Chapter 15 Fluoroscopy & Dynamic Imaging Flashcards
What is the main purpose of fluoroscopy?
To provide real-time, dynamic imaging of moving structures.
What part of the fluoroscopic system converts x-rays into visible light?
The image intensifier.
What does the input phosphor do in a fluoroscopic system?
Converts x-rays into light photons.
What is the role of the photocathode in fluoroscopy?
Converts light photons into electrons via the photoelectric effect.
What is the output phosphor responsible for?
Converts electrons back into visible light for image display.
What is minification gain in an image intensifier?
The increase in brightness due to compression of the electron image onto a smaller output phosphor.
What does automatic brightness control (ABC) do in fluoroscopy?
Adjusts kVp and mA to maintain a constant image brightness.
What is the primary disadvantage of magnification mode in fluoroscopy?
Higher patient dose due to increased mA.
What is flux gain in an image intensifier?
The increase in brightness caused by electron acceleration.
What is the purpose of pulsed fluoroscopy?
Reduces radiation dose by only activating x-rays intermittently.
Why is scattered radiation a major concern in fluoroscopy?
Because it contributes to occupational exposure for radiologic staff.
What does image lag refer to in fluoroscopy?
A blurring effect due to slower response time in some systems.
What type of contrast agent is used for fluoroscopic gastrointestinal exams?
Barium sulfate or iodine-based contrast.
What is the function of a fluoroscopic grid?
Reduces scatter radiation, improving image contrast.
What fluoroscopic mode increases spatial resolution but also increases dose?
Magnification mode.
What is digital fluoroscopy (DF)?
A system that replaces image intensifiers with flat-panel detectors for improved image quality.
What is the primary advantage of DF over conventional fluoroscopy?
Lower radiation dose and better image quality.
What is the function of last-image hold (LIH) in fluoroscopy?
Reduces dose by keeping the last captured image displayed instead of continuous x-rays.
What is the main advantage of indirect digital fluoroscopy?
Uses a scintillator to convert x-rays to light, improving image capture efficiency.
What is dose-area product (DAP) monitoring in fluoroscopy?
Measures total radiation exposure based on dose and field size.
