Diagnostic Imaging- Exam 1 UPDATED
ACTUAL Exam Questions and CORRECT
Answers
What type of radiation are x-rays? - CORRECT ANSWER - electromagnetic
X-rays have a (higher/shorter) frequency and a (higher/shorter) wavelength than visible light -
CORRECT ANSWER - higher frequency
shorter wavelength
How are x-rays produced? - CORRECT ANSWER - high speed electrons striking metal
In an x-ray tube, the metal target is called the _____ - CORRECT ANSWER - anode
In an x-ray tube, the source of the electrons is the _____ - CORRECT ANSWER - cathode
True or false: During x-ray production, some protons "boil off" the hot cathode filament wire and
head towards the anode - CORRECT ANSWER - false, ELECTRONS do this
What is the purpose of housing the anode and cathode in a vacuum? - CORRECT
ANSWER - to ensure that electrons do not interact with air molecules
Is the anode positive or negative? - CORRECT ANSWER - relatively positive
During x-ray production, high voltage imparts high energy to ____ - CORRECT
ANSWER - electrons
What does mAs measure? - CORRECT ANSWER - the number of x-rays
,What does kVp measure? - CORRECT ANSWER - the energy of the x-rays
Voltage between the anode and cathode is called what? - CORRECT ANSWER - kVp
What determines the number of x-rays produced? - CORRECT ANSWER - the total
number of electrons striking the anode
The ____ setting determines the number of x-rays produced. - CORRECT ANSWER -
mAs
Current passes from ___ to ____ - CORRECT ANSWER - cathode to anode
How do you calculate mAs? - CORRECT ANSWER - current passing from cathode to
anode (in mA) x time the x-ray tube is activated (seconds)
In terms of radiographs, what two settings determine "technique"? - CORRECT
ANSWER - kVp and mAs
___% of the electron energy at the anode is converted to heat - CORRECT ANSWER -
90%
What metal is used to make the anode and cathode? Why? - CORRECT ANSWER -
tungsten, high melting point
Electrons are directed onto a "focal spot" using a ___ - CORRECT ANSWER - focusing
cup
The larger the focal spot, the (more/less) electrons can be directed there and (more/less) x-rays
are made - CORRECT ANSWER - more electrons (able to absorb more heat)
,more x-rays (higher mAs)
What are the pros/cons of using a small focal spot when obtaining a radiograph? - CORRECT
ANSWER - pro: better detail
con: cannot use as high of a mAs setting
Why do we care about focal spots? - CORRECT ANSWER - if kVp/mAs is to high for the
small focal spot, you can ruin the x-ray tube
if you always use a large focal spot, you will have less detail on the radiographs
What are the pros/cons of x-ray tubes with stationary anodes? - CORRECT ANSWER -
small size, portable
cannot use high mAs
small focal spots
True or false: most larger x-ray tubes have stationary anodes - CORRECT ANSWER -
false, rotating
Why use a rotating anode? - CORRECT ANSWER - -each exposure takes the same time (s
in mAs)
-if the anode rotates, there is effectively a larger focal spot
-greater heat distribution allows higher mAs to be used
What happens to the anode over time? - CORRECT ANSWER - it becomes pitted with
electrons
-irregularity decreases tube efficiency
-be sure it is spinning at max rpm before exposure
True or false: film is not sensitive to x-ray interactions - CORRECT ANSWER - true
, True or false: x-rays alone are usually insufficient to create a radiographic image - CORRECT
ANSWER - true
What is used in combination with x-rays to create an image on the film?? - CORRECT
ANSWER - screens (in the cassette)
Describe how screens are used to expose film - CORRECT ANSWER - when x-rays strike
the screen, they fluoresce. the blue or green light creates an image on the x-ray film
What two colors can screens fluoresce when struck by x-rays? - CORRECT ANSWER -
green or blue (depends on the film)
Because the screen is so sensitive to x-rays, it allows us to do what? - CORRECT
ANSWER - use much lower technique (mAs especially), than if we didn't use screens
Radiographic film contains ____ crystals - CORRECT ANSWER - silver halide
What are the 4 main steps in film processing? - CORRECT ANSWER - development step
fixer step
wash
dry
Describe the development step of film processing. - CORRECT ANSWER - silver halide
crystals are exposed to light from the screens is changed to elemental silver (black)
Describe the fixer step in film processing - CORRECT ANSWER - fixer chemicals
remove silver halide crystals not exposed to x-rays on the film (unexposed areas are clear, white)
