Ruth B
Gesellschaft für Strahlen- und Umweltforschung mbH München, FRG.
Int J Microcirc Clin Exp. 1990 Feb;9(1):21-45.
Blood flow within the skin is measured by evaluating the dynamics of the laser speckle pattern. Laser light scattered from an object with a rough surface forms a granular structure--the speckles. When the object is moving, the speckle pattern becomes dependent on time. The measurements are performed at a distance of 6 cm which is adjusted by an auxiliary beam. The laser beam forms a spot on the skin with a diameter of approximately 1.5 mm and penetrates the skin. Part of the light is scattered back to the surface by the blood cells in the capillaries. The time dependent speckle intensity I(t) is determined by a photomultiplier. The comparison of spectra of I(t) obtained from measurements on the skin and on adhesive tape attached to the skin shows that there is a "tissue movement", the velocity of which has the same order of magnitude as the blood velocity in the capillaries. This has to be considered when measuring blood flow by the speckle method. Electronic signal processing reduces the influence from tissue movement and yields a value M being a relative measure of the blood flow. The time course of M during ischemia and reactive hyperaemia is compared with concurrent measurements of the skin temperature, the transcutaneous oxygen tension, and the laser Doppler signal. They exhibit similar tracings. Investigations in patients with leg ulcers show that measurements in open wounds can be performed.
通过评估激光散斑图案的动态变化来测量皮肤内的血流。从具有粗糙表面的物体散射的激光形成颗粒结构——散斑。当物体移动时，散斑图案随时间变化。测量在6厘米的距离处进行，该距离由辅助光束调节。激光束在皮肤上形成一个直径约为1.5毫米的光斑并穿透皮肤。部分光被毛细血管中的血细胞散射回表面。随时间变化的散斑强度I(t)由光电倍增管测定。对在皮肤上和贴在皮肤上的胶带上进行测量所获得的I(t)光谱的比较表明存在“组织运动”，其速度与毛细血管中的血流速度具有相同的数量级。在用散斑法测量血流时必须考虑这一点。电子信号处理减少了组织运动的影响，并得出一个值M，它是血流的相对测量值。将缺血和反应性充血期间M的时间进程与同时测量的皮肤温度、经皮氧分压和激光多普勒信号进行比较。它们呈现出相似的曲线。对腿部溃疡患者的研究表明，可以在开放性伤口中进行测量。
