COMPARISON OF TIME-RESOLVED AND TIME-UNRESOLVED MEASUREMENTS OF DEOXYHEMOGLOBIN IN BRAIN
COMPARISON OF TIME-RESOLVED AND TIME-UNRESOLVED MEASUREMENTS OF DEOXYHEMOGLOBIN IN BRAIN
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DOI：
10.1073/pnas.85.14.4971
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发表时间：
1988-07-01
影响因子：
11.1
通讯作者：
BORETSKY, R
中科院分区：
文献类型：
--
作者：
CHANCE, B;LEIGH, JS;BORETSKY, R
连续 (CW) 和脉冲光用于组织中血红蛋白氧合的无创测量。连续照明光谱的双波长方法使用 760 nm（脱氧血红蛋白峰）和 800 nm（氧合血红蛋白-脱氧血红蛋白等吸光点）来测量轻度缺血/缺氧期间大脑中氧合血红蛋白脱氧的动力学和程度。在人造奶/酵母血系统中对吸收和散射进行了建模，给出了 7 cm 深度的吸收与光程长度之间的指数关系。时间分辨光谱（10 ps 分辨率）可显示猫脑响应 10 ps 输入脉冲而发射的光子到达的时间和距离。发射的光子在不到一纳秒的时间内达到峰值，并在几纳秒内呈指数下降。指数衰减的半衰期对应于 4 厘米距离上的光子迁移。当大脑被头骨包裹时，指数光发射持续了几纳秒，这在延长光发射方面起着关键作用。光强度的指数衰减值为 [exp(-.mu.L)]，其中 L 是根据时间/距离尺度和 .mu 确定的路径长度。是光在大脑中迁移的特征。系数.mu。通过增加吸收而增加，并且 .mu.'' = .epsilon.C 其中 .epsilon. C和C是消光系数(ε)和浓度(C)的Beer-Lambert参数。因此，可以量化脑组织中的脱氧血红蛋白。
Continuous (CW) and pulsed light were used for the noninvasive measurement of hemoglobin oxygenation in tissues. A dual wavelength method of continuous illumination spectroscopy used 760 nm (deoxyhemoglobin peak) and 800 nm (an oxyhemoglobin-deoxyhemoglobin isosbestic point) to measure the kinetics and extent of oxyhemoglobin deoxygenation in brains during mild ischemia/hypoxia. Absorption and scattering were modeled in an artificial milk/yeast blood system, which gave an exponential relationship between absorption and optical path length to a depth of 7 cm. Time-resolved spectroscopy (10-ps resolution) afforded a display of the times and distances of arrival of photons emitted by the cat brain in response to a 10-ps input pulse. The emitted photons rose to a peak in a fraction of a nanosecond and declined exponentially over a few nanoseconds. The half-time of exponential decay corresponds to photon migration over a distance of 4 cm. Exponential light emission continued for several more nanoseconds when the brain was encased by the skull, which plays a key role in prolonging light emission. The exponential decline of light intensity has a value [exp(-.mu.L)], where L is the path length determined from the time/distance scale and .mu. is the characteristic of the migration of light in the brain. The factor .mu. is increased by increasing absorption, and .mu.'' = .epsilon.C where .epsilon. and C are the Beer-Lambert parameters of extinction coefficient (.epsilon.) and concentration (C). Thus, deoxyhemoglobin can be quantified in brain tissues.