Ch 14 Flashcards Preview

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Flashcards in Ch 14 Deck (29):
1

Transducer

Converts electrical to acoustic energy (transmission) Converts acoustic to electrical energy (reception)

2

Master Synchronizer

Communicates organizes and times the functions

3

Pulser

determines the amplitude, PRP, and PRF occurs during transmission creates and controls electrical signal sent to transducer

4

Beam Former

determines the firing, delay patterns for phased array system

5

Receiver

transform electrical signals from the transducer into a form suitable for display

6

Display

Monitor

7

Storage

archives the ultrasound studies storage devices include: computer hard drives, CD, DVD, videotape, magneto-optical discs, paper printouts, photographs, and USB

8

Transducer output

effects entire image use during transmission can cause exposure/ bioeffects Adjustable

9

Transducer Synonyms

output gain, acoustic power, pulser power, energy output, transmitter output, power or gain

10

Noise

random and persistent disturbance that obscures or reduces a signal's clarity

11

Signal to Noise when high

signal is much stronger than the noise and the image is a high quality

12

Signal to Noise when low

degrades image strength is closer to strength of the noise

13

Signal to Noise

comparison of the meaningful info (signal) to the amount of contamination (noise)

14

increase output power, signal to noise ratio ______.

increase

15

PRP and PRF are what related

inversely

16

Is PRP adjustable

Yes

17

Shallow Imaging listening time PRP PRF

shorter listening time shorter PRP higher PRF

18

Deep Imaging listening time PRP PRF

longer listening time longer PRP lower PRF

19

Apodization

adjust electrical spikes voltage to reduce love artifacts

20

Order of Receiver Operations

1. Amplification 2. Compensation 3. Compression 4. Demodulation 5. Reject

21

Amplification adjustable? singals processed Effects on image

adjustable all signals trated identically entire image gets brighter or darker

22

Compensation adjustable? singals processed Effects on image

adjustble signals treated differently based on reflector depth image will be uniformly bright from top to bottom

23

Compression adjustable? singals processed Effects on image

adjustable signals treated differently depending on strength changes gray scale mapping

24

Demodulation adjustable? singals processed Effects on image

not adjustable prepares electrical signals to be suitable for display none

25

Reject adjustable? singals processed Effects on image

adjustable only weak signals affects; strong signals remain unchanged weal echoes appear or are eliminated from image

26

Dynamic Frequency Tuning

uses damping material to create short pulses, which provides better axial resolution use only high frequencies

27

ALARA

As Low As Reasonably Achievable minimizes the patients ultrasound exposure

28

Output Power vs Receiver Gain Output Power

changes brightness of entire image alters signal to noise ratio alters patient exposure bioeffect concerns decrease this first if image is too bright

29

Output Power vs Receiver Gain Receiver Gain

changes brightness of entire image doesn't affect signal to noise ratio doesn't change patient exposure no bio effect concern increase this first if image is too dark