Question 1

The uniformity of the CT number of water should not vary by more than ____ HU from the center of the phantom to the periphery.

Accepted Answer

A)  2 
B)  3 
C)  5 
D)  10 C

Question 2

The CTDIvol pass/fail criterion for an adult abdomen is ____ mGy.

Accepted Answer

A)  20 
B)  40 
C)  30 
D)  80 C

Question 3

For ACR CT accreditation, the Water CT Number and Standard Deviation (Noise) should be evaluated by the CT technologist

Accepted Answer

A)  quarterly. 
B)  monthly. 
C)  weekly. 
D)  daily. D

Question 4

For a slice thickness of 5 mm or less, the slice thickness should not vary by more than ____ mm.

Accepted Answer

A)  0.5 
B)  1.0 
C)  2.0 
D)  3.0

Question 5

A visual inspection of a CT unit should be evaluated at least _____ for ACR accreditation programs.

Accepted Answer

A)  daily. 
B)  weekly. 
C)  monthly. 
D)  semi-annually.

Question 6

Patient dose values for CT scans should remain within ____ of the manufacturer's specifications.

Accepted Answer

A) $\pm$2% 
B)  $\pm$5% 
C)  $\pm$10% 
D)  $\pm$20%

Question 7

The CT number of water should not deviate by more than ____ CT numbers from 0.

Accepted Answer

A)  2 
B)  3 
C)  5 
D)  10

Question 8

Section thickness should not vary by more than ____ mm for sections greater than 5 mm.

Accepted Answer

A)  $\pm$0.5 
B) $\pm$1.0 
C)  $\pm$2.0 
D)  $\pm$5.0

Question 9

The laser light field and radiation field should coincide to within ____ mm.

Accepted Answer

A)  0.5 
B)  1.0 
C)  2.0 
D)  5.0

Question 10

The minimum distance between two objects that allows them to be seen as separate and distinct would define what CT imaging parameter?

Accepted Answer

A)  Low-contrast resolution 
B)  Uniformity 
C)  High-contrast resolution 
D)  Image noise

Exam 10: Quality Control in Computed Tomography

The uniformity of the CT number of water should not vary by more than ____ HU from the center of the phantom to the periphery.