Term
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Definition
| High frequency ________ scattering. |
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Term
1)air
2)bone
3)lung
4)soft tissue
5)water |
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Definition
Arrange in order from most to least attenuation:
soft tissue, air, lung, water, bone |
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Term
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Definition
| decrease in intensity, power, and amplitude as sound propagates through a medium |
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Term
reflection
scattering
absorption |
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Definition
| 3 processes that contribute to attenuation |
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Term
oblique incidence
different propagation speeds |
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Definition
| What is necessary for refraction? |
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Term
| attenuation coefficient(dB/cm) = frequency(MHz)/2 |
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Definition
| equation for attenuation coefficient |
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Term
1)smooth boundary 90˚ to sound source
2)boundaries with irregularities larger than the wavelength
yes |
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Definition
When does specular reflection occur?
Is it organized? |
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Term
|
Definition
| When frequency increases, attenuation _______. |
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Term
directly related to frequency
unrelated to path length |
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Definition
| Attenuation coefficient is _______ related to frequency and ________ to path length. |
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Term
temporal average equals temporal peak
SPTP=SPTA;SATP=SATA |
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Definition
In continuous waves _______ average equals temporal ________.
So _______=_______, and ________=________. |
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Term
| PRP(µs) = imaging depth(cm) x 13µs/cm |
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Definition
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Term
| distance of reflector(mm) = 1.54mm/µs x go-return time(µs) / 2 |
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Definition
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Term
| total attenuation(-dB) = path length(cm) x attenuation coefficient(dB/cm) |
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Definition
| equation for total attenuation |
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Term
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Definition
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Term
-10dB = 1/10 initial strength
-20dB = 1/100 initial strength (initial x 1/10 x 1/10) |
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Definition
| -10dB rule for negative numbers |
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Term
-3dB = 1/2 initial strength
-6dB = 1/4 initial strength (initial x 1/2 x 1/2) |
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Definition
| -3dB rule for negative numbers |
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Term
peak
average
spatial
temporal
pulsed |
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Definition
| 5 key words used to describe intensity |
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Term
boundaries that have irregularities approximately the same size as the wavelength
no |
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Definition
When does diffuse reflection occur?
Is it organized? |
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Term
PRP and depth = directly
PRF and depth = indirectly |
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Definition
PRP and depth are ______ related.
PRF and depth are ______ related. |
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Term
| Z(rayls) = density(kg/m^3) x propagation speed(m/s) |
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Definition
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Term
IRC(%) = [(Zˇ2-Zˇ1)/(Zˇ2+Zˇ1)]^2 x 100
ITC(%) = 100% - IRC |
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Definition
| equations for IRC and ITC |
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Term
| May or may not occur; if they do, the angle of reflection equals the angle of incidence. |
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Definition
| What happens with reflection and transmission with oblique incidences? |
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Term
"PORN 90"
Perpendicular
Orthagonal
Right angle
Normal
90˚ |
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Definition
| Other names for normal incidence |
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Term
|
Definition
| largest component of attenuation |
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Term
| SPTP, SPPA, SPTA, SATP, SAPA, SATA |
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Definition
| Rank the 6 types of intensities from largest to smallest |
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Term
frequency and path length
directly |
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Definition
| Attenuation is determined by ______ and ______. It is ______ related to both. |
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Term
boundaries that are similar to or smaller than the wavelength
no
lung |
|
Definition
When does scatter occur?
Is it organized?
Example of scatterer? |
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Term
| difference in impedances of the two media |
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Definition
| What is necessary for reflection with normal incidence? |
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Term
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Definition
| _____ limits maximum imaging depth. |
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Term
10dB = 10x bigger
20dB = 100x bigger (10 x 10) |
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Definition
| 10dB rule for positive numbers |
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Term
|
Definition
| When frequency doubles, Rayleigh scattering is _____ times _______. |
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Term
3dB = 2x bigger
6dB = 4x bigger (2 x 2)
9dB = 8x bigger (2 x 2 x 2) |
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Definition
| 3dB rule for positive numbers |
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Term
| power, intensity, and amplitude |
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Definition
| What parameters are likely to have units of dB? |
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Term
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Definition
| _______ is the type of intensity especially important when studying bioeffects. |
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Term
| every 13µs signifies 1cm of depth |
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Definition
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Term
| incident intensity(W/cm^2) = reflected + transmitted intensities |
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Definition
| equation for incident intensity |
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Term
|
Definition
| Time-of-flight and depth are ______ related. |
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Term
sin(transmission angle)/sin(incident angle) = speed of medium 2/speed of medium 1
If speed of medium 2 is less than medium 1, the angle of transmission will be less than the angle of incidence; if medium 2 is greater, the transmission angle will be greater. |
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Definition
What is Snell's Law?
What does it mean? |
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Term
soft tissue 1%
bone-tissue 50%
air-tissue 99% |
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Definition
| IRC is ____% at soft tissue boundary, ____% at a bone-tissue boundary, and ______% at an air-tissue boundary. |
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Term
reflector is much smaller than the wavelength
yes
red blood cell |
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Definition
When does Rayleigh scatter occur?
Is it organized?
Example of a Rayleigh scatterer? |
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