Proceedings Volume 10469

Optical Imaging, Therapeutics, and Advanced Technology in Head and Neck Surgery and Otolaryngology 2018

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Proceedings Volume 10469

Optical Imaging, Therapeutics, and Advanced Technology in Head and Neck Surgery and Otolaryngology 2018

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Volume Details

Date Published: 14 June 2018
Contents: 9 Sessions, 5 Papers, 19 Presentations
Conference: SPIE BiOS 2018
Volume Number: 10469

Table of Contents

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Table of Contents

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  • Front Matter: Volume 10469
  • Airway Imaging and Vocal Fold Dynamics I
  • Airway Imaging and Vocal Fold Dynamics II
  • Optically Guided Cancer Surgery I
  • Optically Guided Cancer Surgery II
  • Hearing and Diseases of the Ear
  • NBI and Optical Biopsy I
  • NBI and Optical Biopsy II
  • Novel Therapeutics, PDT, and Robotics
Front Matter: Volume 10469
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Front Matter: Volume 10469
This PDF file contains the front matter associated with SPIE Proceedings Volume 10469, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.
Airway Imaging and Vocal Fold Dynamics I
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Long working distance OCT for phonomicrosurgery: preliminary observation of 3D microstructure of ex vivo specimens (Conference Presentation)
Jin-Choon Lee M.D., Soo-Geun Wang M.D., Wuisuk Sung M.D., et al.
Optical Coherence Tomography (OCT) is a promising non-invasive in vivo imaging technology visualizing the 3-dimensional microanatomy of retina, skin and vocal fold. In the field of laryngology, OCT probes installed in an existing laryngoscope have been widely studied. However, there are still a number of critical issues to be resolved to develop a successful phonomicrosurgical OCT system including high-resolution, long working distance (≥400 mm) and rapid 3D image reconstruction, etc. Here we introduce a long working distance OCT with 35µm lateral and 13µm axial resolutions. To the best of our knowledge, this is the first OCT with up to 450mm of working distance as well as µm-level resolutions to identify subepithelial tissue structure of vocal fold. The main purpose of this study is to investigate the feasibility and efficacy of the system in ex-vivo microstructure imaging of vocal fold, especially the Reinke’s space. We tested the imaging capability of the system with the freshly excised canine eyeball and larynx samples before proceeding the study with fresh human laryngectomized specimens. The acquired OCT images were then compared with the corresponding H&E stained histological sections. This correlation study allowed the identification of the epithelial layer, lamina propria, subepithelial glandular structures and vessels of the canine and human specimens from both the OCT and the microscope images ensuring solid correspondence between two different types of visual tissue assessment. This OCT system is developed to directly confirm the lesions during phonomicrosurgeries enabling the clinicians to reduce the number of intraoperative biopsies.
Development of attachable phonomicrosurgical OCT device (Conference Presentation)
Jin-Choon Lee, Euisuk Sung, Kyung Un Choi, et al.
The biggest clinical benefit of OCT as a diagnostic tool for retinal disorders is that it enables the discrimination of subtle pathologic changes in vivo. Though a large number of researches have been done to expand its applications, few of them proved sufficient utility in clinical settings. In laryngology, an OCT system attachable to and working in tandem with an operating microscope may provide solid clinical benefits. Nevertheless, such a system has not been introduced yet, while it is more common to find an OCT system with a hand-held type probe. Hence, we developed a phonomicrosurgical OCT with a long working distance and attachable to an existing operating microscope. The OCT also has a dichroic mirror which splits the coherent IR laser and visual projection to enable dual imaging. We evaluated the efficacy of the system in evaluating subepithelial tissue structure, especially in the Reinke’s space of vocal fold. We tested its imaging capability with excised canine larynx and eyeball. Then, we assessed the surgical margin with the OCT images after treating a live canine larynx with a CO2 laser under general anesthesia. In addition, we compared the images with corresponding histopathologic findings to confirm the diagnostic feasibility. The OCT and histopathologic images showed a significant correlation to identify the epithelial layer, lamina propria, subepithelial glandular structures and vessels from the OCT images. This is the first OCT system attachable to an operating microscope which may provide a promising alternative to frozen biopsies for intraoperative laryngeal cancer margin assessment.
