Insonation Time Research Articles

Ultrasonic vitrectomy ? an alternative technique to presently used mechanical procedures

The liquification of the corpus vitreum by ultrasound is a promising new alternative to presently used mechanical methods of vitrectomy. With regard to the duration time of insonation, as well as to the ultrasonic intensity, there exist thresholds, the exceeding of which causes a discontinuous breakdown of the vitreous frame in a spherical zone around the transducer tip which can be verified by ultrasonic pulse echo methods. Viscosity measurements showed that the vitreous isonified in this area has almost the same viscosity as water whereas its optical transparency remains unchanged. The dependence of the diameter of the liquified zone on insonation time was measured.

Measurement of the temperature increases generated in soft tissue by ultrasonic diagnostic Doppler equipment

Temperature increases on the body surface from the use of two different ultrasonic Doppler blood flow meters were determined experimentally. Using a thermographic method it was shown that the temperature increase can be significant. Two continuous wave ultrasonic Doppler blood flow meters induced temperature increases on the body surface of 12.5°C and 2.3°C respectively, after an insonation time of 100 sec. Theoretical estimates and experimental results have shown an approximate agreement in the values of the temperature increase.

Ultrasound and chromosome damage.

Abstract It has been suggested previously that ultrasonic radiation at diagnostic power and frequency ranges causes chromosome damage. In this study human peripheral blood was insonated in a system of total reflection for two hours with continuous wave and pulsed ultrasound within the frequency range of 1 to 2·5 MHz and up to 8 W cm−2 total power output. Insonation time was increased up to 20 hours. Experimental techniques also included through transmission of ultrasonic energy. Plasma cultures were also examined for chromosome aberrations. Under none of these conditions was there a significant increase in the number of chromosome aberrations when compared with control samples.