Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA.
Department of Biomedical Engineering, College of Optical Sciences, University of Arizona, Tucson, Arizona, USA.
Lasers Surg Med. 2023 Apr;55(4):405-413. doi: 10.1002/lsm.23652. Epub 2023 Mar 16.
Reflectance confocal microscopy (RCM) is an imaging method that can noninvasively visualize microscopic features of the human skin. The utility of RCM can be further improved by increasing imaging speed. In this paper, we report high-speed RCM imaging of human skin with a frame rate that is over 10 times faster and an area imaging rate that is 6-9 times faster than those of commercially available RCM devices.
The higher imaging speed was achieved using a high-speed RCM technique, termed spectrally encoded confocal microscopy (SECM). SECM uses a diffraction grating and a high-speed, wavelength-swept source to conduct confocal imaging at a very high rate. We developed a handheld SECM probe using a scanned-grating approach. The SECM probe was used in conjunction with a wavelength-swept source with a spectral band of 1251-1342 nm.
The SECM probe achieved high lateral resolution of 1.3-1.6 µm and an axial resolution of 3.5 µm. SECM images of the human skin (image size = 439 × 439 µm ) obtained at 100 frames/s clearly show previously reported RCM features of the human skin in vivo with adequate image quality. The fast imaging speed allowed for the rapid acquisiton of volumetric SECM image data (200 frames covering a depth range of 200 µm) within 2 s. The use of 1251-1342 nm provided sufficient signal level and contrast required to visualize key cellular morphologic features.
These preliminary results demonstrate that high-speed SECM imaging of the human skin at 1251-1342 nm is feasible.
反射共聚焦显微镜（RCM）是一种可以非侵入性地可视化人体皮肤微观特征的成像方法。通过提高成像速度，可以进一步提高 RCM 的实用性。在本文中，我们报告了一种高速 RCM 成像技术，其帧率比商业上可用的 RCM 设备快 10 倍以上，面积成像速度快 6-9 倍。
更高的成像速度是通过一种称为光谱编码共聚焦显微镜（SECM）的高速 RCM 技术实现的。SECM 使用衍射光栅和高速、波长扫描源以非常高的速率进行共焦成像。我们使用扫描光栅方法开发了一种手持式 SECM 探头。SECM 探头与具有 1251-1342nm 光谱带宽的波长扫描源一起使用。
SECM 探头实现了 1.3-1.6µm 的高横向分辨率和 3.5µm 的轴向分辨率。以 100 帧/秒获得的人体皮肤 SECM 图像（图像尺寸=439×439µm）清晰地显示了体内先前报道的 RCM 人体皮肤特征，具有足够的图像质量。快速的成像速度允许在 2 秒内快速获取体积 SECM 图像数据（200 帧覆盖 200µm 的深度范围）。使用 1251-1342nm 提供了足够的信号水平和对比度，可用于可视化关键的细胞形态特征。
这些初步结果表明，在 1251-1342nm 处对人体皮肤进行高速 SECM 成像可行。