Evaluation of oxygen consumption and acoustics of human vocal fold by using near-infrared spectroscopy (Conference Presentation)
Han-Yun Cheng, Jung-Chih Chen, Chih-Hsien Liu, et al.
Voice disorder such as vocal fatigue is a common and complex multifaceted clinical problem that presents a significant impact on quality of life. Current diagnostic methods of voice assessment devices are only provide indirect information about the status of vocal fold during voice production. In this study, the near-infrared diffuse optical technique (NIRS-DOT) was proposed as a novel approach for human vocal fold oxygen consumption detection and acoustic assessment simultaneously. A total of twenty healthy subjects including ten male and ten female adults of age-matched were recruited with vocal loading task (to trigger a mild inflammation of the vocal fold) for this study. The concentration changes in oxygenated hemoglobin (Δ[HbO2]) and deoxygenated hemoglobin (Δ[Hb]) of vocal fold and voice production with two conditions i.e., pre-vocal loading and after-vocal loading task, are all measured by using NIRS-DOT for functional and acoustic spectrum analysis. In the results of vocal fold oxygen consumption detection, the Δ[Hb] is increased and the Δ[HbO2] is no significant changed after-vocal loading task that may provide useful information on the relationship between oxygen consumption and supply for vocal cord diagnosis. Besides, the acoustic spectrum analysis of voice production is highly correlated with traditional voice assessment devices. Therefore, with the information obtained from this novel approach, the NIRS-DOT can provide not only oxygen consumption analysis but also acoustic spectrum analysis for clinical applications of voice disorder.
Airway Imaging and Vocal Fold Dynamics II
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Clinical evaluation of subglottic stenosis in neonates using automatic segmentation of optical coherence tomography via dynamic programming (Conference Presentation)
Konrad Kozlowski, Giriraj Sharma, Brian Wong, et al.
Subglottic stenosis is a severe and challenging disease to manage in neonates. Previous reports describe the usage of long-range optical coherence tomography (LR-OCT) to image the subglottis through an endotracheal tube and potentially identify subepithelial changes in subglottic mucosa which are correlated with edema or scar tissue. A major challenge associated with OCT imaging is that large volumes of data (1-2 GB) are acquired with each airway scan, with no existing automated method for image analysis and tissue measurement. We have developed an innovative MATLAB based auto-segmentation program which identifies and measures tissue layers within the mucosa. LR-OCT data sets of 21 neonates were analyzed for mucosal thickness of the proximal trachea, subglottis and larynx. The auto-segmentation measurements were compared with measurements from manual tracings by a single operator. We found statistically significant associations between the thickness of the mucosa (p<0.001) and submucosa (p<0.001) layers in the upper airway when comparing these two segmentation processes. The auto-segmentation program segmented the OCT images on average over 8 times faster than the manual segmentation software. Following auto-segmentation, OCT images were also analyzed for texture analysis properties using ANOVA. Automated segmentation and measurement of OCT data sets is an efficient and precise method to analyze large volume LR-OCT data stacks. This may ultimately help provide vital objective information about the airway in real-time, which would aid clinicians in making management decisions for intubated neonates.
Optically Guided Cancer Surgery I
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Clinical trial results using fluorescently labeled antibodies (Conference Presentation)
Eben L. Rosenthal M.D., Nynke van den Berg, Tarn Teraphongphom, et al.
Over the past two decades, synergistic innovations in imaging technology have resulted in a revolution in which a range of biomedical applications are now benefiting from fluorescence imaging. Fluorescence imaging of lymph nodes after systemic cetuximab-IRDye800CW administration demonstrated high sensitivity and was capable of identifying additional positive nodes on deep sectioning.
