Radiation Characteristics Flashcards
What does the transformer do
alters voltage of incoming electric current
Cathode
-negatively charged
-supplies electrons to generate x-rays
Anode
-positively charged
-target for the electrons; converts the electrons into x-ray photons
Quality
amount of energy (penetrating power) of the x-ray beam ( kV)
Quantity
-number of photons in the primary x-ray beam
-product of current (mA) and exposure time (s)
Intensity
amount of energy emitted from source/ time and unit surface area
What primarily controls quality of the x-ray beam (wavelength and energy)
Kilovoltage
shorter wavelengths=
more penetrating power
longer wavelengths=
less penetrating power
What determines the speed of electrons that travels from cathode to anode?
Voltage (measured in kilovoltage due to use of high voltage in dental units)
1 Kilovolt (Kv) =
1000 volts
What is the range of kV used for dental radiographs
65kV to 100kV
*MCCC capable of producing 65kV
What is kilovoltage peak (kVp)
the maximum peak of voltage
Density
overall blackness or darkness of the image
Radiolucent
black areas
Radiopaque
white areas
True or False; Increase kVp increases density and vice versa
True
In order to maintain proper density, when kVp is increased what must be decreased
exposure time
Contrast
difference in degrees of density on the radiograph
High contrast
image has many black areas and many white areas with few shades of gray
-good for caries detection
Low contrast
image has many shades of gray
-good for detecting periodontal disease
higher kilovoltage= ______ contrast
lower
What is the purpose of a step wedge
-help calibrate the x-ray machine
-demonstrate density steps on the image corresponding to thickness
**usually made of aluminum
short scale image
low kVp
high contrast
