Radiology Tech Flashcards

Which anatomical landmark is used to position for a posteroanterior (PA) chest radiograph?

Answer: Vertebra prominens (C7)

The vertebra prominens (C7) is palpated to confirm proper centering for PA chest projections, with the IR centered at T7.

What is 'beam restriction' and why is it important in radiographic practice?

Answer: Limiting the X-ray field size; reduces patient dose and scatter

Beam restriction (collimation) limits the field of radiation to the area being imaged, reducing patient dose and scatter radiation that degrades image quality.

Which X-ray interaction results in the complete absorption of the photon by an inner-shell electron?

Answer: Photoelectric effect

In the photoelectric effect, an X-ray photon is completely absorbed by an inner-shell electron, which is then ejected from the atom.

What is the recommended source-to-image distance (SID) for routine chest radiography?

Answer: 72 inches (183 cm)

A 72-inch (183 cm) SID is standard for PA chest radiography to minimize magnification of the heart and improve image sharpness.

Which of the following describes 'radiographic density' (optical density) on a conventional film?

Answer: The overall blackness or darkness of the radiographic image

Radiographic density (optical density) refers to the degree of overall blackening of the film, primarily controlled by mAs.

What does 'spatial resolution' measure in a radiographic image?

Answer: The ability to image small, high-contrast details and edges

Spatial resolution refers to the system's ability to resolve fine structural detail and sharp edges, measured in line pairs per millimeter (lp/mm).

Which radiation protection device should always be worn at collar level outside the lead apron during fluoroscopy?

Answer: Collar (thyroid) dosimeter

A collar-level dosimeter worn outside the lead apron during fluoroscopy monitors the highest dose area (head and neck) and is used to estimate effective dose.