There is currently a need for a safe and effective way to detect and diagnose early childhood caries. We have developed a multimodal optical clinical prototype for testing in vivo. The device can be used to quickly image and screen for... more
There is currently a need for a safe and effective way to detect and diagnose early childhood caries. We have developed a multimodal optical clinical prototype for testing in vivo. The device can be used to quickly image and screen for any signs of demineralized enamel by obtaining high-resolution and highcontrast surface images using a 405-nm laser as the illumination source, as well as obtaining autofluorescence and bacterial fluorescence images. Then, when a suspicious region is located, the device can perform dual laser fluorescence spectroscopy using 405-nm and 532-nm laser excitation which is used to compute an autofluorescence ratio. This ratio can be used to quantitatively diagnose enamel health. The device is tested on four in vivo test subjects as well as 17 extracted teeth with clinically diagnosed carious lesions. The device was able to provide detailed images which served to screen for suspected early caries. The autofluorescence ratios obtained from the extracted teeth were able to discriminate between healthy and unhealthy enamel. Therefore, the clinical prototype demonstrates feasibility in screening for and in quantitatively diagnosing healthy from demineralized enamel.
Research Interests:
Research Interests:
Dental caries, the breakdown of tooth enamel by bacteria infection that causes cavities in the enamel, is the most common chronic disease in individuals 6–19 years of age in the U.S. Optical detection of caries has been shown to be... more
Dental caries, the breakdown of tooth enamel by bacteria infection that causes cavities in the enamel, is the most common chronic disease in individuals 6–19 years of age in the U.S. Optical detection of caries has been shown to be sensitive to the presence of bacteria and the resulting demineralization of enamel. The scanning fiber endoscope (SFE) is a miniature camera system that can detect early stages of caries by performing high-quality imaging and laser fluorescence spectroscopy with 405 nm excitation. Because optical imaging of caries does not involve radiation risk, repeated imaging of the teeth is acceptable during treatment of the bacterial infection to monitor healing. A disposable handpiece was designed and fabricated to position the flexible fiber optic SFE probe for quantitative measurements. Plastic 3D-printed handpiece prototypes were tested with the SFE and a fluorescence calibration standard to verify mechanical fit and absence of signal contamination. Design feedback was provided by pediatric dentists and staff engineers to guide iterations. The final design configuration was based on the need to image interproximal regions (contact surfaces between adjacent teeth), ergonomics, and probe safety. The final handpiece design: (1) is safe for both the patient and the probe, (2) allows easy SFE insertion and removal, (3) does not interfere with spectral measurements, (4) standardizes the SFE's positioning during imaging by maintaining a consistent distance from the target surface, and (5) is significantly less expensive to produce and use than purchasing sanitary endoscope sheaths. The device will be used to help determine if new medicinal therapies can arrest caries and repair early interproximal demineralization under the clinical monitoring program. Ultimately, we anticipate that this handpiece will help us move closer toward widespread implementation of a dental diagnostic laser system that is safer and more sensitive than conventional methods for early caries detection.
Research Interests:
Research Interests:
Research Interests:
ABSTRACT
Research Interests:
Research Interests:
Short-wavelength 405 nm laser illumination of surface dental enamel using an ultrathin scanning fiber endoscope (SFE) produced enhanced detail of dental topography. The surfaces of human extracted teeth and artificial erosions were imaged... more
Short-wavelength 405 nm laser illumination of surface dental enamel using an ultrathin scanning fiber endoscope (SFE) produced enhanced detail of dental topography. The surfaces of human extracted teeth and artificial erosions were imaged with 405 nm, 444 nm, 532 nm, or 635 nm illumination lasers. The obtained images were then processed offline to compensate for any differences in the illumination beam diameters between the different lasers. Scattering and absorption coefficients for a Monte Carlo model of light propagation in dental enamel for 405 nm were scaled from published data at 532 nm and 633 nm. The value of the scattering coefficient used in the model was scaled from the coefficients at 532 nm and 633 nm by the inverse third power of wavelength. Simulations showed that the penetration depth of short-wavelength illumination is localized close to the enamel surface, while long-wavelength illumination travels much further and is backscattered from greater depths. Therefore, images obtained using short wavelength laser are not contaminated by the superposition of light reflected from enamel tissue at greater depths. Hence, the SFE with short-wavelength illumination may make it possible to visualize surface manifestations of phenomena such as demineralization, thus better aiding the clinician in the detection of early caries.