Near infrared hyperspectral imaging to evaluate tongue tumor resection margins intraoperatively (Conference Presentation)
Susan G. Brouwer de Koning, M.B. Karakullukcu, L. Smit, et al.
Positive tumor resection margins are reported in up to 45% of the patients undergoing surgery for tongue cancer. With the aim to develop a technique that can assess tumor resection margins intraoperatively, we conducted an ex vivo study to evaluate the feasibility of near infrared hyperspectral imaging for distinguishing tumor from healthy tongue tissue. Fresh surgical specimens of squamous cell carcinoma of the tongue were scanned with a pushbroom camera. The acquired spectral hypercubes contain a measure of the diffuse light reflectance (wavelength range of 900-1700 nm) for each pixel of the hyperspectral image. Spectral bands were selected from the spectrum and used to classify spectra of tumor and healthy tissue. In this, a linear classifier was trained on 80% of the data and its performance in predicting the tissue type of the residual 20% of the data was measured. This was repeated five times and mean accuracy, sensitivity and specificity were used as output for this study. A total of 463 spectra were obtained from tongue tumor tissue and 421 spectra from healthy tongue tissue. The spectral bands between 1060-1130 nm and 1150-1190 nm were used in the classification analysis. Mean accuracy, sensitivity and specificity were 89%±13, 94%±11 and 87%±21, respectively. Near infrared hyperspectral imaging can discriminate tongue tumor tissue from healthy tongue tissue in an ex vivo setting by using specific bands of the reflectance spectrum. Further analyses will be done to assess whether using the whole spectrum can improve the classification results.
Automated detection of oropharyngeal carcinoma using multispectral imaging: a prospective feasibility study (Conference Presentation)
Shamik Mascharak, Brandon Jackson Baird, F. Christopher Holsinger
Multispectral narrow band imaging (NBI) represents a promising screening tool for oropharyngeal cancer (OPC) due to its selective enhancement of tumor vasculature. However, most implementations of NBI for cancer screening have relied on qualitative observations of mucosa (e.g., presence of capillary loops), rather than quantitative measures based on image features. This preliminary study was designed to determine if specific narrow band signal characteristics of tumor vasculature may be used to train a machine learning algorithm for quantitative OPC detection. Adult patients with no tumor (5) and biopsy-proven oropharyngeal squamous cell carcinoma (25) were recruited, and consent was obtained to examine the oropharynx by endoscopy under white light endoscopy (WLE) and narrow band imaging (NBI). De-identified WLE and NBI laryngoscopy videos were then read frame-by-frame into Matlab 2011a and sampled regions of mucosa were processed to extract color (a, b values in L*a*b image space) and texture (pixel entropy) information. Color and texture image features of tumor and non-tumor sides for 5 patients (4 tumor, 1 healthy) were used to train a Naïve Bayesian classifier for the remaining 25 (21 tumor, 4 healthy), and performance under WB and NBI was compared by ROC analysis. Compared to WLE, mNBI significantly enhanced the performance of a Naïve Bayesian classifier trained on low-level image features of oropharyngeal mucosa (76.6% AUC vs 50.5% for WLE). These findings suggest that automated clinical detection of oropharyngeal carcinoma could be used to enhance surgical vision, improve early diagnosis, and allow for high-throughput screening.
Optically Guided Cancer Surgery II
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Machine learning methods for fluorescence lifetime imaging (FLIM) based automated detection of early stage oral cancer and dysplasia (Conference Presentation)
Rodrigo Cuenca, Shuna Cheng, Bilal H. Malik, et al.
