Safety

Question 1

The quantity of radiation dose received by the patient from a series of CT scans is referred to as the:

Answer 1

MSAD

Question 2

Which of the following technical characteristics of a CT system does NOT directly affect patient dose?

A. Source-to-detector distance
B. Filtration
C. Detector efficiency
D. Filament size

Answer 2

D

Question 3

Which of the following statements most accurately describes the relationship between slice sensitivity profile (SSP) and dose profile?

Answer 3

The dose profile is always wider than the SSP

Question 4

The approximate radiation dose measured during a scan of a 100-mm-long pencil ionization chamber is termed the:

Answer 4

CTDI 100

Question 5

The calculation of the average cumulative dose to each section within an acquisition of multiple sections is termed the:

Answer 5

MSAD

Question 6

The multiple-scan average dose (MSAD) is used to describe the:

Answer 6

average dose to a single section within a scan of multiple sections.

Question 7

Which of the following units is used to quantify effective dose?

Answer 7

Sievert (Sv)

Question 8

If you increase detector pitch you will ——- pt dose

Answer 8

Decrease pt dose

Question 9

The interaction between x-radiation and tissue that results in the complete loss of all x-ray photon energy is called:

Answer 9

photoelectric absorption

Question 10

If you decrease pitch you will —— pt dose

Answer 10

Increase pt dose

Question 11

A best practice for the use of in-plane bismuth shielding requires the:

Answer 11

placement of shield after the acquisition of scout (localizer) images.

Question 12

Which of the following is the unit of radiation exposure?

Answer 12

Roentgen (R)

Question 13

A dose check system features which of the following?

1. Dose notification
2. Dose alert
3. Dose report

Answer 13

1 and 2

Question 14

Current CT systems employ which of the following image reconstruction methods to reduce patient radiation dose?

Answer 14

Iterative reconstruction

Question 15

As a patient size decreases, noise ———

Answer 15

Image noise is directly related to patient size. As a patient size decreases, noise decreases

Question 16

Which of the following describes the system that adjusts the mA setting according to part size variations along the z-axis?

Answer 16

Longitudinal tube current modulation

Question 17

Which of the following descriptors accounts for the dose effects of image spacing during axial acquisition?

Answer 17

MSAD

Question 18

Because of the bow-tie filter employed in the CT x-ray system, positioning the patient at isocenter is critical to avoid:

Answer 18

increased patient exposure

Question 19

The CT dose index (CTDI) is calculated for the central slice in a series that is surrounded by ______ slices on each side.

Answer 19

7

Question 20

Which of the following technical factor adjustments would result in a decrease in the CTDIvol for a given acquisition?

Answer 20

Increased pitch

Side note to remember
As the pitch increases, the dose per section (CTDIvol) decreases.

Question 21

A CT system may employ a focal spot tracking system to precisely direct the x-ray beam toward the detector array in an effort to reduce:

Answer 21

overbeaming

Question 22

During helical CT acquisition, there is a small amount of x-ray exposure just before and immediately following the anatomical volume of interest. This may be referred to as:

Answer 22

overranging

Question 23

When employing ECG-triggered tube current modulation during a cardiac CT, as the patient heart rate increases, the radiation dose savings:

Answer 23

Decreases