Multi-channel Brain Blood Oxygen Detecting System

Near-infrared spectroscopy(NIRS) is a means of cortical functional activity detection based on Diffuse Optical Imagin(DOI), which is non-invasive and portability. Oxyhemoglobin and deoxyhemoglobin in blood have different sensitivity to the near-infrared light which wavelength range from 600 nm to 900 nm,so we can obtain the changes of oxyhemoglobin and deoxyhemoglobin concentration in cerebral activity. Compared with some other conventional brain imaging techniques(MRI, PET, EEG and MEG, etc.), Near-infrared Diffuse Optical Imaging has lots of advantages, for example, it owns high time resolution, low cost, portability, simple operation, and so on. And it is a non-invasive detection technology which is able to get real-time, continuous information on cerebral oxygen. NIRS not only provides a new technology for brain research, but also can be applied to clinic. It is of great significance to the monitoring of neonatal cerebral oximetry, and the diagnosis of brain injuries, such as intracranial hemorrhage.However, so far, the domestic oximetry detecting instrument based on near-infrared has a very small-scaled development. It has just been used for simple oxygen detection which means the platform for using it is limited. There are just a few large-scale molding instruments produced in china. In order to promote the neuroscience research, lots of instruments have to be imported by a number of research institutions from other countries which are undoubtedly more expensive with high maintenance cost of the devices. In order to break the monopoly of foreign technologies, and promote the development of proprietary multi-functional near infrared detection technology, to make multi-channel near-infrared devices has been pressing. This paper based on the National Major Scientific Instruments and Equipments Development Project—32 channel NIR and EEG synchronous activity detector. This paper describes design of this near-infrared detection instrument which can achieve a continuous dual-wavelength light and have simultaneous acquisition of cerebral oxygen in 32 channels. The main contents are given as follows:First of all, this paper compared with other traditional cerebral imaging, the author gives an introduction to the background and significance of NIRS, and summarizes the characteristics of near-infrared imaging, then analyzes the principle and theoretical basis of near-infrared imaging detection in detail, focusing on continuous wave imaging algorithm based on Lambert – Beer.Secondly, the overall architecture and the general design principles of multi-channel cerebral blood oxygen monitoring system are introduced in this paper, and the main function module design and implementation, including hardware circuit design and software design are introduced in detail, too.Finally, through testing to the instrument hardware circuit and the experimental data collection, the author analyzes the function of the instrument and sums up the advantages and disadvantages of the instrument.