Chapter 15 Exam Flashcards
- Which of the following is composed of cesium iodide?
a. Conventional fluoroscopic screen
b. Intensifier input phosphor
c. Intensifier output phosphor
d. Intensifier photocathode
b. Intensifier input phosphor
- Which of the following are negatively charges electrodes plated on the inner surface of the glass envelope of the image intensifier?
a. Photocathode
b. Electrostatic focusing lenses
c. Input phosphor
d. Output phosphor
b. Electrostatic focusing lenses
- Which of the following emits electrons in response to light stimulus?
a. Conventional fluoroscopic screen
b. Intensified input phosphor
c. Intensified output phosphor
d. Intensified photocathode
d. Intensified photocathode
- What part of the image intensifier will attract the electrons and increase their kinetic energy?
a. Input phosphor
b. Output phosphor
c. Electrostatic focusing lenses
d. Accelerating anode
d. Accelerating anode
- Which of the following will occur if voltage to the electrostatic focusing lenses is increased?
a. Inversion of the image
b. Reversal of the image
c. Minification of the image
d. Magnification of the image
d. Magnification of the image
- What portion of the TV camera tube will conduct only when illuminated?
a. Electron gun
b. Target layer
c. Signal plate
d. Face plate
b. Target layer
- A signal is received by the monitor from which part of the TV camera tube?
a. Electron gun
b. Target
c. Signal plate
d. Face plate
c. Signal plate
- Which display monitor design used nematic liquid crystals?
a. LCD
b. Plasma
c. Television (CRT)
d. These gases are not used in monitors
a. LCD
- Which of the following is within the spatial resolution range of a flat-panel detector?
a. 1.0 Lp/mm
b. 2.0 Lp/mm
c. 3.0 Lp/mm
d. 4.0 Lp/mm
c. 3.0 Lp/mm
- The maximum air kerma rate for fluoroscopy is:
a. 2 R/min
b. 6 R/min
c. 10 R/min
d. 14 R/min
c. 10 R/min
- The ratio of the number of light photons at the output phosphor to the number at the input phosphor equals:
a. Brightness gain
b. Flux gain
c. Minification gain
d. Magnification gain
b. Flux gain
- What fluoroscopic operation is defined as the number of exposures per second?
a. Frame averaging
b. Pulse width
c. Pulse rate
d. Dose rates
c. Pulse rate
- The ability to adjust the collimator without exposing the patient to additional radiation is known as:
a. Frame averaging
b. Air kerma
c. Virtual collimation
d. Electrostatic focusing lens
c. Virtual collimation
- What fluoroscopic feature defines the exposure length of time during pulsed fluoroscopy?
a. Dose rates
b. Pulse width
c. Pulse rate
d. Flux gain
b. Pulse width
- Which fluoroscopic feature will minimize patient radiation exposure?
a. Frame averaging
b. Last image hold
c. Fluoro loop save
d. All of the above
d. All of the above
Operational QC testing of fluoro unit
The radiographer may be responsible for the operational inspection of the equipment
Fluoro documentation patients’ record
Fluoro machine keeps track of everything
refers to the length of each pulse
Pulse width
refers to how many pulses occur per second of operation (how many exposures occur per second
Pulse rate
Reduces patient dose and image noise by averaging multiple frames together, however, spatial resolution decreased
Frame averaging
When operating the image intensifier in magnification mode, the voltage to the electrostatic focusing lenses is ________
This increases the ability to see _____ ______, but ________ the radiation dose to the patient.
increased, small structures, increases
Digital magnification and radiation dose
Flat panel detector FOV and dynamic range
- Dynamic versions of these detectors must respond in rapid sequences to create a dynamic image.
- Have wider dynamic range, current dynamic versions are capable of up to 60 frames per second
- Present a rectangular field providing more info
The area of each pixel that is sensitive to x-ray detection materials
How much of each dexel can see x-rays (80%)
Fill factor
Advantages of a flat panel detector
- Reduce tower size, bulk, weight
- Replace spot filming
- Do not degrade with age, more durable
- Have better contrast resolution, higher DQE, wider dynamic range, rectangular field, post processing options
- Do not exhibit most image artifacts