Deck 21: Digital Radiographic Artifacts

Question 1

The size and number of digital images has to be compressed to permit _____.

A) transmitting
B) archiving
C) viewing
D) both A and B

Answer 1

both A and B

Question 2

Cassettes used in computed radiography are more highly sensitive to background and scatter radiation than film/screen cassettes are.

Answer 2

True

Question 3

Artifacts are an acceptable part of digital imaging.

Answer 3

False

Question 4

Object artifacts in digital imaging can occur from errors in _____.
I. x-ray beam collimation
II. histogram selection
III. patient positioning

A) I only
B) II only
C) I and II
D) I, II and III

Question 5

Computer aided diagnoses (CAD)requires the use of _____.

A) uncompressed images
B) lossy compression
C) lossless compression
D) either B or C

Question 6

Backscatter radiation artifacts can occur more readily in digital imaging because of the _____.

A) large data file sizes
B) techniques used
C) highly sensitive receptors
D) partitioning errors

Question 7

Which is/are done to the image during preprocessing?
I. Lossless compression
II. Partitioning
III. Flatfielding

A) I only
B) II only
C) III only
D) I and II

Question 8

It is a safe practice to keep CR cassettes in a "radiation safe" area of an x-ray suite during exams.

Question 9

What size is the average CR or DR image file?

A) 10 KB
B) 100 KB
C) 20 MB
D) 200 MB

Question 10

A ghost image can occur in digital imaging because of _____.

A) supernatural phenomena
B) image blur
C) incomplete erasure
D) backscatter

Question 11

_____ is done during preprocessing to correct for an irregular pattern over the image.

A) Lossy compression
B) Signal erasure
C) Partitioning
D) Flatfielding

Question 12

Computed radiography cassettes can sit for _____ between exposures.

A) a few hours
B) a few days
C) up to one year
D) an unlimited time

Question 13

Lossless compression reduces data files _____.

A) 10:1
B) 50:1
C) 100:1
D) 1000:1

Question 14

The three classifications of digital imaging artifacts are _____.

A) processing, exposure, and handling/storage
B) processing, image receptor, and exposure
C) image receptor, software, and object
D) software, object, and exposure

Question 15

Lossy compression can be used for _____.

A) mammography
B) video recordings
C) chest radiographs
D) all of the above

Question 16

Lossy compression reduces data files _____.

A) 10:1
B) 50:1
C) 100:1
D) 1000:1

Question 17

During preprocessing the digital output of the image receptor may need to be manipulated to correct for _____.

A) dead pixels
B) image blur
C) ghost images
D) radiation fatigue

Question 18

The software correction that equalizes the response of each pixel to a uniform exposure of x-rays is called _____.

A) lossless compression
B) flatfielding
C) lossy compression
D) histogram selection

Question 19

Radiation fatigue occurs in _____.

A) film-screen radiography
B) CR digital image plates
C) DR digital image plates
D) all of the above

Question 20

Which modality produces the largest image files?

A) digital or computed radiography
B) computed tomography
C) nuclear medicine
D) digital mammography

Question 21

The largest standard size for a digital imaging plate is _____.

A) 11" * 14"
B) 14" * 17"
C) 35 cm * 35 cm
D) 35 cm * 43 cm

Question 22

Creating distinctly collimated margins on all 4 sides of a DR image is important in preventing _____ errors.

A) flatfielding
B) lossless compression
C) histogram analysis
D) archiving

Question 23

Each anatomical part has an image histogram with a(n)_____ shape.

A) identical
B) characteristic
C) S-curve
D) round

Question 24

Histogram selection is done _____.

A) automatically during each exposure
B) automatically during post-processing
C) by the radiographer before each exam
D) by the radiographer during post-processing

Question 25

A graph of the frequency of occurrence versus digital value intervals is called a(n)_____.

A) histogram
B) compression
C) digitization
D) algorithm