Intro Quiz 2 System Components

Question 1

Knobology

Answer 1

basicas are interchangable between manufactureres

reduces scan time in a clinical setting

know your controls

Question 2

Acoustic power/transmit power

Answer 2

varies energy transmitted to patient

should be used at lowest level

ALARA limit

higher power=brighter image

Question 3

transmit power controls

Answer 3

operator controlled

determines electrical voltage to pulsar

low voltage=gentle PZT vibration

high voltage=forceful vibration

Question 4

Pulsar

Answer 4

creates electrical signals that excite the PZT crystals

only functions during transmission

operator controlled

0-500 volts

important in Bioeffects

Question 5

Pulsar voltage

Answer 5

0-500 volts

high =brighter image

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

Question 6

Pulsar Standardization

Answer 6

Thermal Index

Mechanical Index

Question 7

Noise

Answer 7

random and persistant degradation

unwanted low level echoes

Question 8

Signal to Noise ratio

Answer 8

power increase raises ratio

quiality improves with increase

Question 9

pulser repitition

Answer 9

determines time between voltage spikes

PRP Pulse repition Period

controlled by operator

Question 10

Pulse Repitition Period

PRP

Answer 10

determines depth of scan

operator controlled

Question 11

Pulser single pulse

Answer 11

continuous wave

vascular

Question 12

Pulser numerous pulses

Answer 12

pulsed wave

imaging

Question 13

Shallow imaging

Answer 13

shorter listening time

shorter PRP

higher PRF

Question 14

Deeper imaging

Answer 14

longer listening time

longer PRP

lower PRF

Question 15

Bean Former

Answer 15

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

used advanced microprocessor tech to produce digital format

Question 16

Beam Former Switch

Answer 16

proteects the electrical components in the reciever

Question 17

Reciever

Answer 17

prepares information from returning echoes for display

5 functions

Question 18

5 reciever functions

Answer 18

Amplification

Compensation

Compression

Demodulation

Reject

Question 19

Amplification

Answer 19

first function

affects all signal quality

receiver gain

measured in dB

adjustable

Gain/Overall Gain knob

Question 20

Gain Overall Gain

Answer 20

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

Question 21

Compensation

Answer 21

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

Question 22

TGC

DGC

Answer 22

operator controlled

sliders on console

structures will be same brightness regardless of depth

Question 23

Compression

Answer 23

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

Question 24

Decibels dB

Answer 24

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

Question 25

Demodulation

Answer 25

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

Question 26

Reject

Answer 26

5th function controls whether low level signals will be displayed low leve signasl can be diagnostic or noise called threshhold or suppression operator controlled

Question 27

Amplification overview

Answer 27

Adjustable all signals affected identically entire image gets brighter or darker

Question 28

Compensation Overview

Answer 28

Adjustable signals treated differently bases on reflective depth images will be uniformly bright from top to bottom

Question 29

Compression Overview

Answer 29

Adjustable Signals treated differently depending on strenght changes grayscale mapping

Question 30

Demodulatoin Overview

Answer 30

NOT adjustable prepares electrical signals to be suitable for display NO effect on image

Question 31

Reject Overview

Answer 31

Adjustable Only weak signbals affected Strong signals remain unchanged Weak echoes appear or are eliminated from image

Question 32

CRT Monitor

Answer 32

Displays the information from returning echoes 2 user controls brightness contrast

Question 33

Output Power vs Reciever Gain

Answer 33

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

Question 34

Output Power SUmmary

Answer 34

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

Question 35

Reciever Gain Summary

Answer 35

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

Question 36

Persistance

Answer 36

frame averaging that allows echo information to be accumulated over time

Question 37

Persistence Increase

Answer 37

subtle texture differences will be enhanced

Question 38

Persistence Decrease

Answer 38

allows user to evaluate moving structures more easily

Question 39

Zoom/Magnification

Answer 39

allows image magnification by increasing the pixal size 2 types Read Write

Question 40

Read Zoom

Answer 40

occurs after the image is stored number of pixals or scan lines is the same as original image Can appear blurry

Question 41

Write Zoom

Answer 41

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

Question 42

Calipers

Answer 42

Markers available to measure distance linear ellipsoid trace

Question 43

Annotation

Answer 43

allows the labeling of the image may be keyboard or preprogrammed keys may be voice activated

Question 44

Dual image

Answer 44

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