display/ QA

Question 1

what does cathode ray tube (CRT) contain?

Answer 1

• a phosphor-coated florescent screen

- electron beam generator

Question 2

how does a Cathode ray tube work?

Answer 2

• electorns which strike the inside of the screen will cause the pixels at that spot to temporarily light up

Question 3

CRT- the brighness of the dot on the screen = ?

Answer 3

strength of the electron beam

Question 4

The CRT will generate electron beams that will ‘sweep’ the inner surface of the screen and cause lines to appear on the screen. This is called?

Answer 4

raster scanning

Question 5

raster scanning involves how many horizontal lines?

Answer 5

525 horizontal lines

• grouped into odd and even fields (262.5 line/field)

Question 6

what is twin interlacing?

Answer 6

In a given moment, one field is constructed; in the next moment, the other is constructed

Question 7

in raster scanning how many images/second?

Answer 7

30 images/second

Question 8

what is refresh rate?

Answer 8

how many images are shown on the screen per second

Question 9

what is frame rate?

Answer 9

how quickly frames are built

• number of images entered into the image memory per second

Question 10

refresh rate limits?

Answer 10

frame rate

Question 11

instruments- display?

Answer 11

Frame rate  Image Memory  Refresh rate

Question 12

colour display involves?

Answer 12

• 3 cathode ray tubes

- 1 per colour

Question 13

flat panel display (LCD)?

Answer 13

• Liquid panel display

- matrix of photo-electric elements

Question 14

Amplitude of voltage will decide?

Answer 14

luminance (brightness of element)

Question 15

refresh rate on a typical LCD?

Answer 15

60 Hz

Question 16

LCD advantages over CRT?

Answer 16

• display is much lighter and thinner
• good image quality, brighter image
• reduced eyestrain
• perform well in range of ambient light environments
• lower power consumptions and energy emissions

Question 17

flat panel display (plasma)?

Answer 17

• electrical charge ionizes gas producing UV light
• UV light hits a phosphor coated screen which will glow
• 85Hz

Question 18

flat panel display (organic LED)?

Answer 18

• latest and greatest, even thinner

- involves light emitting diode

Question 19

Information received at the display can be shown in many different ways (3)?

Answer 19

• B-mode
• M-mode
• A-mode

Question 20

brightness mode AKA?

Answer 20

• greyscale
• 2D
• suggests the brightness of each reflector at each anatomical position

Question 21

M-mode?

Answer 21

• motion mode
• cardiac structures
• displays info from a single scan line- beam is stationary
• amplitude at each depth represents brightness of reflector

Question 22

M-mode Y and X axis?

Answer 22

y-axis: depth

x-axis: time

Question 23

in M-mode stationary areas show as?

Answer 23

straight lines

• moving areas show as wiggly lines

Question 24

what is A-mode?

Answer 24

• amplitude mode

- displays info from a single scan line- beam is stationary

Question 25

A-mode y and x axis?

Answer 25

y-axis: amplitude (brightness) | x-axis: depth

Question 26

A-mode is mainly used in what kind of imaging?

Answer 26

opthalmic imaging

Question 27

what is RAM?

Answer 27

- random access memory - information storage - temporary, very quick to access - info lost when machine is turned off

Question 28

'image memory’ within the image processor uses?

Answer 28

RAM

Question 29

ROM?

Answer 29

- rean only memory - permanent info in storage - will remain even if machine is turned off

Question 30

Programmable ROM- PROM?

Answer 30

- permanent information in storage - can still be accessed, adjusted, erased - will remain even is machine is turned off

Question 31

Where might the images we take and store fall under?

Answer 31

PROM

Question 32

HIS – Hospital Information System?

Answer 32

An integrated information system designed to manage the administrative, financial and clinical aspects of a hospital Everything involved in running a hospital (including paper and digital systems)

Question 33

RIS – Radiology Information System?

Answer 33

- built to manage workflow in radiology - Patient scheduling, intake, worklist generation, medical reporting, transcription, and report management - a part of the HIS

Question 34

PACS – Picture Archiving and Communication System

Answer 34

Storage, retrieval and distribution of images

Question 35

2 main types of testing- quality assurance?

Answer 35

1- operational QA 2. acoustic output

Question 36

what is operational quality assurance?

Answer 36

- anatomical imaging/measurements | - doppler evaluation

Question 37

what is acoustic output?

Answer 37

- beam former/transducer | - related to bioeffects

Question 38

operational QA examples?

Answer 38

- tissue equivalent phantom | - test object

Question 39

acoustic output?

Answer 39

hydrophone

Question 40

what is TEP – tissue equivalent phantoms?

Answer 40

- AKA tissue mimicking phantom (TM) - mimics soft tissue characteristics - we scan along the top

Question 41

TEP- tissue equivalent phantoms?

Answer 41

- graphite- filled aqueous gels - urethane rubber - nylon strings used to demarcate echogenic points

Question 42

Graphite-filled aqueous gels?

Answer 42

1.54 mm/μs

Question 43

urethane rubber?

Answer 43

1.45 mm/μs

Question 44

TEP function?

Answer 44

- come with blue prints - compare measurements on screen to blueprints - check accuracy of axial and lateral resolution

Question 45

TEP mimics?

Answer 45

- cysts | - solids

Question 46

Hydrophone?

Answer 46

- aka microprobe - Small transducer element on a long hollow needle (<1mm diameter) - Point transducer at hydrophone, hydrophone picks up pressure wave, converts to a voltage

Question 47

Polyvinylidene Fluoride Membrane (PVDF)

Answer 47

Point transducer at PVDF membrane, picks up pressure wave, converts to a voltage

Question 48

Oscilloscope readings can be used to calculate?

Answer 48

T, PD, PRP, DF | f, λ, SPL

Question 49

Spectrum analyzer?

Answer 49

connected to oscilloscope: able to break down incoming bandwidth to individual frequencies

Question 50

oscilloscape readings can calculate?

Answer 50

amplitude based on peasks of the signal

Question 51

Calorimeter

Answer 51

Measures tiny, tiny changes in temperature Involves a sensitive thermometer Relates the change in temperature to the output power/intensity