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physics

frequency, wavelength, propagation Speed

QuestionAnswer
axial resolution the ability of an ultrasound transducer to distinguish two closely spaced structures separately that lie parallel to the direction of sound travel. Axial resolution is equal to spatial pulse length divided by two.
beam divergence the increase in width of a sound wave as it travels beyond the focal point. Transducer diameter, frequency and focusing affect beam divergencce
lateral resolution the ability of an ultrasound transducer to resolve two closely spaced structures that lie perpendicular to the sound beam
near zone the area of the sound beam that extends from the face of the transducer to the focal point
period the time it takes for a single cycle to occur
pulse a collection of cycles. usually 2 to 5 cycles make up one pulse in clinical imaging ultrasound
pulse duration the time of a single pulse
resolution the ability to separate two closely spaced structures.
spatial pulse length the length of a single pulse
ultrasound transducer a piezoelectric crystal that is able to convert electrical energy into sound energy and vice versa
f frequency
Hertz (Hz) 1 cycle per sec
kilohertz (kHz) 1000 cycles per second
MegaHertz (MHz) 1,000,000 cycles per second
infrasound less than 20 Hz
Audible sound 20 Hz to 20,000 Hz (20 kHz)
clinical imaging 2MHz to 10 MHz
frequency the number of wave cycles per second is
One compression and one rarefaction occurring in one second represent 1 hertz
the frequency range for infrasound less than 20 Hz
the frequency range closest to the lower limit of ultrasound is 20 kHz
the frequency range for clinical ultrasound imaging is 20 to 10 MHz
frequency is determined by the source
frequency decreases, depth of penetration increases
frequency increases, depth of penetration decreases
frequency increases resolution improves
frequency decreases resolution degrades
increasing frequency decreases wavelength, decreases spatial pulse length, decreases period, degrades resolution
increase the frequency does not improve depth of penetration
Created by: t4achange