5.2　Optical Coherence Tomography

Optical coherence tomography（OCT）technique is a biological tissue imaging technique with many advantages，such as high resolution（up to micrometer），non-contact，noninvasive，and real-time.The potential of OCT for in vivo visualization of microstructural morphology in situ has attracted many attentions.In 1991，Huang from Massachusetts Institute of Technology and Schuman from Harvard Medical School developed the first OCT instrument with a semiconductor laser（A=830 nm）to measure isolated coronary arteries and retinas.OCT was then introduced in the clinical field of ophthalmology and the first in vivo OCT image was presented in 1993.Since 1997，OCT had been introduced in dermatology，gastroenterology，urology，gynecology and neurosurgery，etc.，and several manufactures of OCT systems have made OCT imaging for dermatological purposes commercially available.During the last decade，OCT has advanced from being an interesting scientific tool in the laboratory to being a useful bedside tool for supplementing the clinical diagnosis and also for treatment monitoring of different types of skin tumors.One limitation of OCT is the restricted imaging depth of maximum 2 mm that usually makes it inadequate in the evaluation of skin changes stretching beyond the reticular dermis.(https://www.daowen.com)