RAD 165 FINAL EXAM WITH COMPLETE SOLUTIONS
100% VERIFIED!!
another term for unsharpness - ANSWER blur
a perfect MTF for an imaging system - ANSWER 1
which of the following represents the formula for calculating geometric unsharpness -
ANSWER 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 - ANSWER
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? - ANSWER new mAs
the effect on sharpness of recorded detail: increase SID from 40-48 inches - ANSWER +
the effect on sharpness of recorded detail: decrease OID from 10 to 3 - ANSWER +
the effect on sharpness of recorded detail: use CR imaging plate known to have dust
particles on plate - ANSWER -
the effect on sharpness of recorded detail: use 200mA instead of 100mA - ANSWER 0
the effect on sharpness of recorded detail: increase the filtration from 2mm to 3mm Al -
ANSWER 0
,the effect on sharpness of recorded detail: change the focal spot size from large to
small - ANSWER +
the effect on sharpness of recorded detail: a 280lb patient abdomen compared to a
115lb pt abdomen - ANSWER -
in digital systems spatial resolution frequency signal must be samples twice from each
cycle. This is known as - ANSWER 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? - ANSWER increase exposure quantity
which of the following does not cause poor contact in an IR? - ANSWER increased room
temp
sharpness of detail is ______________ property - ANSWER geometric
the smaller the focal spot the ________ the detail - ANSWER better
the longer the OID the ___________ the detail - ANSWER worse
the longer the SID the ___________ the detail - ANSWER better
what is the term used to describe the unsharpness at the edges of curved objects (like
our bones or vessels) - ANSWER edge gradient
according to your text, normal human visual acuity is limited to the ability to distinguish
____line pairs/mm - ANSWER 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 - ANSWER moire
focal spots are not capable of imaging structures smaller than themselves (T/F) -
ANSWER true
which of the following uses the divergence of the beam to an advantage for less
distortion - ANSWER PA lumbar spine
proper explanation of the procedure and the use of immobilization is most helpful in the
control of - ANSWER voluntary motion
short exposure times are more helpful in controlling - ANSWER involuntary motion
another term for magnification is - ANSWER size distortion
magnification is influenced by the geometric factors of - ANSWER OFD or OID and TFD
or SID
the width of penumbra (unsharpness) can be mathematically calculated using which of
the following formulas - ANSWER FSS x OID/SOD
which of the terms means to disperse equally in all directions - ANSWER isotropic
true distortion may involve which of the following - ANSWER shape
when the central ray part IR relationship is aligned so the beam is centered to the IR and
area of interest, the _______ amount of shape distortion occurs - ANSWER least
, The part, or area of interest, is usually recorded with minimal distortion if it is placed: -
ANSWER parallel with the IR
magnification is ________ related to sharpness of detail - ANSWER Inversely
the central ray of the x-ray beam should usually be directed __________to the structure
or plane of interest of the body part being examined - ANSWER perpendicular
procedures that employ distortion to an advantage - ANSWER tangenital os calcis
lordotic clavicle
oblique ankle
sacrum coccyx
emulation of shape distortion is subjective and relies on the radiographers knowledge of
- ANSWER normal anatomy, and the expected appearance of the projected image
+ or - distortion? the mA is changed from 100mA with a small focal spot to 400mA with a
large focal spot - ANSWER 0
+ or - distortion? the SID is changed from 40" to 72" with an appropriated mAs increase -
ANSWER -
+ or - distortion? the tube is angled 25deg caudad instead of being perp to the area of
interest - ANSWER +
+ or - distortion? a table top exposure is made with a grid cap placed over the IR instead
of using the IR without a grid - ANSWER 0
+ or - distortion? an ankle is taken with a 2' sponge under the calcaneus instead of
placing it directly upon the IR - ANSWER +
100% VERIFIED!!
another term for unsharpness - ANSWER blur
a perfect MTF for an imaging system - ANSWER 1
which of the following represents the formula for calculating geometric unsharpness -
ANSWER 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 - ANSWER
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? - ANSWER new mAs
the effect on sharpness of recorded detail: increase SID from 40-48 inches - ANSWER +
the effect on sharpness of recorded detail: decrease OID from 10 to 3 - ANSWER +
the effect on sharpness of recorded detail: use CR imaging plate known to have dust
particles on plate - ANSWER -
the effect on sharpness of recorded detail: use 200mA instead of 100mA - ANSWER 0
the effect on sharpness of recorded detail: increase the filtration from 2mm to 3mm Al -
ANSWER 0
,the effect on sharpness of recorded detail: change the focal spot size from large to
small - ANSWER +
the effect on sharpness of recorded detail: a 280lb patient abdomen compared to a
115lb pt abdomen - ANSWER -
in digital systems spatial resolution frequency signal must be samples twice from each
cycle. This is known as - ANSWER 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? - ANSWER increase exposure quantity
which of the following does not cause poor contact in an IR? - ANSWER increased room
temp
sharpness of detail is ______________ property - ANSWER geometric
the smaller the focal spot the ________ the detail - ANSWER better
the longer the OID the ___________ the detail - ANSWER worse
the longer the SID the ___________ the detail - ANSWER better
what is the term used to describe the unsharpness at the edges of curved objects (like
our bones or vessels) - ANSWER edge gradient
according to your text, normal human visual acuity is limited to the ability to distinguish
____line pairs/mm - ANSWER 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 - ANSWER moire
focal spots are not capable of imaging structures smaller than themselves (T/F) -
ANSWER true
which of the following uses the divergence of the beam to an advantage for less
distortion - ANSWER PA lumbar spine
proper explanation of the procedure and the use of immobilization is most helpful in the
control of - ANSWER voluntary motion
short exposure times are more helpful in controlling - ANSWER involuntary motion
another term for magnification is - ANSWER size distortion
magnification is influenced by the geometric factors of - ANSWER OFD or OID and TFD
or SID
the width of penumbra (unsharpness) can be mathematically calculated using which of
the following formulas - ANSWER FSS x OID/SOD
which of the terms means to disperse equally in all directions - ANSWER isotropic
true distortion may involve which of the following - ANSWER shape
when the central ray part IR relationship is aligned so the beam is centered to the IR and
area of interest, the _______ amount of shape distortion occurs - ANSWER least
, The part, or area of interest, is usually recorded with minimal distortion if it is placed: -
ANSWER parallel with the IR
magnification is ________ related to sharpness of detail - ANSWER Inversely
the central ray of the x-ray beam should usually be directed __________to the structure
or plane of interest of the body part being examined - ANSWER perpendicular
procedures that employ distortion to an advantage - ANSWER tangenital os calcis
lordotic clavicle
oblique ankle
sacrum coccyx
emulation of shape distortion is subjective and relies on the radiographers knowledge of
- ANSWER normal anatomy, and the expected appearance of the projected image
+ or - distortion? the mA is changed from 100mA with a small focal spot to 400mA with a
large focal spot - ANSWER 0
+ or - distortion? the SID is changed from 40" to 72" with an appropriated mAs increase -
ANSWER -
+ or - distortion? the tube is angled 25deg caudad instead of being perp to the area of
interest - ANSWER +
+ or - distortion? a table top exposure is made with a grid cap placed over the IR instead
of using the IR without a grid - ANSWER 0
+ or - distortion? an ankle is taken with a 2' sponge under the calcaneus instead of
placing it directly upon the IR - ANSWER +