Research Interests:
ABSTRACT
Research Interests:
Research Interests:
The current rise in childhood caries worldwide has increased the demand for portable technologies that can quickly and accurately detect and diagnose early stage carious lesions. These lesions, if identified at an early stage, can be... more
The current rise in childhood caries worldwide has increased the demand for portable technologies that can quickly and accurately detect and diagnose early stage carious lesions. These lesions, if identified at an early stage, can be reversed with remineralization treatments, education, and improvements in home care. A multi-modal optical prototype for detecting and diagnosing occlusal caries demineralization in vivo has been developed and pilot tested. The device uses a 405-nm laser as a scanned illumination source to obtain high resolution and high surface contrast reflectance images, which allows the user to quickly image and screen for any signs of demineralized enamel. When a suspicious region is located, the device can be switched to perform dual laser fluorescence spectroscopy using 405-nm and 532-nm laser excitations. These spectra are used to compute an auto-fluorescence (AF) ratio of the suspicious region and the percent difference of AF ratios from a healthy region of the same tooth. The device was tested on 7 children’s teeth in vivo with clinically diagnosed carious lesions. Lesion depth was then visually estimated from the video image using the 405-nm scanned light source, and within a month the maximum drill depth was assessed by a clinician. The researcher and clinicians were masked from previous measurements in a blinded study protocol. Preliminary results show that the ratiometric percent difference measurement of the AF spectrum of the tooth correlates with the severity of the demineralization as assessed by the clinician after drilling.
Research Interests:
Inherited mutations in BRCA1 and BRCA2 lead to 20-50% lifetime risk of ovarian, tubal, or peritoneal carcinoma. Clinical recommendations for women with these genetic mutations include the prophylactic removal of ovaries and fallopian... more
Inherited mutations in BRCA1 and BRCA2 lead to 20-50% lifetime risk of ovarian, tubal, or peritoneal carcinoma. Clinical recommendations for women with these genetic mutations include the prophylactic removal of ovaries and fallopian tubes by age 40 after child-bearing. Recent findings suggest that many presumed ovarian or peritoneal carcinomas arise in fallopian tube epithelium. Although survival rate is <90% when ovarian cancer is detected early (Stage_I), 70% of women have advanced disease (Stage_III/IV) at presentation when survival is less than 30%. Over the years, effective early detection of ovarian cancer has remained elusive, possibly because screening techniques have mistakenly focused on the ovary as origin of ovarian carcinoma. Unlike ovaries, the fallopian tubes are amenable to direct visual imaging without invasive surgery, using access through the cervix. To develop future screening protocols, we investigated using our 1.2- mm diameter, forward-viewing, scanning fiber endoscope (SFE) to image luminal surfaces of the fallopian tube before laparoscopic surgical removal. Three anesthetized human subjects participated in our protocol development which eventually led to 70-80% of the length of fallopian tubes being imaged in scanning reflectance, using red (632nm), green (532nm), and blue (442nm) laser light. A hysteroscope with saline uterine distention was used to locate the tubal ostia. To facilitate passage of the SFE through the interstitial portion of the fallopian tube, an introducer catheter was inserted 1- cm through each ostia. During insertion, saline was flushed to reduce friction and provide clearer viewing. This is likely the first high-resolution intraluminal visualization of fallopian tubes.
Research Interests:
Research Interests:
Endoscopic visualization in brain tumor removal is challenging because tumor tissue is often visually indistinguishable from healthy tissue. Fluorescence imaging can improve tumor delineation, though this impairs reflectance-based... more
Endoscopic visualization in brain tumor removal is challenging because tumor tissue is often visually indistinguishable from healthy tissue. Fluorescence imaging can improve tumor delineation, though this impairs reflectance-based visualization of gross anatomical features. To accurately navigate and resect tumors, we created an ultrathin/flexible, scanning fiber endoscope (SFE) that acquires reflectance and fluorescence wide-field images at high-resolution. Furthermore, our miniature imaging system is affixed to a robotic arm providing programmable motion of SFE, from which we generate multimodal surface maps of the surgical field.To test this system, synthetic phantoms of debulked tumor from brain are fabricated having spots of fluorescence representing residual tumor. Three-dimension (3D) surface maps of this surgical field are produced by moving the SFE over the phantom during concurrent reflectance and fluorescence imaging (30Hz video). SIFT-based feature matching between reflectance images is implemented to select a subset of key frames, which are reconstructed in 3D by bundle adjustment. The resultant reconstruction yields a multimodal 3D map of the tumor region that can improve visualization and robotic path planning.Efficiency of creating these 3D maps is important as they are generated multiple times during tumor margin clean-up. By using pre-programmed motions of the robot arm holding the SFE, the computer vision algorithms are optimized for efficiency by reducing search times. Preliminary results indicate that the time for creating these multimodal maps of the surgical field can be reduced to one third by using known trajectories of the surgical robot moving the image-guided tool.
