1230 Fluoroscopy assessment Questions With Complete
Solutions
4 factors affecting image quality Correct Answers Contrast
resolution, spatial resolution, distortion/artifacts, noise
Anode Correct Answers Charge of 25-35 kV. In front of output
screen. Electrons accelerated from photo cathode to output
phosphor through hole in centre of anode
At shortest SID possible, fluoroscopic unit radiation dose must
not exceed: Correct Answers a. ___50 mGy/min___ for
equipment NOT equipped with an automatic intensity control
b. _100 mGy/min___ for equipment equipped with an automatic
intensity control
c. _150 mGy/minute_ for equipment equipped with both an
automatic intensity control and a high-level irradiation control
when the high level irradiation control is activated
At what time does the timer on fluoro buzz and why? Correct
Answers At 5 minutes for radiologist awareness
Barrel distortion Correct Answers Caused by projecting image
from curved surface (input phosphor) onto flat surface (output
phosphor). magnification/distortion at center
Collimation/tube shielding Correct Answers useful beam should
be centred on II, tube must have leakage shielding and filtration.
Collimation must have step-less adjustment
, Continuous fluoro (higher dose) Correct Answers Low mA
(<5mA). Used for arteriogram where higher frame rate and
resolution is needed
Contrast in relation to fluoro Correct Answers Affected by
scatter radiation (subject contrast/contrast media, part thickness,
field size, kV (decreased is higher contrast), and grid) and
retrograde light (light thats going backwards)
Conversion factor relating to II Correct Answers Relates to the
luminance relative to radiation exposure. = intensity of
OP/(mR/sec). Useful for comparing the performance of the II
over time.
Distortion in relation to fluoro Correct Answers Size distortion:
SID and affected primarily by OID. Shape distortion: patient
position (tube and IR always aligned), caused primarily by shape
of II tube
Do collimators close somewhat during mag? Correct Answers
Yes they are suppose to to expose only the specific area so you
are not fluoroing a larger field than necessary
Does a higher conversion factor mean less or more patient dose?
Correct Answers less patient dose
Does noise carry any diagnostic information? Correct Answers
No
Does the output phosphor receive the entire image from the
input? Correct Answers No
Solutions
4 factors affecting image quality Correct Answers Contrast
resolution, spatial resolution, distortion/artifacts, noise
Anode Correct Answers Charge of 25-35 kV. In front of output
screen. Electrons accelerated from photo cathode to output
phosphor through hole in centre of anode
At shortest SID possible, fluoroscopic unit radiation dose must
not exceed: Correct Answers a. ___50 mGy/min___ for
equipment NOT equipped with an automatic intensity control
b. _100 mGy/min___ for equipment equipped with an automatic
intensity control
c. _150 mGy/minute_ for equipment equipped with both an
automatic intensity control and a high-level irradiation control
when the high level irradiation control is activated
At what time does the timer on fluoro buzz and why? Correct
Answers At 5 minutes for radiologist awareness
Barrel distortion Correct Answers Caused by projecting image
from curved surface (input phosphor) onto flat surface (output
phosphor). magnification/distortion at center
Collimation/tube shielding Correct Answers useful beam should
be centred on II, tube must have leakage shielding and filtration.
Collimation must have step-less adjustment
, Continuous fluoro (higher dose) Correct Answers Low mA
(<5mA). Used for arteriogram where higher frame rate and
resolution is needed
Contrast in relation to fluoro Correct Answers Affected by
scatter radiation (subject contrast/contrast media, part thickness,
field size, kV (decreased is higher contrast), and grid) and
retrograde light (light thats going backwards)
Conversion factor relating to II Correct Answers Relates to the
luminance relative to radiation exposure. = intensity of
OP/(mR/sec). Useful for comparing the performance of the II
over time.
Distortion in relation to fluoro Correct Answers Size distortion:
SID and affected primarily by OID. Shape distortion: patient
position (tube and IR always aligned), caused primarily by shape
of II tube
Do collimators close somewhat during mag? Correct Answers
Yes they are suppose to to expose only the specific area so you
are not fluoroing a larger field than necessary
Does a higher conversion factor mean less or more patient dose?
Correct Answers less patient dose
Does noise carry any diagnostic information? Correct Answers
No
Does the output phosphor receive the entire image from the
input? Correct Answers No
