1.Who discovered x-rays?
X-rays was discovered by Wilhelm Konrad Roentgen
What are 9 characteristics of x-rays?
a. the ability to penetrate opaque
... [Show More] substances
b. the ability to affect silver halide salts on films in the same manner as light does
c. the ability to stimulate or destroy tissue by ionization
d. they travel at a constant speed, the speed of light
e. they cause fluorescence
f. they are high energy waves
g. they travel as electromagnetic waves or energy
h. they have no mass
i. they travel in a straight line and are invisible
What is ionization?
It is the production of ions by the removal of electrons from the atoms of the matter that is
struck by the x-rays
When does ionization occur?
Ionization occurs whenever x-rays penetrate matter
What is an electric current?
It is the flow of electrons from one point to another or through a conductor
What is an electric current measured in?
Electric current is measured in amperes
What is a direct current?
current flowing in one direction, that is, from positive and negative. Direct current can be
interrupted at certain set intervals
What is kilovoltage usually designated as?
Kilovoltage peak (kVp)
What is kilovoltage?
the measure of the force between the negative cathode and the positive anode and controls
the energy of the electrons striking the tungsten target.
What does kilovoltage control?
the penetrating ability of the x-rays
What is milliamperage?
- the measurement of the quantity or the number of electrons passing from cathode to anode
per second.
What does milliamperage have to do with the x-ray beams?
- milliamperage only deals with the strength of the x-ray beams
What is the maximum permissible dose for occupationally exposed persons?
- 5 rems per year (.1 in one week, 3 rem in any 13 week period)
What is the maximum permissible dose formula for occupationally exposed persons?
- MPD=5rem x (N-18)
What does the N stand for in the MPD formula?
- The patients age
What does the MPD formula subtract 18 from a person's age?
- because people 18 years or younger are not supposed to work around x-rays
What is erythema?
- a temporary reddening of the skin
What is an erythema dose?
- the amount of radiation necessary to produce erythema
What is a lead diaphragm and what is its purpose in the x-ray cone?
- The lead diaphragm is a metal disk 0.16 cm thick of lead with a hole in the center. Its purpose
is to collimate or limit the size of the beam of radiation.
What is primary radiation?
- radiation coming directly from the target of the x-ray tube
What is secondary radiation?
- radiation that is produced whenever x-rays strike matter.
When are secondary x-rays produced?
- when x-rays pass through the tissues of the face during dental x-ray procedures
What primary radiation that has been deviated in direction during passage through a
substance?
- scattered radiation
Where does leakage radiation come from?
- May come from the wall of the tube housing or may come from around the cone
What are the 3 important conditions necessary for the production of x-rays?
1. a source of electrons (heated filament)
2. a means of accelerating the high speed electrons between one third and one half the speed
of light (a high positive potential)
3. A means of stopping these high-speed electrons suddenly (tungsten target)
What is the focal spot of an x-ray tube?
- The small area on the tungsten target to which the electrons are directed [Show Less]