X-Ray Certification Patient Protection 2 — Questions and Answers
Question 1: Which of the following best describes the ALARA principle in radiography?
- Use the highest kVp possible to penetrate tissue
- Keep radiation exposure as low as reasonably achievable (Correct answer)
- Always use lead aprons regardless of body part
- Limit repeat exposures to no more than three per patient
Correct answer: Keep radiation exposure as low as reasonably achievable
ALARA (As Low As Reasonably Achievable) means minimizing patient dose while still obtaining diagnostic-quality images.
Question 2: A gonadal shield should be used when the gonads are within how many centimeters of the primary beam?
- 1 cm
- 3 cm
- 5 cm (Correct answer)
- 10 cm
Correct answer: 5 cm
Gonadal shielding is recommended when the gonads are within 5 cm of the primary x-ray beam.
Question 3: Which factor, when increased, reduces patient dose by requiring fewer photons to reach the detector?
- mAs
- kVp (Correct answer)
- SID
- Collimation
Correct answer: kVp
Increasing kVp increases photon energy and penetrability, allowing the same image quality with less mAs and therefore lower patient dose.
Question 4: What is the primary purpose of beam collimation in patient protection?
- Increase image sharpness by reducing scatter
- Limit the x-ray field to only the area of clinical interest (Correct answer)
- Reduce generator load and tube heating
- Improve contrast by increasing kVp
Correct answer: Limit the x-ray field to only the area of clinical interest
Collimation restricts the x-ray beam to the anatomy of interest, reducing the volume of tissue irradiated and lowering patient dose.
Question 5: Which imaging modality uses no ionizing radiation and therefore poses no radiation risk to the patient?
- Computed tomography (CT)
- Fluoroscopy
- Magnetic resonance imaging (MRI) (Correct answer)
- Nuclear medicine scanning
Correct answer: Magnetic resonance imaging (MRI)
MRI uses magnetic fields and radiofrequency waves, not ionizing radiation, so it carries no radiation risk.
Question 6: When a pregnant patient requires a pelvic radiograph for urgent clinical reasons, the radiographer should:
- Refuse the examination until after delivery
- Proceed with the exam using appropriate shielding and minimum technique (Correct answer)
- Double the mAs to ensure a single exposure is sufficient
- Use fluoroscopy instead to reduce dose
Correct answer: Proceed with the exam using appropriate shielding and minimum technique
When clinically necessary, the exam should proceed with proper shielding and minimal technique to protect the fetus while obtaining diagnostic information.
Question 7: Increasing the source-to-image distance (SID) while keeping mAs constant will have what effect on patient dose?
- Increase patient dose due to longer path
- Have no effect on patient dose
- Decrease patient dose due to the inverse square law (Correct answer)
- Double the patient dose
Correct answer: Decrease patient dose due to the inverse square law
Per the inverse square law, increasing SID reduces the intensity of radiation reaching the patient, lowering entrance skin dose.
X-Ray Certification Patient Protection 2
Which of the following best describes the ALARA principle in radiography?