Safety Of Ultrasound
The acoustic outputs of diagnostic machines have increased up to seven times greater than they were prior to 1992. the year that the US Food and Drug Administration raised their limits. Although, there have been no reports of any adverse effect in humans in the absence of contrast agents occurring from the ultrasound exposure, there is concern since nearly all of the epidemiological evidence is from studies performed before the rise in outputs. In the laboratory, there is evidence that biological effects can be produced in animals at diagnostic ultrasound intensities. Furthermore, when contrast agents have been employed in humans, premature ventricular contractions and other cardiac arrhythmias have occurred. There is also concern over the growing use of ultrasound for non-medical purposes such as the taking of "keep-sake" ultrasound photos of the fetus. This lecture will present mechanisms underlying the production of ultrasound bioeffects, and the latest thinking in the safe use of ultrasound in diagnostic medicine.
The WFUMB Ultrasound Safety Committee has responded to this concern by organizing several symposia for evaluating internationally agreed upon recommendations and guidelines for the safe use of diagnostic ultrasound. These symposia included leading experts in ultrasound safety for all parts of the world. Each expert was instructed to participate as an independent scientist and not as a representative of any group or governmental body. One symposium focused on bioeffects arising for a thermal mechanism, another focused on bioeffects arising from non-thermal mechanisms. In each case a set of recommendations and guidelines were voted upon. Approved recommendations and guideline were ultimately adopted by WFUMB as official policy.
The WFUMB Ultrasound Safety Committee has also been collecting the regulations and guidelines of national and international organizations, such as the International Electrotechnical Commission (IEC), the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), the American Institute of Ultrasound in Medicine (AIUM), the Australasian Society for Ultrasound in Medicine (ASUM), and the United States Food and Drug Administration (FDA). We find that there is great agreement amongst these organizations. Differences tend to be more related to specific values than to any principle. Perhaps, an important reason for this agreement is the unusually good working relationships amongst scientists that have developed through international conferences and symposia.