Laser pill has potential benefits over upper GI endoscopy



A small, swallowed, laser imaging capsule provides full-thickness imaging of the upper gastrointestinal tract without biopsy, and is quicker and less invasive than traditional endoscopy, according to the Harvard University researchers who are developing it.

About the size of a large multivitamin pill, the transparent capsule generates a near-infrared beam that spins rapidly about its circumference during transit. Changes in the reflected light allow cross-sectional imaging of the esophagus in a few minutes. Sequential cross-sections can be compiled into three-dimensional models of the entire lumen (Nat. Med. 2013 Jan. 13 [doi: 10.1038/nm.3052]).

Courtesy Wellman Center for Photomedicine, Massachusetts General Hospital

This reusable, tethered, inch-long endomicroscopy capsule can provide three-dimensional imaging of the microscopic structure of the esophageal lining, giving it the potential for Barrett's esophagus screening.

"This system gives us a convenient way to screen for Barrett’s [esophagus] that doesn’t require patient sedation, a specialized setting and equipment, or a physician who has been trained in endoscopy. By showing the three-dimensional, microscopic structure of the esophageal lining, it reveals much more detail than can be seen with even high-resolution endoscopy. The images produced have been some of the best we have seen of the esophagus," investigator Dr. Guillermo Tearney, a Harvard Medical School pathology professor and the associate director of the Wellman Center for Photomedicine at Massachusetts General Hospital, Boston, said in a statement.

The capsule is on a tether, which carries its fiber optic line and laser driveshaft and helps with positioning. The capsule is pulled up and out after use, and disinfected for the next patient.

In early testing, 15 cm of esophagus in seven healthy and six Barrett’s esophagus patients was imaged in a mean of 58 seconds; it took about 6 minutes to make two down- and two up-transits. The technique, dubbed tethered capsule endomicroscopy, clearly distinguished the cellular abnormalities of Barrett’s. Standard upper GI endoscopy takes about 90 minutes.

Courtesy Wellman Center for Photomedicine, Massachusetts General Hospital

By manipulating the plastic ball attached to the flexible tether (lower, right hand) the system operator can control the position of the endomicroscopy capsule in a patient's esophagus.

"We originally were concerned that we might miss a lot of data because of the small size of the capsule, but we were surprised to find that, once the pill has been swallowed, it is firmly grasped by the esophagus, allowing complete microscopic imaging of the entire wall," Dr. Tearney said.

There were no complications, and 12 of the 13 subjects said they preferred the capsule to previous endoscopies.

"Because the tethered endomicroscopy pill traverses the gastrointestinal tract without visual guidance, the training required to conduct the procedure is minimal. This fact, combined with the brevity and ease with which the procedure is performed, will enable internal microscopic imaging in almost any health care setting, including in the office of the primary care physician," Dr. Tearney and his colleagues wrote in their paper.

The research was supported by grants from the National Institutes of Health. The researchers said they had no disclosures.

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