDI using nebulized ICG may be considered a potential pneumonia treatment, and pulmonary decontamination with PDI may be used as a single therapy or as an adjuvant for antibiotics.

Sensorineural hearing loss (SNHL) is the most common sensory deficit in the world, caused by damage to cellular structures within the inner ear, or cochlea. Visualization of the cellular pathology underlying different types of SNHL has been difficult due to the small size of the cochlea, its complex three-dimensional structure, and embedded location within the temporal bone. Micro-optical coherence tomography (µOCT) is a recently-developed cross-sectional imaging technology that can obtain images with sufficient detail to elucidate specific aetiologies of SNHL. In this work, we developed a high resolution, ultra-small-diameter, flexible probe for imaging the human cochlea in situ. The 500 µm diameter, circumferential scanning µOCT imaging probe contains self-imaging wavefront division optics that provide maximal lateral resolution of 2.5 µm and better than 5 µm resolution over an extended depth of focus of 1 mm in air. Using a supercontinuum light source with a 300 nm bandwidth and a common path interferometery configuration, axial resolution is 1.9 µm in air. Images of 3D-intact cochleae extracted from human cadavers were acquired with the µOCT probe in situ; these images demonstrate the system’s ability to visualize the entire cross-section of the scala tympani, in addition to cellular structures in the cochlea’s sensory epithelium, the organ of Corti and bundles of auditory nerves. These results suggest that this new device has the potential to facilitate personalized diagnosis and therapy for SNHL.

Osteoarthritis involves the progressive degeneration of the cartilage surface, which leads to joint pain and dysfunction. Arthroscopy is the standard procedure for monitoring cartilage degeneration in situ. However, this evaluation depends on the surgeon's subjective interpretation, and therefore may lack reliability. Full-field optical coherence tomography (FFOCT) is a promising technique that could enable micrometer scale cartilage evaluation in situ. A preliminary study was carried out by the Grenoble-Alpes University Hospital in collaboration with TIMC-IMAG laboratory and LLTech to evaluate the ability of the FFOCT microscope commercialized by LLTech to evaluate cartilage quality. FFOCT images were acquired and matching histology sections were prepared for 33 ex vivo cartilage samples. A strong and significant correlation was found between the histology and FFOCT evaluation of the cartilage quality, both qualitatively and quantitatively. In order to use FFOCT for the evaluation of cartilage quality at the micrometer scale in situ, LLTech has developed an endomicroscope version of the FFOCT microscope. When held in contact with the tissue to image, the FFOCT rigid endomicroscope acquires a micron resolution virtual optical slice at a depth of 20 microns below the surface, showing the tissue architecture at this depth in an 'en face' view of 1 mm diameter. This FFOCT endomicroscope has been assessed through images that have been acquired of fresh ex vivo human cartilage samples using both the microscope and endomicroscope. Chondrocytes have been identified in both the microscope and endomicroscope images. Furthermore, a localization environment is under development by the TIMC-IMAG laboratory in order to be able to track the movement of the endomicroscope such that multiple endomicroscope images can be mosaicked together.

While Optical Coherence Microscopy (OCM), Multiphoton Microscopy (MPM), and narrowband imaging are powerful imaging techniques that can be used to detect cancer, each imaging technique has limitations when used by itself. Combining them into an endoscope to work in synergy can help achieve high sensitivity and specificity for diagnosis at the point of care. Such complex endoscopes have an elevated risk of failure, and performing proper modelling ensures functionality and minimizes risk. We present full 2D and 3D models of a multimodality optical micro-endoscope to provide real-time detection of carcinomas, called a salpingoscope. The models evaluate the endoscope illumination and light collection capabilities of various modalities. The design features two optical paths with different numerical apertures (NA) through a single lens system with a scanning optical fiber. The dual path is achieved using dichroic coatings embedded in a triplet. A high NA optical path is designed to perform OCM and MPM while a low NA optical path is designed for the visible spectrum to navigate the endoscope to areas of interest and narrowband imaging. Different tests such as the reflectance profile of homogeneous epithelial tissue were performed to adjust the models properly. Light collection models for the different modalities were created and tested for efficiency. While it is challenging to evaluate the efficiency of multimodality endoscopes, the models ensure that the system is design for the expected light collection levels to provide detectable signal to work for the intended imaging.

