The use of portable coherence tomography device on human skin

Optical coherence tomography (OCT) is a relatively new imaging modality developed in the early 1990’s primarily for retinal imaging. Further modifications allowed OCT’s to be used on other parts of the human body, and later on, beyond medicine, extending to industry, agriculture, etc. The skin is the most apparent organ of the human body. However there are multitudes of skin lesions that is difficult to characterize through mere visualization and palpation, as these lesions might go deep down several of its layers. OCT performs “optical biopsy”, the real time, in situ visualization of tissue microstructure, without the need to remove and process specimens, thus, sparing the patient of unnecessary pain, since the probe only scans over the surface. Furthermore, the image formed on the monitor also has much higher resolution than ultrasound. OCT is an application of the principle of low-coherence interferometry (LCI), which measures the echo time delay of backscattered light by characterizing the interference intensity of the light from the sample and reference arms. In low- coherence interferometry, a broadband light source, in this case, a super luminescent diode (SLD) is used, producing an interference pattern. The reflected light received by a photodiode will be processed by the computer into a 1-dimensional signal (A-scan). Subsequent A-scans on adjacent structures are combined to form a 2-dimensional image. A prototype portable OCT, with its corresponding data acquisition software, is being developed in the laboratory. The initial phase of the project involves measuring epidermal thickness, and later will be extended to other tissues and then to non-biological applications