光学相干层析术在人体皮肤成像方面的实验研究

Experiment Research on Optical Coherence Tomography of Human Skin

光学相干层析术(OCT)在人体皮肤病的临床诊断及科学研究方面有着广阔的应用前景。为获得活体状态下人体皮肤形态结构图像及其散射特性参数,研制了一套OCT系统(16μm纵向分辨率,-90 dB的系统灵敏度),应用该系统对人体多个部位的皮肤进行了活体成像,基于扩展的Huygens-Fresnel原理推导了OCT外差信号的表达式,利用该表达式对不同区域的OCT纵向信号曲线段进行线性拟合,提取人体皮肤的散射系数。从获得的结构图像可以清晰地分辨出角质层(掌趾部位)、表皮层、真皮上层等皮肤结构,分析得到了角质层和表皮层的厚度信息以及散射系数。从而验证了OCT用于表层皮肤研究的可行性。

Optical coherence tomography （OCT） is a promising new imaging method for clinical diagnosis and scientific research. In order to obtain the morphologic structure and the scattering coefficient of in vivo human skin,an OCT system with 16 μm axial resolution and -90 dB detection sensitivity is created. With this system in vivo OCT image of human skin in several locations is formed. And the heterodyne signal expression is deduced from the OCT model based on the extended Huygens-Fresnel principle. Through the fit of heterodyne signal expression to the various parts of the OCT axial signal curve,the scattering coefficients is acquired. Structures of the stratum corneum （plamoplantar）,the epidermis,and the upper dermis can be identified from the obtained cross-sectional images. The thickness of the stratum corneum and the epidermis are measured,as well as the scattering coefficients. It is demonstrated that OCT is a feasible method for investigation of morphologic structure of superficial layers of human skin.