We present a proof-of-concept for side-viewing endoscopic optical coherence tomography probes designed for real-time imaging. The design employs a commercial rotating micro-engine (Kinetron), with a 1 mm outer diameter and maximum speed of 10,000 rpm, to steer the beam from a GRIN lens-terminated optical fiber (Agiltron), 360 degrees around the probe body. The engine is encapsulated inside a PET tube with an outer diameter of 1.6 mm, and coupled to a swept-source based optical coherence tomography (SS-OCT) system operating at 1300 nm with an A-scan rate of 100 kHz. Large material dispersion mismatch between the reference and sample arms, which would otherwise degrade the axial resolution, is compensated for by using the Master-Slave OCT technique to process the interferograms. This allows for more convenient interchange of probes without exactly matching the fibre length. The probe can be configured using GRIN lenses at the end of the fibers with different focal lengths, and the fiber lengths can differ by several cm. When the probe is changed, the reference path is adjusted, but no dispersion compensation is needed, due to use of the Master Slave method developed by our group. We will demonstrate the performance of such systems with full 360 degree tomographic images of scattering phantoms taken at different probe driving speeds, with different configurations of the probe heads.

We present a scanning fiber endoscope (SFE) designed for near-infrared (nir) imaging. The SFE piezo actuator drives a single mode fiber in spiral patterns; meanwhile return fibers collect the reflective light; then signals from detector are mapped onto an image according to the fiber scan trajectory. Many SFE prototypes have been developed based on red/green/blue reflectance, enhanced spectral, fluorescence, optical coherence, and multimodal imaging. These forward-view SFE prototypes have the advantage of miniature size (1-3mm), flexible shaft, video-speed frame rate (10-30Hz), wide field of view (60-100 degree) and good resolution quality. A new SFE prototype is being developed that operates entirely in near-infrared wavelength range, which is expected to have great potential in imaging dental lesions and monitoring therapy. The first nirSFE probe has a diameter of around 3mm, frame rate of 17Hz, 53 degree FOV and spatial resolution of 40um. Although the specific optical fibers made for nir makes the probe stiffer than previous prototypes, the flexible 2m shaft allows for easy orientation. Using this prototype we can achieve reflectance mode imaging and also switch between different wavelengths (1310nm, 1460nm, 1550nm) and light sources (SLD or laser). In the development of this prototype, we encounter several issues: 1) the speckle noise caused by interference of laser beams, 2) uneven illumination and reduced visual field caused by collection fiber distribution and numerical aperture, and 3) specular reflection patterns which can obscure important enamel target detail. We explore solutions to these issues by using multiple detector channels, light sources, and filtering.

Utilizing spatial wavelength encoding, spectrally encoded endoscopy (SEE) makes it possible to create miniature, small diameter endoscopic probes that can allow easy access to hard-to-reach locations within the body. Previously described SEE probes have been side-viewing, which limits their use for guiding the navigation of narrow passages. Forward-viewing SEE probes are advantageous as they provide a look ahead that facilitates navigation and surveillance of a wider field of view. In this work, we present a novel forward-viewing SEE probe. The 500-µm illumination optics are designed in such a way that the shortest wavelength (460 nm) propagates along the optical axis, while an angle of approximately 56° is formed between the longest wavelength (720 nm) and the optical axis. Two-dimensional illumination was accomplished by rotating the illumination optics at a speed of 15 rps using a miniature torque coil. Reflected light from the sample was collected by 8 multimode detection fibers that were arranged into a circular array around the illumination optics. The proximal ends of the detection fibers were polished at a 17° angle, resulting in a total angle of detection of approximately 100°. Light coming out from the distal end of the detection fibers, which were rearranged into a linear array, was detected using a custom spectrometer with a tall-pixel linear CCD camera. Similar to the theoretical value, an effective FOV of 23 mm at a focal distance of 10 mm was measured by imaging a grid pattern. Preliminary results demonstrate the potential of the forward-viewing SEE probe for a variety of medical imaging applications.

Sensing the full vibrational patterns of the tympanic membrane could serve as a direct diagnostic tool for outer and middle ear pathologies, and could assist various surgical intervention procedures that depend on detailed inspection of the tympanic membrane. Three-dimensional imaging of acoustic vibrations in an excised tympanic membrane was demonstrated using optical coherence tomography, while stroboscopic holography was used for ex vivo measurement of the motion at discrete phase delays of a surgically exposed tympanic membrane within a fresh temporal bone. Using interferometric Fourier-domain imaging of a single spectrally encoded transverse line, combined with slow single-axis scanning for capturing a two-dimensional field of view, we have previously demonstrated high-resolution imaging of both amplitude and phase of a vibrating surface. In this work, we design our interferometric spectrally encoded imaging system for incorporation into a commercially available digital otoscope. The system uses a new compact design that was integrated into the optical path of the otoscope, where the acoustic waveform was generated in a simple earbud and coupled to the ear canal through the insufflation port of the device. Using data processing with variable spectral windowing, we demonstrate vibrational imaging of a membrane inside an outer ear model with approximately 4.5-mm-diameter field of view and up to 0.6 nm axial resolution. Future in vivo experiments with human volunteers will allow the study and development of the system for clinical diagnostics applications.

