Basics, Sound & Waves
What is the standard speed of sound in soft tissue?
1540cm/sec
is the formula describing ___________
Intensity
The Range equation calculates what?
The depth of the reflection.
The ability of distinguish structures along the path of the sound beam.
Axial Resolution
What is another name for the Far field?
Fraunhofer Zone.
Sound is classified as what type of wave in ultrasound
Longitudinal Wave
What does SPPA stand for?
Spatial Peak Pulse Average
What is the depth of a reflections if it has a go-return time of 65 microseconds?
5 cm
Focusing improves which type of resolution
Lateral Resolution.
This part of the transducer is used to minimize reflection at the transducer-skin interface
Matching Layer
Parameter that describes number of cycles per second.
Frequency
Acoustic Impedance (Z) is calculated by:
Density x Speed of sound
This part of the transducer is used to dampen the pulse (Shorten spatial pulse length)
The backing material
LAARD represents what type of resolution
Axial
If the impedance mismatch btw 2 tissues is LARGE, what occurs with the reflection
Strong reflection
What has the GREATEST influence on propagation speed in a medium?
Stiffness
A change in sound wave direction btw media at an oblique angle is called:
Refraction
What occurs when the transducers is heated above the Curie point
Depolarization
What the relationship btw SPL and axial resolution?
Inversely proportional
What type of scattering occurs when a structure is SMALLER than the wavelength?
Rayleigh Scattering
The measurement of the difference between max/min and average values is
Amplitude
The main contributor to ultrasound attenuation in tissue.
Absorption
Power is proportional to _________2
Amplitude
Beam Diameter is the primary determinant of this type of resolution at the focal point.
Lateral resolution
In Biostatics, a person without disease who tests negative is an exam of which parameter?
True Negative