Oral cancer is a global public health challenge, particularly affecting low-resource regions. To address the early detection requirement, we introduce a novel intraoral probe combining conventional oral examination (COE), autofluorescence visualization (AFV), and optical coherence tomography (OCT) for multidimensional oral cancer screening. Real-time COE and AFV offer a broad field of view, while OCT provides depth-resolved imaging. Our handheld probe demonstrates widefield, autofluorescence, and depth-resolved imaging capabilities in clinical settings, holding promise for enhanced early detection and management of oral cancer.
Head and neck cancers are the 16th most prevalent globally, and survival relies on early detection. Widefield autofluorescence (WFAF) shows potential for identifying neoplastic sites but lacks specificity. We investigate multispectral WFAF imaging to identify spectral features from endogenous biomarkers in native and neoplastic oral mucosa, using a DMBA-treated hamster buccal pouch model, with the aim to increase specificity. Spatially resolved spectra revealed variations between nonneoplastic and neoplastic areas. Analyses will compare spectral features in benign, dysplastic, and carcinoma sites from preclinical animal model and human tissues. Refinements in the red/green WFAF approach, by analyzing spectral features, are considered.
KEYWORDS: Deep learning, Cancer, Artificial intelligence, Image analysis, Evolutionary algorithms, Design and modelling, Visualization, Visual process modeling, Reliability, Systems modeling
Deep learning is a powerful tool for image analysis and medical applications. However, due to their intricate black-box nature, comprehending deep learning model predictions are often challenging. Oral cancer is globally prevalent, necessitating reliable AI algorithms for screening, especially for low-income regions. Interpretability is crucial for reliable AI. Visual explanation, generating attention maps highlighting decision-influencing regions, aids interpretability and also helps guide AI focus. Elevating AI reliability involves assessing decision confidence as well. Quantifying model output certainty helps identify uncertain cases, which need additional examination. Dataset quality is also pivotal for reliable AI development. Methods to evaluate and enhance the data and label/annotation quality will also be essential.
This study explores the development of a multimodal imaging system for disease assessment. Various experiments were conducted to evaluate performance in terms of power density, illumination uniformity, and fluorescence emission properties, comparing the handheld setup to the benchtop system. Test samples included phantom gels and oral cancer samples. Preliminary results indicate that the compact LED ring illuminator provided sufficient power for detectable emission signals and improved emission distribution due to sample scattering. The presentation also discusses solutions for achieving a more uniform illumination field and provides insights into imaging in oral epithelial neoplasia with the compact widefield system, along with considerations for translating from a benchtop test system to a compact handheld multimodal system.
Significance: Oral squamous cell carcinoma (OSCC) has an exceptionally high rate of incidence and mortality in India, with 15 cases per 100,000 people and over 70,000 deaths annually. The problem is exacerbated due to insufficient medical infrastructure for widescale screening and oncology care, particularly in rural regions. New technologies are urgently needed to detect oral cancer and provide timely treatment at the point of care. This work draws upon previous development and clinical validation of low-cost hardware for photodynamic therapy (PDT) treatment of oral lesions combined with an intraoral probe for cancer screening, incorporated here into an integrated theranostic device for image-guided PDT. Aim: This study aimed to validate technical performance of a novel hand-held smartphone-coupled intraoral device designed for simultaneous imaging and photodynamic therapy (PDT) of oral lesions. The imaging and PDT light delivery capabilities of the handheld system were evaluated using tissue phantoms containing protoporphyrin IX (PpIX) and a mouse model of OSCC photosensitized using 5-aminolevulinic acid (ALA)-induced PpIX. Approach: The probe’s built-in multi-channel fluorescence and polarized white light imaging capabilities were evaluated using tissue phantoms with TiO2 and controlled PpIX concentrations. In-vivo testing was performed using mice with subcutaneous TR146 OSCC implants before and after administering ALA, and again to assess photobleaching after light delivery (a total of 100J/cm2 at 635nm from the integrated diode laser). Results: Quantification of fluorescence images generated using the device showed that the PpIX signal scaled linearly with concentration, and the extent of photobleaching increased with increasing PDT dose as expected. In murine xenografts, PDT treatment delivered through the intraoral probe reduced tumor volume significantly in comparison to untreated control animals. Conclusion: Our findings demonstrate the effectiveness of a low-cost handheld device for simultaneous quantitative imaging of PpIX fluorescence and image-guided PDT in vivo. The integration of intraoral imaging and image-guided treatment into the same handheld device paves the way for a streamlined approach to cancer screening and early intervention with PDT at the point of care.
