ARRT Radiation Safety 2

Question 1

Which radiation weighting factor (wR) applies to X-rays used in CT imaging?

Accepted Answer

1

Answer

2

Answer

5

Answer

20

Question 2

What is the primary purpose of the CT dose index (CTDI)?

Accepted Answer

To characterize radiation output of a CT scanner independent of patient size

Answer

To measure patient absorbed dose in a single organ

Answer

To calculate the effective dose to the technologist

Answer

To determine scatter radiation levels in the control room

Question 3

A patient weighing 300 lbs is scanned using a standard adult protocol. How should the technologist respond?

Accepted Answer

Apply size-specific dose estimates (SSDE) and adjust technique for body habitus

Answer

Use pediatric technique factors

Answer

Reduce mAs by 50% regardless of image quality

Answer

Increase kVp to 140 and decrease mAs proportionally

Question 4

Which of the following best describes the ALARA principle in CT imaging?

Accepted Answer

Keep radiation exposure as low as reasonably achievable while maintaining diagnostic image quality

Answer

Use the lowest dose that produces any visible image

Answer

Always use the minimum protocol mAs regardless of indication

Answer

Limit CT exams to one per patient per year

Question 5

The dose length product (DLP) is calculated by multiplying CTDI_vol by which parameter?

Accepted Answer

Scan length (cm)

Answer

Pitch factor

Answer

Rotation time

Answer

Number of detector rows

Question 6

Which type of shielding is most effective for reducing scattered X-ray radiation outside a CT suite?

Accepted Answer

Lead-lined walls or concrete barriers

Answer

Aluminum sheeting

Answer

Acrylic barriers

Answer

Wooden partitions with lead paint

Question 7

A CT technologist is concerned about cumulative occupational dose. Which dosimeter provides the most accurate record of whole-body exposure?

Accepted Answer

Optically stimulated luminescence (OSL) badge worn at collar level

Answer

Finger ring TLD

Answer

Pocket ionization chamber

Answer

Electronic personal dosimeter worn at waist