Radiography Exam Fluoroscopy and Interventional Procedures 1 — Questions and Answers
Question 1: What is the primary function of the image intensifier in a fluoroscopic system?
- To increase kVp automatically during exposure
- To amplify and convert X-ray energy into a brightened visible image, reducing patient dose (Correct answer)
- To collimate the X-ray beam to the area of interest
- To process and store digital images in PACS
Correct answer: To amplify and convert X-ray energy into a brightened visible image, reducing patient dose
The image intensifier converts X-ray photons to visible light and electronically amplifies the signal, producing a bright enough image for real-time viewing while significantly reducing patient dose compared to older fluoroscopic methods.
Question 2: Per FDA regulations (21 CFR 1020.32), what is the maximum air kerma rate at the reference point for standard fluoroscopic systems?
- 50 mGy/min
- 120 mGy/min
- 88 mGy/min (Correct answer)
- 25 mGy/min
Correct answer: 88 mGy/min
FDA regulations cap the air kerma rate at 88 mGy/min (10 R/min) at the reference point for standard fluoroscopic units to limit entrance skin dose during procedures.
Question 3: What is the primary advantage of pulsed fluoroscopy over continuous fluoroscopy?
- Higher spatial resolution
- Increased frame rate per second
- Better contrast visualization at low kVp
- Reduced patient radiation dose (Correct answer)
Correct answer: Reduced patient radiation dose
Pulsed fluoroscopy delivers X-rays in brief discrete bursts rather than continuously, substantially lowering the total radiation dose to the patient while maintaining diagnostic image quality.
Question 4: What does the 'last image hold' (LIH) feature do in a fluoroscopic system?
- Records all fluoroscopic images automatically throughout the procedure
- Holds the X-ray beam at a fixed intensity while the foot pedal is depressed
- Displays the final fluoroscopic frame as a static image after the beam is turned off (Correct answer)
- Stores the highest quality image of the exam for permanent record
Correct answer: Displays the final fluoroscopic frame as a static image after the beam is turned off
Last image hold freezes the last acquired fluoroscopic frame on the monitor as a static image when the foot pedal is released, allowing the radiologist to review anatomy without continuing to irradiate the patient.
Question 5: What is the primary purpose of automatic brightness control (ABC) in fluoroscopy?
- To increase the frame rate of image acquisition
- To automatically adjust technical factors to maintain consistent image brightness as beam penetration changes (Correct answer)
- To reduce the physical size of the image intensifier
- To automatically store images at preset time intervals
Correct answer: To automatically adjust technical factors to maintain consistent image brightness as beam penetration changes
ABC continuously monitors image brightness and automatically adjusts kVp, mA, or both to compensate for varying tissue densities, ensuring consistent image quality throughout the examination.
Question 6: What is the minimum source-to-skin distance (SSD) required for fixed fluoroscopic equipment per FDA regulations?
- 20 cm (8 inches)
- 30 cm (12 inches)
- 45 cm (18 inches)
- 38 cm (15 inches) (Correct answer)
Correct answer: 38 cm (15 inches)
FDA regulations mandate a minimum SSD of 38 cm (15 inches) for fixed fluoroscopic units to limit entrance skin dose by ensuring adequate distance between the X-ray tube and the patient's skin.
Question 7: What is the primary purpose of spot imaging during a fluoroscopic examination?
- To periodically calibrate the image intensifier
- To provide continuous real-time imaging of patient movement
- To measure entrance skin dose at a specific point
- To record selected high-quality static images of specific anatomy or pathology for documentation (Correct answer)
Correct answer: To record selected high-quality static images of specific anatomy or pathology for documentation
Spot imaging captures permanent high-resolution static radiographic frames of areas of interest identified during real-time fluoroscopy, providing diagnostic-quality images for the final report.
Radiography Exam Fluoroscopy and Interventional Procedures 1
What is the primary function of the image intensifier in a fluoroscopic system?