SignificanceIndia has one of the highest rates of oral squamous cell carcinoma (OSCC) in the world, with an incidence of 15 per 100,000 and more than 70,000 deaths per year. The problem is exacerbated by a lack of medical infrastructure and routine screening, especially in rural areas. New technologies for oral cancer detection and timely treatment at the point of care are urgently needed.AimOur study aimed to use a hand-held smartphone-coupled intraoral imaging device, previously investigated for autofluorescence (auto-FL) diagnostics adapted here for treatment guidance and monitoring photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence (FL).ApproachA total of 12 patients with 14 buccal mucosal lesions having moderately/well-differentiated micro-invasive OSCC lesions (<2 cm diameter and <5 mm depth) were systemically (in oral solution) administered three doses of 20 mg / kg ALA (total 60 mg / kg). Lesion site PpIX and auto-FL were imaged using the multichannel FL and polarized white-light oral cancer imaging probe before/after ALA administration and after light delivery (fractionated, total 100 J / cm2 of 635 nm red LED light).ResultsThe handheld device was conducive for access to lesion site images in the oral cavity. Segmentation of ratiometric images in which PpIX FL is mapped relative to auto-FL enabled improved demarcation of lesion boundaries relative to PpIX alone. A relative FL (R-value) threshold of 1.4 was found to segment lesion site PpIX production among the patients with mild to severe dysplasia malignancy. The segmented lesion size is well correlated with ultrasound findings. Lesions for which R-value was >1.65 at the time of treatment were associated with successful outcomes.ConclusionThese results indicate the utility of a low-cost, handheld intraoral imaging probe for image-guided PDT and treatment monitoring while also laying the groundwork for an integrated approach, combining cancer screening and treatment with the same hardware.
SignificanceOral cancer is one of the most prevalent cancers, especially in middle- and low-income countries such as India. Automatic segmentation of oral cancer images can improve the diagnostic workflow, which is a significant task in oral cancer image analysis. Despite the remarkable success of deep-learning networks in medical segmentation, they rarely provide uncertainty quantification for their output.AimWe aim to estimate uncertainty in a deep-learning approach to semantic segmentation of oral cancer images and to improve the accuracy and reliability of predictions.ApproachThis work introduced a UNet-based Bayesian deep-learning (BDL) model to segment potentially malignant and malignant lesion areas in the oral cavity. The model can quantify uncertainty in predictions. We also developed an efficient model that increased the inference speed, which is almost six times smaller and two times faster (inference speed) than the original UNet. The dataset in this study was collected using our customized screening platform and was annotated by oral oncology specialists.ResultsThe proposed approach achieved good segmentation performance as well as good uncertainty estimation performance. In the experiments, we observed an improvement in pixel accuracy and mean intersection over union by removing uncertain pixels. This result reflects that the model provided less accurate predictions in uncertain areas that may need more attention and further inspection. The experiments also showed that with some performance compromises, the efficient model reduced computation time and model size, which expands the potential for implementation on portable devices used in resource-limited settings.ConclusionsOur study demonstrates the UNet-based BDL model not only can perform potentially malignant and malignant oral lesion segmentation, but also can provide informative pixel-level uncertainty estimation. With this extra uncertainty information, the accuracy and reliability of the model’s prediction can be improved.
India has one of the highest rates of oral squamous cell carcinoma (OSCC) in the world, with an incidence of 15 per 100,000 and more than 70,000 deaths per year. The problem is exacerbated by lack of medical infrastructure and routine screening, especially in rural areas. This collaboration recently developed, and clinically validated, a low-cost, portable and easy-to-use platform for intraoral photodynamic therapy (PDT) specifically engineered for use in global health settings. Here, we explore the implementation of our low-cost PDT system in conjunction with a small, handheld smartphone-coupled, multichannel fluorescence and white-light oral cancer imaging probe, which was also developed for global health settings. Our study aimed to use this mobile intraoral imaging device for treatment guidance and monitoring PDT using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PS; PpIX) fluorescence. A total of 12 patients with 14 lesions having moderately/well-differentiated micro-invasive OSCC lesions (<2 cm diameter, depth <5 mm) were systemically administered with three doses of 20mg/kg ALA (total 60mg/kg). Lesion site PpIX and auto fluorescence was analyzed before/after ALA administration, and again after light delivery (fractionated, total 100 J/cm2 of 630nm red LED light). Quantification of relative PpIX fluorescence enables lesion area segmentation to improve guidance of light delivery and reports extent of photobleaching. These results indicate the utility of this approach for image-guided PDT and treatment monitoring while also laying groundwork for an integrated approach, combining cancer screening and treatment with the same hardware.
