Deck 10: Quality Control in Computed Tomography

Question 1

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

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

Answer 1

$\pm$ 10%

Question 2

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

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

Answer 2

C
Edge-to-center mean CT number difference must be less than 5 HU for all four edge positions.

Question 3

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

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

Answer 3

$\pm$ 1.0

Question 4

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

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

Question 5

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

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

Question 6

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

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

Question 7

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

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

Question 8

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

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

Question 9

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

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

Question 10

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

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