Shared Flashcard Set

Details

Radiation Characteristics
Chapter 3-Radiation Characteristics
50
Other
Professional
09/30/2012

Additional Other Flashcards

 


 

Cards

Term
What is quality?
Definition
the penetrating ability of an Xray beam
Term
What is quality controlled by?
Definition
kilovoltage
Term
What does wavelength determine?
Definition
the energy and penetrating ability of the xray beam
Term
Do xrays with shorter wavelengths have more or less penetrating power?
Definition
more
Term
What is voltage?
Definition
force that drives an electrical current through the circuit
-effects how fast electrons travel from cathode to anode
Term
What happens to the speed of electrons when voltage is increased?
Definition
speed of electrons increases
Term
How many volts does a kilovole equal?
Definition
1 kilovolt=1000 volts
Term
How many kv does a dental radiography require?
Definition
65-100
Term
What happens if kv is under 65? Over 100?
Definition
inadequate penetration, over penetration
Term
What is kVp
Definition
peak voltage of alternating current
Term
What is an alternating current?
Definition
current that flows both directions
Term
What is quality controlled by?
Definition
kVp
Term
What does kVp regulate? What does it determine?
Definition
the speed of electrons, the penetrating ability of xray beam
Term
How does kVp affect density?
Definition
increase kVp=darker density

decrease kVp=lighter
Term
What is contrast?
Definition
varying shades of grey-
high contrast=just whites and blacks
low contrast=many shades of grey
Term
How does kVp effect contrast?
Definition
High kVp=low contrast
Low kVp=high contrast
Term
What are high contrast radiographs used for?
Definition
detection of caries
Term
What are low contrast radiographs used for?
Definition
Detection of periodontal or periapical disease
Term
What is considered low and high kvp?
Definition
low-65-70
high-90<
Term
If you have a high kvp what will the density and contrast be like?
Definition
high density, low contrast
Term
If you have a low kvp what will the density and contrast be like?
Definition
low density, high contrast
Term
How is exposure time of radiographs measured?
Definition
impulses
Term
How many impulses are in a second?
Definition
60 impulses
Term
what is something you must change if you change kpv?
Definition
exposure time
Term
If you increase kvo then what should you do to exposure time?
Definition
decrease it
Term
if kvp is increased by 15 then what should you do with your exposure time?
Definition
cut it in half
Term
If kvp is decreases by 15 then what should you do with your exposure time?
Definition
double it
Term
what is beam quantity?
Definition
number of xrays produced in the dental xray unit
Term
What is amerage?
Definition
Determines number of electrons passing from cathode to anode
Term
What is quantity controlled by?
Definition
milliamperage
Term
1 amp=how many mA?
Definition
1 amp=1000 mA *or*

1/1000 amp= 1 mA
Term
What is the mA range of dental radiography?
Definition
7-15
Term
What will anything higher than 15 mA cause?
Definition
too much heat
Term
What does mA regulate?
Definition
the temp of the tungstan filament the cathode
Term
what are three things a increase in mA causes?
Definition
1.Increases number of electrons produced in cathode
2.Increases number electrons to strike anode
3.Increases number of xrays emitted from the tube
Term
How does mA effect density?
Definition
increase mA results in a increase in density
Term
What are two things that regulate the number of xrays being produced?
Definition
mA and exposure time
Term
What is the formula for mA and exposure time?
Definition
mAxsec=mAs
Term
What determines the intensity of the xray beam?
Definition
quantity and quality of xray photons
Term
What are four components that contribute to intensity?
Definition
1.mA
2.kVp
3.Distance
4.impulses
Term
What is the equation used to determine intesity?
Definition
intensity= (mAxkVp)/(distanceximpulse)
Term
What does kVp do?
Definition
regulates the penetrating power of the xray beam by controlling speed of electrons traveling between the anode and cathode
-effect quality
Term
What does mA do?
Definition
controls the penetrating power of the xray beam by controlling the number of electrons produced in the xray tube and the number of xrays produced
-mA effectss quantity
Term
What does increasing exposure time do?
Definition
increases number xrays, increases intensity, increases density
Term
How does distance effect the penetrating power of electrons?
Definition
the greater the distance the less the penetrating power
Term
What is the inverse square law measuring?
Definition
intensity's relationship to distance
Term
What is the inverse square law?
Definition
I1/I2=(D2)^2/(D1)^2
Term
Where are aluminum filters found?
Definition
placed in path of the beam inside of the dental xray tubehead
Term
What do aluminum filter do?
Definition
help us filter out low energy, longer, less penetrating energy waves
Term
What is the half value layer?
Definition
the thickness of aluminum that reduces the intensity of the xray beam by halk
Supporting users have an ad free experience!