Research Interests:
Research Interests:
ObjectivesTo integrate morphological, haemodynamic and mechanical analysis of carotid atheroma driving plaque disruption.Materials and methodsFirst, we analysed the phenotypes of carotid endarterectomy specimens in a photographic dataset... more
ObjectivesTo integrate morphological, haemodynamic and mechanical analysis of carotid atheroma driving plaque disruption.Materials and methodsFirst, we analysed the phenotypes of carotid endarterectomy specimens in a photographic dataset A, and matched them with the likelihood of preoperative stroke. Second, laser angioscopy was used to further define the phenotypes in intact specimens (dataset B) and benchmark with histology. Third, representative vascular geometries for each structural phenotype were analysed with Computational Fluid Dynamics (CFD), and the mechanical strength of the complicated atheroma to resist penetrating forces was quantified (n=14).ResultsIn dataset A (n=345), ulceration (fibrous cap disruption) was observed in 82% of all plaques, intraplaque haemorrhage in 68% (93% subjacent to an ulcer) and false luminal formation in 48%. At least one of these ‘rupture’ phenotypes was found in 97% of symptomatic patients (n=69) compared with 61% in asymptomatic patients. I...
Research Interests:
3D pathology is intrinsically dependent on 3D microscopy, or the whole tissue imaging of patient tissue biopsies (TBs). Consequently, unsectioned needle specimens must be processed whole: a procedure which cannot necessarily be... more
3D pathology is intrinsically dependent on 3D microscopy, or the whole tissue imaging of patient tissue biopsies (TBs). Consequently, unsectioned needle specimens must be processed whole: a procedure which cannot necessarily be accomplished through manual methods, or by retasking automated pathology machines. Thus "millifluidic" devices (for millimeter-scale biopsies) are an ideal solution for tissue handling/preparation. TBs are large, messy and a solid-liquid mixture; they vary in material, geometry and structure based on the organ biopsied, the clinician skill and the needle type used. As a result, traditional microfluidic devices are insufficient to handle such mm-sized samples and their associated fabrication techniques are impractical and costly with respect to time/efficiency. Our research group has devised a simple, rapid fabrication process for millifluidic devices using jointed skeletal molds composed of machined, reusable metal rods, segmented rods and stranded wire as structural cores; these cores are surrounded by Teflon outer housing. We can therefore produce curving, circular-cross-section (CCCS) millifluidic channels in rapid fashion that cannot normally be achieved by microfabrication, micro-/CNC-machining, or 3D printing. The approach has several advantages. CLINICAL: round channels interface coring needles. PROCESSING: CCCS channels permit multi-layer device designs for additional (processing, monitoring, testing) stages. REUSABILITY: for a biopsy/needle diameter, molding (interchangeable) components may be produced one-time then reused for other designs. RAPID: structural cores can be quickly removed due to Teflon®'s ultra-low friction; housing may be released with ethanol; PDMS volumes cure faster since metal skeleton molds conduct additional heat from within the curing elastomer.by Ronnie Das, Chris W. Burfeind, Saniel D. Lim, Shubham Patle, and Eric J. Seibe
Research Interests:
Research Interests:
Research Interests:
Research Interests:
A deformable membrane mirror is being used to generate multiple focal planes within a scanned light display, or virtual retinal display (VRD). The MEMS deformable mirror changes the focal plane of the display by varying the wavefront of... more
A deformable membrane mirror is being used to generate multiple focal planes within a scanned light display, or virtual retinal display (VRD). The MEMS deformable mirror changes the focal plane of the display by varying the wavefront of the optical beam entering the eye. Dynamically changing the focal plane will allow the viewer to see 3‐D objects using the natural accommodative response of the eye, unlike current stereographics that rely on retinal disparity. The display system can successfully generate a focal range from infinity to −3 diopters, verified through measurements on human subjects made with a laser autorefractor.
