Browsing by Author "Keahey, Pelham"
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Item Differential structured illumination microendoscopy for in vivo imaging of molecular contrast agents(National Academy of Sciences, 2016) Keahey, Pelham; Ramalingam, Preetha; Schmeler, Kathleen; Richards-Kortum, Rebecca R.Fiber optic microendoscopy has shown promise for visualization of molecular contrast agents used to study disease in vivo. However, fiber optic microendoscopes have limited optical sectioning capability, and image contrast is limited by out-of-focus light generated in highly scattering tissue. Optical sectioning techniques have been used in microendoscopes to remove out-of-focus light but reduce imaging speed or rely on bulky optical elements that prevent in vivo imaging. Here, we present differential structured illumination microendoscopy (DSIMe), a fiber optic system that can perform structured illumination in real time for optical sectioning without any opto-mechanical components attached to the distal tip of the fiber bundle. We demonstrate the use of DSIMe during in vivo fluorescence imaging in patients undergoing surgery for cervical adenocarcinoma in situ. Images acquired using DSIMe show greater contrast than standard microendoscopy, improving the ability to detect cellular atypia associated with neoplasia.Item High resolution microendoscope employing differential structured illumination and method of using same(2023-10-31) Keahey, Pelham; Richards-kortum, Rebecca; William March Rice University; United States Patent and Trademark OfficeA high-resolution microendoscope system includes a light source, a fiber optic bundle configured to transmit light from the light source to a sample, a disc configured to receive light returned from the sample, the disc having spaced apart segments, the spaced-apart segments being at least one of openings and transparent portions, a first camera configured to capture a first image based at least in part on light passing through the disc, and a second camera configured to capture a second image based at least in part on light reflected from the disc.Item Optical Molecular Imaging in the Gastrointestinal Tract(Elsevier, 2013-05) Carns, Jennifer; Keahey, Pelham; Quang, Timothy; Anandasabapathy, Sharmila; Richards-Kortum, RebeccaRecent developments in optical molecular imaging allow for real-time identification of morphological and biochemical changes in tissue associated with gastrointestinal neoplasia. This review summarizes widefield and high resolution imaging modalities currently in pre-clinical and clinical evaluation for the detection of colorectal cancer and esophageal cancer. Widefield techniques discussed include high definition white light endoscopy, narrow band imaging, autofluoresence imaging, and chromoendoscopy; high resolution techniques discussed include probe-based confocal laser endomicroscopy, high-resolution microendoscopy, and optical coherence tomography. Finally, new approaches to enhance image contrast using vital dyes and molecular-specific targeted contrast agents are evaluated.Item Structured Illumination in a Fiber-Optic Microendoscope to Image Nuclear Morphometry in Columnar Epithelium(2015-03-23) Keahey, Pelham; Richards-Kortum, Rebecca Rae; Tkaczyk, Tomasz S; Natelson, Douglas; Drezek, Rebekah AFiber-optic microendoscopes have shown promise to image the changes in nuclear morphometry that accompany the development of precancerous lesions in tissue with squamous epithelium such as in the oral mucosa and cervix. However, fiber-optic microendoscopy image contrast is limited by out-of-focus light generated by scattering within tissue. The scattering coefficient of tissues with columnar epithelium can be greater than that of squamous epithelium resulting in decreased image quality. To address this challenge, I present a small and portable microendoscope system capable of performing optical sectioning using structured illumination (SI) in real-time. Several optical phantoms were developed and used to quantify the sectioning capabilities of the system. Columnar epithelium from cervical tissue specimens was then imaged ex vivo, and I demonstrate that the addition of SI achieves higher image contrast, enabling visualization of nuclear morphology.