Measure blood flow in vessels as small as 0.8 mm Determine blood flow velocity through extracorporeal
cannulae Measure blood flow in vessels as small as 0.8 mm Determine blood flow velocity through extracorporeal
cannulae 
The Triton Technology Model 100 Pulsed Doppler Flowmeter Module is a precision instrument designed to measure blood flow velocity in experimental preparations. As a stand-alone instrument it operates individually or in conjunction with other external synchronized instruments. The Pulsed Doppler Flowmeter is a state-of-the-art system for measuring blood flow velocity. The low-mass, inexpensive transducers are ideal for long term, chronic implantation, particularly when compared to the bulky, heavy transducers required for other technologies. These transducers use lightweight, non-shielded PVC-insulated wire.
Blood flow velocity is measured by projecting bursts of high frequency ultrasound diagonally across the blood vessel. Sound is backscattered from blood cells and the frequency of the scattered sound is shifted in proportion to the velocity of the cells. The scattered signal is detected and a voltage proportional to the velocity of the blood flow is developed for recording. A variable range gate control allows the user to measure blood flow velocity at many points across a blood vessel.
This module incorporates a number of unique features not found in other designs: A patented noise reduction circuit, Dynamic Noise Reduction, improves the signal-to-noise ratio by as much as 10 dB compared to other pulsed Doppler flowmeter designs. Range information is presented on a front panel LED display in 0.5 mm increments and as a proportional DC voltage at the back panel. The instantaneous flow velocity and direction sense is displayed on a dynamic LED bar graph display also on the front panel.
The most unique feature of the Model 100 is its internal calibration circuitry. The calibration is a true end-to-end calibration using a family of frequencies developed from the main quartz crystal clock. These stable, accurate frequencies are determined from the Doppler equation, the operating frequency and the transducer geometry. Other commercial pulsed Doppler designs utilize a simple voltage divider across the power supply as a calibration.
The pulsed Doppler Flow Module is available in 20 and 10 MHz versions for use on small and medium blood vessels. Many different implantable transducers are available to suit specific applications.
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Updated March 28, 2006
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