Quiz 1 Flashcards
Which of the following is impervious to the penetration
of x-rays?
Lead
The quality of energy that is produced by the central
x-ray is determined by the:
kVp
The size of the collimated x-ray beam for an intraoral
radiograph is measured at the patient’s skin at:
2.75 inches
What is the purpose of the lead collimator in the
dental x-ray tube head?
Retards the size of the x-ray beam
The maximum protection for the patient is provided by a:
Lead shielded, open-ended P.I.D.
How does filtration of the x-ray beam protect the patient?
Elimination of weak wavelengths from the x- ray beam
A woman who is pregnant should:
Avoid x-rays during the first trimester of pregnancy.
Where does secondary radiation emanate from?
All of the above
When exposing an intraoral radiograph, where should
the operator stand in order to be in a protected area?
At least six (6) feet from the x-ray tube head
Proper collimation for the film size and target–film distance will
Decrease the radiation received by the
patient.
The quality, or penetrating power, of secondary radiation is
Less than that of primary radiation.
To avoid exposure to secondary radiation, the operator should stand
At least 6_____ from the x-ray tube head
The dental assistant’s goal in radiation protection is zero occupational exposure. This is accomplished by
- Never holding the film for the patient.
- Always being 6 feet away from the machine.
- Working in a shielded area.
- Wearing a film badge.
all of the above
After each use, the lead lap apron must be
Draped over a support rod unfolded.
The best technique for reducing the radiation exposure to both patient and operator is the use of
Fast film
If the mA is increased while the kVp and the exposure time are kept constant, the resulting films will
Be darker
For maximum penetration of x-rays, which of the following combinations would you select?
90 kVp and 10 mA
Which of the following is not a main component of a panoramic x-ray unit?
Panoramic film
Why does digital radiograph require less radiation than traditional x-rays?
It uses lower wave-length radiation
Which type of radiation initially comes from the x rays tube?
Primary radiation
A lead apron with a thyroid collar will protect a patient from what type of radiation?
Scatter
The x-ray tube has a positive side called the anode and a negative side called:
Cathode
The production or boiling off of electrons from the heated tungsten filament is called:
Thermionic emission effect
The unit of measurement used to described the amount of electric current flowing through a circuit is called:
Ampere
The term used to describe the electric potential or force that drives an electric current through a circuit is called:
Voltage
The target of the x-ray tube is also called the:
Focal spot
The x-ray at the center of the beam is referred to as the
Central ray
The quality or penetrating power of the x-ray beam is controlled by:
Kilovoltage
The range _____ is used for the dental radiograph.
65 to 100 kVp
What determines the number of x-rays produced in a given exposure time period by controlling the heating of the tungsten filament?
Milliamperage
Miliamperage higher than 15 would produce too many electrons bombarding the target and too much heat
True
Federal regulations require that long non-penetrating rays are removed from the primary beam. This is accomplished by a:
Filter
Federal regulation require that for dental x-ray machines operating above 70 kVp, the thickness of the filter must be
2.5 mm thick
The size and shape of the x-ray beam as it leaves the tube head are restricted by
Collimator
The diaphragm is made out of:
Lead
According to federal regulations, the size and shape of the x-rays beam should not exceed ________in diameter.
2.75 inches
The radiation that originates from the target of the x- ray machine is referred to as:
Primary radiation
The radiation that results from the interaction of primary radiation with matter is called:
Secondary radiation
The degree of blackness or darkness on a radiograph is referred to as:
Density
The difference in the degree of blackness or darkness between adjacent areas on a processed radiograph is referred to as:
Contrast
The object contrast is determinate by:
A. The thickness of the object
B. The density of the object
C. Chemical composition of the object
D. Quality of the x-ray beam
E. Scatter radiation
F. All of the above
The image difference between the films produced at the different kVp choices in the dental range is the resulting contrast.
True
High contrast film will appear:
Black and white and short scale
A and C
As you increase your kVp, the contrast will:
Decrease
Scatter radiation causes:
Film fog
Film contrast is determined by:
A. The amount of radiation transmitted
B. The type of film
C. Intensifying screens
D. Film processing
E. All of the above
The distance between the focal spot at the anode and the film in the patient’s mouth is referred to as:
A. Focal-film distance
B. Anode-film distance
Both
The measurement of ionization in the air is referred to as:
Roentgen
The radiation that is produced by the machine is referred to as:
Exposure
Radiation that escapes through the protective shielding of the x-ray tube head is called:
Head leakage
The operator should stand a minimum of ____feet away from the tube head.
6 feet
The maximum permissible dose of whole body radiation for dental personnel is:
5 Rem per year
The maximum whole body dose that a worker is allowed is:
100 millirem per week
If the proper exposure time at 15 mA and 65 kVp is 0.25 seconds and an 8 inch FFD is used, what would the exposure time be at 16 inches?
1.0 seconds
A ______ is a personnel monitoring device that can be worn by the staff to measure radiation received.
Dosimeter
When an x-ray causes an electron to be ejected from its orbit, the effect is called:
Photoelectric effect
When the electrons bombard the target in the x-ray tube, what percent of the energy produced is radiation?
1%
When an x-ray causes an electron to be ejected from its orbit, it is called:
Ionization
Primary radiation is the energy contained by the x- rays that come from the target of the x-ray tube.
True
Secondary radiation is defined as radiation that comes from any matter being struck by primary radiation.
True
The radiation dose is the measure of ionization that is in the air.
False
The positive side of the dental x-ray tube is called the
ANODE
The ___________ is the unit of measure used for
measuring the exposure the air.
ROENTGEN
X-rays of longer wavelengths that have low penetration are called _____________.
SOFT X RAYS.
The distance from the crest of one wave to the crest of another wave is called
WAVELENGTH.
The legal limit of how long a dentist must keep a patient’s x-rays is _____ years.
7 years
The x-ray at the center of the primary beam is called the
Central ray
________________________ The electrical pressure or force that drives the current through a circuit of the x-ray machine.
VOLTAGE
________________________
A unit of electromotive force or potential.
Volt
_____ a device that is used to measure density and contrast
Step wedge
________________________ A device used for
measuring the electromotive force across the x-ray tube.
VOLMETER
_______________________ Electric device that is capable of increasing or decreasing voltage.
TRANSFORMER
______________________Part of the primary beam that is permitted to emerge from the housing of the tube.
USEFUL RADIATION