Fiber-bundle based confocal laser endomicroscopy combined with fluorescent biomarkers has shown promise for high-resolution imaging of tissue microstructure in vivo and in situ. However, limited image acquisition speed and a restriction to single fluorescence agents (due to single channel excitation and fluorescence collection spectral bands) for most existing systems makes simultaneous visualization of multiple morphological and functional features difficult. In this paper, we report the development of a high-speed dual-wavelength line-scan confocal laser endomicroscopy system suitable for multiplexed molecular imaging applications using 488 nm and 660 nm laser sources. The fluorescent confocal images are captured by a rolling-shutter CMOS camera at a constant frame rate of 120 Hz, with the rolling shutter of the CMOS camera acting as a virtual detector slit. Dual-wavelength imaging is achieved by switching between the laser sources for alternate frames, avoiding bleed-through, and providing an effective frame rate of 60 Hz. The two channels are pseudo-coloured and combined, and large area dual-wavelength mosaics are created by registering and stitching the image frames as the probe moves across the tissue. Preliminary images with a resolution of 1.2 µm are presented from fluorescently stained phantoms and ex vivo tissue, demonstrating the clinical feasibility of the technique.

Tethered capsule endomicroscopy (TCE) is a new method for performing comprehensive microstructural OCT imaging of gastrointestinal (GI) tract in unsedated patients in a well-tolerated and cost-effective manner. These features of TCE bestow it with significant potential to improve the screening, surveillance and management of various upper gastrointestinal diseases. To achieve clinical adoption of this imaging technique, it is important to validate it with co-registered histology, the current diagnostic gold standard. One such method for co-registering OCT images with histology is laser cautery marking, previously demonstrated using a balloon-centering OCT catheter that operates in conjunction with sedated endoscopy. With laser marking, an OCT area of interest is identified on the screen and this target is marked in the patient by exposing adjacent tissue to laser light that is absorbed by water, creating superficial, visible marks on the mucosal surface. Endoscopy can then be performed after the device is removed and biopsies taken from the marks. In this talk, we will present the design of a tethered capsule laser marking device that uses a distal stepper motor to perform high precision (< 0.5 mm accuracy) laser targeting and high quality OCT imaging. Ex vivo animal tissue tests and pilot human clinical studies using this technology will be presented.

Environmental enteric dysfunction (EED) is a poorly understood condition of the small intestine prevalent in low and middle income countries. This disease is believed to cause nutrient malabsorption and poor oral vaccine uptake, resulting in arrested neurological development and growth stunting in children that persists as they grow into adulthood. Optical coherence tomography (OCT) imaging of the small intestine can potentially capture some of the microstructural changes, such as villous blunting, in the small gut that accompany EED, and hence could potentially improve the understanding of EED and help in determining and monitoring the effectiveness of EED interventions. Notably, EED must be studied and diagnosed in infants, aged 0-24 months as this is the only window in which interventional strategies can reverse the disease. In order to address this need, we propose a trans-nasal OCT imaging technique for imaging the small intestine that may be suitable for low-resource settings owing to its simplicity, ease of administration, and implementation in unsedated infants. To demonstrate the potential of transnasal OCT intestinal imaging, we have created a 10 Fr transnasal OCT imaging probe and have submitted an IRB application for a first-in-human study using this probe to image the adult small intestine. We anticipate that the results from this pilot study will justify the development of a transnasal OCT intestinal imaging device for infants.