Despite of the ease accessibility of the oral cavity, only ~30% of oral cancer patients are diagnosed at early stages. Some of the factors that contribute to this low rate of early detection are: asymptomatic oral cancer lesions, similarity to benign lesions, and sampling error during biopsy procedures. Progression of oral cancer is accompanied by alterations in the intrinsic fluorescence properties of the oral tissue, making fluorescence lifetime imaging (FLIM) suitable for the diagnosis of oral cancer. In this study, in vivo human oral lesions from 70 patients were imaged using a multispectral FLIM endoscopy system. The collected database consisted of 50 benign lesions, and 20 dysplastic and early stage cancerous lesions, as determined by histopathological diagnosis. For each pixel, three fluorescence decays were collected corresponding to three emission bands (390 nm, 450 nm, 500 nm), and analyzed using a biexponential decay model. Selected parameters of this fitting algorithm along with the normalized intensities at each emission band were used as features for a quadratic discriminant analysis (QDA) classifier. The classification performance was estimated using a 10 fold cross-validation approach, resulting on levels of sensitivity and specificity >85%, and an ROC AUC of 0.9 for detecting dysplastic and cancerous oral lesions from benign lesions. These results demonstrate the potential of endogenous FLIM endoscopy for automated early detection of oral cancer.
Autofluorescence lifetime imaging endoscopy for automated label-free early detection of oral epithelial cancer and dysplasia (Conference Presentation)
Javier A. Jo, Shuna Cheng, Rodrigo Cuenca, et al.
Despite the fact that the oral cavity is easily accessible, only ~30% of oral cancers are diagnosed at an early stage, which is the main factor attributed to the low 5-year survival rate (63%) of oral cancer patients. Several screening tools for oral cancer have been commercially available; however, none of them have been demonstrated to have sufficient sensitivity and specificity for early detection of oral cancer and dysplasia. We hypothesized that an array of biochemical and metabolic biomarkers for oral cancer and dysplasia can be quantified by endogenous fluorescence lifetime imaging (FLIM), thus enabling levels of sensitivity and specificity adequate for early detection of oral cancer and dysplasia. Our group has recently developed multispectral FLIM endoscopes to image the oral cavity with unprecedented imaging speed (>2fps). We have also performed an in vivo pilot study, in which endogenous multispectral FLIM images were acquired from clinically suspicious oral lesions of 70 patients undergoing tissue biopsy. The results from this pilot study indicated that mild-dysplasia and early stage oral cancer could be detected from benign lesions using a computed aided diagnosis (CAD) system developed based on biochemical and metabolic biomarkers that could be quantified from endogenous multispectral FLIM images. The diagnostic performance of this novel FLIM based clinical tool was estimated using a cross-validation approach, showing levels of sensitivity >90%, specificity >80%, and Area Under the Receiving Operating Curve (RO- AUC) >0.9. Future efforts are focused on developing cost-effective FLIM endoscopes and validating this novel clinical tool in prospective multi-center clinical studies.
Compact and cost-effective handheld multispectral fluorescence lifetime imaging (FLIM) system for oral mucosa in vivo imaging based on a frequency-domain implementation (Conference Presentation)
Shuna Cheng, Michael Serafino, Rodrigo Cuenca, et al.
A compact handheld system for simultaneous multispectral frequency-domain (FD) FLIM imaging is presented. The handheld endoscope consists of a handheld enclosure (10 X 5 X 3 cm3 in volume) with a rigid probe (0.8 cm diameter, 12 cm length). The customized enclosure holds the MEMS scanner and a dichroic mirror whose tip and tilt angle can be adjusted. The rigid probe includes four achromatic lenses (f = 30mm). Two of the four lenses form a relay system to extend the length of the probe. The most distal lens works as an objective to focus the light onto the sample. An additional lens is placed in the intermediate image plane of the relay system to increases the imaging FOV from ~3.6 mm to ~5 mm. The excitation for the handheld FD FLIM system is a 375nm CW diode laser modulated at 1.25MHz and 20MHz. The fluorescence emission is spectrally divided in three emission bands (405/40nm, 440/40nm, and 525/50nm) and detected by three independent APDs. The multispectral signals are further digitized and processed by a FPGA. Phase shift and decreased magnitude are computed at 1.25MHz, 20MHz and its harmonic frequencies (40MHz, 60MHz, 80MHz and 100MHz) via Discrete Fourier Transform (DFT) for lifetime estimation. The current pixel rate is 12.5 KHz which is limited by the SNR. The system is validated by imaging standard fluorescent dyes and human healthy oral mucosa in vivo. This handheld FLIM system offers a cost reduction of at least 50% compared to previous time-domain implementations.
