Master/slave optical coherence tomography imaging of eyelid basal cell carcinoma.

Optical coherence tomography (OCT) is fast emerging as an additional non-interventional modality for skin tumor detection and diagnosis. A master/slave flying spot OCT configuration was assembled to detect periocular basal cell carcinomas (BCC). A swept source at 1300 nm and sweeping speed of 50 kHz were used. A three-step process was involved. First, 384 channeled spectra using a mirror were stored for 384 optical path differences at the master stage. Then, the stored channeled spectra (masks) were correlated with the channeled spectrum from the BCC tissue to produce 384 en face OCT images (200×200 pixels) for the optical path difference values used to acquire the masks. Finally, these en face slices were stacked to form a volume to cross-reference BCC tumor margins in the orthogonal plane. Per each eyelid sample, several en face images of 200×200 lateral pixels are produced in the time to scan laterally a complete raster of 1.6 s. Combination of the en face views with the cross-sectioning views allow for better discrimination of BCCs comparable to using cross-sectional imaging alone, as previously reported using the conventional fast-Fourier-transform-based OCT techniques.