Sound medicine at Acoustics Meeting( Nov 13 2007 -- The use of sound in m...),Health

Nov 13, 2007 -- The use of sound in medicine has a long history. Doctors have used stethoscopes to listen to the internal sounds of the human body since the early 19th century, and ultrasound imaging has become so powerful in obstetrics that expectant parents in the United States typically know the gender of their offspring by 20 weeks of gestationabout the midpoint of a typical pregnancy.

Now scientists are finding many more advanced applications of sound in medicine. Acoustical energy can be focused and used for imaging and treating a variety of ailments, including cancer, stroke, and Parkinsons disease. Sound waves can be focused deep inside the body to control hemorrhages, they can assist doctors in delivering drugs to specific areas in tissues, and they can disrupt adverse bacterial biofilms.

Many of these applications will be discussed in presentations at the 154th meeting of the Acoustical Society of America (ASA), which takes place from Tuesday, Nov. 27 to Friday, Nov. 30 in New Orleans. Some highlights:

1) THERAPEUTIC ULTRASOUND FOR DRUG DELIVERY AND HEMORRHAGE CONTROL

Just as a magnifying glass can focus light on a point, a concave transducer can focus acoustical waves onto a small spot of intense energy about the size of a grain of rice. Such a high-intensity acoustical focus can be aimed almost anywhere in the body, even through the skin and into deep tissue (with some exceptions). The ability to penetrate deep within the body makes therapeutic ultrasound attractive for a variety of medical applications.

Vesna Zderic (zderic@gwu.edu) at George Washington University, Shahram Vaezy at the University of Washington, and their colleagues are exploring the use of high-intensity focused ultrasound to control bleeding. In this application, acoustical energy can be absorbed as heat by the tissue, which cauterizes the wound. The blood coagulates due to heating and also possibl
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