Significance: Convolutional neural networks (CNNs) show the potential for automated classification of different cancer lesions. However, their lack of interpretability and explainability makes CNNs less than understandable. Furthermore, CNNs may incorrectly concentrate on other areas surrounding the salient object, rather than the network’s attention focusing directly on the object to be recognized, as the network has no incentive to focus solely on the correct subjects to be detected. This inhibits the reliability of CNNs, especially for biomedical applications.
Aim: Develop a deep learning training approach that could provide understandability to its predictions and directly guide the network to concentrate its attention and accurately delineate cancerous regions of the image.
Approach: We utilized Selvaraju et al.’s gradient-weighted class activation mapping to inject interpretability and explainability into CNNs. We adopted a two-stage training process with data augmentation techniques and Li et al.’s guided attention inference network (GAIN) to train images captured using our customized mobile oral screening devices. The GAIN architecture consists of three streams of network training: classification stream, attention mining stream, and bounding box stream. By adopting the GAIN training architecture, we jointly optimized the classification and segmentation accuracy of our CNN by treating these attention maps as reliable priors to develop attention maps with more complete and accurate segmentation.
Results: The network’s attention map will help us to actively understand what the network is focusing on and looking at during its decision-making process. The results also show that the proposed method could guide the trained neural network to highlight and focus its attention on the correct lesion areas in the images when making a decision, rather than focusing its attention on relevant yet incorrect regions.
Conclusions: We demonstrate the effectiveness of our approach for more interpretable and reliable oral potentially malignant lesion and malignant lesion classification.
KEYWORDS: Cancer, Image classification, Data modeling, Tumor growth modeling, Medical imaging, Neural networks, Medical research, Breast cancer, Biomedical optics, Mobile devices
Significance: Early detection of oral cancer is vital for high-risk patients, and machine learning-based automatic classification is ideal for disease screening. However, current datasets collected from high-risk populations are unbalanced and often have detrimental effects on the performance of classification.
Aim: To reduce the class bias caused by data imbalance.
Approach: We collected 3851 polarized white light cheek mucosa images using our customized oral cancer screening device. We use weight balancing, data augmentation, undersampling, focal loss, and ensemble methods to improve the neural network performance of oral cancer image classification with the imbalanced multi-class datasets captured from high-risk populations during oral cancer screening in low-resource settings.
Results: By applying both data-level and algorithm-level approaches to the deep learning training process, the performance of the minority classes, which were difficult to distinguish at the beginning, has been improved. The accuracy of “premalignancy” class is also increased, which is ideal for screening applications.
Conclusions: Experimental results show that the class bias induced by imbalanced oral cancer image datasets could be reduced using both data- and algorithm-level methods. Our study may provide an important basis for helping understand the influence of unbalanced datasets on oral cancer deep learning classifiers and how to mitigate.
Significance: Oral cancer is among the most common cancers globally, especially in low- and middle-income countries. Early detection is the most effective way to reduce the mortality rate. Deep learning-based cancer image classification models usually need to be hosted on a computing server. However, internet connection is unreliable for screening in low-resource settings.
Aim: To develop a mobile-based dual-mode image classification method and customized Android application for point-of-care oral cancer detection.
Approach: The dataset used in our study was captured among 5025 patients with our customized dual-modality mobile oral screening devices. We trained an efficient network MobileNet with focal loss and converted the model into TensorFlow Lite format. The finalized lite format model is ∼16.3 MB and ideal for smartphone platform operation. We have developed an Android smartphone application in an easy-to-use format that implements the mobile-based dual-modality image classification approach to distinguish oral potentially malignant and malignant images from normal/benign images.
Results: We investigated the accuracy and running speed on a cost-effective smartphone computing platform. It takes ∼300 ms to process one image pair with the Moto G5 Android smartphone. We tested the proposed method on a standalone dataset and achieved 81% accuracy for distinguishing normal/benign lesions from clinically suspicious lesions, using a gold standard of clinical impression based on the review of images by oral specialists.
Conclusions: Our study demonstrates the effectiveness of a mobile-based approach for oral cancer screening in low-resource settings.
