ARRT Image Quality 2

Question 1

Which CT parameter most directly controls the amount of radiation dose delivered to the patient?

Accepted Answer

mAs

Answer

mAs (milliampere-seconds) directly determines the number of X-ray photons produced and is the primary controller of patient dose.

Question 2

Increasing the reconstruction field of view (FOV) while keeping matrix size constant will:

Accepted Answer

Increase pixel size and decrease spatial resolution

Answer

Larger FOV with the same matrix means each pixel covers more area, increasing pixel size and reducing spatial resolution.

Question 3

A 'blooming artifact' in CT most commonly results from:

Accepted Answer

High-density metallic objects causing overestimation of structure size

Answer

Blooming occurs when high-attenuation objects like metals or calcifications appear larger than their true size due to beam hardening and partial volume effects.

Question 4

Which factor primarily determines the z-axis (longitudinal) resolution in a multislice CT scanner?

Accepted Answer

Detector row width

Answer

Z-axis resolution is primarily determined by detector row width (collimation), which defines slice thickness in the longitudinal direction.

Question 5

Quantum mottle in CT images is primarily caused by:

Accepted Answer

An insufficient number of detected photons

Answer

Quantum mottle (noise) occurs when too few photons reach the detector, causing statistical fluctuations that appear as grainy image texture.

(ARRT) American Registry of Radiologic Technologists Computed Tomography Certification Practice Test

(ARRT) American Registry of Radiologic Technologists Computed Tomography Certification Practice Test

ARRT Image Quality 2