Radiography Exam Radiography 2 — Questions and Answers
Question 1: Which Bucky factor is typically used when the grid ratio is 12:1?
- 3-4
- 5-6 (Correct answer)
- 2-3
- 7-8
Correct answer: 5-6
A 12:1 grid ratio has a Bucky factor of approximately 5-6, meaning exposure must be increased by that factor to compensate for absorbed scatter.
Question 2: What is the primary purpose of the anode heel effect in radiography?
- Increase focal spot size
- Allow positioning of thicker anatomy under the cathode end (Correct answer)
- Reduce patient dose
- Improve contrast resolution
Correct answer: Allow positioning of thicker anatomy under the cathode end
The anode heel effect causes lower intensity at the anode end, so thicker anatomy should be placed under the cathode end where intensity is higher.
Question 3: A patient receives 200 mR at 100 cm SID. What is the approximate dose at 200 cm SID?
- 50 mR (Correct answer)
- 100 mR
- 400 mR
- 800 mR
Correct answer: 50 mR
Using the inverse square law, doubling the distance quarters the intensity: 200 × (100/200)² = 50 mR.
Question 4: Which type of ionizing radiation has the greatest penetrating power?
- Alpha particles
- Beta particles
- Gamma rays (Correct answer)
- Neutrons
Correct answer: Gamma rays
Gamma rays have the greatest penetrating power among the common forms of ionizing radiation used in medical imaging contexts.
Question 5: What does the term 'penumbra' refer to in radiographic imaging?
- Optical density of the film
- Geometric unsharpness at the edge of a shadow (Correct answer)
- Scatter radiation fog
- Overexposed area on the image
Correct answer: Geometric unsharpness at the edge of a shadow
Penumbra refers to the zone of geometric unsharpness or partial shadow at the edge of a radiographic image caused by the finite size of the focal spot.
Question 6: In computed radiography (CR), the latent image is stored in which material?
- Silver halide crystals
- Photostimulable phosphor (Correct answer)
- Cesium iodide
- Gadolinium oxysulfide
Correct answer: Photostimulable phosphor
CR imaging plates contain photostimulable phosphor (barium fluorohalide) that stores the latent image as trapped electrons until laser-stimulated.
Question 7: Which technical factor has the GREATEST effect on radiographic contrast?
- mA
- Exposure time
- kVp (Correct answer)
- SID
Correct answer: kVp
kVp primarily controls the energy of the x-ray beam and therefore has the greatest influence on radiographic contrast.
Radiography Exam Radiography 2
Which Bucky factor is typically used when the grid ratio is 12:1?