Increased heating by diagnostic ultrasound due to nonlinear propagation

• DOI: 10.1121/1.399950
• Publication Date: 2005-10-13T20:06:59Z
• Authors: David R. Bacon; Edwin L. Carstensen
• Keywords: Distortion (music); Nonlinear acoustics

The heating of tissues by the absorption ultrasound is an important safety consideration in use diagnostic ultrasound. This paper shows that models ultrasonic for this situation need to take account nonlinear propagation. Measurements were made temperature rise a sample tissue-mimicking gel, caused application 3.6-MHz focused beams 3 min. propagation path focus was water, mimic where fetus scanned through full bladder. effect seen changing pressure amplitude pulse, while altering pulsing regime preserve constant spatial-peak temporal-average intensity 1 W cm−2. When distortion present, enhancement observed, which correlated with value shock parameter. ratio typically up factor 3, and maximum observed 2 °C. enhanced both at surface gel after 23 mm material. Under conditions propagation, usually occurs prefocal region, rather than focus.