Study On Brain Functional Imaging System Based On Near Infrared Spectroscopy

Brain is the most important and complex organ in human’s body. It’s a highernervous center to control of body movements and Generate consciousness. The test ofbrain function detection has very important significance for life to explore anddevelop the brain potential, diagnosis and treatment of the disease.Nowadays, Brain function detection methods has lots of obstruction, such as it’saffected by electromagnetic interference, human’s detecting posture and breathingwill cause certain interference to the measurement results, fMRI would made a greaterimpact for human when plus a powerful magnetic and so on. Based on the problemsmentioned above, a brain imaging system based on near infrared spectrum is designedthis paper.Near infrared spectroscopy is a noninvasive detecting technology, it has manycharacteristics such as high measurement speed, simple operation, so it’s becomingmore and more widely used.Near infrared spectroscopy is a noninvasive detecting technology, it has manycharacteristics such as high measurement speed, simple operation, so it’s becomingmore and more widely used. The technology mainly used to detectConcentration of hemoglobin oxygenation and reducing variation which can reflectbrain functional activity when applied to test brain function.This paper studied the following contents:1. We selected two specific wavelength according to the oxyhemoglobin anddeoxyhemoglobin’s light absorption characteristics in the near infrared spectrum areaand deduced oxyhemoglobin and deoxyhemoglobin’s calculation formula ofconcentration variation based on modified Beer-Lambert’s law.2. On this basis, we designed the brain imaging system which contained hardwareand software. Hardware circuit includes main controller, the multichannel senor, light source driver, the signal processing circuit. MSP430F149is used as main controller;3leds combining with8photoelectric detectors make for the multichannel senor. Thesame proportion amplifier and the second-order low-pass filter which is composed ofOP07that make up the signal conditioning circuit. The software of brain functionalimaging system is realized by C#and MATLAB programming. It consists ofcommunication management module, data management module, brain functionparameter analysis module. Communication management module could be realized bySerialPort that provided by C#; Furthermore, data management module could berealized by System.IO that provided by C#; MATLAB is used for signal denoisingand extracting. Then plotting the curve of reduced oxygenate and hemoglobinconcentration change to realize parametric analysis of brain function module.3. We carried out experimental testing to the system. Forearm blocking experimentresults shows that using the system to detect the changes in Oxyhemoglobin,Deoxyhemoglobin concentration trends is consistent with that in tissues. Valsalvaexperiment results show the detection results of the system are consistent withexisting research findings which have proved that brain function imaging system isfeasible to be applied to test brain function based on near infrared spectroscopy.