Exam 3 principles II

History of Fluoroscopy

Fluoroscopy was invented by Thomas C. Edison, with the first commercial fluoroscope available in 1896, producing faint images and requiring dark adaptation.

Image Intensification

A process involving several components: input phosphor, photocathode, electrostatic focusing lenses, and output phosphor, which collectively enhance the brightness and clarity of the imaging.

Electrostatic Focusing Lenses

Charged plates in the image intensifier that repel electrons and focus them toward the output phosphor using electrostatic repulsion.

Output Phosphor

The final component of the image intensifier that absorbs electrons and emits multiple light photons, greatly increasing image brightness compared to the input phosphor.

Camera Tube

A device attached to the image intensifier that converts the light signal from the output phosphor into an electronic signal for processing and display.

Minimum Source-to-Skin Distance

The requirement that the distance between the x-ray tube and the patient’s skin must not be less than 30 cm to ensure patient safety.

Fluoroscopic Mode vs. Radiographic Mode

In fluoroscopic mode, low mA (2-5 mA) is used for real-time imaging, whereas in radiographic mode, high mA (100-1200 mA) is utilized for capturing static images.

Photospot Camera

A device that allows radiologists to view and record images while they are being recorded, improving accuracy and quality of assessment.

When increasing the kVp in Fluoroscpy….

it increases the avg energy of the primary beam

During image intensification, it takes _______ electron(s) to make ____ light photons

one; many

The Electric charge of D

negative

Image intensification process in order, from Exposure to display

x-ray photons, light photons, electrons, light photons, electrons

which substance is used as the photodetector in digital fluoroscopy flat panel detectors

Amorphous Silicon

Which of the component is typically composed pf Cesium and Antimony

Photocathode

G

output phosphor

What is the minimum SSD for a Mini C-Arm

45 cm

What is the milliamperage range that is commonly used in image intensified fluoro

0.5-5 mA

Equation for Minification Gain

What component is D

Electrostatic Lens

Brightness lag occurs when…

ABC adjusts for varying part thickness

Disadvantage of using mag mode in conventional fluoroscopy

increased patient dose

C

photocathode

avg size of input phosphor used in image intensification

25 cm

What formula measures radiation dose received by tech standing in room during an exposure compared to patient dose

inverse square law

in an imaging intensifier which device is located closest to the output phosphor

anode

What component is F

accelerating anode

image intensification steps from beginning to end

x-ray photons are converted to light, light photons are converted to electrons, electrons merge to a point, and electrons are converted back to light at output phosphor

During image intensification, it takes ___ light photon(s) at the photocathode to create ____ electron(s)

many; one

purpose of red goggles in early fuoroscopy

adjust viewer’s eyes to better visualize dim images

equation for magnification mode

full size input of phosphor / selected size of input phosphor

What mA is more common in digital fluoroscopy when a FPD is utilized

50 - 1200 mA

point of intersection

focal point

what component of the image intensification faces the patient

input phosphor

what term describes the number of images per second in a pulsed fluoroscopy

pulse rate

what type of phosphor is commonly used in the indirect-capture of digital fluoroscopy

Cesium Iodide

What is the electric charge of F

positive

what technique absorbs x-rays with a photoconductor in fluoroscopic imaging

direct capture FPD

this describes the ratio of light photons at the output phosphor compared to the number of x-ray photons at the input phosphor

flux gain

during magnification mode in fluoro the electrostatic lens receive ___ _____ cahrge

increased negative

this term describes the length of each pulse in pulsed fluoroscopy

pulse width

input phosphor_____ and emits _____.

remnant beam; light energy

flux gain equation

#light photons at output phosphor/#x-ray photons at input phosphor

what component is B

input phosphor

Brightness gain of the image intensifier is the:

combination of minification gain and flux gain

What component is responsible for the process of photoemission

photocathode

What device prevents ghosting in flat panel detectors?

backlighting

What percentage of DEL is composed of scintillating material

80%

what type of phosphor is commonly used in conventional fluoroscopy?

Cesium Iodide

function of electrostatic lens in image intensifier

repel electrons

B

input phosphor

what is the constant charge of the accelerating anode

25 kV

What is the minimum SSD for a C-Arm

30 cm

order of image intensification in fluoroscopy

input phosphor, photocathode, electrostatic lens, anode, output phosphor, camera tube, ACD

G

output phosphor

function of anode in the image intensifier

attract electrons

What absorbs x-ray photons with scintillator in digital fluoroscopy

indirect-captured -FPD

this term represents the ability of an image intensifier to convert x-ray energy into light energy and increase brightness of the image in the process

brightness gain

What are associated with magnification in image-intensified fluoroscopy

Higher patient dose and smaller input phosphor use

what is the type of phosphor used in the direct flat panel detectors?

N/A none are used

what is the minimum amount of lead required for protective aprons used in fluoroscopic imaging

0.5 mm Pb

in the image intensifier, the output ohosphor:

absorbs electrons and produces a brighter image

The focal point of an image intensifier is….

where electrons convergewh

what. occurs when electronic magnification is used?

FOV enlarged to fill display screen

input phosphor

absorbs x-ray photons and emits light

what is the input phosphor made up of?

Cesium Iodideor Sodium Iodide crystals.

accelerating anode

attracts electrons toward output phosphor

in image intensification the input phosphor….

absorbs remnant beam and emits light in response

brightness gain

ability of the image intensifier to convert x-ray to light

a higher brightness gain will create…

greater efficiency of image intensifier

why is more radiation needed as the image intensifier ages

it loses its efficiency and needs more radiation to produce same brightness level

minification gain

diameter of input phosphor vs diameter of output phosphor causing a brighter image output