Term
|
Definition
Compared to visible light, x-ray photons have:
- greater velocity
- shorter wavelength
- lower frequency
- less energy |
|
|
Term
|
Definition
compared to radio waves, x-ray photons have:
- greater velocity
- shorter wavelength
- lower frequency
- less energy |
|
|
Term
|
Definition
Compared to gamma rays, x-ray photons have:
- greater velocity
- shorter wavelength
- lower frequency
- more energy |
|
|
Term
|
Definition
At what component of the x-ray tube are x-rays produced?
- filament
- focusing cup
- target
- added filtration |
|
|
Term
|
Definition
At what component are the electrons emitted from?
- filament
- focusing cup
- target
- added filtration |
|
|
Term
|
Definition
At what component are the electrons drawn across?
- filament
- focusing cup
- target
- x-ray tube |
|
|
Term
|
Definition
What component is tungsten:
- filament
- focusing cup
- target
- x-ray tube |
|
|
Term
|
Definition
Which of the following is true regarding brehmsstrahlung radiation?
- makes up 85-90% of x-rays produced in x-ray tube
- consists of x-rays with a single energy level
- results from interaction with K shell electrons in tungsten |
|
|
Term
|
Definition
Which of the following is true regarding characteristic radiation?
- makes up 85-90% of x-rays produced in x-ray tube
- consists of x-rays with a single energy level
- consists of x-rays with multiple energy levels |
|
|
Term
|
Definition
which components of the x-ray unit most directly control the energy level of the primary beam of x-rays?
- kVp and added filtration
- added filtration and exposure time
- exposure time and milliamperage
- Milliamperage and kVp |
|
|
Term
| exposure time and milliamperage (and kVp) |
|
Definition
which components of the x-ray unit most directly control the number of electrons in the primary beam of x-rays?
- kVp and added filtration
- added filtration and exposure time
- exposure time and milliamperage
- Milliamperage and added filtration |
|
|
Term
45
1 impulse/60 sec = x impulses/.75sec |
|
Definition
an exposure time of 0.75 second is equivalent to how many impulses?
- 0.125
- 0.75
- 3
- 7.5
- 45 |
|
|
Term
2.5 seconds
150imp x 1imp/60 sec = x imp |
|
Definition
150 impulses is equivalent to how many seconds?
- 9000
- 2.5
- 0.4
- 150 |
|
|
Term
|
Definition
Which component of the x-ray unit is may of molybdenum?
- filament
- added filtration
- target
- focusing cup |
|
|
Term
| greater thickness of tissue |
|
Definition
which of the following factors will increase the absorption of x-rays in matter?
- higher kVp setting
- shorter exposure time
- greater thickness of tissue
- lower atomic number atoms in tissue |
|
|
Term
65 kVp and 44 impulses
(You would lower the kVp and raise the impulses) |
|
Definition
your x-ray unit is set to 80 kVp, 10 mA and an exposure time of 22 impulses The dentist wants to increased the contrast of the images. Which of the following modifications will result in an increase in contrast with no change in the density of the image?
- 65 kVp and 44 impulses
- 65 kVp and 11 impulses
- 95 kVp and 44 impulses
- 95 kVp and 11 impulses |
|
|
Term
95 kVp and 11 impulses
(You would raise the kVp and lower the impulses) |
|
Definition
your x-ray unit is set to 80 kVp, 10 mA and an exposure time of 22 impulses The dentist wants to decrease the contrast of the images. Which of the following modifications will result in a decrease in contrast with no change in the density of the image?
- 65 kVp and 44 impulses
- 65 kVp and 11 impulses
- 95 kVp and 44 impulses
- 95 kVp and 11 impulses |
|
|
Term
|
Definition
which of the following position-indicating devices (PID) results in the smallest radiation dose to patient?
- 8" round
- 16" round
- 8" rectangular
- 16" rectangular |
|
|
Term
|
Definition
which of the following PIDs results in the greatest radiation dose to the patient?
