DHA Diagnostic Imaging & Radiology

Question 1

Which unit is used to measure radiation absorbed dose in tissue?

Accepted Answer

Gray (Gy)

Answer

The Gray (Gy) is the SI unit of absorbed dose, defined as one joule of radiation energy absorbed per kilogram of tissue.

Question 2

What does the acronym ALARA stand for in radiation protection?

Accepted Answer

As Low As Reasonably Achievable

Answer

ALARA (As Low As Reasonably Achievable) is the guiding principle of radiation protection, aiming to minimize exposure while maintaining diagnostic quality.

Question 3

Which imaging modality uses magnetic fields and radiofrequency waves to produce images?

Accepted Answer

MRI

Answer

MRI (Magnetic Resonance Imaging) uses strong magnetic fields and radiofrequency pulses to align and then perturb hydrogen nuclei, generating detailed soft-tissue images.

Question 4

The standard diagnostic chest radiograph is taken in which projection?

Accepted Answer

Posteroanterior (PA)

Answer

The standard chest X-ray is taken in the posteroanterior (PA) projection with the patient standing and the X-ray beam passing from back to front, minimizing cardiac magnification.

Question 5

Which contrast agent is most commonly used to enhance MRI images?

Accepted Answer

Gadolinium

Answer

Gadolinium-based contrast agents (GBCAs) are the standard MRI contrast agents, shortening T1 relaxation times and improving tissue differentiation.

DHA - Dubai Health Authority Practice Test

DHA - Dubai Health Authority Practice Test

DHA Diagnostic Imaging & Radiology