Development of Endoscopic Optical Coherence Tomography System

In this proposal, an endoscopic optical coherence tomography (OCT) system capable of high-speed and three-dimensional imaging ability will be developed. The main contents of this proposal include the development of a high-speed frequency-sweeping laser (swept source) and fabrication of a miniature optical scanning catheter. In an OCT system, the light source is a key component, which dominates the depth resolution and imaging speed. However, it will greatly increase the cost by using a commercial swept-source. In this study, a Fourier-domain mode locking laser (FDML) will be developed. Compared with the commercial products, FDML can achieve higher imaging speed, higher output power and better phase stability. Although OCT can provide higher resolution, high imaging speed and non-invasive examination, the imaging depth will be limited to 2-3 mm by the absorption effects of the water and melanin for the most biological tissues. Hence, to scan the inner tissues of human bodies or animals, the sample arm of OCT system has to be minimized such as an optical catheter. Additionally, in order to cooperate with the endoscope, we design an optical catheter to insert into the working channel of the endoscope. The diameter of catheter is about 2.5 mm. Therefore, in clinical, the same locations of tissue can be examined by the endoscope and scanned with OCT system simultaneously. At last, the FDML laser and optical catheter will be integrated with OCT system. Also, the trachea and esophagus of pig will be scanned ex vivo with endoscopic OCT system. In the future, we expect this endoscopic OCT system can be used for early diagnoses in human precancers of trachea and esophagus in the future.

Project ID:PB9812-0397
External Project ID:NSC98-2218-E182-009