Intro Quiz 2 System Components Flashcards Preview

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Flashcards in Intro Quiz 2 System Components Deck (44):
1

Knobology

basicas are interchangable between manufactureres

reduces scan time in a clinical setting

know your controls

2

Acoustic power/transmit power

varies energy transmitted to patient

should be used at lowest level

ALARA limit

higher power=brighter image

3

transmit power controls

operator controlled

determines electrical voltage to pulsar

low voltage=gentle PZT vibration

high voltage=forceful vibration

4

Pulsar

creates electrical signals that excite the PZT crystals

only functions during transmission

operator controlled

0-500 volts

important in Bioeffects

5

Pulsar voltage

0-500 volts

high =brighter image

also called output gain, accoustic power, energy output or transmitter output

6

Pulsar Standardization

Thermal Index

Mechanical Index

7

Noise

random and persistant degradation

unwanted low level echoes

 

8

Signal to Noise ratio

power increase raises ratio

quiality improves with increase

9

pulser repitition

determines time between voltage spikes

PRP Pulse repition Period

controlled by operator

 

10

Pulse Repitition Period

PRP

determines depth of scan

operator controlled

11

Pulser single pulse

continuous wave

vascular

12

Pulser numerous pulses

pulsed wave

imaging

13

Shallow imaging 

shorter listening time

shorter PRP

higher PRF

14

Deeper imaging

longer listening time

longer PRP

lower PRF

15

Bean Former

recieves the electrical spike from pulser and distributes to the active elements in an array transducer

used advanced microprocessor tech to produce digital format

16

Beam Former Switch

proteects the electrical components in the reciever

 

17

Reciever

prepares information from returning echoes for display

5 functions

 

18

5 reciever functions

Amplification

Compensation

Compression

Demodulation

Reject

19

Amplification

first function

affects all signal quality

receiver gain

measured in dB

adjustable

Gain/Overall Gain knob

20

Gain Overall Gain

controls degree of echo amplification or brightness or image

too much can fill artifactual echoes into a fluid structure

too little can negate echo information

21

Compensation

creates and image of uniform brightness

known as TGC Time Gain Compensation

DGC Depth Gain COmpensation

sompensates for the sound wave as it weakens or attentuates

22

TGC

DGC

operator controlled

sliders on console

structures will be same brightness regardless of depth

23

Compression

3rd function

keeps image grayscale content with range of human eye (20 shades)

keeps electrical signal level within accuracy range

called log compression or dynamic range (DR) most common

dB

operator controlled

24

Decibels dB

relative term that compares on one signal to another

important in quantifying strenght of sound beams, electrical signal strenght and brightness of image

notatoin is logarithmic

 

25

Demodulation

4th function

two part process that changes electrical signals in reciever into a more suitable form for the CRt or monitor

rectifies and smooths electrical signal

NOT adjustable

no effect on image

26

Reject

5th function

controls whether low level signals will be displayed

low leve signasl can be diagnostic or noise

called threshhold or suppression

operator controlled

27

Amplification overview

Adjustable

all signals affected identically

entire image gets brighter or darker

28

Compensation Overview

Adjustable

signals treated differently bases on reflective depth

images will be uniformly bright from top to bottom

29

Compression Overview

Adjustable

Signals treated differently depending on strenght

changes grayscale mapping

30

Demodulatoin Overview

NOT adjustable

prepares electrical signals to be suitable for display

NO effect on image

31

Reject Overview

Adjustable

Only weak signbals affected

Strong signals remain unchanged

Weak echoes appear or are eliminated from image

32

CRT 

Monitor

Displays the information from returning echoes

2 user controls

brightness

contrast

33

Output Power

vs

Reciever Gain

patient exposure to sound energy is affected by output power NOT by reciever amplification

34

Output Power SUmmary

changes brightness of image

alters signal to noise ratio

alters patient exposure

bioeffect concerns

decrease this first if image too bright

35

Reciever Gain Summary

Changes brightness of entire image

does not affect signal to noise ratio

does not change patient exposure

NO bioeffect concern

increase this first if image is too dark

36

Persistance

frame averaging that allows echo information to be accumulated over time

 

37

Persistence Increase

subtle texture differences will be enhanced

38

Persistence Decrease

allows user to evaluate moving structures more easily

39

Zoom/Magnification

allows image magnification by increasing the pixal size

2 types

Read

Write

40

Read Zoom

occurs after the image is stored

number of pixals or scan lines is the same as original image

Can appear blurry 

41

Write Zoom

Occurs while active scanning

box is placed on screen and the area seen within can be expanded to fill screen

number of pixals and scan lines remain the same

image is not degraded

42

Calipers

Markers available to measure distance

linear

ellipsoid

trace

43

Annotation

allows the labeling of the image

may be keyboard or preprogrammed keys

may be voice activated

44

Dual image

allows the screen to be split in order to show 2 views of an image or compare anatomy of abnormal side to normal side