摘要 |
Flow measuring apparatus includes an excitation laser 30 for irradiating a sample 26 with excitation laser light 34 . The light is modulated by modulator 32 . In the excitation region 38 , the light excites ultrasound which is picked up by an ultrasound detector 6 and processed in demodulator 6 . The equipment is of particular application to measuring the speed of blood flow in human or animal tissue. By exciting ultrasound using light rather than directly sending ultrasound in tissue a good ultrasound signal from the blood 10 in blood vessel 8 may be generated since light is strongly absorbed by blood.
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