Dai Li-Juan, Wang Hui-Nan, Qian Zhi-Yu, Yu Guo-Qiang
Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2008 Jul;28(7):1468-72.
Total hemoglobin concentration (THC) and hemoglobin oxygen saturation (SO2) are essential parameters to doctors who wonder patients' hematogenous conditions and oxygen supplies and consumptions. Instruments presently used for measuring these parameters have big size of detecting probes that limit their applications to inner bodies. An optical probe involving two fibers with source-detector separations of one hundred micrometers was developed in the present study for purpose of minimally invasive inner detecting, which uses steady-state, broadband (300-1 000 nm) light source. The source light is delivered to targets through one fiber and the reflected light from the targets is collected and transferred to a spectrometer through the other fiber. Reflectance spectrum is obtained from the spectrometer. The method of reading THC and SO2 from the reflectance spectrum was developed using liquid-tissue phantoms containing intralipid and blood. Firstly, reflex spectrum of intralipid was recorded before mixtures of intralipid and blood with different THC were made as tissue phantoms. Then the fiber optical spectrometer was used to obtain reflex spectra as the phantoms' SO2 changed; simultaneously their corresponding THC and SO2 were recorded as the scale values by an oximeter. Differences of reflex spectra in 520-590 nm between intralipid and tissue models were proved reliably. Secondly, after data collections of absorption spectra and scale values were finished, two artificial neural networks (ANN) were build to model the relationship between scale values and absorption spectra. After being trained, the ANNs could output THC and SO2 correctly when an absorption spectrum was input. The ANNs produced errors of less than 4 micromol x L(-1) for THC and 5% for SO2. In vivo and minimally invasive measurements of THC and SO2 of brain tissues in different depth were finished on 30 rats by this specific system with the ANNs. The probe was inserted stereotactically to a depth of 6 mm with measurements obtained every 0.2 mm. SO2 of gray mater and white mater of rats was respectively obtained as 0.60-0.70 and 0.45-0.55. The highest THC, 110 micromol x L(-1) was measured around rat cortex. THC of brain tissue in other depth is 70-90 micromol x L(-1). These values agree well with reported data. This simple, inexpensive method deserves further study to establish its efficacy for THC and SO2 measurements of inner body.
总血红蛋白浓度（THC）和血红蛋白氧饱和度（SO2）是医生了解患者血液状况以及氧气供应和消耗情况的重要参数。目前用于测量这些参数的仪器检测探头尺寸较大，限制了其在体内的应用。本研究开发了一种光学探头，它包含两根源探测器间距为100微米的光纤，用于微创体内检测，采用稳态宽带（300 - 1000纳米）光源。源光通过一根光纤传输到目标，目标反射光被收集并通过另一根光纤传输到光谱仪。从光谱仪获得反射光谱。利用含有脂类和血液的液体组织模型，开发了从反射光谱中读取THC和SO2的方法。首先，在将不同THC的脂类和血液混合物制成组织模型之前，记录脂类的反射光谱。然后，当模型的SO2变化时，使用光纤光谱仪获得反射光谱；同时，通过血氧计将其相应的THC和SO2记录为标度值。可靠地证明了脂类和组织模型在520 - 590纳米处反射光谱的差异。其次，在完成吸收光谱和标度值的数据收集后，建立了两个人工神经网络（ANN）来模拟标度值与吸收光谱之间的关系。经过训练后，当输入吸收光谱时，ANN能够正确输出THC和SO2。ANN对THC产生的误差小于4微摩尔·升-1，对SO2产生的误差小于5%。利用该特定系统和ANN对30只大鼠不同深度脑组织的THC和SO2进行了体内微创测量。探头通过立体定位插入到6毫米深度，每0.2毫米进行一次测量。大鼠灰质和白质的SO2分别为0.60 - 0.70和0.45 - 0.55。在大鼠皮层周围测得的最高THC为110微摩尔·升-1。其他深度脑组织的THC为70 - 90微摩尔·升-1。这些值与报道的数据吻合良好。这种简单、廉价的方法值得进一步研究，以确定其在体内THC和SO2测量中的有效性。
