mobile & fluoro Flashcards
how far should you stand from the portable?
6 feet away (6ft cord w deadman switch)
the most popular type of portable
battery operated
what type of grid would you use for portables
lower grid ratio - 6:1 - 8:1
who invented fluoroscopy & when ?
thomas edison in 1896
dynamic imaging is
live imaging
designed to convert remnant radiation from the patient to an amplified light image
image intensification tube
fluoro x ray tubes use what type of mA ?
lower mA - 0.5-5 mA
(diagnostic is 50-1200)
what is the fixed tube target in fluoro x ray tubes
15” , used to prevent SOD (source to object)
emission of light is called
photoemission
the output screen absorbs the ________ & emits ______ ________
electrons , light photons
what is the active layer in the input screen
sodium activated cesium iodide
csl absorbs _____ of incident beam
66%
series of charged electrons in the glass envelop of the tube
electrostatic lenses
what reverses the image from the input screen image
focal point
the active layer in the output screen
sliver activated zinc cadmium sulfide phosphor
the measurement of the increases in image intensity achieved by an image intensification tube
total brightness gain
minification formula
minification gain = input screen diameter^2 / output screen diameter ^2
brightness gain formula
brightness gain = minification gain x flux gain
does flux gain increase or decrease image quality
causes a decrease
unit of luminous intensity
candelas
the measurement of the increase in light photons due to the conversion efficiency of the output screen
flux gain
automatically adjust exposure factor according to
pt density
what is apart of the video camera system, has fast response time, does not change exposure factors & works with an electronic signal
AGC - automatic gain control
warps the appearance of the image formed
pinchushion
what all is contrast affected by
scatter , penumbras light scatter, light scatter within tube
what is digital fluoro made up of that contacts the image intensifier output anode screen
TFT - thin film transistor
combining pixels to reduce noise (better detail)
pixel binning
advantages of digital fluoro include
high contrast , low dose, exam speed reduced
distance from the center of one pixel to the center of the next one in the display
pixel pitch
8 bit processing =
256 shades of gray
table top exposure should not exceed
10 R/ min
minimum SSD from mobile
12”
minimum SSD for stationary
15”
mag mode _______ pt dose
increases
lead apron & gloves should be at least ____Pb/eq
0.5mm
highest energy is at ____ degrees to the beam
90
lead shield on bucky slot cover & lead curtain should be at least ____ Pb/eq
0.25mm
name the 5 parts of the intensifier
input phosphor
photo cathode
electrostatic lens
accelerating anode
output phosphor
what is the emission of light from the photocathode called
absorption of light & emission of electrons
how does magnification of the image occur ?
change in voltage to lenses - changes focal spot
describe conversion efficiency
how well or how poorly the light conversion is at the output screen (light photons)
what kV is the anode inside the intensification tube supplied with
25 kV
what can be done to decrease quantum mottle
increase tube mA
battery powered portable units have a generator equal to what type of generator output
high frequency generators
