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Flashcards in Digital Radiography Deck (25):
1

what is digital radiography?

The map of x ray transmission through patient is converted to a digital file

2

what determines the shade of the pixal in digital radiography?

x ray intensity

lots of radiation=black, not a lot of radiation= white, intermediate=grey

3

T/F A digital radiograph is composed of many small pixels, each with an assigned shade of gray

true

4

what format are the digital images converted to?

DICOM

(digital imaging communications in medicine) 

5

what does CR stand for?

computed radiography 

image plate in cassette-like housing 

6

what does DDR stand for?

direct digital radiography 

flat panel detector

7

what does cassettes contain in CR?

imaging plate, not film!

cassettes must be processed in plate reader, images better than film

8

properties of DDR

no cassette to process 

no plate reader 

image available immediately 

9

what are the 2 types of flat panel DDR?

 

indirect digital detector and direct digital detector 

10

What type of flat panel DDR is represented here?

indirect: light intermediary 

11

what type of flat panel DDR is represented here?

drect: no light intermediary 

 

12

T/F direct is theorectically better but practically there is no detectable difference 

true 

13

properties of flat panel digital radiography (DR)

No cassettes

Immediately after exposure, image is viewable and ready to QC

Excellent quality image

Image plate is portable but subject to damage

14

what does the processing algorithm control?

Contrast 

15

T/F the image detail is better with digital radiograph 

False it's contrast resolution 

16

what are the advantages of digital 

Professional Image

No darkroom, film, envelopes

Post Processing

Consultation – teleradiology

Exposure Latitude

Contrast optimization

17

what is the exposure latitude

the extent to which a film, image plate or flat panel can be over or underexposed and still achieve an acceptable result.

18

T/F Exposure Latitude means that exposure factors are not important

False 

under/overexposure is still a problem 

19

what does a low exposure image have more of?

noise

 

20

what happens when the plate overexposure passes its limit?

the plate becomes saturated and anatomy disappears 

21

what has happened here

plate has been saturated, overexposure 

22

what is contrast optimization 

Application of additional processing ‘normalizes’ the image.

  • Dark regions are made lighter and lighter regions darker
  • = smooth ‘wide latitude’ radiograph

23

T/F exposure factors are lower with DR than with film-screen systems

False

proper exposure factors should be about the same 

exposures can creep up-don't recognize its happening and can create safety concerns 

24

what artifacts/technical problems can you still have with DR 

poor positioning 

poor radiation safety practices

insufficient views

wrong part radiographed 

25

What is PACS? 

Picture Archive and Communication System 

Host of technologies that contribute to: Image creation, Image distribution/viewing, Image archiving