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
How must mAs be adjusted to double image density?
100% or double
You experience a tube overload what should be done to correct it?
Decrease mA and increase time
mAs can be rounded ____ without a change in radiographic density
30%
State the formula for REM
RAD x QF
What is the relationship b/t x-ray frequency and wavelength?
inversely related
State the heat unit formula
kVp x mAs
Which x-ray production method is respobsible for producing the majority of the x-rays in the beam?
bremsstrahlung
Optimum kVp for extremities under 10 cm is in the _____ range
50-60
This type of rectification produces the highest energy x-ray?
High frequency (Three-phase as well)
Describe the bremsstrahlung x-ray production process:
Electron is decelerated by the nuclear force field and changes the direction. Kinetic energy is converted to EM radiation.
State the optimum kVp range for spine imaging
70-90
Is optimum kVp higher for high frequency or full wave rectification?
Full wave
Define ALARA
As low as reasonably achievable
_____mRad=1 RAD
1000
Why doe sth path of film travel matter in automatic processing?
Chemical replenishment rates
The anode side of the tube can be located by?
Positive Label, Listening for the spin , finding the wire for the AC current
What is radiographic density?
Blacks on the film
Which side of a radiograph will exhibit the least radiographic density?
Anode
Where should the anode side of the tube be placed when performing a lateral thoracic spine radiograph?
Down
Where should the anode side of the tube be placed when performing a lateral lumbar spine radiograph?
Up
Where should the anode side of the tube be placed when performing an AP thoracic spine radiograph?
Up
Where should the anode side of the tube be placed when performing a full spine radiograph on a 14x36 film?
Up
Where should the anode side of the tube be placed when performing a lateral cervical?
It doesn’t matter on a 10x12 film at 40
When the anode heel effect becomes important in terms of film size and SID
Large film sizes at short SID
How does placing the anode/cathode side in the proper place affect the radiograph’s overall density.
Produces uniform in density
How should you have your tube installed?
Anode
Which side of the radiograph will be the sharpest?
Anode
What causes fog?
Compton scatter x-ray interaction w/ mater
Another name for a radiographic grid?
Bucky
Photographic factor that improves with the use of a radiographic grid
Contrast
Above this energy Compton scatter increases so much that it is necessary to use a radiographic grid
> 60 kVp
cm thickness of the patient’s anatomy in which it becomes necessary to use a radiographic
> 10cm
Appx cost of a 14x17 radiographic grid
$1000
Grid stip material that absorbs Compton Scatter
Lead
Typical grid strip interspace material
Aluminum
The number of grid strips per centimeter or inch
Grid Frequency
High frequency radiographic grid does this
Decrease the visibility of grid lines
Causes the shadows of the grid strips blur out and become almost invisible
Moving grid
Direction that the x-ray beam may be angled when using a parallel or focused grid
Cephalad or caudal
Direction that x-ray tube can not be angled when using a grid
Left or Right
Grid in which the strips are angled so that divergent x-ray beam coincides with the angled strips
Focused Grid
Radiographic grid that is not useful in chiropractic
Crosshatch grid
This happens when the lead strips absorb the primary radiation on one or both lateral edges of the images
Grid cutoff
This will be indicated on a focused grid
Tube side
Increase in mAs necessary when using a 10:1 ration grid
mAs x 4
Ration grid adequate for low amounts of scatter production such as that produced in 8x10 and 10x12 upper cervical tech
8:1 and 10:1
Ratio grid adequate for large amounts of scatter production such as that produced in 14x36 Full Spine
12:1 and 16:1
Focal spot size depends upon?
Filament
If you double mAs what happens to density?
Double density
What type of rectification gives short exposure time
High frequency
What are the 2 aka’s for SID
FFD and TFD
What side of the tube has the greatest geometric sharpness?
Anode
What is the SI unit for REM?
Seivert
State the exposure factor representing the total # of X-rays in beam
mAs
The majority of x-rays produced in a beam are created via this process
Bremsstrahlung
State the technical factor that controls the energy of the x-ray
kVp
You need a ____ change in mAs to see a minimal change in density
30%
Radiographic density is controlled by?
mAs
What is the SI unit for R?
Coulombs/kg
How many Rem= 1 Seivert
100
What is the formula for heat units?
kVp x mAs
What is the relationship b/t frequency and wavelength?
Inversely related
How does kVp effect film density?
Raise kVp 15%, lower density by 1/2
How do you fix tube overload?
lower mA, raise time
if you double SID, what happens to the density?
1/4 it
What is the unit of energy absorbed in matter?
RAD
When is the exposure terminated?
When the light goes off
What is the SI unit for RAD
Gray
What doe the EMI motor do in the tube?
spins the anode
How often must the lead walls be replaced?
never
Why is the back of the cassette line with lead?
stop compton back scatter
Why do you put the film in the processor a certain way?
Controls the amount of chemical
What is the formula for REM?
