RADT 1010 EXAM 3 QUESTIONS & ANSWERS
What are the two main components of the X-ray tube? - Answer -anode and cathode
anode electrons are... - Answer -positive
cathode electrons are... - Answer -negative
part of the X-ray tube that maintains a vacuum and is made of pyrex glass - Answer -
evacuated glass tube
filament emits electrons through... - Answer -thermionic emission
what is the anode and the cathode made of and why? - Answer -tungsten, to withstand
high heat
describe the flow of electrons in the x-ray tube - Answer -filaments in the cathode give
off electrons when heated, they travel a short distance at a high speed, they strike the
anode with high kinetic energy, electrons convert into heat and x-rays
percentage of heat and x-rays created at the anode - Answer -99% heat 1% x-rays
collimator - Answer -open lead shutters that permit the radiographer to determine size
of exposure field on the patient
2 advantages of direct digital radiography - Answer -the speed of image acquisition and
the ability to postprocess images
list from least dense to most dense 6 radiographic densities - Answer -1. air or gas
2. fat
3. water
4. muscle
5. bone
6. tooth enamel
the thicker the part the... - Answer -greater the radiation absorption
name 3 factors controlled by the radiographer (prime factors) - Answer -mAs, kVp, and
distance
define milliamperage - Answer -determines the amount of x-rays produced per unit of
time
define kilvoltage - Answer -determines the wavelength/penetrating power of the x-rays
, the greater the kVp... - Answer -1. the lower the patient dose
2. increases contrast
the greater the mAs... - Answer -1. the greater the patient dose
2. the greater the image darkness
always responsible for patient dose.... - Answer -mAs
what is the equation to find total mAs - Answer -mA x sec = mAs
as __________ is doubled, the _________ of the beam _____________ 4 times -
Answer -distance, intensity, decreases
if _________ is halfed, the _________ of the beam ___________ 4 times - Answer -
distance, intensity, increases
what are 4 characteristics of the radiographic image - Answer -image brightness, image
contrast, spatial resolution, and distortion
areas of greater brightness.... - Answer -less dense areas of the body
image brightness is determined by... - Answer -the intensity of radiation striking the
image receptor
define contrast - Answer -difference in density/difference in grayness of a radiographic
image
define subject contrast - Answer -contrast of the subject compared to the surrounding
area in a radiographic image
what controls the penetration of x-rays through the body? - Answer -kVp
name the 3 contrast agents used - Answer -barium, iodine, air/gas
what does a grid do? - Answer -absorbs scatter radiation
define spatial resolution - Answer -the sharpness of lines/clarity in an image accurately
portrayed
what 3 things have the greatest impact on spatial resolution? - Answer -1. SID
2. OID
3. patient motion
higher resolution occurs when... - Answer -longest practical SID and lowest practical
OID is used
What are the two main components of the X-ray tube? - Answer -anode and cathode
anode electrons are... - Answer -positive
cathode electrons are... - Answer -negative
part of the X-ray tube that maintains a vacuum and is made of pyrex glass - Answer -
evacuated glass tube
filament emits electrons through... - Answer -thermionic emission
what is the anode and the cathode made of and why? - Answer -tungsten, to withstand
high heat
describe the flow of electrons in the x-ray tube - Answer -filaments in the cathode give
off electrons when heated, they travel a short distance at a high speed, they strike the
anode with high kinetic energy, electrons convert into heat and x-rays
percentage of heat and x-rays created at the anode - Answer -99% heat 1% x-rays
collimator - Answer -open lead shutters that permit the radiographer to determine size
of exposure field on the patient
2 advantages of direct digital radiography - Answer -the speed of image acquisition and
the ability to postprocess images
list from least dense to most dense 6 radiographic densities - Answer -1. air or gas
2. fat
3. water
4. muscle
5. bone
6. tooth enamel
the thicker the part the... - Answer -greater the radiation absorption
name 3 factors controlled by the radiographer (prime factors) - Answer -mAs, kVp, and
distance
define milliamperage - Answer -determines the amount of x-rays produced per unit of
time
define kilvoltage - Answer -determines the wavelength/penetrating power of the x-rays
, the greater the kVp... - Answer -1. the lower the patient dose
2. increases contrast
the greater the mAs... - Answer -1. the greater the patient dose
2. the greater the image darkness
always responsible for patient dose.... - Answer -mAs
what is the equation to find total mAs - Answer -mA x sec = mAs
as __________ is doubled, the _________ of the beam _____________ 4 times -
Answer -distance, intensity, decreases
if _________ is halfed, the _________ of the beam ___________ 4 times - Answer -
distance, intensity, increases
what are 4 characteristics of the radiographic image - Answer -image brightness, image
contrast, spatial resolution, and distortion
areas of greater brightness.... - Answer -less dense areas of the body
image brightness is determined by... - Answer -the intensity of radiation striking the
image receptor
define contrast - Answer -difference in density/difference in grayness of a radiographic
image
define subject contrast - Answer -contrast of the subject compared to the surrounding
area in a radiographic image
what controls the penetration of x-rays through the body? - Answer -kVp
name the 3 contrast agents used - Answer -barium, iodine, air/gas
what does a grid do? - Answer -absorbs scatter radiation
define spatial resolution - Answer -the sharpness of lines/clarity in an image accurately
portrayed
what 3 things have the greatest impact on spatial resolution? - Answer -1. SID
2. OID
3. patient motion
higher resolution occurs when... - Answer -longest practical SID and lowest practical
OID is used
