Final Review Flashcards
How do you clean intensity screens?
Use manufactures cleaner and gauze
What color is the filter for rare earth film-screen systems?
Red
What is the specific name for the red safelight
GBX
Can pregnant women take x-rays?
Yes
Who receives somatic effects of radiation?
Exposed patient, these effects are increased incidence of cancer, effects on the developing embryo, cataracts, and life span shortening
Why do we leave the developer lid open at night?
Cross Contamination of fixer and developer due to condensation
Describe the degree and direction that can be used with a single cross hatched grid?
Perpendicular, no degrees
What is the relationship b/t Compton scatter and collimator field size?
Inverse, as you inc. collimation you dec. scatter
What is the new mAs 80 SID if old is 5 @ 40 SID?
20 mAs
What is the whole bod occupational exposure allowed for pregnant radiation workers?
.5 REM/gestation period
What is the whole body non-occupational exposure allowed for the general public?
.1 REM/year
Describe the effect of oxidizing developer has on the density of films?
Decreases density so films get lighter
White areas on film are a result of this x-ray w/ matter?
Photoelectric absorption
Probability of compton interaction increases when kV____
Increases
Define leakage radiation
Any radiation coming from tube housing other than from the port
Where is hydroquinone?
Developer
Random effects such as cancer are called?
Stochastic
Define total filtration
Combination of added which is equivalent to 2 mm of Al and inherent which is .5 mm from the Pyrex tube itself there going you 2.5 mm of Al equivalent
What happens to the x-rays in photoelectric interaction?
Photoelectric Absorption
What is hormesis?
A bit of X-ray is good for you
Where would you find the clearing agent, hardener, and preservative?
Fixer
Improper grid radius results in this kind of cute off?
Both sides underexposed
Name two radiation induced malignancies
Leukemia, Skin, bone, lung, thyroid, and breast cancer
Height of lead strips divided by width of lead strips is called?
Grid Ratio
Name two devices used to reduce scatter
Compression band, Collimator, grid
What is the relationship b/t patient thickness and Compton scatter?
Direct, inc. atoms—>inc. scatter
What size grid is appropriate for 14x17 films?
10:1
What size grid is appropriate for 14x36 films?
12:1 or 16:1
What type of grid should you buy if you are using both 14x36 @72 SID and 14x17 @ 40 SID?
Parallel
What is PBL?
Auto collimation–positive beam limitation
What is the purpose of the air gap?
Decrease scatter
What is the advantage of using air gap technique?
Reduce patient exposure
Describe grid cut off with lateral angulation error
One side underexposed
Define latent image.
Image on film before developing
Where is the hardener in auto developer?
Developer and Fixer
What is the current cumulative life time exposure factor?
Age times 1
As TFD increases what happens to blur?
Decreases, TFD=SID
What is the occupational whole body exposure amount?
5 REM
What is the annual MPD for extremities?
50 REM
Where do you wear film badges?
Collar
Where does a pregnant woman wear film badges?
Collar and waster over lead apron
How is a safe light filter installed?
Gel Substance is on outside so you should be able to read the letters
Where does silver recovery happen?
Fixer
What is the max watts for safe light?
15
How far should the safe light be from the work station?
4 feet
Describe the appearance of oxidized developer?
Used motor oil
What is the purpose of intensifying screens?
Decrease pt exposure
Quantum mutual is caused by>
High speed/screen film combo
What is the relationship between crossover exposure and blur?
Inverse, decrease cross over increase blur
What color should you paint your dark room?
White
What kind of contrast do you get w. high kV and low mAs?
Long Scale
What will happen to film if it spends excess time in the developer?
Darker
What will happen to film if developing temperature is to warm?
Darker
Hypo
Fixer
IF x-rays turn yellow or stab with age what caused that?
To much fixer
If you have a fixed kvp chart then you must have?
A mAs that will change
Optimal kVp for extremities is ____ and for body is _____
50-60 and 70-90
How does grid ratio affect patient exposure?
direct
What is the grad ratio for upper cervical?
8:1
Name 3 things that affect Compton scatter
Pt thickness, collimation, kV
How does use of a small filament/focal spot effect the radiograph?
Increase detail sharpness
3 factors that influence Compton scatter production
kVp, Collimated area, compression
How does collimating to a smaller area effect contrast?
Contrast is increased
Name two radiosensitive cells
Lymphocytes and sperm+eggs
State two factors that increase the probability that a photon will undergo a photoelectric absorption interaction
Low kVp and High atomic #
Dosimeter reports express occupationally exposed persons does in _____ units
REM
Increasing OFD _____ detail Sharpness
Decreases
When collimating from a 14x17 area to an 8x10 area the mAs must?
Be increased by 50%
Using oxidized developer ____ density and contrast
Decreases
State two conditions for using a bucky grid
Greater than 10 cm and kVp greater than 60
What is the purpose of using a bucky grid?
To reduce scatter radiation
State one of the purposes of the fixer solution
To clear the unexposed silver halide
Where should a radiation dosimeter be worn?
On the collar, outside the apron
To maintain radiographic density: If the mAs is decreased by 50% the kVp should be?
Increased by 15%
This technical factor controls the quantity of x-rays in the beam
mAs
kVp controls this photographic property
contrast
Name 3 radiation protection devices
Filter, Collimator, Intensify screen, Lead shield, Lead apron
Name the crystals found in the film emulsion
silver halide
The developer solution converts silver halide crystals to?
Black metallic silver
Define linearity
The ability to manipulate mA x sec= mAs and achieve the same radiographic density
State the charge that is on the focusing cup
Negative
This type of ionizing radiation can be stopped by the outer layers of the skin
Alpha Particle
State the two parts that make up the cathode
Filament and Focusing Cup
X-rays are produced by ____ Current
DC
What does a rectifier do?
Converts from AC to DC
The anode side of the tube should be ____ when imaging an AP thoracic
Up
In the x-ray tube, the electrons travel from the ____ to the _____
Cathode to Anode
How often must lead walls be replaced?
NEVER
Assuming patient motion may be an issue how should mA and time settings be set?
Highest mA shortest time
Assuming all other factors are constant, as exposure time increases, image density _____
increases
The _____ side of the image will exhibit the least radiographic denisty
anode
How do you select the small filament on the console?
Select a low mA setting
Descrive a photon in term of mass, charge, and velocity
No mass, No charge, and travels at the speed of light
What photographic property does mAs control?
Density
The _____ controls the wavelength of the x-rays
kVp
Compare the wavelengths of the x-rays to radio waves
X-ray wavelengths are shorter
