Ch. 36 Fluoroscopy (Exp II) Flashcards
Fluoroscopy is a _______ x-ray examination
Dynamic, real-time
Fluoroscopy is the domain of the _______
Radiologist
Fluoroscopy is commonly used for observation of…
- Cardiovascular structures
- Surgical procedures
- The GI tract
The fluoroscopic X-ray tube and image receptor are mounted _______
Coincident to each other
The fluoroscopic carriage commonly supports the _______
- IR
- Power-assist drive controls
- Digital spot film selector
Fluoroscopic mA range is commonly _______
0.5-5 mA
During fluoroscopy, the SOD on a fixed unit cannot be less than _______ inches.
15
During fluoroscopic image intensification, the primary x-ray beam exits the patient and strokes the _______ of the image intensifier.
Input screen
The input screen absorbs _______ and emits _______.
X-ray photons; light photons
The photocathode absorbs _______ and emits _______.
Light photons; electrons
Electrostatic lenses are used to accelerate and focus _______.
Electrons
The primary _______ occurs from the acceleration and focusing of the electron beam.
Brightness gain
The output screen absorbs _______ and emits _______.
Electrons; light photons
The input screen is _______ in shape.
Concave
The shape of the input screen helps to control _______.
Distortion
The photocathode is composed of _______ metals.
Photoemissive
Photoemissive materials absorb _______ and emit _______.
Light photons; electrons
Electrostatic lenses are actually _______
Charged electrodes
The greater the voltage supplied to the electrostatic lenses, the _______ the acceleration and the _______ the focal point to the input screen.
Greater; closer
Total brightness gain is…
- A measure of the increase in image intensity
- Determined by minification gain
- Determined by flux gain
Fluoroscopic resolution with image intensification will vary according to…
- Minification gain
- Electrostatic focal point
- Input and output screen diameter
The edge distortion problem in image intensification tubes is called _______.
Vignetting
The most common solution for quantum mottle is to _______.
Increase the fluoro tube mA
The most commonly used fluoroscopic viewing system is _______.
Real-time video monitors
Cassette-based spot filming has been replaced by _______.
Digital photo spots
Digitization of he fluoroscopic image permits…
- Image post processing
- Transfer via PACS
- Electronic archival
Digital fluoro pixels are between _______ micrometers.
200 and 300
Flat panel digital detectors used for fluoroscopy use…
- Amorphous silicon as the digital detector
- A cesium iodide scintillator
- TFT technology
In order to reduce visible noise using digital fluoroscopic detectors, _______
Pixels are binned
All of the following are common post processing features with digital fluoroscopy except…
A. Last image hold (LIH)
B. Digital subtraction
C. Window level and width
D. Edge enhancement
A. Last image hold (LIH)
During fluoroscopy, the principal source of radiation exposure to personnel in the room is the _______.
Patient
In a fluoroscopy system, the X-ray tube and IR must be interlocked in order to enable fluoroscopy. This classifies the IR as the _______.
Primary barrier
All of the following are true of the fluoroscopic lead apron drape except:
A. It should be 0.25 mm Pb equivalent
B. It is designed to absorb a large percentage of patient scatter
C. It covers the Bucky slot in the table
D. It may detach for specific cases
C. It covers the Bucky slot in the table
Methods to reduce fluoroscopic radiation exposure include:
- Automatic Brightness Control
- Bucky tray slot cover
- Fluoroscopic lead apron drape
- Dead-man type fluoroscopy switch
- Last Image Hold (LIH)
- Decrease the IOD
Digital fluoroscopy is typically…
- A progressive, pulsed fluoroscopic exposure
- capable of producing highly contrast images
- Capable of 256 shades of gray through 8-bit processing
_______ deals with the gain resulting from the conversion of light at the output phosphor.
Flux gain
Mobile fluoroscopic systems are different from fixed systems in that they…
Have a minimum SOD of 12 inches
When using automatic brightness control (ABC), it is important to remember that
A dark video image indicates photon starvation to the receptor
Digital fluoroscopy typically…
- Uses pulsed x-ray exposures timed with the detector
- Uses indirect detector technology with thin film transistors (TFT)
- Provides resolution of 1-2 lp/mm
The fluoroscopic X-ray tube is different from a radiographic tube in that the fluoro tube…
Cannot have an SOD of less than 15 inches
