Biological tissues, ultrasound effects

Significant attention has thus been given to investigating the effects of ultrasound on biological tissues. Ultrasound affects biological tissues via three main effects thermal, cavita-tional, and acoustic streaming. 

As described earlier, ultrasound affects biological tissues via three main effects, thermal effects, cavitational effects, and acoustic streaming. Conditions under which these effects become critical are given below. ... 

In this chapter, relevant background information will be provided regarding the principles of PEF and ultrasound technology, and its impact on biological tissues. The application of PEF as a pretreatment of raw materials prior to osmotic dehydration, air- and freeze-drying, with the resultant effects on drying characteristics and product quality, will be discussed. In the case of ultrasound, concepts for... 

Ultrasound waves produce a variety of thermal and cavitational effects in biological tissues [1]. Given their widespread use in medical diagnostic and treatment since the sixties [2], stringent standards have been developed to keep the intensity of these waves within safe levels [3], Thus, calibration techniques have also been actively developed such as wideband hydrophones, calorimetric, optical and radiation-force measurement systems [3], When the intensity increases, as it is the case in HIFU (high intensity focused ultrasound) and lithotripters, calibration becomes more delicate [1],... 

As ultrasound energy penetrates the body tissues, biological effects can be expected to occur if the tissues absorb the energy. The absorption coefficient (a) is used as a measure of the absorption in various tissues. For an ultrasound consisting of longitudinal waves with perpendicular incidence on homogeneous tissues, the following equation applies ... 

In order to understand the mechanisms of sonophoresis, it is important to identify various effects of ultrasound exposure on the human tissue since one or more of these effects may contribute to the mechanism of sonophoresis. A brief description of the various biological effects of ultrasound is provided below. 

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