phyrev ch.3 - The 13 (us) Microsecond Rule in soft tissue,...

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The 13 (us) Microsecond Rule – in soft tissue, every 13us of go-return time means the reflector is 1 cm deeper in the body. FOR EXAM, depth and distance are not the same meaning. . . . ex. Time-of-flight Reflector depth Distance traveled 13 us 1 cm 2 cm Ch 7. Transducers Any device that converts one form of energy into another Piezoelectric effect – the conversion of electrical energy into mechanical (sound) energy and vise versa. Or a property of certain materials to create a voltage when they are mechanically deformed. Piezoelectric material – natural – quartz, Rochelle salts - man made - barium titanate, lead zirconate titanate (PZT) PZT – called ceramic, active element , or crystal. Cannot heat or it’s depolarized Active element (PZT) = ½ wavelength thick Matching Layer – has an impedance between those of the skin and the active element to increase the percentage of transmitted us between the active element and the skin.
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This note was uploaded on 11/22/2010 for the course ULTRASOUND 729 taught by Professor Barnes during the Spring '10 term at El Centro College.

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phyrev ch.3 - The 13 (us) Microsecond Rule in soft tissue,...

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