Lecture 6

Question 1

Amplitude

Answer 1

Maximum variation in pressure (or other acoustic variable)

Question 2

If intensity is proportional to amp square then so is

Answer 2

Power

Question 3

Amplitude and intensity indicate

Answer 3

Strength of the sound

Question 4

Attenuation

Answer 4

As sound travels through tissue it gets weaker

Question 5

What happens with intensity and amplitude as sound attenuates

Answer 5

They decrease

Question 6

Weaker sound beam =

Answer 6

Weaker echo

Question 7

In attenuation absorption what is sound turned into

Answer 7

Heat

Question 8

Unit of attenuation

Answer 8

dB (decibels)

Question 9

2 ratios of 2 intensities (decibels to X)

Answer 9

3db = 2x

10 db = 10x

Question 10

6 dB = _____% reduction in intesnity

Answer 10

75%

Or 4x reduction

Question 11

10 dB = _____% reduction in intensity

Answer 11

90% or 10x

Question 12

To break down dB into component it is

Answer 12

Addition

Question 13

To break down multiples it is

Answer 13

Multiplication

Question 14

Because the intesity is dropping we can use a _____ on the answer

Answer 14

Negative sign

Question 15

Attenuation coefficient

Answer 15

Attenuation that occurs with each cm the sound travels

Question 16

Attenuation is based on

Answer 16

Type of tissue
Length/distance travel
Frequency

Question 17

The Ac of bone

Answer 17

6-9, heavy attenuation

Question 18

Water Ac

Answer 18

0.0022 - weak attenuation

Question 19

What happens to attenuation if frequency is increased

Answer 19

It increases

Question 20

Frequency affects the _____

Answer 20

Penetration

Question 21

If we want to see a deep structure we have to turn the freq _____

Answer 21

Down

Question 22

The longer the distance the ____ the attenuation

Answer 22

More

Question 23

Deeper tissue will have ____ intense echoes

Answer 23

Less

Question 24

Attenuation is ______ in bone than soft tissue

Answer 24

Higher

Question 25

Attenuation _________ imaging depth

Answer 25

Limits