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5 Acoustics in Biology and Medicine
• Ultrasound Gastroenterology: Search for gas bubbles, fat deposits, and appendicitis along gastric track and organs.
• Ultrasound Neonatology: Search for fetal abnormalities.
• Sonographic Urology: Investigation of urinary functions, including fluid in
bladder, pelvic organs, prostate, and testicles.
5.22.5 Other Applications
Dental Ultrasonics
Dental cleaning now often involves a stream of water which contains ultrasonic
waves with frequencies in the 40 kHz range. The vibration in the water tends to
shake loosely held material from the teeth, such as tartar and bacteria. This descaling
process is generally more effective than mechanical scraping.
Ultrasonic Cleanings
High intensity US waves in a cleaning solution are effective in vibrating the cleaning
solution near the surfaces of medical instruments. The vibration will emulsify soft
material on the surface of harder materials, particularly if intensities are high enough
to cause fluid bubble-cavitation.
Ultrasonic Study of Chemical Kinetics
Chemical reaction rates are quite sensitive to variations in temperature and pressure. As we have described, sound waves produce pressure variations and also
temperature variations, since heat does not have much time to equilibrate during
the ultrasonic wave vibration period. At high intensities, ultrasonic cavitation can
create chemical reactions under extreme conditions. This application is called
‘sonochemistry’.
Given that ultrasonic frequencies in the 10 GHz range are easily produced in
liquids, the study of relaxation kinetics at the picosecond range is possible. (In
contrast, laser pulse studies can reveal chemical kinetics at the femtosecond range.)
The formation of mesoscopic structures in solutions occurs in the picosecond range.
5.23 Acoustical Dosimetry
Elderly humans are likely to have significant hearing loss for frequencies above
10,000 Hz, and individuals who listen to loud sound at rock concerts (which often
5 Acoustics in Biology and Medicine
• Ultrasound Gastroenterology: Search for gas bubbles, fat deposits, and appendicitis along gastric track and organs.
• Ultrasound Neonatology: Search for fetal abnormalities.
• Sonographic Urology: Investigation of urinary functions, including fluid in
bladder, pelvic organs, prostate, and testicles.
5.22.5 Other Applications
Dental Ultrasonics
Dental cleaning now often involves a stream of water which contains ultrasonic
waves with frequencies in the 40 kHz range. The vibration in the water tends to
shake loosely held material from the teeth, such as tartar and bacteria. This descaling
process is generally more effective than mechanical scraping.
Ultrasonic Cleanings
High intensity US waves in a cleaning solution are effective in vibrating the cleaning
solution near the surfaces of medical instruments. The vibration will emulsify soft
material on the surface of harder materials, particularly if intensities are high enough
to cause fluid bubble-cavitation.
Ultrasonic Study of Chemical Kinetics
Chemical reaction rates are quite sensitive to variations in temperature and pressure. As we have described, sound waves produce pressure variations and also
temperature variations, since heat does not have much time to equilibrate during
the ultrasonic wave vibration period. At high intensities, ultrasonic cavitation can
create chemical reactions under extreme conditions. This application is called
‘sonochemistry’.
Given that ultrasonic frequencies in the 10 GHz range are easily produced in
liquids, the study of relaxation kinetics at the picosecond range is possible. (In
contrast, laser pulse studies can reveal chemical kinetics at the femtosecond range.)
The formation of mesoscopic structures in solutions occurs in the picosecond range.
5.23 Acoustical Dosimetry
Elderly humans are likely to have significant hearing loss for frequencies above
10,000 Hz, and individuals who listen to loud sound at rock concerts (which often