Research On Real Time, In Vivo, Minimal Invasive Measurement Of Brain Tissues' Parameters By Near Infrared Spectroscopy And Its Application

In vivo accurate measurements of tissue optical, blood oxygenic and blood dynamic parameters are important contents of brain science researching of biomedical fields. However, all parameters'simultaneous measurment with one minimally-invasive system havn't been reported, which can provide more useful information and more characteristic factors for brain tissue recognization, brain tumor quality analysis, neurosurgery operation guidance and brain function research.This study is based on minimally-invasive, in vivo measurement with a needle probe including two fibers. The researching goals are exact measurement of brain tissue optical, blood oxygenic and blood dynamic parameters with a minimally-invasive system. Basical measurement theories of brain tissue's paremeters, light distributions in brain tissues, system design, standard establishment and calibration, and clinic application are studied. The main contents of this study include building a real time in vivo measurement system which can measure and analysis three kinds of parameters automatically based on a steady-state fiber spectrometeric and a minimally-invasive needle probe, researching about the basical theories of measurements of brain tissue paremeters and experimental equations, including extracting spectra characteristics from absorption and scattering spectra, characteristic modeling of artificial neural network and regression analysis, building relationships between the characteristics and optical, blood oxygenic and blood dynamic parameters, and applying this system in measuring parameters (optical, blood oxygenic and blood dynamic parameters) of rats'C6 glioma. The main achievements and innovative results:1. An experimental system of a minimally-invasive, real time, in vivo tissue parameters measurement system, which realizes simultaneous measurement of reduced scattering coefficient, absorption coefficient, hemoglobin oxygen saturation, total hemoglobin concentration, blood flow and blood volume of the puncturing track.2. Empiricism equations for reduced scattering coefficient, hemoglobin oxygen saturation and total hemoglobin concentration are obtained through model experiments. These equations'precisions are validated in animal experiments. The results are exact and reliable.3. Artifical Neural Network is used to design spectra analysis model in minimal-invasive measurement of hemoglobin oxygen saturation, which has higher precision compared with traditional methods in measurement of hemoglobin oxygen saturation.4. Preliminary exploring of system application in clinical medicine. In vivo optical, blood oxygenic and blood dynamic parameters of C6 glioma are obtained in real time. Obvious diversities between C6 glioma and normal brain tissue are found from these parameters, which can supply reference for tumor diagnose.5. Pathological characters of glioma are explored by combining MRI and near infrared technique. Relationship between these parameters and pathological level are discussed and some methods for glioma classification by these parameters are proposed, which make good foundation for clinical application.