- 8" round
- 16" round
- 8" rectangular
- 16" rectangular |
|
|
Term
| absorb low energy x0rays from primary beam |
|
Definition
The function of added filtration in the x-ray unit is to:
- absorb low energy rays from the primary beam
- absorb low energy electrons from the tube current
- absorb scattered photons from patient's head
- absorb photoelectrons produced in tungsten |
|
|
Term
| absorb x-rays in x-ray tube/head |
|
Definition
The function of inherent filtration in the x-ray unit is to:
- absorb low energy rays from the primary beam
- absorb x-rays in x-ray tube or head
- absorb scattered photons from patient's head
- absorb photoelectrons produced in tungsten |
|
|
Term
|
Definition
| Your normal exposure settings are 75 kVp, 10 mA, and an exposure time of 22 impulses If you accidentally set the exposure time at 15 impulses, how will the radiograph appear? |
|
|
Term
|
Definition
| Your normal exposure settings are 75 kVp, 10 mA, and an exposure time of 22 impulses If you accidentally set the exposure time at 50 impulses, how will the radiograph appear? |
|
|
Term
Use the mA-s law: to produce the same number of x-ray photons, the new mAxs must equal the original mAxs
10mA x 0.2s = 2mA-s
7mA x ?s = 2mA-s
2mA-s / 7mA = 0.28 s |
|
Definition
| one of your x-ray units operates at 10 mA and an exposure time of 0.2 second. Your new unit is set at 7 mA. If you want to produce the same quality of x-rays on the new unit, what exposure time should you select? |
|
|
Term
If the PID is longer, the intensity of the radiation is weaker. Double the length, intensity decreases (1/2)2 or 1/4 of the original intensity. So you must increase exposure time by 4times to make up for this change.
Tn/To = (Dn/Do)2
Tn= new exposure time
To= original exposure time
Dn= new PID length
Do= original PID length
Tn/0.12 = (16/8)2 = (2)2 = 4
Tn = 0.12 x 4 = 0.48 sec |
|
Definition
| Your unit operates at 70 kVp, 7 mA and an exposure time of 0.12 second with a PID length of 8". The dentist decides to use a 16" PID instead. What exposure time should you use to produce radiographs with the same degree of darkness? |
|
|
Term
If the PID is shorter, the intensity of the radiation is stronger. 1/2 the length, intensity increases (2)2 or 4 of the original intensity. So you must decrease exposure time by 4times to make up for this change.
Tn/To = (Dn/Do)2
Tn= new exposure time
To= original exposure time
Dn= new PID length
Do= original PID length
Tn/0.12 = (8/16)2 = (.5)2 = .25
Tn = 0.12 x .25 = 0.03 sec |
|
Definition
| Your unit operates at 70 kVp, 7 mA and an exposure time of 0.12 second with a PID length of 16". The dentist decides to use a 8" PID instead. What exposure time should you use to produce radiographs with the same degree of darkness? |
|
|
Term
0.56 second
(7mA x 0.8 second = 5.6 mA-s)
(5.6 mA-s = 10 mA x ? s)
(0.56 s) |
|
Definition
You are happy with the degree of darkness of the radiographs produced at settings of 7mA and 0.8 second exposure time. Your new x-ray machine has a setting of 10 mA. What exposure time should you use to produce radiographs with the same degree of darkness?
- 0.4 second
- 0.56 second
- 0.8 second (no change needed)
- 1.1 second
- 1.6 second |
|
|
Term
| shorter wavelengths, higher frequencies, greater energy |
|
Definition
compared to visible light, x-rays have which of the following?
- longer wavelengths, lower frequencies, greater energy
- shorter wavelentsh, higher freuencies, lower energy
- longer wavelengths, lower frequencies, greater energy
- longer wavelengths, higher frequencies, lower energy
- shorter wavelengths, higher frequencies, greater energy |
|
|
Term
| 24 (ximp/.4sec = 60imp/1 sec = 24 imp) |
|
Definition
an exposure time of 0.4 second is equal to how many impulses?
- 0.007
- 0.40
- 4
- 24
- 40 |
|
|
Term
| film exposed to visible light |
|
Definition
a radiograph emerges from the processor and is totally black. which of the following could explain this?
- film never exposed
- mA setting too low
- exposure time too long
- film exposed to visible light
- PID too short |
|
|
Term
| absorbs more x-rays, light |
|
Definition
compared to the soft tissue of the gingiva, a gold crown ____ and appears ____ on the radiograph after processing.
- absorbs more x-rays, light
- absorbs more x-rays, dark
- allows transmission of more x-rays, light
- allows transmission of more x-rays, dark |
|
|
Term
|
Definition
which of the following controls the energy level of the x-ray photons:
- kVp
- mA
- exposure time
- PID |
|
|
Term
|
Definition
your radiographs have proper degrees of darkness when exposed at 75 kVp, 7mA and 1.0 second exposure time with a 16" PID. If you replace the 16" PID and use an 8" PID, what exposure time should you use?
- 0.25 sec
- 0.5 sec
- 1.0 sec
- 2.0 sec
- 4.0 sec |
|
|
Term
|
Definition
approximately what percentage of interactions of electrons and target materialin the x-ray tube results in the production of x-ray photons?
