28. Ultrasound Flashcards
1
Q
Threshold of hearing (dB)
A
4dB
2
Q
Normal speech (dB)
A
60dB
3
Q
Pain threshold (dB)
A
120-140dB
4
Q
Acoustic frequency range
A
20-20kHz
5
Q
Ultrasonic frequency range
A
20k-2M Hz
6
Q
Acoustic impedance formula
A
Z = c * rho = p/v
c : speed of sound
rho : density of the medium
7
Q
attenuation coefficient unit
A
dB/[Mhz * cm]
8
Q
speed of ultrasound formula
A
c = sqrt (1/(rho*k))
k : compressibility (relative volume decrease / pressure)
9
Q
attenuation coefficient formula
A
alpha = 20 * log (e) * mu
10
Q
Speed of propagation in soft tissues and water
A
1540m/s