Hearing and Diseases of the Ear
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Visualizing cellular markers of sensorineural hearing loss in the murine cochlea using micro-optical coherence tomography (Conference Presentation)
Janani S. Iyer, Gargi Sharma, Guillermo J. Tearney, et al.
Although sensorineural hearing loss (SNHL) affects 600 million people globally and its prevalence is increasing, therapies remain limited. Advances in therapy development for SNHL are slow because we do not possess a method for visualizing the cochlea’s interior in living humans and relating visualized pathology to a patient’s hearing ability. To this end, we are investigating the ability of micro-optical coherence tomography (µOCT), a low-coherence interferometric imaging technique that requires no contrast agent and improves upon standard OCT in resolution and depth of focus, to visualize the micron-sized cellular structures in the cochlea. We recently demonstrated µOCT’s ability to resolve individual micro-anatomical structures that are critical to the hearing mechanism in the guinea pig cochlea; here, we further establish µOCT’s efficacy by demonstrating its ability to detect cellular-level differences between noise-damaged and healthy organ of Corti tissue in mice in situ. 3D volumetric and cross-sectional image analyses reveal severe damage to structures including sensory hair cells and supporting cells in noise-exposed but not healthy ears. In the most severe cases, complete elimination of the organ of Corti and surrounding supporting cells (i.e. “flat epithelium”) is visualized; this finding is particularly relevant for the development of gene therapies for hearing loss, as these therapies are ineffective in cases of flat epithelium morphology. Our results are the first to demonstrate µOCT’s ability to distinguish between healthy and damaged organ of Corti tissue, and motivate investigation into its potential to be translated into a clinical diagnostic tool for SNHL.
Electrical and optical co-stimulation in the deaf white cat
Zhiping Cao, Yingyue Xu, Xiaodong Tan, et al.
Spatial selectivity of neural stimulation with photons, such as infrared neural stimulation (INS) is higher than the selectivity obtained with electrical stimulation. To obtain more independent channels for stimulation in neural prostheses, INS may be implemented to better restore the fidelity of the damaged neural system. However, irradiation with infrared light also bares the risk of heat accumulation in the target tissue with subsequent neural damage. Lowering the threshold for stimulation could reduce the amount of heat delivered to the tissue and the risk for subsequent tissue damage. It has been shown in the rat sciatic nerve that simultaneous irradiation with infrared light and the delivery of biphasic sub-threshold electrical pulses can reduce the threshold for INS [1]. In this study, deaf white cats have been used to test whether opto-electrical co-stimulation can reduce the stimulation threshold for INS in the auditory system too. The cochleae of the deaf white cats have largely reduced spiral ganglion neuron counts and significant degeneration of the organ of Corti and do not respond to acoustic stimuli. Combined electrical and optical stimulation was used to demonstrate that simultaneous stimulation with infrared light and biphasic electrical pulses can reduce the threshold for stimulation.
NBI and Optical Biopsy I
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Optical biopsy of head and neck cancer using hyperspectral imaging and convolutional neural networks
Martin Halicek, James V. Little, Xu Wang, et al.
