FIELD: medical equipment.
SUBSTANCE: invention relates to ultrasonic sensors for measuring blood flow velocity in vessels using the Doppler method. A method of measuring blood flow velocity by a system of ultrasonic sensors consists of spatially placing mutually oriented ultrasonic sensors, emitting a probing signal and receiving reflected signals, measuring Doppler frequency shifts in the sensors and calculating blood flow velocity. One transceiver sensor is placed in the body of the device in the form of a truncated cone in the center of the larger base of the cone applied to the body area, and three receiving side sensors located around the circumference of the larger base of the cone with a mutual angular deviation of 120°. The signal is emitted by the central sensor along the axial line of the cone in the direction of the test control volume of the vessel and the reflected signal is received by the side sensors inclined at an adjustable angleα to the center line of the cone. The Doppler frequency shift in three lateral sensors is measured and, based on the measured frequencies, the vector V of three coordinates of the blood flow velocity is calculated using the formula V=λ⋅A-1⋅F, where λ is ultrasonic wavelength, F is vector of three measured Doppler frequencies, A is matrix of the form
then the speed value is displayed as the norm of the vector V in real time on the indicator screen and an adjustable tilt angleα is selected by the maximum velocity value, which is taken as the measured maximum blood flow velocity. To measure the speed of blood flow in vessels at great depths, the number of receiving sensors with an adjustable angle of inclination is doubledα, the sensors are placed around the circumference in pairs with an angular distance between adjacent pairs of 90° so that the opposite sensors do not lie on the same straight line, additional three Doppler frequencies are included in the vector F, matrix A is replaced with matrix B:
and the velocity vector V is calculated using the formula
, where T is the transposition symbol.
EFFECT: invention is aimed at measuring the speed of blood flow in the vessels of any part of the body, synchronous operation of all sensors and a simplified procedure for setting only one angle of rotation.
1 cl, 2 tbl, 1 dwg
