The layer of material within the transducer which has an intermediate impedance
between the transducer element and the human tissue in known as the: -
️️matching layer
Huygen's Principle - ️️states that waves are the result of the interference of many
wavelets produced at the face of th...
SPI ULTRASOUND REGISTRY REVIEW
The layer of material within the transducer which has an intermediate impedance
between the transducer element and the human tissue in known as the: -
✔️✔️matching layer
Huygen's Principle - ✔️✔️states that waves are the result of the interference of many
wavelets produced at the face of the transducer
What happened to intensity if the amplitude of a signal is halve? - ✔️✔️Quarted/
Intensity is proportional to the amplitude squared, so if the amplitude is halved, the
resulting intensity is one fourth the original intensity
With phased array transducers, the transmitted sound beam is steered by -
✔️✔️Varying the timing of pulses to the individual piezoelectric elements
What type of wave is sound? - ✔️✔️mechanical and longitudinal
The Frequency ranges for Ultrasound are: - ✔️✔️> 20,000 Hz (20kHz)
The speed of sound in soft tissue is: - ✔️✔️1540 m/s
Linear sequence Array - ✔️✔️transducer that fires the elements in groups
Unit for Wavelength - ✔️✔️is millimeters
Enhancement is caused by - ✔️✔️weakly attenuating structures (such as a cyst)
The wavelength in a material having a propagation speed of 1.5 mm/us employing a
transducer frequency of 5.0 MHz is: - ✔️✔️0.3 mm Wavelength= c/f = 1.5mm/us ÷
5MHz = 0.3mm
An ultrasound transducer converts: - ✔️✔️electrical energy into mechanical energy and
vice versa
The order of attenuation, from the lowest attenuation to highest: - ✔️✔️fat, muscle,
bone, air
Propagation Speed from the lowest to highest: - ✔️✔️air, fat, muscle, bone
, If the frequency doubled, what to wavelength? - ✔️✔️Decrease by one half/ Frequency
and wavelength are inversely related
Duty factor - ✔️✔️is the percentage of the time the sound is being transmitted
A 3dB gain would indicated in intensity by: - ✔️✔️2 times (A gain of 3dB results in
doubling of intensity (or power))
SPL - ✔️✔️wavelength x # of cycles
Ignoring the effects of attenuation, the intensity of ultrasound beam is usually greater at
the focal zone because of: - ✔️✔️The smaller beam diameter (Intensity equals power
divided by area. The area is smallest in the focal zone; therefore, the intensity is
highest)
Attenuation denotes: - ✔️✔️is the weakening of the strength of the beam, typically from
absorption, reflection, or scattering
SATA - ✔️✔️is the lowest of the intensities
Beam Uniformity Ratio - ✔️✔️BUR= SP/SA
Continuous Wave Doppler has a duty factor of: - ✔️✔️100%
SPL - ✔️✔️The spatial pulse length is defined as the product of the wavelength and the
number of cycles in a pulse (SPL= wavelength time the number of cycles in the pulse)
SPTP - ✔️✔️highest intensity
The unit for impedance is ________. - ✔️✔️Rayl
ALARA stands for - ✔️✔️As Low As Reasonably Achievable
Snell's law describes: - ✔️✔️refraction at an interface
Matching Layer - ✔️✔️Has an impedance between skin and the active element so
more sound energy is transmitted between the crystal and skin
spatial resolution - ✔️✔️is the ability to discern two closely reflectors as individual
reflectors
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