ARRT Radiography Flashcards

Which radiographic projection best demonstrates the carpal tunnel?

Answer: Tangential (inferosuperior) projection

The tangential (inferosuperior) carpal canal projection profiles the carpal tunnel and its contents.

Scattered radiation reaching the image receptor is primarily reduced by using a:

Answer: Radiographic grid

A radiographic grid absorbs scattered photons before they reach the image receptor, improving image contrast.

Which ionizing radiation interaction with matter is responsible for most scattered radiation in diagnostic imaging?

Answer: Compton scattering

Compton scattering is the predominant interaction in diagnostic energy ranges and produces most clinically relevant scatter.

A patient's arm is externally rotated 45° for an AP oblique projection of the elbow. Which structure is best demonstrated?

Answer: Radial head and capitulum

The AP oblique elbow with external rotation (lateral oblique) profiles the radial head free of superimposition with the ulna.

Which of the following is the recommended lead apron thickness for gonadal shielding in radiography?

Answer: 0.50 mm Pb equivalent

A minimum of 0.50 mm lead equivalent is recommended for protective aprons used in diagnostic radiography.

The PA chest radiograph is preferred over the AP projection primarily because it:

Answer: Decreases magnification of the heart

With the patient facing the detector (PA), the heart is closer to the image receptor, reducing its geometric magnification.

Which blood vessel is most susceptible to injury when performing a femoral artery puncture too far inferior?

Answer: Profunda femoris artery

The profunda femoris (deep femoral artery) branches from the common femoral just below the inguinal ligament; puncture below this level risks entering this vessel.