Microscopic evaluation of resected tissue plays a central role in the surgical management of cancer. Because optical microscopes have a limited depth-of-field (DOF), resected tissue is either frozen or preserved with chemical fixatives, sliced into thin sections placed on microscope slides, stained, and imaged to determine whether surgical margins are free of tumor cells—a costly and time- and labor-intensive procedure. Here, we introduce a deep-learning extended DOF (DeepDOF) microscope to quickly image large areas of freshly resected tissue to provide histologic-quality images of surgical margins without physical sectioning. The DeepDOF microscope consists of a conventional fluorescence microscope with the simple addition of an inexpensive (less than $10) phase mask inserted in the pupil plane to encode the light field and enhance the depth-invariance of the point-spread function. When used with a jointly optimized image-reconstruction algorithm, diffraction-limited optical performance to resolve subcellular features can be maintained while significantly extending the DOF (200 µm). Data from resected oral surgical specimens show that the DeepDOF microscope can consistently visualize nuclear morphology and other important diagnostic features across highly irregular resected tissue surfaces without serial refocusing. With the capability to quickly scan intact samples with subcellular detail, the DeepDOF microscope can improve tissue sampling during intraoperative tumor-margin assessment, while offering an affordable tool to provide histological information from resected tissue specimens in resource-limited settings.

Optical endoscopy is the primary diagnostic and therapeutic tool for management of gastrointestinal (GI) malignancies. Most GI neoplasms arise from precancerous lesions; thus, technical innovations to improve detection and diagnosis of precancerous lesions and early cancers play a pivotal role in improving outcomes. Over the last few decades, the field of GI endoscopy has witnessed enormous and focused efforts to develop and translate accurate, user‐friendly, and minimally invasive optical imaging modalities. From a technical point of view, a wide range of novel optical techniques is now available to probe different aspects of light–tissue interaction at macroscopic and microscopic scales, complementing white light endoscopy. Most of these new modalities have been successfully validated and translated to routine clinical practice. Herein, we provide a technical review of the current status of existing and promising new optical endoscopic imaging technologies for GI cancer screening and surveillance. We summarize the underlying principles of light–tissue interaction, the imaging performance at different scales, and highlight what is known about clinical applicability and effectiveness. Furthermore, we discuss recent discovery and translation of novel molecular probes that have shown promise to augment endoscopists' ability to diagnose GI lesions with high specificity. We also review and discuss the role and potential clinical integration of artificial intelligence‐based algorithms to provide decision support in real time. Finally, we provide perspectives on future technology development and its potential to transform endoscopic GI cancer detection and diagnosis.

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Cervical cancer incidence and mortality rates remain high in medically underserved areas. In this study, we present a low-cost (<$5,000), portable and user-friendly confocal microendoscope, and we report on its clinical use to image precancerous lesions in the cervix. The confocal microendoscope employs digital apertures on a digital light projector and a CMOS sensor to implement line-scanning confocal imaging. Leveraging its versatile programmability, we describe an automated aperture alignment algorithm to ensure clinical ease-of-use and to facilitate technology dissemination in low-resource settings. Imaging performance is then evaluated in ex vivo and in vivo pilot studies; results demonstrate that the confocal microendoscope can enhance visualization of nuclear morphology, contributing to significantly improved recognition of clinically important features for detection of cervical precancer.

Abstract.Colonoscopy is routinely performed for colorectal cancer screening but lacks the capability to accurately characterize precursor lesions and early cancers. High-resolution microendoscopy (HRME) is a low-cost imaging tool to visualize colorectal polyps with subcellular resolution. We present a computer-aided algorithm to evaluate HRME images of colorectal polyps and classify neoplastic from benign lesions. Using histopathology as the gold standard, clinically relevant features based on luminal morphology and texture are quantified to build the classification algorithm. We demonstrate that adenomatous polyps can be identified with a sensitivity and specificity of 100% and 80% using a two-feature linear discriminant model in a pilot test set. The classification algorithm presented here offers an objective framework to detect adenomatous lesions in the colon with high accuracy and can potentially improve real-time assessment of colorectal polyps.

Traditional methods to detect and quantify nucleic acids rely on polymerase chain reaction (PCR) and require the use of expensive thermocyclers with integrated fluorescence detection of amplicons. Isothermal nucleic acid amplification technologies eliminate the need for thermal cycling; however, fluorescence-based detection of products is still required for real-time, quantitative results. Several portable isothermal heaters with integrated fluorescence detection are now commercially available; however, the cost of these devices remains a significant barrier to widespread adoption in resource-limited settings. Described here is a protocol for the design and assembly of a modular, low-cost fluorimeter constructed from off-the-shelf components. Enclosed in a compact 3D printed housing, the fluorimeter is designed to be placed atop a commercially available heat block holding a PCR tube. The fluorimeter described here was optimized to detect fluorescein isothiocyanate (FITC) dye, but the system can be modified for use with dyes commonly used as reporters in real-time nucleic acid amplification reactions. Clinical applicability of the system is demonstrated by performing real-time nucleic acid detection with two isothermal amplification technologies: recombinase polymerase amplification (RPA) for detection of positive control DNA provided in a commercial kit and reverse transcription loopmediated isothermal amplification (RT-LAMP) for detection of clinically meaningful levels of SARS-CoV-2 RNA.

Abstract. Fiber-optic endomicroscopy is a minimally invasive method to image cellular morphology in vivo. Using a coherent fiber bundle as an image relay, it allows additional imaging optics to be placed at the distal end of the fiber outside the body. In this research, we use this approach to demonstrate a compact, low-cost linescanning confocal fluorescence microendoscope that can be constructed for <$5000. Confocal imaging is enabled without the need for mechanical scanning by synchronizing a digital light projector with the rolling shutter of a CMOS camera. Its axial performance is characterized in comparison with a nonscanned high-resolution microendoscope. We validate the optical sectioning capability of the microendoscope by imaging a two-dimensional phantom and ex vivo mouse esophageal and colon tissues. Results show that optical sectioning using this approach improves visualization of nuclear morphometry and suggest that this low-cost line-scanning microendoscope can be used to evaluate various pathological conditions.