Scanning Single Fiber Endoscopy: A New Platform Technology for Integrated Laser Imaging, Diagnosis, and Future Therapies
Section snippets
State of the art in gastrointestinal endoscopy
Since the early nineteenth century, endoscopic techniques and clinical procedures have developed in synchrony with technological advances and the advent of new medical imaging tools. The use of endoscopic tools and devices invented during this time have allowed for an increasing number of minimally invasive imaging, diagnostic, and surgical procedures. A brief timeline outlining key developments of the endoscope is shown in Fig. 1, which has been expanded from Berci and Forde [1] and Sivak [2].
Scanning fiber endoscope
SFE technology shows promise as an ultrathin and flexible endoscope resembling a catheter in shape and size [8], [9]. The means for imaging are completely different from all white-light endoscopes, which rely on one optical fiber or image sensor per display pixel. Instead, the SFE scans red, green, and blue (RGB) laser light that is focused onto the tissue; the backscattered light is collected by several optical fibers and the image is generated by a computer one pixel at a time. Although only
Tethered-capsule endoscopic imaging of human esophagus
To allow the patient to swallow the SFE probe for unsedated imaging of the esophagus, a capsule 18 mm in length and 6.4 mm in diameter was placed around the rigid distal tip of the SFE probe, as shown in Fig. 5A. The 1.4-mm diameter tether is extremely soft and flexible allowing the patient to swallow the TCE probe with a cup of water as shown in Fig. 6A. One resulting image of the gastroesophageal junction is shown in Fig. 5B. The maximum FOV of this forward-viewing device was measured to be
Ultrathin endoscopic imaging of pig bile duct
The small size of the SFE makes it suitable for optical imaging inside the biliary tree and main pancreatic ducts. Although several endoscopic devices have been developed for direct optical imaging of these organs, these devices have yet to gain widespread acceptance because of their inferior image quality, expense, and fragility (eg, minimum bend radius of fiberoptic image bundles is typically greater than 30 mm). To make the SFE probe compatible with endoscopic retrograde
Laser-induced fluorescent imaging
In recent years, laser-induced fluorescent (LIF) imaging has been a popular technique for tissue diagnosis. LIF imaging uses low wavelength light as an excitation source, stimulating autofluorescent emission from endogenous fluorophores in tissue. Detection of the autofluorescent light provides insight into the biochemistry and microarchitecture of imaged tissues and can be used to distinguish between healthy and diseased tissue in single-point acquisition and imaging devices. Investigators
Summary
Preliminary results of testing the SFE technology show that the TCE imaging of the human esophagus demonstrates the potential for a low-cost screening application for esophageal pathology, such as Barrett's esophagus or esophageal varices. In the bile duct of the pig, the 4-m long SFE probe demonstrates the potential for a longer and more flexible babyscope, extending the use of endoscopy to previously inaccessible regions of the body. At 1.2 mm in outer diameter and a shaft of calibrated
Acknowledgments
Special thanks to the SFE Team of engineers at the University of Washington who have designed and built the prototype systems: Rich Johnston, Dave Melville, Cameron Lee, Ryland Bryant, Janet Crossman-Bosworth, and Bernie Murray. Animal testing was conducted in the laboratories of Dr. R. Glenny and Dr. L. Maggio-Price.
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Financial support was provided to Eric Seibel by NIH/NCI and the PENTAX Corporation, Tokyo, Japan. Chris Brown was supported by NIH/NCI grants CA094303 and CA110184. Michael Kimmey was supported in part by NIH/NCI grant CA094303, PI-Eric Seibel.