BSIP LAURENT / SCIENCE PHOTO LIBRARY BSIP LAURENT / SCIENCE PHOTO LIBRARY
Doppler ultrasound scan. A doctor uses ultrasound scanning to examine blood flow through the carotid arteries in a man's neck. He is watching the image on a monitor (upper left) while holding a transducer to the patient's neck. Doppler ultrasound scanning enables doctors to detect turbulence in the flow of blood, which might reveal narrowing of blood vessels, clots or aneurysms (swellings). The small transducer emits ultra high frequency (inaudible) sound, which is reflected by blood vessels. The frequency of the echo reveals the rate of blood flow.
Model release available. Property release not required.