Successful outcomes of surgical cancer resection necessitate negative, cancer-free surgical margins. Currently, tissue samples are sent to pathology for diagnostic confirmation. Hyperspectral imaging (HSI) is an emerging, non-contact optical imaging technique. A reliable optical method could serve to diagnose and biopsy specimens in real-time. Using convolutional neural networks (CNNs) as a tissue classifier, we developed a method to use HSI to perform an optical biopsy of ex-vivo surgical specimens, collected from 21 patients undergoing surgical cancer resection. Training and testing on samples from different patients, the CNN can distinguish squamous cell carcinoma (SCCa) from normal aerodigestive tract tissues with an area under the curve (AUC) of 0.82, 81% accuracy, 81% sensitivity, and 80% specificity. Additionally, normal oral tissues can be sub-classified into epithelium, muscle, and glandular mucosa using a decision tree method, with an average AUC of 0.94, 90% accuracy, 93% sensitivity, and 89% specificity. After separately training on thyroid tissue, the CNN differentiates between thyroid carcinoma and normal thyroid with an AUC of 0.95, 92% accuracy, 92% sensitivity, and 92% specificity. Moreover, the CNN can discriminate medullary thyroid carcinoma from benign multi-nodular goiter (MNG) with an AUC of 0.93, 87% accuracy, 88% sensitivity, and 85% specificity. Classical-type papillary thyroid carcinoma is differentiated from benign MNG with an AUC of 0.91, 86% accuracy, 86% sensitivity, and 86% specificity. Our preliminary results demonstrate that an HSI-based optical biopsy method using CNNs can provide multi-category diagnostic information for normal head-and-neck tissue, SCCa, and thyroid carcinomas. More patient data are needed in order to fully investigate the proposed technique to establish reliability and generalizability of the work.
NBI and Optical Biopsy II
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Diffuse Reflectance Spectroscopy (DRS) of radiation-induced re-oxygenation in sensitive and resistant head and neck tumor xenografts
Currently, anatomical assessment of tumor volume performed several weeks after completion of treatment is the clinical standard to determine whether a cancer patient has responded to a treatment. However, functional changes within the tumor could potentially provide information regarding treatment resistance or response much earlier than anatomical changes. We have used diffuse reflectance spectroscopy to assess the short and long-term re-oxygenation kinetics of a human head and neck squamous cell carcinoma xenografts in response to radiation therapy. First, we injected UM-SCC-22B cell line into the flank of 50 mice to grow xenografts. Once the tumor volume reached 200 mm3 (designated as Day 1), the mice were distributed into radiation and control groups. Members of radiation group underwent a clinical dose of radiation of 2 Gy/day on Days 1, 4, 7, and 10 for a cumulative dose of 8 Gy. DRS spectra of these tumors were collected for 14 days during and after therapy, and the collected spectra of each tumor were converted to its optical properties using a lookup table-base inverse model. We found statistically significant differences in tumor growth rate between two groups which is in indication of the sensitivity of this cell line to radiation. We further acquired significantly different contents of hemoglobin and scattering magnitude and size in two groups. The scattering has previously been associated with necrosis. We furthermore found significantly different time-dependent changes in vascular oxygenation and tumor hemoglobin concentration in post-radiation days.
In vivo metabolic imaging of early stage oral cancer and dysplasia based on autofluorescence lifetime endoscopy (Conference Presentation)
Elvis Duran, Dae Yon Hwang, Shuna Cheng, et al.
Increased metabolic activity, a hallmark of epithelial cell malignant transformation, induces subtle changes in the oral tissue autofluorescence. The optical “redox-ratio”, defined as the autofluorescence intensity of NADH divided by that of FAD, is sensitive to changes in the cellular metabolic rate. A decrease in the redox-ratio indicates increased cellular metabolic activity, as is typically observed in malignant cells. Specific changes in the fluorescence lifetime of both NADH and FAD have also been associated with increased metabolic activity in malignant oral epithelial cells. We therefore hypothesized that more specific biomarkers of oral cancer and dysplasia can more accurately be quantified by endogenous fluorescence lifetime imaging (FLIM). In this work, FLIM images of benign, dysplastic and early stage cancerous oral lesions from 52 patients were acquired at three emission channels (390±20nm, 452±22.5nm and >500nm) using a handheld multispectral FLIM endoscope. For each pixel, the fluorescence decays collected at the three emission bands were analyzed using a biexponential decay model, resulting on 16 FLIM-derived parameters per pixel. Statistical analysis was performed on each of the computed FLIM parameters (Wilcoxon test: Normal vs. Benign, Normal vs. Dysplasia/Cancer; Mann-Whitney test: Benign vs. Dysplasia/Cancer). Results from this analysis revealed that FLIM-derived parameters associated with collagen lifetime, NADH lifetime, FAD autofluorescence, and the optical redox ratio were statistical different between dysplastic/cancerous vs. benign oral lesions. This study provides the first demonstration for the clinical imaging of autofluorescence biochemical and metabolic biomarkers of oral epithelial cancer and dysplasia, which could potentially enable early detection of oral cancer.
