CBET Diagnostic Imaging Equipment 1 — Questions and Answers
Question 1: What type of radiation does a conventional X-ray machine produce?
- Ionizing electromagnetic radiation (X-rays) (Correct answer)
- Non-ionizing infrared radiation
- Ultrasonic sound waves
- Gamma radiation from isotopes
Correct answer: Ionizing electromagnetic radiation (X-rays)
X-ray tubes produce ionizing electromagnetic radiation by accelerating electrons into a tungsten anode, emitting photons in the X-ray spectrum.
Question 2: Which unit measures absorbed radiation dose in tissue?
- Gray (Gy) (Correct answer)
- Sievert (Sv)
- Roentgen (R)
- Becquerel (Bq)
Correct answer: Gray (Gy)
The Gray is the SI unit of absorbed dose, defined as one joule of energy deposited per kilogram of tissue.
Question 3: What is the primary safety concern for BMETs working on MRI equipment?
- Extremely strong static magnetic field attracting ferromagnetic objects (Correct answer)
- High voltage electric shock only
- Radioactive contamination
- Laser eye injury
Correct answer: Extremely strong static magnetic field attracting ferromagnetic objects
MRI scanners operate with static fields up to 3 T or higher; ferromagnetic tools or implants can become dangerous projectiles near the bore.
Question 4: In ultrasound imaging, what physical principle allows tissue boundaries to be visualized?
- Reflection of sound waves at acoustic impedance mismatches (Correct answer)
- Absorption of X-ray photons
- Fluorescence under UV light
- Nuclear magnetic resonance
Correct answer: Reflection of sound waves at acoustic impedance mismatches
Sound waves reflect at interfaces between tissues of different acoustic impedance; the transducer detects these echoes to reconstruct an image.
Question 5: A CT scanner's X-ray tube requires replacement. Which parameter most directly indicates tube wear?
- Total accumulated milliampere-seconds (mAs) / heat units (Correct answer)
- Display screen brightness
- Gantry rotation speed
- Patient table weight limit
Correct answer: Total accumulated milliampere-seconds (mAs) / heat units
Accumulated heat units or mAs track the thermal stress on the anode; manufacturers define tube replacement thresholds based on this metric.
Question 6: Which regulatory body requires X-ray equipment registration and inspection programs in US states?
- State radiation control programs (under agreement with NRC/FDA) (Correct answer)
- OSHA only
- The Joint Commission
- CMS billing office
Correct answer: State radiation control programs (under agreement with NRC/FDA)
State radiation control programs register X-ray equipment and conduct inspections under authority delegated by the NRC and FDA.
CBET Diagnostic Imaging Equipment 1
What type of radiation does a conventional X-ray machine produce?