ACTUAL Exam Questions and CORRECT
Answers
What type of radiation are x-rays? - CORRECT ANSWER - electromagnetic
X-rays have a (higher/shorter) frequency and a (higher/shorter) wavelength than visible light -
CORRECT ANSWER - higher frequency
shorter wavelength
How are x-rays produced? - CORRECT ANSWER - high speed electrons striking metal
In an x-ray tube, the metal target is called the _____ - CORRECT ANSWER - anode
In an x-ray tube, the source of the electrons is the _____ - CORRECT ANSWER - cathode
True or false: During x-ray production, some protons "boil off" the hot cathode filament wire and
head towards the anode - CORRECT ANSWER - false, ELECTRONS do this
What is the purpose of housing the anode and cathode in a vacuum? - CORRECT
ANSWER - to ensure that electrons do not interact with air molecules
Is the anode positive or negative? - CORRECT ANSWER - relatively positive
During x-ray production, high voltage imparts high energy to ____ - CORRECT
ANSWER - electrons
What does mAs measure? - CORRECT ANSWER - the number of x-rays
,What does kVp measure? - CORRECT ANSWER - the energy of the x-rays
Voltage between the anode and cathode is called what? - CORRECT ANSWER - kVp
What determines the number of x-rays produced? - CORRECT ANSWER - the total
number of electrons striking the anode
The ____ setting determines the number of x-rays produced. - CORRECT ANSWER -
mAs
Current passes from ___ to ____ - CORRECT ANSWER - cathode to anode
How do you calculate mAs? - CORRECT ANSWER - current passing from cathode to
anode (in mA) x time the x-ray tube is activated (seconds)
In terms of radiographs, what two settings determine "technique"? - CORRECT
ANSWER - kVp and mAs
___% of the electron energy at the anode is converted to heat - CORRECT ANSWER -
90%
What metal is used to make the anode and cathode? Why? - CORRECT ANSWER -
tungsten, high melting point
Electrons are directed onto a "focal spot" using a ___ - CORRECT ANSWER - focusing
cup
The larger the focal spot, the (more/less) electrons can be directed there and (more/less) x-rays
are made - CORRECT ANSWER - more electrons (able to absorb more heat)
,more x-rays (higher mAs)
What are the pros/cons of using a small focal spot when obtaining a radiograph? - CORRECT
ANSWER - pro: better detail
con: cannot use as high of a mAs setting
Why do we care about focal spots? - CORRECT ANSWER - if kVp/mAs is to high for the
small focal spot, you can ruin the x-ray tube
if you always use a large focal spot, you will have less detail on the radiographs
What are the pros/cons of x-ray tubes with stationary anodes? - CORRECT ANSWER -
small size, portable
cannot use high mAs
small focal spots
True or false: most larger x-ray tubes have stationary anodes - CORRECT ANSWER -
false, rotating
Why use a rotating anode? - CORRECT ANSWER - -each exposure takes the same time (s
in mAs)
-if the anode rotates, there is effectively a larger focal spot
-greater heat distribution allows higher mAs to be used
What happens to the anode over time? - CORRECT ANSWER - it becomes pitted with
electrons
-irregularity decreases tube efficiency
-be sure it is spinning at max rpm before exposure
True or false: film is not sensitive to x-ray interactions - CORRECT ANSWER - true
, True or false: x-rays alone are usually insufficient to create a radiographic image - CORRECT
ANSWER - true
What is used in combination with x-rays to create an image on the film?? - CORRECT
ANSWER - screens (in the cassette)
Describe how screens are used to expose film - CORRECT ANSWER - when x-rays strike
the screen, they fluoresce. the blue or green light creates an image on the x-ray film
What two colors can screens fluoresce when struck by x-rays? - CORRECT ANSWER -
green or blue (depends on the film)
Because the screen is so sensitive to x-rays, it allows us to do what? - CORRECT
ANSWER - use much lower technique (mAs especially), than if we didn't use screens
Radiographic film contains ____ crystals - CORRECT ANSWER - silver halide
What are the 4 main steps in film processing? - CORRECT ANSWER - development step
fixer step
wash
dry
Describe the development step of film processing. - CORRECT ANSWER - silver halide
crystals are exposed to light from the screens is changed to elemental silver (black)
Describe the fixer step in film processing - CORRECT ANSWER - fixer chemicals
remove silver halide crystals not exposed to x-rays on the film (unexposed areas are clear, white)
