Radiography Flashcards

Which positioning term describes rotation of the forearm so the palm faces posteriorly?

Answer: Pronation

Pronation is the movement that rotates the forearm so the palm faces posteriorly (downward when arm is at side).

The Waters projection (parietoacanthial) is primarily used to demonstrate which structures?

Answer: Maxillary sinuses

The Waters projection is the preferred view for demonstrating the maxillary sinuses with minimal superimposition of the petrous ridges.

Which photon interaction is the PRIMARY source of scatter radiation in diagnostic radiography?

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.

What is the recommended minimum source-to-skin distance (SSD) for mobile fluoroscopy units?

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.

A radiograph shows the medial and lateral epicondyles superimposed. Which elbow projection was obtained?

Answer: Lateral

Superimposition of the medial and lateral epicondyles is the hallmark of a true lateral elbow projection.

Which radiation measurement unit is used to express occupational dose equivalent in SI units?

Answer: Sievert (Sv)

The Sievert (Sv) is the SI unit for dose equivalent, which accounts for the biological effectiveness of different types of radiation.

Which view best demonstrates the scaphoid (navicular) bone of the wrist free of superimposition?

Answer: PA with ulnar deviation

The PA projection with ulnar deviation elongates and projects the scaphoid free from superimposition of adjacent carpal bones.