Study On The Terahertz Absorption Characteristics Of Ischemic Brain Tissue And Arterial Blood Rat

Terahertz generation and detection technology is developing rapidly in recent years, so that the terahertz technology attracted great concern of domestic and foreign research institutions and scholars. Terahertz technology has been widely used in national defense, security and biomedicine now. Terahertz time-domain spectroscopy is based on the ultra-fast femtosecond laser technology terahertz spectral measurement technology, it is mainly the use of electro-optic sampling or photoconductive sampling method recorded transmitted or reflected from the sample terahertz electric field time-domain waveform directly, then after its Fourier transform a frequency domain spectrum received, and then after the correlation calculation terahertz wave optical parameters related to the test sample obtained, such as dielectric constant, absorption coefficient, refractive index and extinction coefficient, and so on. This paper is the use of new biomaterials terahertz parameter extraction method to different ischemic time of rat brain and rat arterial blood samples for research and analysis, now the main results of this paper are described below:(1) The biological material has a high absorption strength to terahertz. By using different reference light measurement method, a new method of extracting optical parameters of biological material in the terahertz band was proposed for solid and liquid biological materials. Using this method, the optical parameters of biological materials related to terahertz can be measured more accurately.(2) Based on the terahertz optical parameter extraction method of the biological material, a biological material optical parameter in the terahertz band extraction software was made by Python. With the software, the time-domain spectroscopy, frequency domain spectrum, phase spectrum, absorption spectrum, refractive index and extinction coefficient and other parameters of the testing biological sample can quickly be obtained and can be visualized.(3) Ischemic brain tissue of rats were studied with the use of terahertz time-domain spectroscopy. The absorption spectrum of rat ischemia brain with different time in 0.4 THz~0.95 THz was obtained. The results show that different times of ischemic brain tissue exhibits different absorption characteristics to terahertz wave is due to excitatory amino acids, intermediates produced by anaerobic respiration and calcium overload resulting in large quantities of nitric oxide synthesis induced by brain injury.These will have an important role in helping us to study the pathology mechanisms of ischemic brain injury,and that will have a certain value in the biomedical field.(4) Arterial blood of rats were studied with the use of terahertz time-domain spectroscopy. The absorption spectrum of rat arterial blood with different concentrations in 0THz~0.8THz was obtained. The results showed that the absorption coefficient of blood to terahertz wave decreases with the concentration increased, that indicating that terahertz time-domain spectroscopy technique can be used for real-time detection and monitoring of blood viscosity, It plays an important role in the prevention and treatment of cardiovascular disease caused by hyperlipidemia.