Introduction: Biological side effects of diagnostic ultrasound are primarily via two main mechanisms: thermal and nonthermal/mechanical. The last refer to damage caused by oscillation of small gas bubbles within the ultrasound field (lung, intestines and ultrasound contrast agents). The change in size and location of the bubble can cause tissue damage. Other mechanical effects of ultrasound are formation of free radicals and radiation force. During ultrasound exposure, acoustic energy is absorbed by tissue and converted into heat – thermal effects of the ultrasound cause damage with tissue heating. Control of the safe use of ultrasound is provided by thermal (standard that allows user to assess the risk of tissue heating) and mechanical (indicator of the ability of the ultrasound to cause cavitation) index. We take into the account guidelines and recommendations for safe use: what the temperature rise can be, we are extra careful with using Doppler and examining tissues with gas bodies present and/or using ultrasound contrast agents. Purpose: Purpose of master thesis is to describe basic principle of diagnostic ultrasound, ultrasound safety, recommendations and guidelines for safe use of diagnostic ultrasound. Methods: We used descriptive method and systematic review of literature. We acquired literature from December of 2021 to February of 2023 from different database. From initial 3045 results we narrowed it down to 23 articles using inclusion and exclusion criteria. Results: We have organized articles in two separate tables: authors, year of the research and technical parameters (frequency, time of the examination, target, thermal and mechanical index and other technical information about the research) in one and purpose with main findings in other table. Discussion and conclusion: Diagnostic ultrasound can cause temperature rise from 1 to 2 °C, sometimes up to 5 °C. When there are gas bubbles present during the exam, acoustic cavitation causes rupture of capillaries and small vessels, damage on the muscle, fat and abnormal heart function. Also, the values of thermal and mechanical index exceeded the permissible ones many times. It is important to know how ultrasound works, what are the side effects, guidelines and recommendations for safe use. The examination is carried out only when it is necessary and the benefit is greater than the possible harm, during the examination we monitor the value of thermal and mechanical index and adjust the exposure parameters according to them, we are especially careful when examining pregnant women, performing examinations in pediatrics and when we use contrast agents; also always follow the ALARA principle.
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