University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390, USA.
Anal Chem. 2011 Oct 1;83(19):7424-30. doi: 10.1021/ac201467v. Epub 2011 Aug 31.
We report use of a novel hyperspectral imaging system utilizing digital light processing (DLP) technology to noninvasively visualize in vivo tissue oxygenation during surgical procedures. The system's novelty resides in its method of illuminating tissue with precisely predetermined continuous complex spectra. The Texas Instruments digital micromirror device, DMD, chip consisting of 768 by 1024 mirrors, each 16 μm square, can be switched between two positions at 12.5 kHz. Switching the appropriate mirrors controls the intensity of light illuminating the tissue as a function of wavelength, active spectral illumination. Meaning, the tissue can be illuminated with a different spectrum of light within 80 μs. Precisely, predetermined spectral illumination penetrates into patient tissue, its chemical composition augments the spectral properties of the light, and its reflected spectra are detected and digitized at each pixel detector of a silicon charge-coupled device, CCD. Using complex spectral illumination, digital signal processing and chemometric methods produce chemically relevant images at near video rates. Specific to this work, tissue is illuminated spectrally with light spanning the visible electromagnetic spectrum (380 to 780 nm). Spectrophotometric images are detected and processed visualizing the percentage of oxyhemoglobin at each pixel detector and presented continuously, in real time, at 3 images per second. As a proof of principle application, kidneys of four live anesthetized pigs were imaged before, during, and after renal vascular occlusion. DLP Hyperspectral Imaging with active spectral illumination detected a 64.73 ± 1.5% drop in the oxygenation of hemoglobin within 30 s of renal arterial occlusion. Producing chemically encoded images at near video rate, time-resolved hyperspectral imaging facilitates monitoring renal blood flow during animal surgery and holds considerable promise for doing the same during human surgical interventions.
我们报告了一种利用数字光处理（DLP）技术的新型高光谱成像系统，该系统可在手术过程中无创地可视化体内组织的氧合作用。该系统的新颖之处在于其用精确预定的连续复杂光谱照射组织的方法。德州仪器的数字微镜器件（DMD）芯片由 768×1024 个镜子组成，每个镜子为 16μm 见方，可在 12.5kHz 下在两个位置之间切换。切换适当的镜子可以控制光的强度，从而使组织随波长变化而被照明，这就是主动光谱照明。这意味着可以在 80μs 内用不同的光谱照射组织。精确预定的光谱照明穿透到患者组织中，其化学成分增强了光的光谱特性，并且其反射光谱在硅电荷耦合器件（CCD）的每个像素探测器上被检测和数字化。使用复杂的光谱照明，数字信号处理和化学计量学方法以接近视频的速度产生与化学相关的图像。具体来说，本工作中，组织用跨越可见电磁光谱（380nm 至 780nm）的光谱光进行光谱照射。检测分光光度图像并进行处理，以可视化每个像素探测器的氧合血红蛋白的百分比，并以每秒 3 幅图像的速度实时连续显示。作为原理证明应用，对四只麻醉活猪的肾脏在肾血管闭塞前后进行了成像。主动光谱照明的 DLP 高光谱成像在肾动脉闭塞后 30s 内检测到血红蛋白的氧合作用降低了 64.73±1.5%。以接近视频的速度产生化学编码图像，时间分辨高光谱成像有利于在动物手术期间监测肾血流，并且在人类手术干预期间也具有很大的应用前景。
