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一、超声波诊断的原理超声波是人耳听不到的高周波声响。通常声波的传播是以空气为介质;超声波,除了气体之外,还可借液体、固体等各种物质为传播介质。由于超声波的频率很高,故波长极短。一般诊断用的超声波,它的频率为2百万赫(2MHz),在机体中的波长为0.75毫米。这种波长极短的声波,其传播特性与光波非常接近,可以被集聚成一束狭窄的声束,直线地指向一定的方向,并可在不同的介质中以不
First, the principle of ultrasonic diagnosis Ultrasound is the human ear can not hear the high frequency sound. Usually the spread of sound waves is the air as a medium; ultrasound, in addition to gas, but also by liquid, solid and other substances as the propagation medium. Due to the high frequency of ultrasound, the wavelength is extremely short. Ultrasound for general diagnosis, it has a frequency of 2 megahertz (2 MHz) and a wavelength of 0.75 mm in the body. This very short wavelength of sound waves, its propagation characteristics and light waves are very close to the beam can be gathered into a narrow beam, pointing straight in a certain direction, and in different media to not