Research Interests:
ABSTRACT We developed a multispectral fluorescence-reflectance scanning fiber endoscope (SFE) for wide-field molecular imaging of fluorescence-labeled molecular probes. Concurrent multi-channels imaging with the wide-field SFE also allows... more
ABSTRACT We developed a multispectral fluorescence-reflectance scanning fiber endoscope (SFE) for wide-field molecular imaging of fluorescence-labeled molecular probes. Concurrent multi-channels imaging with the wide-field SFE also allows for real-time mitigation of background autofluorescence (AF) signal, especially when the FDA approved fluorescein is used as the target fluorophore. In the current study, we demonstrated a real-time AF mitigation algorithm on a tissue phantom which featured molecular probe targeted cells of high grade dysplasia on a substrate containing AF species. The targetto- background ratio was enhanced by over an order of magnitude when applying the real-time AF mitigation algorithm. By minimizing the background signal, multispectral fluorescence imaging can provide sufficient image contrast and quantitative target information for detecting small pre-cancerous lesions in vivo.
Research Interests:
ABSTRACT We developed a stable, reproducible three-dimensional optical phantom for the evaluation of a wide-field endoscopic molecular imaging system. This phantom mimicked a human esophagus structure with flexibility to demonstrate body... more
ABSTRACT We developed a stable, reproducible three-dimensional optical phantom for the evaluation of a wide-field endoscopic molecular imaging system. This phantom mimicked a human esophagus structure with flexibility to demonstrate body movements. At the same time, realistic visual appearance and diffuse spectral reflectance properties of the tissue were simulated by a color matching methodology. A photostable dye-in-polymer technology was applied to represent biomarker probed &quot;hot-spot&quot; locations. Furthermore, fluorescent target quantification of the phantom was demonstrated using a 1.2mm ultrathin scanning fiber endoscope with concurrent fluorescence-reflectance imaging.
Research Interests:
ABSTRACT Previously we developed an ultrathin, flexible, multimodal scanning fiber endoscope (SFE) for concurrent white light and fluorescence imaging. Autofluorescence (AF) arising from endogenous fluorophores (primarily collagen in the... more
ABSTRACT Previously we developed an ultrathin, flexible, multimodal scanning fiber endoscope (SFE) for concurrent white light and fluorescence imaging. Autofluorescence (AF) arising from endogenous fluorophores (primarily collagen in the esophagus) act as major confounders in fluorescence-aided detection. To address the issue of AF, a real-time mitigation algorithm was developed and has been show to successfully remove AF during SFE imaging. To test our algorithm, we previously developed flexible, color-matched, synthetic phantoms featuring a homogenous distribution of collagen. In order to more rigorously test the AF mitigation algorithm, a phantom that better mimicked the in-vivo distribution of collagen in tissue was developed.
Research Interests:
Research Interests: Materials Science, Optics, Biomedical Engineering, Laser, Confocal Microscopy, and 15 moreMedicine, Biomedical Optics, Humans, Optical physics, Optometry and Ophthalmology, Image Enhancement, Scattering, Reproducibility of Results, Oral Diagnosis, Dental Enamel, Fiber Optic Technology, Equipment Design, Equipment Failure Analysis, Endoscopes, and image resolution
Research Interests:
Research Interests:
An ultrathin scanning fiber endoscope, originally developed for cancer diagnosis, was used in a case study to locate plaque and caries. The imaging system incorporated software mitigation of background auto-fluorescence (AF). In... more
An ultrathin scanning fiber endoscope, originally developed for cancer diagnosis, was used in a case study to locate plaque and caries. The imaging system incorporated software mitigation of background auto-fluorescence (AF). In conventional fluorescence imaging, varying AF across a tooth surface can mask low-level porphyrin signals. Laser-induced auto-fluorescence signals of dental tissue excited using a 405-nm laser typically produce fluorescence over a wavelength range extending from 440-nm to 750-nm. Anaerobic bacterial metabolism produces various porphyrin species (eg. protoporphyrin IX) that are located in carious enamel, dentin, gingivitis sites, and plaque. In our case study, these porphyrin deposits remained as long as one day after prophylaxis. Imaging the tooth surface using 405-nm excitation and subtracting the natural AF enhances the image contrast of low-level porphyrin deposits, which would otherwise be masked by the high background AF. In a case study, healthy tissues as well as sites of early and advanced caries formations were scanned for visual and quantitative signs of red fluorescence associated with porphyrin species using a background mitigation algorithm. Initial findings show increasing amplitudes of red fluorescence as caries severity increases from early to late stages. Sites of plaque accumulation also displayed red fluorescence similar to that found in carious dental tissue. The use of real-time background mitigation of natural dental AF can enhance the detection of low porphyrin concentrations that are indicators of early stage caries formation.
