Diagnostic Medical Sonography – which is more commonly referred to as an ultrasound – is a high-tech mechanism that produces moving imagery of the internal workings of the human body. This technology has significantly advanced doctor’s preventative and diagnostic abilities.
An ultrasound machine sends high frequency pulses of sound into the body using a hand-held, wand-like device. The scientific principle behind how sonography works is very similar to the way in which dolphins and whales – and submarines for that matter – are able to navigate underwater.
Sonography devices have evolved since their late 1950s inception in England while maintaining the same working principles. Many of the biggest developments that led to the modern ultrasound machine stemmed from radar and sonar research conducted during World War II.
The typical sonograph machine includes seven major components, including: a transducer probe that sends and receives signals; a central processing unit that computes all of the data; transducer pulse controls which change the amplitude, frequency and duration of sound pulses; a monitor where images are displayed; a keyboard and cursor for inputting data; a storage device such as a CD; and a printer to make hard copies of the data and imaging.
When the sound waves penetrate the body’s soft tissue and hit something internally – fluid, organs or bone, for example – some of the wave is refracted back toward the probe while the remainder continues forward until it runs into another boundary and reverberates back toward the surface.
The probe detects the reverberating waves and sends the data to the ultrasound machine which calculates the distance from the probe to the boundary and how long it took for the wave to bounce back to the surface. As the machine increases the rate of echoes, a two-dimensional picture is developed. In general, a diagnostic sonograph may issue millions of sound pulses and record millions of echoes in the course of just a few seconds. As the sonographer moves the probe around on the body, various angles can be produced in the picture.
This method won’t diagnose a yeast infection or the flu; however, it is a painless and totally safe way for doctors to measure the size of a fetus to determine the gestational stage of a pregnancy, how many fetuses are present and the sex of the baby. It may also be used to identify abnormalities in the heart, measure blood flow and detect various forms of cancer among a growing list of other applications. Unlike X-rays, ultrasounds do not employ radiation in order to generate diagnostic images.