Flashcards in Lesson 6 Deck (24)

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1

## What allows attenuation to occur? (3)

###
1. Absorption

2. Reflecting

3. Scattering

2

## What is absorption?

### The transfer of sound to heat

3

## What makes up an image? (2)

###
1. Reflecting

2. Scattering

4

## What does 0dB mean?

### You cant hear anything

5

## What happens as decibels get higher?

### It gets louder

6

## What does 3dB mean?

### 2x

7

## What does 10dB mean?

### 10x

8

## What is the unit for attenuation?

###
Decibels

- dB

9

## What do decibels describe?

### The relationship between various measured sound levels

10

## What is the formula for attenuation?

###
a = ac x L

a = attenuation

ac = attenuation coefficient

L = length traveled

11

## Attenuation coefficient

### Attenuation that occurs with each cm the sound travels

12

## What is the unit for attenuation coefficient?

### dB/cm

13

## What is attenuation depend on? (3)

###
1. Type of tissue

2. Length/distance of travel

3. Frequency

14

## What does it mean when your image is more fuzzy?

### Less sound is traveling through

15

## How much sound goes through bone?

### None

16

## What structures have high attenuation? (4)

###
1. Bone

2. Stomach

3. Lungs

4. Fatty liver

17

## What structures have low attenuation? (2)

###
1. Normal liver

2. Bladder

18

## What is ac in soft tissues?

###
Half of the frequency

- 0.5 x freq. x length

19

## What happens to attenuation if frequency increases?

### It increases

20

## What happens to attenuation if distance increases?

### It increases

21

## What are 5 forms of energy?

###
1. Heat

2. Light

3. X-rays

4. Microwaves

5. Mechanical motion

22

## What happens to attenuation if the coefficient increases?

### It increases

23

## What happens to penetration if frequency increases?

### It decreases

24