Amount of density a film produces for a given amount of exposure
Film that is an exact copy of a radiograph and is already presolarized
Duplication Film
Presolarized
Exposing the film up to the point of the reversal phase, can only become lighter
what type of film is used for cerebral angiography?
Subtraction Film
Film should be stored______, at the temp of______, and _____ - _____ % humidity.
on end
68 degrees F
30-60 %
The process of turning a latent image into a visible/ manifest image is called..
Automatic Processing
4 steps of automatic processing
1. developing
2. fixing
3. washing
4. drying
The reducing agent is part of the __________solution and consists of ______ and ______.
developer
Phenidone
Hydroquinone
Phenidone provides ______ & ______ shades. It also works ______.
fine detail & gray
quickly
Hydroquinone controls the _____, heavy shades of ______.
slow
black
When P & Q work better together, its called?
superadditivity
Oxidize-
Reduced-
reducing agent gives up electron
silver ion accepting an electron
The more exposure = _____ black metallic silver atoms = _______ film
more
darker
Activator (devloper)
creates an alkine enviroment, which makes the reducing agent work
Restrainer (developer)
prevents reducing agents from over reacting/ keep darkening the film
Preservative (developer)
decreases oxidation of reducing agents when exposed to air (styrofoam)
Hardener(developer&fixer)
controls swelling of the gelatin
Water (developer & fixer)
SoLvEnT
Fixer can't get into the developer due to the acidity of the fixer, if this would happen it would cause?
contamination
Clearing Agent
Fixer
Removes unexposed silver hallides from the film
Activator (fixer)
maintain fixer acidity
makes the reducing agents stop working because of the low pH
Preservative
fixer
keeps fixer from being exhausted
ammoniumthosilversulfate = ammoniumthiosulfate
takes silver out = silver recovery
Archiving consists of 3 processes.
Washing- gets excess fixer & developer from film
Drying
Storage
Too much fixer left on the film causes________ and is called _________.
film to be yellow
Fixer Retention
Transport system consists of...
Rollers
Racks
motor driven
volume replinishment
high # of flims going in/out of processor
replenished w/ each new film
What type of replenishment system has.. low number of films, refills chemicals hourly, timer controlled, and helps with mixing new chemicals
flood replenishment system
Silver is found on ______ & ______. Its recovered by ____________________________
fixer and film
providing electrons to make black metallic silver
What has more sliver, developed or undeveloped?
undeveloped (x2)
The measure of characteristic responses the film has to exposure & processing is called?
sensitometry
This device is made up of aluminum and provides a range of densities on a film. Two names..
Pentrometer
Step Wedge
This device uses a light source, not an actual xray machine & is used to tell how well the processor is fucntioning.
Sensitometer
What is the function of a desitometer?
To read the degree of blackening on a film
Optical Density formula...
OD = log10 Io/ It
Opacity formula and definition of ...
Opacity = Io/It
films ability to stop light
Other names for D log E curve (3)
Characteristic
Sensitometric
Hurter & Driffield (H&D)
B + F
Base + Fog
density of the film at no exposure
Toe
phenidone
controls grays early on
shoulder
hydroquinone
controls blacks later on
Part of the curve where diagnostic info is found
straight line portion
Dmax
max. density the film is capable of recording
-all the silver hallides have all the silver atoms they can except
more exposure = less density
- called solarization
Resolution is..
sharpness AND detail
bigger crystal size = less resolution
graininess = poor resolution
The amount of density a film produces for a given amount of exposure is called..
Film speed
film speed is controlled by
Speed goes up = patient does decreases
phenidone (toe portion)
large crystal size = high speed= decrease in resolution= less patient dose (T or F)
thin emulsion = high speed= low resolution = less patient dose (T or F)
True
False (thick emulsion)
Contrast in terms of the D log E curve is defined as
slope of the straight line portion
Average Gradient
straight line portion of D log E
(OD .25 + b + f & OD 2.5 + b + f)
what we can see
The width of exposures that will produce densities in the diagnostic range.....
latittude
latittude increases = contrast decreases
Device inside the cassette that contains phosphors that absorb xray photons & emit light photons
1% xray, 99% light
Intensifying Screen
Emission of light from intenisifying screen when stimulated by radiation
Luminescence
good phosphors, only emit light when exposed to radiation
fluorescence
phosphors continue to clow after the exposure has stopped
Phosphorescence
AKA- screen lag, after glow
What is considered the active layer of the intensifying screen
phosphor layer
what is the reflective layer of the intensifying screens job?
to reflect light back towards the film
single emulsion cassettes, what way does the film have to be placed in it?
emulsion side of film down on top of intensifying screen
creates less OID
Calcium Tungstate intensifying screen
old, glows blue
Rare earth intensifying screen, why used today (3 things)
1. greater absoprtion
2. better resolution
3. produces more light - glows blue & green
Intensifying screen speed
capability of film to produce light
high screen speed= less patient dose ( high kVp, low mAs)
Describe Quatum Mottle & what is the cure
occurs when too few photons form an image
less than 3 silver ions on sensitivity speck
salt & pepper apperance
Cure- high mAs, low kVp OR slower screen speed
good film screen contact creates...
good resolution
no hair/dirt b/w film and intensifying screen
Mwatching the color the phosphors of the screen glow to the sensitivity of the film is called...
spectral matching
spectral emission = color the screens glow
Relative Speed
RS # goes up = patient does goes down = resolution goes down = fast film screen combo = less latittude
mAs1/mAs2=RS2/RS1
What is line spread function?
LSF
measures the boundries
what is modulation transfer function?
MTF
compares the detail
Resolution...
lp/mm
5 lp/mm is what we can see (dont get tricked, 10 lines= 5 line pairs)
how is resolution limited?
by the intensifying screen
Hi..
i'm disgusted with how many cards this turned into and i'm never typing them again. It gives my pinky a hinky feeling after I type too much.
