Frequency Used in Ultrasonic Imaging
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| Bibliographic Entry | Result (w/surrounding text) |
Standardized Result |
|---|---|---|
| Cutnell, Johnson. Physics, 3rd Edition. New York: Wiley, 1995. | "high frequencies in the range from 1 to 15 MHz are the norm, so the wavelengths are small." | 1–15 MHz |
| World Book Encyclopedia. Chicago: World Book, 1995. | "Ultrasound is sound waves with a frequency over 20,000 Hz." | > 0.02 MHz |
| Samuels, Mike. The New Well Pregnancy Book. New York: Farside, 1996. | "In medical ultrasound a sound wave of 2 million cycles per second is produced." | 2.0 MHz |
| Joseph C. Segen. The Patient's Guide to Medical Tests. New York: Facts On File, 1998. | "Electricity applied to a crystal in a transducer causes a high frequency (2.25–5.0 MHz) mechanical vibration." | 2.25–5.0 MHz |
| Ultrasound Transducers. Department of Electrical Measurements. Lunds Tekniska Högskola. | "Ultrasound frequency: 200 KHz–15 MHz (in water/tissue)." | 0.2–15 MHz |
Ultrasonic waves are used in medicine in many diagnostic procedures. These waves are produced by a rapidly oscillating crystal, and are inaudible to humans. They are directed toward a patient's body and are then reflected when they reach the boundaries between tissues of different densities. These reflected waves are detected as echoes by the transducer and displayed on a monitor. Using ultrasonic waves doctors can obtain sonograms of their patient's inner anatomy. Ultrasound can also be used to detect malignancies and hemorrhaging in various organs. It is also used to monitor real-time movement of heart valves and large blood vessels. Air, bone, and other calcified tissues absorb most of the ultrasound beam; therefore this technique cannot be used to examine the bones or the lungs.
Boris Zolotaryov -- 1999
| Bibliographic Entry | Result (w/surrounding text) |
Standardized Result |
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| ter Haar, Gail. "Acoustic Surgery." Physics Today. December 2001: 31. |
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1–20 MHz |
Editor's Supplement -- 2001