Research Interests: Engineering, Computer Science, Chemistry, Metabolism, Cancer, and 3 moreTeeth, Luminescence, and Porphyrin
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Engineering, Algorithms, Materials Science, Optics, Biomedical Engineering, and 15 moreFluorescence, Medicine, Molecular Imaging, Biomedical Optics, Humans, LaTeX, Color, Luminescence, Optical physics, Optometry and Ophthalmology, Esophagus, Optical Fibers, Esophagoscopy, fluorescent dyes, and Optical Phenomena
Research Interests:
Research Interests: Materials Science, Optics, Medicine, Cerebellum, Mice, and 14 moreMicroscope, Animals, Fluorescence Imaging, Dendrites, Optical physics, Femtosecond, Image Enhancement, Rats, Miniaturization, Fiber Optic, Optical Fibers, Medicine and Health Sciences, Fiber Optic Technology, and Electrical And Electronic Engineering
Escherichia coli bacteria are a source of food related illness. If irrigation water is contaminated by fecal matter runoff, crops may become infected prior to harvesting, processing, or packaging. Existing test methods require 16-48 hours... more
Escherichia coli bacteria are a source of food related illness. If irrigation water is contaminated by fecal matter runoff, crops may become infected prior to harvesting, processing, or packaging. Existing test methods require 16-48 hours for confirmation of bacterial infection in the irrigation water. Therefore, providing a means for a rapid detection of water borne coliform and E. coli within a typical workday of 8-10 hours would allow a preventative response. We have developed a method to determine bacteria presence by a measure of metabolic activity with a spectral analysis system. Metabolic activity of live bacteria will appear as a drop in solution pH in a relatively short time frame during the growth phase of the cultured bacteria. A blue LED is used to excite fluorescein fluorescence in the bacterial growth media. The fluorescence exhibits pH sensitive spectral properties within a range of pH 4-7. Unmixing of the fluorescence spectral profile yields the pH and confirms a growing bacteria culture. Results can be provided in hours instead of days, depending on the initial concentration of living bacteria.
Research Interests:
Research Interests:
As prevalence of dental caries in children rises worldwide, there is an increasing need for a safe, easy to use and cost-effective technique to detect and identify childhood caries at an early stage where remineralization of the tooth is... more
As prevalence of dental caries in children rises worldwide, there is an increasing need for a safe, easy to use and cost-effective technique to detect and identify childhood caries at an early stage where remineralization of the tooth is possible and damage may be reversed. We have developed a simple and robust autofluorescence (AF) laboratory device that uses the dental AF spectra from 405 nm and 532 nm laser excitation and computes a ratio of the integrated areas of the spectra. Ten human extracted teeth with early stage natural caries lesions and an additional 8 human extracted teeth with artificially created erosion lesions were used for the study. The 405/532 nm AF ratio was obtained from healthy as well as unhealthy enamel regions for all teeth. A clear distinction between the ratios for healthy enamel and unhealthy enamel was seen. A percent change in 405/532 nm AF ratio of 62% was seen between natural white spot lesions and healthy enamel, with progressively more severe lesions leading to greater percent changes in AF ratios. The 405/532 nm AF ratio is a promising technique that may be used to detect the presence of early stage dental caries and triage high risk children. A cost effective clinical device can be developed which utilizes the proposed technique to screen children in underserved communities.
Research Interests:
Undetected caries can lead to painful cavities and surgical restorations. Lack of proper detection tools makes caries prevention dependent on dentist’s expertise and presents obstacles in oral health monitoring. To overcome this problem,... more
Undetected caries can lead to painful cavities and surgical restorations. Lack of proper detection tools makes caries prevention dependent on dentist’s expertise and presents obstacles in oral health monitoring. To overcome this problem, we have developed a new approach to predict early stages of enamel demineralization caused by oral bacteria. These bacteria metabolize sugars in our food and produce organic acids that lead to cavities. Measuring the acidity level can help predict early stages of tooth decay. pH paper or pH electrodes can be used to monitor acidity, but neither are able to track pH levels in all dental locations. Our device, DpOW, is a noncontact optics-based pH device that uses changes in the spectral fluorescence of FDA allowed fluorescein dye to measure acidity levels in difficult to access dental locations such as occlusal fissures. A prototype has been tested over a wide pH range (7.12 to 3.89) and shown to track the change in pH with 0.94 correlation coefficient.
