Fluoroscopy Flashcards
_________ uses a continuous beam of x-rays to create images of the movement of internal structures that can be viewed on a monitor.
Fluoroscopy
_____ imaging is accomplished with fluoroscopy as opposed to radiography.
Dynamic
The process that the exit radiation from the anatomic area of interest interacts with the input phosphor for conversion to visible light, which are converted to electrons by a photocathode, then focused by electrostatic focusing lenses, and accelerated toward an anode to strike the output phosphor is:
Image intensification
The ___________ consists of a light-emitting material (like cesium iodide) to absorbs x-rays and emits light.
input phosphor
This part of the image intensifier absorbs light and converts light to electrons.
photocathode
This is measured in cd/m2/mR/s.
conversion factor
The formula for brightness gain is:
brightness gain = minification gain × flux gain.
When operated in magnification mode, the electrostatic lenses have ________ voltage.
increased
A disadvantage of using magnification mode during fluoroscopy is:
the patient receives additional dose.
Vidicon refers to a type of:
camera tube
Increasing the mA is the way to correct a fluoroscopic image that has:
noise
When the electron beam in the camera travels back and forth across, from the top to bottom, it is moving in a _____ pattern.
raster
The CCD’s electrical charge from the capacitors is sent to the:
display monitor
The fiber-optic bundle or optical lens system is used to:
link the output phosphor and camera or CCD.
When using the mobile C-Arm unit, the x-ray tube should be positioned under the patient and the image intensifier above the patient because:
reduce radiation exposure to operator.
The newest fluoroscopy systems use a flat-panel detector in place of the:
image intensifier
What feature has replaced automatic brightness control (ABC) on newer fluoroscopic units?
Automatic exposure rate control (AERC)
_____ reduces the number of images each second, decreases patient dose, and reduces the visibility of patient motion.
pulsed fluoroscopy
Fluoroscopic equipment should be inspected every:
6 months
Who invented the fluoroscope?
Thomas Edison
What is the primary job of the image intensifier?
To increase brightness
Light emitted by the input phosphor is directly proportional to:
How many x-rays it receives
flux gain x minification gain =
brightness gain
T/F: Fluoroscopy is lower in mA than radiographic mode.
True
Coated with light emitting crystals to absorb electrons and emit light:
output phosphor
Digital fluoroscopy is improved by:
CCD
T/F: When a CCD is exposed to light, it generates and briefly stores light energy.
False
The ratio of the size of the input phosphor versus the size of the output phosphor
minification gain
Maximum mA station for fluoroscopy
5 mA
Emitting electrons from a light source
Photoemission
Focuses electrons toward the anode
Electrostatic lenses
Accelerates electrons to send to the output phosphor
Anode
Converts electrons into light photons
Output phosphor
What is the input phosphor made of?
Cesium iodide
What is the output phosphor made of?
Zinc Cadmium sulfide
Converts light back to electrical signal
Charged coupled device (CCD)
Collects electrical signal and sends it to the ADC (analog to digital converter)
Charged coupled device (CCD)
Converts to digital signal
Analog to digital converter (ADC)
The ratio of light photons at the output phosphor divided by the number of input x-ray photons
flux gain
The total number of light photons produced by each electron
flux gain
T/F: Magnification mode increases the input phosphor size
False
Magnification mode increases:
A. Spatial resolution
B. Contrast resolution
C. Image Brightness
D. Patient Dose
A, B, and D
Smaller input size = [increased/decreased] dose
increased
converts x-rays to light using a flat panel detector (FPD)
Cesium Iodide Scintillator
Converts light to electrons using a FPD
Photodiode
Collects electrical signal using a FPD
Thin film transistor (TFT)
Smaller DELs = [increased/decreased] spatial resolution
increased
The loss of shape at the edges of the fluoro image
Pincushion artifact
reduction of an image’s brightness or saturation toward the periphery compared to the image’s center
Vignetting
Image in a fluoroscopic system to distort with an ‘S’ shape
S shape distortion
The exposure switch in fluoro
Dead Man Switch
Allows the image to be saved, reducing the need for another exposure
Last image hold (LIH)
T/F: Electrons emitted from the photocathode are directly proportional to the intensity of light that reaches the photocathode
True
Formula to find minification gain
(diameter of input phosphor/diameter of output phosphor)^2
Output phosphor illumination/input exposure rate
Conversion factor
Distortion of image-intensified fluoroscopic image that appears as unequal magnification is
pincushion appearance
In image-intensified fluoroscopy, shape distortion is caused by:
the curved shape of the photocathode.
The CCD’s electrical charge from the capacitors is sent to the:
display monitor
Because the DELs of a flat-panel detector are arranged in a grid pattern (uniform columns and rows), they do not exhibit:
pincushion artifacts and S distortion artifacts
Which of the following C-arm advancements can provide both static and dynamic images along with 2D and 3D during surgical procedures?
O-arm
Adjusting the collimator without exposing the patient to additional radiation is known as:
virtual collimation
Photoemission occurs at the:
Photocathode
T/F: The ABC can be slow in responding, seen as a brief delay in the brightness adjustment.
True
T/F: When using magnification mode, the fluoroscopist needs to manually set the exposure factors higher to compensate for the reduced diameter input phosphor.
False
What is essentially the sum total of air kerma over the exposed area of the patient’s body surface?
dose area product
Which of the following are types of ionizing radiation that produce virtually the same biologic effect for equal absorbed doses in body tissue?
X-rays, beta particles, and gamma rays
T/F: In fluoroscopy, pulse rate is the number of exposures per second.
True
