1 | Page
rad 165 final Questions and Correct Answers/
Latest Update / Already Graded
another term for unsharpness
Ans: blur
a perfect MTF for an imaging system
Ans: 1
which of the following represents the formula for calculating geometric unsharpness
Ans: focal spot size x OID/ SOD
which of the following shapes would exhibit the least structural shape unsharpness if
each was radiographed after being accurately aligned to the x-ray beam
Ans: trapezoid
if you change source to image distance in order to increase detail, which formula
must be considered if equal density is to be maintained?
Ans: new mAs
the effect on sharpness of recorded detail: increase SID from 40-48 inches
Ans: +
the effect on sharpness of recorded detail: decrease OID from 10 to 3
Ans: +
the effect on sharpness of recorded detail: use CR imaging plate known to have
dust particles on plate
, 2 | Page
Ans: -
the effect on sharpness of recorded detail: use 200mA instead of 100mA
Ans: 0
the effect on sharpness of recorded detail: increase the filtration from 2mm to 3mm
Al
Ans: 0
the effect on sharpness of recorded detail: change the focal spot size from large to
small
Ans: +
the effect on sharpness of recorded detail: a 280lb patient abdomen compared to
a 115lb pt abdomen
Ans: -
in digital systems spatial resolution frequency signal must be samples twice from
each cycle. This is known as
Ans: Nyquist criterion
quantum mottle is "grainy" unwanted noise with a degradation of image detail.
What is the best way to combat or avoid quantum mottle?
Ans: increase exposure quantity
which of the following does not cause poor contact in an IR?
Ans: increased room temp
, 3 | Page
sharpness of detail is ______________ property
Ans: geometric
the smaller the focal spot the ________ the detail
Ans: better
the longer the OID the ___________ the detail
Ans: worse
the longer the SID the ___________ the detail
Ans: better
what is the term used to describe the unsharpness at the edges of curved objects
(like our bones or vessels)
Ans: edge gradient
according to your text, normal human visual acuity is limited to the ability to
distinguish ____line pairs/mm
Ans: 5
aliased images that occur during low frequency wrapped over high frequency
imaging resulting in 2 slightly out of alignment images are said to have this type of
appearance/pattern
Ans: moire
focal spots are not capable of imaging structures smaller than themselves (T/F)
Ans: true
, 4 | Page
which of the following uses the divergence of the beam to an advantage for less
distortion
Ans: PA lumbar spine
proper explanation of the procedure and the use of immobilization is most helpful
in the control of
Ans: voluntary motion
short exposure times are more helpful in controlling
Ans: involuntary motion
another term for magnification is
Ans: size distortion
magnification is influenced by the geometric factors of
Ans: OFD or OID and TFD or SID
the width of penumbra (unsharpness) can be mathematically calculated using which
of the following formulas
Ans: FSS x OID/SOD
which of the terms means to disperse equally in all directions
Ans: isotropic
true distortion may involve which of the following
Ans: shape
rad 165 final Questions and Correct Answers/
Latest Update / Already Graded
another term for unsharpness
Ans: blur
a perfect MTF for an imaging system
Ans: 1
which of the following represents the formula for calculating geometric unsharpness
Ans: focal spot size x OID/ SOD
which of the following shapes would exhibit the least structural shape unsharpness if
each was radiographed after being accurately aligned to the x-ray beam
Ans: trapezoid
if you change source to image distance in order to increase detail, which formula
must be considered if equal density is to be maintained?
Ans: new mAs
the effect on sharpness of recorded detail: increase SID from 40-48 inches
Ans: +
the effect on sharpness of recorded detail: decrease OID from 10 to 3
Ans: +
the effect on sharpness of recorded detail: use CR imaging plate known to have
dust particles on plate
, 2 | Page
Ans: -
the effect on sharpness of recorded detail: use 200mA instead of 100mA
Ans: 0
the effect on sharpness of recorded detail: increase the filtration from 2mm to 3mm
Al
Ans: 0
the effect on sharpness of recorded detail: change the focal spot size from large to
small
Ans: +
the effect on sharpness of recorded detail: a 280lb patient abdomen compared to
a 115lb pt abdomen
Ans: -
in digital systems spatial resolution frequency signal must be samples twice from
each cycle. This is known as
Ans: Nyquist criterion
quantum mottle is "grainy" unwanted noise with a degradation of image detail.
What is the best way to combat or avoid quantum mottle?
Ans: increase exposure quantity
which of the following does not cause poor contact in an IR?
Ans: increased room temp
, 3 | Page
sharpness of detail is ______________ property
Ans: geometric
the smaller the focal spot the ________ the detail
Ans: better
the longer the OID the ___________ the detail
Ans: worse
the longer the SID the ___________ the detail
Ans: better
what is the term used to describe the unsharpness at the edges of curved objects
(like our bones or vessels)
Ans: edge gradient
according to your text, normal human visual acuity is limited to the ability to
distinguish ____line pairs/mm
Ans: 5
aliased images that occur during low frequency wrapped over high frequency
imaging resulting in 2 slightly out of alignment images are said to have this type of
appearance/pattern
Ans: moire
focal spots are not capable of imaging structures smaller than themselves (T/F)
Ans: true
, 4 | Page
which of the following uses the divergence of the beam to an advantage for less
distortion
Ans: PA lumbar spine
proper explanation of the procedure and the use of immobilization is most helpful
in the control of
Ans: voluntary motion
short exposure times are more helpful in controlling
Ans: involuntary motion
another term for magnification is
Ans: size distortion
magnification is influenced by the geometric factors of
Ans: OFD or OID and TFD or SID
the width of penumbra (unsharpness) can be mathematically calculated using which
of the following formulas
Ans: FSS x OID/SOD
which of the terms means to disperse equally in all directions
Ans: isotropic
true distortion may involve which of the following
Ans: shape
