Formulas Ch. 6,7,8

Question 1

Rayleigh Scattering

Answer 1

Rayleigh scattering (infinity) frequency ^4

Question 2

Total attenuation

Answer 2

Total attenuation (dB) = atten. coefficient (dB/cm) x distance (cm)

Question 3

Attenuation Coefficient in Soft Tissue

Answer 3

Atten. coef. (dB/cm) = frequency (MHz) / 2

Atten. coef. = 0.5 dB/ cm/ MHz

Question 4

Impedance

Answer 4

Impedance (rayls) = density (kg/m^3) x prop. speed (m/s)

Question 5

Incident intensity

Answer 5

incident (starting) intensity = reflected intensity + transmitted intensity

Question 6

Intensity Transmission Coefficient (ITC)

Answer 6

100% = inten. reflection coef. (IRC) (%) + intensity trans. coef. (ITC) (%)

ITC = transmitted intensity / incident intensity x 100

Question 7

Reflection with normal incidence

Answer 7

IRC (%) = [ z^2 - z^1 / z^2 + z^1] x 100

IRC + ITC = 100%

Question 8

The law of conservation of energy

Answer 8

100% = reflection coefficient + transmission coefficient

Question 9

Incident intensity

Answer 9

Incident intensity (W/cm^2) = reflected intensity + transmitted intensity

Question 10

Reflection angle = Incident angle

Answer 10

Angle of incidence = angle of reflection

Question 11

Snell’s law

Answer 11

sin (transmission angle) / sin (incident angle) = speed of medium 2 / speed of medium 1

Question 12

Th depth of reflector

Answer 12

Depth (mm) = 1.54 mm/ us x go-return time (us) / 2

Question 13

Pulse repetition period

Answer 13

PRP (us) = imagining depth (cm) x 12 us/cm

Question 14

Pulse repetition frequency

Answer 14

PRF (Hz) = 77,000 cm/s / imaging depth (cm)

Question 15

Low quality factor

Answer 15

Quality factor = main frequency / bandwidth

Question 16

Frequency of pulsed wave imaging transducers

Answer 16

frequency (MHz) = sound’s speed in PZT (mm/us) / 2 x thickness (mm)