Radiography Exam Radiography 3 — Questions and Answers
Question 1: Which positioning term describes rotation of the forearm so the palm faces posteriorly?
- Supination
- Pronation (Correct answer)
- Eversion
- Inversion
Correct answer: Pronation
Pronation is the movement that rotates the forearm so the palm faces posteriorly (downward when arm is at side).
Question 2: The Waters projection (parietoacanthial) is primarily used to demonstrate which structures?
- Mastoid air cells
- Maxillary sinuses (Correct answer)
- Sphenoid sinus
- Frontal sinuses only
Correct answer: Maxillary sinuses
The Waters projection is the preferred view for demonstrating the maxillary sinuses with minimal superimposition of the petrous ridges.
Question 3: Which photon interaction is the PRIMARY source of scatter radiation in diagnostic radiography?
- Photoelectric effect
- Compton scattering (Correct answer)
- Pair production
- Coherent scattering
Correct answer: Compton scattering
Compton scattering is the dominant interaction at diagnostic energy ranges (60-120 kVp) and is the primary source of scatter radiation that degrades image quality.
Question 4: What is the recommended minimum source-to-skin distance (SSD) for mobile fluoroscopy units?
- 15 cm
- 30 cm
- 38 cm (Correct answer)
- 50 cm
Correct answer: 38 cm
The National Council on Radiation Protection (NCRP) recommends a minimum SSD of 38 cm (15 inches) for mobile fluoroscopy to limit skin dose.
Question 5: A radiograph shows the medial and lateral epicondyles superimposed. Which elbow projection was obtained?
- AP
- Lateral (Correct answer)
- Medial oblique
- Lateral oblique
Correct answer: Lateral
Superimposition of the medial and lateral epicondyles is the hallmark of a true lateral elbow projection.
Question 6: Which radiation measurement unit is used to express occupational dose equivalent in SI units?
- Gray (Gy)
- Sievert (Sv) (Correct answer)
- Becquerel (Bq)
- Coulomb/kg (C/kg)
Correct answer: Sievert (Sv)
The Sievert (Sv) is the SI unit for dose equivalent, which accounts for the biological effectiveness of different types of radiation.
Question 7: Which view best demonstrates the scaphoid (navicular) bone of the wrist free of superimposition?
- PA wrist
- Lateral wrist
- PA with ulnar deviation (Correct answer)
- Carpal canal projection
Correct answer: PA with ulnar deviation
The PA projection with ulnar deviation elongates and projects the scaphoid free from superimposition of adjacent carpal bones.
Radiography Exam Radiography 3
Which positioning term describes rotation of the forearm so the palm faces posteriorly?