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Ultrasound Essay

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For nearly half a century ultrasound has been used in the clinical setting for medical diagnosis. It is the most common imaging modality of obstetrics and gynecology and to this day, there has been no evidence showing harmful effects of ultrasound at the clinical exposure levels. There has been research into the possible biological effects of ultrasound and while ultrasound is still generally seen as a safer form of diagnostic imaging, it is still important to understand what those biological effects are. Understanding the bioeffects of ultrasound will allow the user to know under what conditions ultrasound remains bioeffect free, and what the sonographer can do to keep ultrasound safe for the patient. This paper will go over the bioeffects …show more content…

Non thermal bioeffects include cavitation. Cavitation may be the most important non-thermal bio-effect and deals with the formation and sometimes collapse of bubbles in ultrasound. Cavitation is then divided into two different types: Stable cavitation and transient cavitation. Stable cavitation occurs at lower MI levels and the bubbles that for may expand but do not burst. Transient cavitation occurs with higher MI levels and the bubbles where the bubbles can form, grow rapidly, and then collapse giving off a lot of heat and pressure changes. The amount of pressure given off can physically damage cells in the area of the collapse. There are two places where you see cavitation in ultrasound. Naturally occurring gas bodies are those seen in lungs or bowel; “The outputs of some currently available diagnostic ultrasound devices can generate levels that produce capillary hemorrhage in the lungs and intestines of laboratory animals. “ (AIUM, 2015). For this reason, it is important to pay attention to the mechanical index show on the machine. The minimum threshold value of the experimental MI (the in situ value of the peak rarefactional pressure amplitude divided by the square root of the frequency) for pulmonary capillary hemorrhage in laboratory mammals is approximately 0.4. The corresponding threshold for the intestine is MI = 1.4. (AIUM,

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