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Experimental Study of a Simulated Blood Flow Velocity Measurement System via Very-High-Frequency Ultrasound

To design and implement a simulated blood flow velocity measurement system via very-high-frequency (VHF)ultrasound, which can be used to complete an experimental study that simulates the real-time detection of blood flow information from human superficial organs. We prepared a blood phantom that was composed of nylon particles, pure water, glycerol, dextran and non-ionic surfactant. The experimental platform of this system included a simulated blood circulation system consisting of a medical injection pump for controlling the flow velocity, a medical silicone tube, and a simulated blood phantom; a single pulse, mechanical, linear scanning probe with an operation frequency of 50 MHz; the ultrasound echo signal acquisition circuit of the slave computer; and the VHF ultrasound blood flow imaging system composed of the host computer modules. The transducer was placed approximately 9 mm above the simulated blood vessel, and the direction of blood flow was same to the scanning direction of the probe. The pushing speed of the injection pump was adjusted to obtain the simulated blood imaging near the focal area. The acoustic characteristics of the homemade blood phantom were nearly unchanged for 150 days, which met the requirements of experimental research. According to the imaging results of the simulated blood flow at various flow velocities, the red blood cell imaging particles are large and the number is small when the flow velocity is low, and the red blood cell imaging particles are small and the number is large when the flow velocity is high. The directly proportional relationship between the number of red blood cell imaging particles of the simulated blood and the blood flow velocity can preliminarily be obtained by the designed blood flow velocity measurement system via VHF ultrasound, and the blood flow velocity can be determined accordingly.