Fluoroscopy

The input phosphor in Fluoro is usually made of?

Cesium iodode

The photocathode in fluoroscopy is made of?

Cesium and antimony compounds

The focusing lenses in fluorscopy have what type of charge?

Negative

The ouput phosphor in fluorscopy is made of?

Zinc cadmium phosphate

Kinetic energy gained during acceleration from photocathode to output phosphor

Flux gain

Electrons strike the output phosphor with up to __-__ times more kinetic energy than when they left the photocathode

50-75

What is the voltage difference between the photocathode and anode assembly in an image intensifier?

25000-30000 volts

Which of the following is the first order of events when operating an image intensifier?

X-rays strike the input phosphor

Which of the following components collects light photons from the output phosphor and converts them to electrons

CCD

What is the final image intensifier energy conversion that occurs before the visualization of the image of a monitor?

ADC

What is the purpose of the electrostatic focusing lenses within an image intensifier?

Funnel the photoelectrons into a concentrated stream

Role of the anti-scatter grid in the image intensifier

Increase image contrast

Fluoroscopy requires a ____ grid ratio than regular radiography

Lower

Interventional fluoroscopy may use _____ grid type

Crossed

Conventional fluorscopy uses only _____ or ______ grids

Linear or focused

The Concentration of photoelectrons from the input phosphor to the output phosphor

Minification gain

Measure of the ability of the image intensifier to increase the brightness level of the image

Brightness gain

What determines brightness gain?

Flux gain x Minification gain

Percentage that measures the efficiency of the image intensifier

Conversion factor

Flux gain formula

Output/input (Photons)

Minification gain formula

Input²/Output² (Diameter)

When radiation levels are high, automatic gain control (AGC) functions by?

Decreasing the amplification

AGC functions to adjust image brightness without?

Impacting patient dose

Decrease in image brightness around edge of the image in fluoroscopy

Vignetting

Cause of vignetting?

Curved input phosphor and OID

Parts of the image appear curved or bent inward toward the center of the image

Pincushioning

Parts of the image white out, loses visual sharpness

Blooming

High energy xay photons hitting the input phosphor can cause?

Blooming

Peripheral fall off of image brightness with image intensifiers is primarily due to the?

Concave; curved shape of the input phophor

Which of the following minimizes the fluorscopic image blooming with image intensifiers

more precise positioning of the patient anatomy

Flat panel detectors have the same components as?

Indirect DR

Benefits of flat panel detectors?

Less bulky and easier to maintain

Flat panel detectors have a _____ FOV and ____ dynamic range

Larger; wider

Which is more efficient Image intensifiers or flat panel detectors?

Flat panel

Basically the only con of flat panel detectors over image intensifiers?

Flat panels are more expensive

What causes magnification mode

Increases voltage to electrostatic lenses

Magnification factor formula

Full size/Selected size

Magnification _____ patient dose and _____ image quality

Increases; increases

mA levels in conventional fluoroscopy?

.5-5 mA

Magnification mode has what effect on patient dose?

Increases

What is the advantage of using a fluoroscopic unit with a digital detector system over a system using image intensifiers?

Lower radiation dose to the patient

During a fluoroscopic exam, using a higher kVp and lower mA would ___ the DAP to the patient

Reduce