- 1%
- 10-15%
- 50%
- 85-90%
- 99% |
|
|
Term
|
Definition
A radiograph of the mandibular molars is found to be too light. Which of the following could explain this problem?
- exposure too long
- PID length too short
- mA too low
- kVp too high |
|
|
Term
|
Definition
Who discovered x-radiation?
- Wilhelm Roentgen
- Albert Einstein
- Andre Ampere
- Alessandro Volta
- Malcolm X |
|
|
Term
|
Definition
the target of the x-ray tube is made of what material?
- copper
- tungsten
- lead
- aluminum |
|
|
Term
|
Definition
in a dental x-ray tube, two factors affect the quantity of x-rays photons produced but not the quality (energy) of the photons. What are these two factors?
- mA and exposure time
- exposure time and kVp
- kVp and inherent filtration
- inherent filtration and mA |
|
|
Term
|
Definition
An exposure time of 0.2 sec is equal to how many impulses?
- 0.003
- 0.2
- 12
- 20
- 120 |
|
|
Term
|
Definition
a radiograph comes out of the processor looking too dark. Which of the following could cause this error:
- exposure time too short
- mA setting too low
- kVp setting too low
- PID length too short |
|
|
Term
|
Definition
An x-ray unit produces radiographs of proper density at settings 70 kVp, 10 mA and an exposure time of 0.3 seconds. The dentist purchased a new x-ray unit that operates at 70 kVp and 15 mA. What exposure time should be used to produce the same amount of radiation as the first x-ray unit?
- 0.2
- 0.4
- 0.6
- 0.8 |
|
|
Term
| lower kVp instead of higher kVp |
|
Definition
Which of the following are associated with increased absorption of x-rays in a patient?
- soft tissues instead of hard tissues
- thinner tissues instead of thicker tissues
- lower kVp instead of higher kVp
- lower exposure time instead of higher exposure time |
|
|
Term
|
Definition
A dentist uses an 8" PID on his x-ray machine with settings of 80 kVp, 10 mA and an exposure time of 10 impulses. He replaces the 8" with a 16" PID. What exposure time should he use to produce the same intensity of radiation on the film?
- 2.5
- 5
- 20
- 40 |
|
|
Term
|
Definition
If you change from a 8" to a 16", how will the radiograph appear if the dentist does not change the exposure time when using the 16" PID?
- too light
- too dark
- fogged
- increased contrast |
|
|
Term
| contrast is increased with lower kVp |
|
Definition
which of the following statements about radiographic contrast is true?
- contrast is the amount of darkness on the radiograph
- contrast is increased with shorter exposure time
- contrast is increased by scattered radiation
- contrast is increased with lower kVp |
|
|
Term
| shorter wavelength that visible light |
|
Definition
Which of the following is true regarding x-rays?
- (+) charge
- shorter wavelength that visible light
- mass = to e-
- absorbed more in soft tissue than in bone
- lower frequency than radio waves |
|
|
Term
|
Definition
A dentist uses a 12" PID for periapical radiographs, with an exposure time of 24 impulses. To expose an occlusal readiograph, he uses an 8" circular PID. What exposure time should he use with the 8" PID?
- 96
- 56
- 24
- 11
- 3 |
|
|
Term
|
Definition
If you go from 12" PID to a 8" PID, how will the occlusal radiograph look if no change in exposure time is made?
- clear
- too light
- accurate
- too dark
- black |
|
|
Term
|
Definition
A radiograph is too dark. which of the following could explain this?
- exposure time oo short
- fixing time too long
- development temperature too high
- mA too low
- kVp too low |
|
|
Term
|
Definition
What terem is defined as the difference in darkness btwn different areas on the radiograph?
- film fog
- density
- latent image
- contrast |
|
|
Term
|
Definition
x-rays are produced at the ___ of the ___.
- focal spot, anode
- focal spot, filament
- focusing cup, anode
- focusing cup, filament |
|
|
Term
|
Definition
An exposure time of 0.8 second is equal to how many impulses?
- 0.01
- 0.6
- 6
- 3.6
- 36 |
|
|
Term
|
Definition
which of the following will increase the transmission of x-rays through tissue?
- lower energy x-rays
- higher atomic # elements in tissue
- less thickness of tissue
- greater density of atoms in tissue |
|
|
Term
|
Definition
which of the following is most radiolucent?
- pulp
- amalgam
- dentin
- enamel
- bone |
|
|
