MRSO Technical & Clinical Practice Exam With
A+ Graded Solution.
1. What is the specific ASTM definition of an "MR Safe" item?
Correct Answer: An item that poses no known hazards in all MRI
environments (non-conducting, non-metallic, and non-paramagnetic).
2. If an implant is labeled "MR Conditional," what three parameters are
most commonly restricted?
Correct Answer: Static magnetic field strength (Tesla), spatial gradient,
and RF heating limits (SAR).
3. What is the "Normal Operating Mode" limit for Whole Body SAR over a
6-minute period?
Correct Answer: 2.0 W/kg.
4. What is the "First Level Controlled Operating Mode" limit for Whole
Body SAR over 6 minutes?
Correct Answer: 4.0 W/kg.
5. At what core body temperature increase must a scan be stopped
according to IEC guidelines?
Correct Answer: 1 degree Celsius.
6. What is the primary safety concern with "abandoned" epicardial or
transvenous leads?
Correct Answer: RF-induced resonant heating at the lead tip, which can
cause tissue thermal damage.
7. Which physical phenomenon causes a conductive, non-ferrous object to
resist movement within a static field?
Correct Answer: Lenz’s Law (Eddy currents).
8. What is the maximum spatial field gradient (SFG) typically expressed in?
Correct Answer: Gauss per centimeter (G/cm) or Tesla per meter (T/m).
9. Why is the "B1+rms" value increasingly preferred over SAR for labeling
MR Conditional implants?
Correct Answer: It measures the actual RF magnetic field strength rather
than estimated energy absorption, which varies by patient weight.
, 10.What is the "Missile Effect" technically called in physics terms?
Correct Answer: Translational Attraction.
11.What defines a Level 2 MR Personnel?
Correct Answer: Individuals with extensive safety training who can
ensure the safety of themselves and others in Zone IV.
12.How does a "Passive Shield" differ from an "Active Shield"?
Correct Answer: Passive shielding uses steel in the walls; active shielding
uses additional coils within the magnet to oppose the fringe field.
13.What is the most critical screening step for a patient with a suspected
intraocular metallic fragment?
Correct Answer: Obtaining and reviewing a recent X-ray of the orbits
(Waters view).
14.What is the risk of scanning a patient with a "tissue expander"?
Correct Answer: Most contain a magnetic port that can be
demagnetized, displaced, or cause severe artifacts.
15.What are the three standard safety zones defined by the ACR?
Correct Answer: Zones I, II, III, and IV.
16.Which zone is technically the "interface" between the unregulated public
areas and the strictly controlled areas?
Correct Answer: Zone II.
17.In the event of a fire in the MRI suite, what is the MRSO’s first
responsibility regarding the fire department?
Correct Answer: Ensuring they do not enter Zone IV with ferrous
equipment (axes, tanks, etc.) unless the magnet has been quenched.
18.What is the "Faraday Cage"?
Correct Answer: The copper or aluminum shielding in the walls that
prevents outside RF interference from entering the scan room.
19.Why is a "Cold Head" essential in a superconducting magnet?
Correct Answer: It re-condenses boiled-off helium back into liquid form
to prevent a quench.
20.What is the maximum dB/dt limit?
Correct Answer: It is the level that stays below the threshold for painful
peripheral nerve stimulation (PNS).
A+ Graded Solution.
1. What is the specific ASTM definition of an "MR Safe" item?
Correct Answer: An item that poses no known hazards in all MRI
environments (non-conducting, non-metallic, and non-paramagnetic).
2. If an implant is labeled "MR Conditional," what three parameters are
most commonly restricted?
Correct Answer: Static magnetic field strength (Tesla), spatial gradient,
and RF heating limits (SAR).
3. What is the "Normal Operating Mode" limit for Whole Body SAR over a
6-minute period?
Correct Answer: 2.0 W/kg.
4. What is the "First Level Controlled Operating Mode" limit for Whole
Body SAR over 6 minutes?
Correct Answer: 4.0 W/kg.
5. At what core body temperature increase must a scan be stopped
according to IEC guidelines?
Correct Answer: 1 degree Celsius.
6. What is the primary safety concern with "abandoned" epicardial or
transvenous leads?
Correct Answer: RF-induced resonant heating at the lead tip, which can
cause tissue thermal damage.
7. Which physical phenomenon causes a conductive, non-ferrous object to
resist movement within a static field?
Correct Answer: Lenz’s Law (Eddy currents).
8. What is the maximum spatial field gradient (SFG) typically expressed in?
Correct Answer: Gauss per centimeter (G/cm) or Tesla per meter (T/m).
9. Why is the "B1+rms" value increasingly preferred over SAR for labeling
MR Conditional implants?
Correct Answer: It measures the actual RF magnetic field strength rather
than estimated energy absorption, which varies by patient weight.
, 10.What is the "Missile Effect" technically called in physics terms?
Correct Answer: Translational Attraction.
11.What defines a Level 2 MR Personnel?
Correct Answer: Individuals with extensive safety training who can
ensure the safety of themselves and others in Zone IV.
12.How does a "Passive Shield" differ from an "Active Shield"?
Correct Answer: Passive shielding uses steel in the walls; active shielding
uses additional coils within the magnet to oppose the fringe field.
13.What is the most critical screening step for a patient with a suspected
intraocular metallic fragment?
Correct Answer: Obtaining and reviewing a recent X-ray of the orbits
(Waters view).
14.What is the risk of scanning a patient with a "tissue expander"?
Correct Answer: Most contain a magnetic port that can be
demagnetized, displaced, or cause severe artifacts.
15.What are the three standard safety zones defined by the ACR?
Correct Answer: Zones I, II, III, and IV.
16.Which zone is technically the "interface" between the unregulated public
areas and the strictly controlled areas?
Correct Answer: Zone II.
17.In the event of a fire in the MRI suite, what is the MRSO’s first
responsibility regarding the fire department?
Correct Answer: Ensuring they do not enter Zone IV with ferrous
equipment (axes, tanks, etc.) unless the magnet has been quenched.
18.What is the "Faraday Cage"?
Correct Answer: The copper or aluminum shielding in the walls that
prevents outside RF interference from entering the scan room.
19.Why is a "Cold Head" essential in a superconducting magnet?
Correct Answer: It re-condenses boiled-off helium back into liquid form
to prevent a quench.
20.What is the maximum dB/dt limit?
Correct Answer: It is the level that stays below the threshold for painful
peripheral nerve stimulation (PNS).