RADxQuality Factor
In humans, what is most likely, a direct effect on DNA or an indirect effect on water?
Indirect effect on water
These “characteristic” x-rays are useful when produced in tungsten target
k-shell
What is the relationship b/t film screen system and sharpness?
Inverse, faster the speed the lower the sharpness
What is the relationship b/t system speed and quantum mottle?
Direct, faster the speed the more mottle
What is the relationship between system speed and exposure?
inverse
What part of the processing solution contains hydroquinone?
Developer
What is the purpose of using intensifying screens?
Lower patient exposure
As crossover increases what happens to the sharpness of detail?
It lowers
What is a laten image?
An image on the film you can’t see
Describe a long latitude film
More room for error due to a wide range of useful densities
How is quantum mottle reduced?
Lower the film screen system speed
What is another name for hypo?
Fixer chemical
The random effect for exposure
Stochastic effect
Producing an image with low kv and high mAs is?
short scale, high contrast
Silver is recovered from this solution
Fixer
When performing manual processing at 66 degress, what time do you need to process the film?
5.5 min
When x-raying for 14x36 what grid ratio should you use?
12:1
The percentage of time the primary beam is aimed at the wall is called its?
Use factor
Describe the effect of oxidized developer on the image density
Lower Density
What is a controlled area?
Anyplace where one has a benefit to being there that outweighs the risk of exposure
What cells are most resistant?
Nerve cells
What cells are most sensitive?
Lymphocytes
State the level at which no genetic or somatic damage will occur below
None
What is the advantage of a high frequency grid?
Don’t have to have a moving grid
What are the 3 cardinal principles of radiation protection?
Distance, time, shielding
State annual full body mpd to the public
.1 REM
What color should you not paint your dark room?
Black
What direction should the central ray point when using a linear grid?
Angled in the direction of the strips, cephalad or caudal
Black tree light effects are a result of?
Static
State maximum safe light bulb wattage
15 Watts
The dose-respones curve labeled “A” defines the LNT model
True
Which of these does-respones curves indicates that a threshold of exposure to radiation would be required before a response would be expected?
B
Which rectifier is consistent w/ ALARA concept?
High frequency
Ionization
The total removal of an electron from its atomic shell level
The quality factor of x-ray is?
1
REM=RADx_____
QF
5 rem = _____mrem
5000
Which x-ray interaction with matter is the most likely to happen in high atomic number matter?
Photoelectric Absorption
Which x-ray interaction with matter has a probability of occurring when the x-ray energy is in the 60-125 keV range?
Compton scatter
Which grid would require the most exposure to the patient?
16:1
X-ray beam may be angled in this direction when using a linear grid
Direction of the strips
Which grid requires that the SID be within a very specific range
Focused
Which imaging system to image extremities?
100 speed
Which imaging system will result in most quantum mottle?
1200 speed
The intensify of radiation standing 3 feet from the tube housing is 100 mR/hr. What is the intensify of radiation if you step back to 6 feet?
25mR/hr
As mA increases, the cathode filament
Gets hotter
What will produce the most skin does?
Short SID
Reproducibility
take the same exposure repeatedly with same result
Therapeutic absorption should not be considered with exposure below _____ RAD to the abdominal area of a pregnant woman
10
The ten day rule suggest that x-rays of a female with reproductive ability should only be performed?
In the 10 days following the onset of menstruation
A 16 year old is working for you for the summer. What is his/her annual MPD?
0.1 REM
If velocity is constant, when frequency increases, wavelength ?
Decreases
Controlling factor of radiographic contrast?
kVp
A patient who is very muscular will require an increase in kVp
Ture
Which of these standard chiropractic image can make use of the air gap technique to reduce patient exposure?
Lateral Cervical Spine
Use a long _____ will decrease magnification distortion
SID
Use of a long ______ will increase magnification distortion
OID
kVp controls the _____ in the beam,
Energy
Differential absorption of x-rays results in this image property
Contrast
When closing down a processor, it is important to be certain that?
The water is turned off and the drain is open
When anatomy is of various thicknesses, the use of ______ to achieve a uniform image density it is consistent with the consistent with the concept of ALARA
Compensating filters
Film badge dosimeter should be sent in for monitoring every?
Month
Human cells are capable of recovery from radiation effects
True
The purpose of the control badge dosimeter is to monitor background and transportation exposure to radiation and it should be kept next to the machines console.
False
High proliferative, poorly differentiated cells are very resistant to radiation effects
False
Short term radiation effects are exhibited in patients who have been exposed to diagnostic x-rays
False
Long term radiation effects may be exhibited in people exposed to diagnostic x-ray
True
Biological effects from x-ray exposure are the result of?
Ionization
Which trimester is the most risky to the fetus from exposure to ionizing radiation?
First
An abortion should be recommend to a pregnant who has had any diagnostic x-ray exposure to abdominal area
False
The anode side of the image will display the least radiographic density
True