Optimizing dynamic optical contrast imaging: signal characterization in the head and neck animal model (Conference Presentation)
Karam W. Badran, Harrison Cheng, Shijun Sung, et al.
Objective: DOCI is a novel imaging modality with the ability to detect variations in endogenous fluorophore lifetimes by illuminating tissue with pulsed ultraviolet (UV) light. We have previously shown that DOCI is capable of delineating tumor margins. Tissue macro-/micro-environments, however, vary with organ site and histology. We therefore sought to better characterize DOCI signal analysis within the varying subsites of the oral cavity in this ex-vivo animal model. Design: Fresh ex-vivo oral cavity specimens (n=66) from three New Zealand white rabbits were harvested for pulsed UV illumination utilizing a 6-diode in-series DOCI system. Photons produced were detected and fluorophore lifetimes calculated over a specified, homogenous, region of interest. Specimen site, size, histology, and relative average DOCI values analyzed. Results: 66 specimens produced over 2 million data points for fluorophore lifetime analysis. The oral tongue muscle, dentition, and mucosa from the dorsal tongue, floor of mouth, and hard palate all produced unique DOCI relative average values. Each subsite was found to be uniquely different from one another and produced statistically significant differences in DOCI value (p<0.05). Conclusions: DOCI has the ability to distinguish subtle differences in oral cavity subsites following fresh ex vivo harvest. The fluorophore lifetime relative average values of each tissue is uniquely different posing a novel strategy for intra operative oncologic imaging, surveillance, and possibly aid in the workup of pre-cancerous lesions. Growing a repository of normal tissue subsites is crucial for integrating an automated real-time deep learning algorithm for rapid tissue analysis.
Molecular imaging of PARP in oral cancer (Conference Presentation)
Thomas Reiner
More sensitive and specific methods for early detection are imperative to improve survival rates in oral cancer. However, oral cancer detection is still largely based on visual examination and histopathology of biopsy material, offering no molecular selectivity or spatial resolution. Intuitively, the addition of optical contrast could improve oral cancer detection and delineation. Our fluorescently labeled small molecule inhibitor PARPi-FL binds to the DNA repair enzyme PARP1 and is a potential diagnostic aid for oral cancer delineation. Recently, our most advanced optically active PARP imaging probe, PARPi-FL, has advanced to a phase I/II clinical trial and will be evaluated as a contrast agent for oral cancer imaging (NCT03085147). In short, 1) PARP1 is highly overexpressed in human oral cancer biospecimen, 2) PARPi-FL accumulated with high specificity in PARP1 expressing oral cancer xenografts, and 3) oral cancer imaging is also feasible when PARPi-FL is applied topically instead of intravenously. We will also compare the potential benefits of our molecularly targeted PARPi-FL guided imaging approach in comparison to existing oral cancer screening adjuncts and mention the adaptability of PARPi-FL imaging to other environments and tumor types.