Endomicroscopy techniques such as confocal, multi-photon, and wide-field imaging have all been demonstrated using coherent fiber-optic imaging bundles. While the narrow diameter and flexibility of fiber bundles is clinically advantageous, the number of resolvable points in an image is conventionally limited to the number of individual fibers within the bundle. We are introducing concepts from the compressed sensing (CS) field to fiber bundle based endomicroscopy, to allow images to be recovered with more resolvable points than fibers in the bundle. The distal face of the fiber bundle is treated as a low-resolution sensor with circular pixels (fibers) arranged in a hexagonal lattice. A spatial light modulator is located conjugate to the object and distal face, applying multiple high resolution masks to the intermediate image prior to propagation through the bundle. We acquire images of the proximal end of the bundle for each (known) mask pattern and then apply CS inversion algorithms to recover a single high-resolution image. We first developed a theoretical forward model describing image formation through the mask and fiber bundle. We then imaged objects through a rigid fiber bundle and demonstrate that our CS endomicroscopy architecture can recover intra-fiber details while filling inter-fiber regions with interpolation. Finally, we examine the relationship between reconstruction quality and the ratio of the number of mask elements to the number of fiber cores, finding that images could be generated with approximately 28,900 resolvable points for a 1,000 fiber region in our platform.

Esophageal cancer has a 5-year survival rate below 20%, but can be curatively resected if it is detected early. At present, poor contrast for early lesions in white light imaging leads to a high miss rate in standard-of- care endoscopic surveillance. Early lesions in the esophagus, referred to as dysplasia, are characterized by an abundance of abnormal cells with enlarged nuclei. This tissue has a different refractive index profile to healthy tissue, which results in different light scattering properties and provides a source of endogenous contrast that can be exploited for advanced endoscopic imaging. For example, point measurements of such contrast can be made with scattering spectroscopy, while optical coherence tomography generates volumetric data. However, both require specialist interpretation for diagnostic decision making. We propose combining wide-field phase imaging with existing white light endoscopy in order to provide enhanced contrast for dysplasia and early-stage cancer in an image format that is familiar to endoscopists. Wide-field phase imaging in endoscopy can be achieved using coherent illumination combined with phase retrieval algorithms. Here, we present the design and simulation of a benchtop phase imaging system that is compatible with capsule endoscopy. We have undertaken preliminary optical modelling of the phase imaging setup, including aberration correction simulations and an investigation into distinguishing between different tissue phantom scattering coefficients. As our approach is based on phase retrieval rather than interferometry, it is feasible to realize a device with low-cost components for future clinical implementation.

Usually, tissue images at cellular level need biopsies to be done. Considering this, diagnostic devices, such as microendoscopes, have been developed with the purpose of do not be invasive. This study goal is the development of a dual-channel microendoscope, using two fluorescent labels: proflavine and protoporphyrin IX (PpIX), both approved by Food and Drug Administration. This system, with the potential to perform a microscopic diagnosis and to monitor a photodynamic therapy (PDT) session, uses a halogen lamp and an image fiber bundle to perform subcellular image. Proflavine fluorescence indicates the nuclei of the cell, which is the reference for PpIX localization on image tissue. Preliminary results indicate the efficacy of this optical technique to detect abnormal tissues and to improve the PDT dosimetry. This was the first time, up to our knowledge, that PpIX fluorescence was microscopically observed in vivo, in real time, combined to other fluorescent marker (Proflavine), which allowed to simultaneously observe the spatial localization of the PpIX in the mucosal tissue. We believe this system is very promising tool to monitor PDT in mucosa as it happens. Further experiments have to be performed in order to validate the system for PDT monitoring.

Colorectal adenoma (CA) is a disease caused by various factors (such as genetic factors or environmental exposures). The appearance of colon polyp (CP) within colorectal might indicate the hint of CA development. Ball-lens hollow fiber Raman probe (BHRP) may has a high capability for detection of CA in living experimental animal and have already tested to rat’s CP in this study, which was designed to collaborate between BHRP with mini-endoscopy to observe the biochemical alteration within normal colon tissue and rat’s colon polyps in real time. BHRP and mini-endoscopy can distinguish the differences in their finger print spectra and make pictures the control and CP in the real time. At the first step, the real situation of normal colon and Rat’s CP were washed by saline and observed with mini-endoscopy. BHRP was introduced to Dextran sodium sulphate (DSS)-induced Rat's CP to detect some of biochemical alteration. The main purpose of this study was to introduce mini-endoscopy to guide the BHRP for diagnosing of CP in real time and to compare it with spectra of normal colon (control group) in living rat. As the result, BHRP can provide the differences in band of control and CP group, which can inform that the biochemical of normal and CP has changed. As a major parameter to distinct normal and CP tissue were phosphatidylinositol, phosphodiester group, lipid, and collagen. Mini endoscopy and BHRP is very sensitive devices for diagnosing of CP in real time.