Research Interests:
Research Interests:
A pH measurement of oral biofilms is helpful for monitoring the impact of acidogenic bacteria in the caries process. Demineralization of dental enamel is closely related to the time dependent pH of human plaque. Therefore, providing a... more
A pH measurement of oral biofilms is helpful for monitoring the impact of acidogenic bacteria in the caries process. Demineralization of dental enamel is closely related to the time dependent pH of human plaque. Therefore, providing a means to easily measure the local pH of biofilms is a useful clinical diagnostic in the arsenal of caries prevention tools. Optical measurement methods of plaque metabolism can use intrinsic fluorescence or extrinsic fluorescence from added dyes. Autofluorescence spectral features of human oral biofilms at green (500 nm) and red (634 nm) fluorescence wavelengths using 405 nm excitation did not demonstrate a spectral or intensity shift between neutral and acidic conditions. Chlorin e6, an ingredient in chlorophyllin food supplement, exhibited a spectral and intensity shift of fluorescence emission in buffered solutions, but this quantitative pH-dependence was not transferable to a human plaque environment. Finally, a ratiometric quantitative pH measure ...
Research Interests:
We have developed a new tool to measure the acid production by plaque oral bacteria. Many species of oral bacteria metabolize sugars in food and produce organic acids that demineralize the dental enamel leading to the formation of... more
We have developed a new tool to measure the acid production by plaque oral bacteria. Many species of oral bacteria metabolize sugars in food and produce organic acids that demineralize the dental enamel leading to the formation of cavities. Measuring the acidity level before and after a sugar rinse can indicate the susceptibility of an individual to tooth decay and location of active caries. In a case study on two subjects, a non-contact optics-based pH device was able to track pH before and after a sugar rinse. The fiber optic probe measures acidity level in difficult to access dental locations such as occlusal pits and fissures based on changes in the spectral fluorescence profile of fluorescein (FL) dye. Fiber coupled 420 nm LED excites 200uM aqueous FL solution in the mouth. The fluorescence spectrum in 450-650 nm range is obtained using an adjacent fiber optic cable coupled to a spectrometer. Chemometric analysis of endmember dianion and anion species using least-square fitting...
Research Interests:
For patients with malignant brain tumors (glioblastomas), a safe maximal resection of tumor is critical for an increased survival rate. However, complete resection of the cancer is hard to achieve due to the invasive nature of these... more
For patients with malignant brain tumors (glioblastomas), a safe maximal resection of tumor is critical for an increased survival rate. However, complete resection of the cancer is hard to achieve due to the invasive nature of these tumors, where the margins of the tumors become blurred from frank tumor to more normal brain tissue, but in which single cells or clusters of malignant cells may have invaded. Recent developments in fluorescence imaging techniques have shown great potential for improved surgical outcomes by providing surgeons intraoperative contrast-enhanced visual information of tumor in neurosurgery. The current near-infrared (NIR) fluorophores, such as indocyanine green (ICG), cyanine5.5 (Cy5.5), 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX), are showing clinical potential to be useful in targeting and guiding resections of such tumors. Real-time tumor margin identification in NIR imaging could be helpful to both surgeons and patients by reducing the operation time and space required by other imaging modalities such as intraoperative MRI, and has the potential to integrate with robotically assisted surgery. In this paper, a segmentation method based on the Chan-Vese model was developed for identifying the tumor boundaries in an ex-vivo mouse brain from relatively noisy fluorescence images acquired by a multimodal scanning fiber endoscope (mmSFE). Tumor contours were achieved iteratively by minimizing an energy function formed by a level set function and the segmentation model. Quantitative segmentation metrics based on tumor-to-background (T/B) ratio were evaluated. Results demonstrated feasibility in detecting the brain tumor margins at quasi-real-time and has the potential to yield improved precision brain tumor resection techniques or even robotic interventions in the future.
