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6720 Lecture 9_ultrasound imaging

6720 Lecture 9_ultrasound imaging - Lecture IX 1 2 3 4...

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1 PHYS 6720 - Lecture IX 1 Lecture IX Ultrasound Imaging 1. Introduction 2. Acoustic waves 3. Acoustic detection 4. Ultrasound and Doppler imaging PHYS 6720 - Lecture IX 2 IX-1 Introduction Historical development In 1870s, Francis Galton in England invented an ultrasound whistle to test the upper threshold frequency of human and animals and reported that the limit decreases as man ages In 1880s, French physicists Pierre Curie and Jacques Curie observed the piezoelectric phenomenon of quartz crystal and other materials that laid foundation for ultrasound transducers In 1920s and 30s, Sergei Y. Sokolov of Soviet Union, among others, reported detection of flaws metal objects with ultrasonic waves, first through transmission mode and later suggested improvement with a higher frequency (~3MHz) and a reflection mode In 1945 and later, F.A. Firestone of University of Michigan filed several patents for flaw detection using a “supersonic reflectoscope” 3 IX-1 Introduction Historical development In 1941 and right after WWII, K.T. Dussik of Austria published a paper on medical use of ultrasound imaging (“On the possibility of using ultrasound waves as a diagnostic aid”) and experimental results with quartz transducers in transmission mode T1 - ultrasonic generator, Q1- transmitter, Q2 - receiver, T2 - converter amplifier, W – water bath, L - light, P - photographic/ heat-sensitive paper http://www.ob-ultrasound.net/dussikbio.html PHYS 6720 - Lecture IX 4 IX-1 Introduction Historical development After the rapid development of radar technology through WWII, several research groups in Japan, U.S. and Europe have pursued ultrasound detection equipment and ultrasound imaging devices In 1958, Ian Donald published the first OBGY clinical paper on using pulse-echo technique in A and B-mode to diagnose a huge, easily removable, ovarian cyst in a woman who had been diagnosed as having inoperable cancer of the stomach Wide applications of ultrasound in medical diagnosis started in 1960s in obstetrics and gynecology and other specialties when commercial equipment became available The "First World Congress on Ultrasonic Diagnostics in Medicine" was held in Vienna in 1969 PHYS 6720 - Lecture IX 5 IX-1 Introduction Historical development Publications on ultrasound imaging in OBGY increased from 1 in 1958 to 296 in 1978 PHYS 6720 - Lecture IX 6 IX-1 Introduction Advantage of ultrasound and Doppler imaging No ionization radiation Safety concerns include tissue temperature rise at low intensity and additional shock-wave generation under high-frequency and short- pulse (<~ns) conditions So for diagnostic applications with low intensity and long-pulse (>~ μ s), ultrasound can be used in regular clinics by non-specialist physicians (do need training) Fast signal acquisition: real-time imaging Low-cost: an ultrasound imager costs between $30k and $100k
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