Significance: The rates of melanoma and nonmelanoma skin cancer are rising across the globe. Due to a shortage of board-certified dermatologists, the burden of dermal lesion screening and erythema monitoring has fallen to primary care physicians (PCPs). An adjunctive device for lesion screening and erythema monitoring would be beneficial because PCPs are not typically extensively trained in dermatological care.
Aim: We aim to examine the feasibility of using a smartphone-camera-based dermascope and a USB-camera-based dermascope utilizing polarized white-light imaging (PWLI) and polarized multispectral imaging (PMSI) to map dermal chromophores and erythema.
Approach: Two dermascopes integrating LED-based PWLI and PMSI with both a smartphone-based camera and a USB-connected camera were developed to capture images of dermal lesions and erythema. Image processing algorithms were implemented to provide chromophore concentrations and redness measures.
Results: PWLI images were successfully converted to an alternate colorspace for erythema measures, and the spectral bandwidth of the PMSI LED illumination was sufficient for mapping of deoxyhemoglobin, oxyhemoglobin, and melanin chromophores. Both types of dermascopes were able to achieve similar relative concentration results.
Conclusion: Chromophore mapping and erythema monitoring are feasible with PWLI and PMSI using LED illumination and smartphone-based cameras. These systems can provide a simpler, more portable geometry and reduce device costs compared with interference-filter-based or spectrometer-based clinical-grade systems. Future research should include a rigorous clinical trial to collect longitudinal data and a large enough dataset to train and implement a machine learning-based image classifier.
Oral cancer is one of the most common malignant tumors. There are 354,864 new cases and 177,384 death per year globally according to Globocan 2018 report. Most of the cases are in low- and middle-income countries that lack trained specialists and health services, of which India accounts for approximately one-third of the new cases and two-fifth deaths. Point-of-care oral screening tool to enable early diagnosis is urgently needed. We developed a dual-mode intraoral oral cancer screening platform and an automatic classification algorithm for oral dysplasia and malignancy images using deep learning.
Oral cancer is a growing health issue in low- and middle-income countries due to betel quid, tobacco, and alcohol use and in younger populations of middle- and high-income communities due to the prevalence of human papillomavirus. The described point-of-care, smartphone-based intraoral probe enables autofluorescence imaging and polarized white light imaging in a compact geometry through the use of a USB-connected camera module. The small size and flexible imaging head improves on previous intraoral probe designs and allows imaging the cheek pockets, tonsils, and base of tongue, the areas of greatest risk for both causes of oral cancer. Cloud-based remote specialist and convolutional neural network clinical diagnosis allow for both remote community and home use. The device is characterized and preliminary field-testing data are shared.
Oral cancer is a rising health issue in many low and middle income countries (LMIC). Proposed is an implementation of autofluorescence imaging (AFI) and white light imaging (WLI) on a smartphone platform providing inexpensive early detection of cancerous conditions in the oral cavity. Interchangeable modules allow both whole mouth imaging for an overview of the patients’ oral health and an intraoral imaging probe for localized information. Custom electronics synchronize image capture and external LED operation for the excitation of tissue fluorescence. A custom Android application captures images and an image processing algorithm provides likelihood estimates of cancerous conditions. Finally, all data can be uploaded to a cloud server where a convolutional neural network classifies the images and a remote specialist can provide diagnosis and triage instructions.
KEYWORDS: Luminescence, In vivo imaging, 3D acquisition, Imaging systems, Cameras, 3D image processing, Signal detection, Multispectral imaging, Quantum dots, Charge-coupled devices
Fluorescence is a powerful tool for in-vivo imaging in living animals. The traditional in-vivo fluorescence imaging equipment is based on single-view two-dimensional imaging systems. However, they cannot meet the needs for accurate positioning during modern scientific research. A near-infrared in-vivo fluorescence imaging system is demonstrated, which has the capability of deep source signal detecting and three-dimensional positioning. A three-dimensional coordinates computing (TDCP) method including a preprocess algorithm is presented based on binocular stereo vision theory, to figure out the solution for diffusive nature of light in tissue and the emission spectra overlap of fluorescent labels. This algorithm is validated to be efficient to extract targets from multispectral images and determine the spot center of biological interests. Further data analysis indicates that this TDCP method could be used in three-dimensional positioning of the fluorescent target in small animals. The study also suggests that the combination of a large power laser and deep cooling charge-coupled device will provide an attractive approach for fluorescent detection from deep sources. This work demonstrates the potential of binocular stereo vision theory for three-dimensional positioning for living animal in-vivo imaging.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.