ARRT Equipment Operation and Quality Control 2

Question 1

What does the term 'detector efficiency' refer to in CT scanner performance?

Accepted Answer

The ability of detectors to capture and convert X-ray photons into usable signal

Answer

The speed at which the gantry rotates

Answer

The number of detector rows in the system

Answer

The FOV coverage per rotation

Question 2

In CT quality control, 'low-contrast detectability' refers to the system's ability to:

Accepted Answer

Distinguish objects with small differences in attenuation from background

Answer

Resolve fine structural detail in bone

Answer

Measure exact CT numbers for each tissue type

Answer

Determine the maximum scan field of view

Question 3

Which of the following best describes the purpose of the CT table indexing accuracy test?

Accepted Answer

To confirm the table moves the correct prescribed distance between scan acquisitions

Answer

To verify the table weight tolerance

Answer

To measure the table speed during helical scans

Answer

To evaluate gantry isocenter alignment

Question 4

The 'noise' measured in a CT image is quantified as:

Accepted Answer

The standard deviation of CT numbers in a uniform region of interest

Answer

The mean CT number in a region of interest

Answer

The difference between maximum and minimum CT numbers in the image

Answer

The number of image artifacts present

Question 5

Which generator component is responsible for converting AC power to the high-voltage DC supply required by the X-ray tube in modern CT systems?

Accepted Answer

High-frequency inverter generator

Answer

Filament transformer

Answer

Autotransformer

Answer

Rectifier diode bridge

Question 6

On a CT system, what does the term 'isocenter' refer to?

Accepted Answer

The precise center of gantry rotation where the X-ray beam and detector array intersect

Answer

The center of the X-ray beam at the detector plane

Answer

The center of the patient table surface

Answer

The midpoint of the scan field of view display

Question 7

What is the primary reason CT scanners use slip-ring technology?

Accepted Answer

To allow continuous gantry rotation by eliminating the need for cables to wind and unwind

Answer

To improve detector quantum efficiency

Answer

To increase the kVp range of the X-ray tube

Answer

To synchronize gantry rotation with patient respiration