[Current problems of the effects of contact ultrasound in medicine and other branches of the national economy]

Abstract

The physiological and hygienic estimation of the working conditions of the new occupational groups of medical workers who service ultrasound (diagnostic, surgical, sterilization, and physiotherapeutic) equipment has demonstrated the intensity of contact ultrasound in the area of contact with hands to undergo changes within wide limits; exposure also changes, correspondingly by a factor of 10 or 10(2), amounting on the average to 1.2-1104 joules for different occupational groups. As a result of the long-term exposure to ultrasonic sources, the workers may develop neurovascular dose-dependent disorders in the form of angiodystonic syndrome of vegetative polyneuritis of the hands. The rate of the augmentation of constant shifts of the thresholds of vibration sensitivity may constitute 1.3 and 0.9 dB per year for those exposed to low and high-frequency sources, respectively. The principle of the frequency dependence of the effects of contact ultrasound is thus based; the maximum permissible level of factor is corrected with regard to the spectral parameters. The joint action of air and contact ultrasound has been examined and the additive effect has been revealed. This made it possible to establish a decreasing correction (5 dB) for the maximum permissible level of contact ultrasound characterized by a more remarkable biological action. The hygienic classification of contact ultrasound has been elaborated, the use of a complex of preventive measures has been based.