Near-infrared autofluorescence image-guided parathyroid gland mapping in thyroidectomy (Conference Presentation)
Although several intraoperative methods to localize parathyroid gland(PG) were introduced, their clinical application has been limited. Thus, the current solution has been based on visual inspection of the surgeon. Recently, we reported excellent results (PPV = 100%, n=16) of Near infrared and infrared imaging technique for identifying surgically exposed PGs (JCEM, 2016). However, it is more important to predict the location of PGs before they are exposed to the naked eye. We investigated the feasibility of PG mapping (navigation) with NIR autofluorescence imaging to localize unexposed PGs. Seventy PGs from 38 thyroidectomy patients were enrolled in this prospective study. NIR imaging was taken at the areas where PGs were predicted to exist. We named the procedure as Parathyroid Navigation. The parathyroid navigation was photographed in three stages. Stage P1, taking images at pre-identification by the naked eye, step P2, at post-identification, and step P3, at removed specimens. Of 69 PGs identified, 64 (92.8%) were found at P1, 4 (5.8%) at P2, and 1 (1.4%) at P3. Even when PGs were covered by connective or fat tissues, NIR navigation at step P1 showed the sensitivity (92.75 %), specificity (100 %), PPV (100 %), NPV (16.66 %), accuracy (92.85 %). Five PGs of step P1 negative were identified at step P2 and P3 revealing 100% of total accuracy rate. The average parathyroid/background ratio was 4.78. These results suggest the concept of parathyroid navigation is feasible. We believe surgeons can get benefits of preserving parathyroid gland with the use of our NIR imaging method.
Novel Therapeutics, PDT, and Robotics
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Novel platform for optically guided head and neck robotic surgery (Conference Presentation)
The goal of oncologic resection is to eradicate all malignant cells, while minimizing loss of surrounding normal tissue (or so-called “negative margins”). Failure to achieve negative margins constitutes an adverse prognostic factor, which has a significant impact on patient’s quality of life and cancer recurrence. Significant barriers to obtaining a negative margins resection in real time exist and novel imaging platforms are needed which can be utilized during robotic tumor resection. In order to develop a novel endoscopic imaging platform for head and neck surgery: We propose to combine functional measurement of molecular tissue constituents with lifetime molecular imaging of metabolism. This will couple traditional stereo laparoscopic images with Single Snapshot of Optical Properties (SSOP)/ Fluorescence Lifetime Imaging FLI NIR, and Phasor computational lifetime imaging technology (PHASOR) simultaneously into a dual channel robotic endoscope and tested via optical phantoms having realistic tissue properties. This platform will use a variety of techniques including to image endogenous molecular constituents, namely oxyhemoglobin, deoxyhemoglobin, water, NADH, and NADPH providing a quantitative measurement of physiological parameters. Such information can be used to identify healthy and diseased tissue intraoperatively, providing a unique opportunity to delineate surgical margins in real-time. Pre-clinical mice models bearing tumor xenografts will be imaged using the tri-modal system to record: visible light image, hemodynamics parameters and metabolic status and test the feasibility of the identification of tumor margins in real time.
Antibacterial studies of ZnO nanoparticle coatings on nanocrystalline YSZ irradiated with femtosecond laser light
Crysthal Alvarez, Valeria Garcia, Natanael Cuando, et al.
Recently, efforts have been made to create a transparent ceramic cranial implant comprised of nanocrystalline yttriastabilized zirconia (nc-YSZ) that will provide optical access to the brain. This has been referred to as Window to the Brain (WttB) in the literature. WttB will allow the use of laser and photonic treatments and diagnostics in areas with difficult optical access in the brain. Nevertheless, infection is still one of the frequent cranial implant complications. In most cases a second surgery is required to replace the infected implant. To address potential infections in the WttB platform, we have studied the antibacterial effect of a Zinc Oxide (ZnO) nanoparticles coating on nc-YSZ. After coating with ZnO nanoparticles, the implant was irradiated with infrared femtosecond laser light. We synthesized ZnO nanoparticles through the Laser Ablation of Solids in Liquids (LASL) method, using a Zinc solid target in a liquid medium (water/acetone). Antibacterial coatings were obtained by air brush, using a precursor solution of ZnO nanoparticles in distilled water. Escherichia coli (E. coli) have been used as representative, clinical relevant bacteria to probe the antibacterial effect of the coating. Our previous studies suggested that the use of ZnO nanoparticles inhibit bacterial growth. Laser irradiation treatment alone also offers inhibition of bacterial growth, up to 70%. The incorporation of nanoparticles offers an additional 20% inhibition. Thus, this work represents the next step towards the development of a clinically-oriented transparent cranial implant.