Radiology Tech Flashcards

What is the primary advantage of digital radiography (DR) over computed radiography (CR)?

Answer: Faster image acquisition with no cassette handling

Direct digital radiography (DR) captures images instantly via a flat-panel detector, eliminating the cassette handling and plate-scanning steps required in CR.

What is the inverse square law as applied to X-ray intensity?

Answer: Intensity is inversely proportional to the square of the distance from the source

The inverse square law states that radiation intensity decreases as the inverse square of the distance from the source (I1/I2 = D2²/D1²).

Which structure in the X-ray tube acts as the source of electrons?

Answer: Filament (cathode)

The filament, located within the cathode assembly, undergoes thermionic emission when heated, releasing electrons that are accelerated toward the anode.

What does OID stand for and how does it affect image magnification?

Answer: Object-Image Distance; larger OID increases magnification

OID (Object-Image Distance) is the distance between the patient part and the image receptor; increasing OID increases geometric magnification and blur.

Which type of ionizing radiation has the greatest penetrating power?

Answer: Gamma rays

Gamma rays (and X-rays), as high-energy electromagnetic radiation, have the greatest penetrating power among common ionizing radiations.

What is the purpose of collimation in radiography?

Answer: Restrict the X-ray beam to the area of interest

Collimators use lead shutters to restrict the X-ray beam to the anatomical area of interest, reducing patient dose and scattered radiation.

Which artifact on a digital radiograph is caused by insufficient X-ray exposure to the detector?

Answer: Quantum mottle (noise)

Quantum mottle (image noise) results from too few X-ray photons reaching the detector, producing a grainy, speckled appearance.