Research Interests:
As the rapid progress in the development of optoelectronic components and computational power, 3D optical metrology becomes more and more popular in manufacturing and quality control due to its flexibility and high speed. However, most of... more
As the rapid progress in the development of optoelectronic components and computational power, 3D optical metrology becomes more and more popular in manufacturing and quality control due to its flexibility and high speed. However, most of the optical metrology methods are limited to external surface. This paper proposed a new approach to measure tiny internal 3D surfaces with a scanning fiber endoscope and axial-stereo vision algorithm. A dense, accurate point cloud of internally machined threads was generated to compare with its corresponding X-ray 3D data as ground truth, and the quantification was analyzed by iterative closest points (ICP) algorithm.
Research Interests:
ABSTRACT A dual-modal optical projection tomography microscope (OPTM) is presented, which produces three-dimensional images of single cells with isometric high resolution both in fluorescence and absorption mode. Depth of field of a high... more
ABSTRACT A dual-modal optical projection tomography microscope (OPTM) is presented, which produces three-dimensional images of single cells with isometric high resolution both in fluorescence and absorption mode. Depth of field of a high numerical aperture objective is extended by scanning the focal plane through the sample in order to enable reconstruction by back-projection method. Cells are fixed, stained, and mixed with optical gel and injected into the capillary for imaging. Combining absorption and fluorescence mode allows us to image different aspects of the disease process. Images of cells stained with both hematoxylin and fluorescence probes are shown. Registrations between two modes are discussed.
Research Interests: Engineering, Materials Science, Optics, Microscopy, Cancer, and 15 moreTomography, Cancer Diagnosis, Three Dimensional Imaging, Bios, Luminescence, Absorption, Modal, Single Cell, High Resolution, Fluorescent probes, Optical Projection Tomography, Projection Method, Depth of Field, Numerical Aperture, and Dual (grammatical number)
Research Interests:
ABSTRACT The optical projection tomography microscope (OPTM) acquires three-dimensional images with isometric high resolution both in absorption and fluorescence modes, employing computed tomographic image reconstruction. The... more
ABSTRACT The optical projection tomography microscope (OPTM) acquires three-dimensional images with isometric high resolution both in absorption and fluorescence modes, employing computed tomographic image reconstruction. The three-dimensional chromosome structure of a female muntjac cell is shown.
Research Interests: Physics, Optics, Biomedical Engineering, Microscopy, Imaging, and 12 moreFluorescence Microscopy, Tomography, Microscope, Fluorescence Imaging, Optical physics, High Resolution, NTM, Optometry and Ophthalmology, Spatial resolution, Tomographic Reconstruction, Depth of Field, and hematoxylin and eosin
Research Interests:
G A A b st ra ct s histology. Methods: BE patients with and without early neoplasia underwent endoscopic resection (ER) of areas marked in-vivo with electrocoagulation markers (ECM). Subsequently ER specimens underwent additional ex-vivo... more
G A A b st ra ct s histology. Methods: BE patients with and without early neoplasia underwent endoscopic resection (ER) of areas marked in-vivo with electrocoagulation markers (ECM). Subsequently ER specimens underwent additional ex-vivo marking with several different markers (ink, pin, ECM) followed by ex-vivo VLE scanning. Tissue blocks were carefully sectioned guided by the placed markers. After further histological processing a histopathology slide was sectioned from each block. When necessary, extensive sectioning of tissue blocks was performed in order to visualize all markers that were included in the tissue block on histology. All histopathology and VLE slides were evaluated by 2 researchers and considered a match if a) ≥ 2 markers were visible on both modalities and b) mucosal patterns aside from these markers matched on both histology and VLE. All slides were evaluated by an expert BE pathologist. Results: From 16 ER specimens (overall diagnosis: 7 non-dysplastic BE, 9 dysplastic BE (1 LGD, 4 HGD, 4 EAC)) 120 tissue blocks were sectioned of which 57 contained multiple markers and thus could potentially be matched with VLE. Based on several combinations of these markers in total 14 histology-VLE matches could ultimately be constructed. Markers that achieved the best yield of matches respectively were: invivo placed ECMs (8 matches with 12 markers), pins (7 with 11), and ink (4 with 5). Histopathological evaluation was not hindered by marker use. In this pilot study the last 6 ER specimens yielded 9/14 matches demonstrating a clear learning curve due to methodological improvements in marker placement and tissue block sectioning. Conclusion: One-to-one correlation of VLE and histology is complex but feasible. The groundwork laid in this study will provide high-quality histology-VLE correlations that will allow further research on VLE structures and VLE features of early neoplasia in BE.