A+ Graded Solutions(2026/2027)
1. What is the primary role of the MRSO in a clinical setting?
Correct Answer: To ensure the daily implementation of MRI safety
policies and act as the point of contact for safety-related questions.
2. Which zone is the "magnet room" where the static field is always
present?
Correct Answer: Zone IV.
3. What is the maximum static magnetic field allowed for clinical imaging of
children over 1 month old?
Correct Answer: 8.0 Tesla.
4. What is the limit for whole-body SAR in the "Normal Operating Mode"?
Correct Answer: 2.0 W/kg.
5. What is the limit for whole-body SAR in the "First Level Controlled
Operating Mode"?
Correct Answer: 4.0 W/kg.
6. Which operating mode requires a physician’s decision to weigh benefit
vs. risk before scanning?
Correct Answer: First Level Controlled Operating Mode.
7. What is "Peripheral Nerve Stimulation" (PNS) primarily caused by?
Correct Answer: Rapidly changing gradient magnetic fields (dB/dt).
8. Which law of physics describes how a moving magnetic field induces an
electric current in a conductor?
Correct Answer: Faraday’s Law of Induction.
9. What is the "Missile Effect"?
Correct Answer: The rapid acceleration of a ferromagnetic object toward
the center of the magnet.
10.What is the "Torque" effect in MRI?
Correct Answer: The rotational force that attempts to align a
ferromagnetic object with the main magnetic field (B0).
, 11.What does the term "MR Conditional" mean?
Correct Answer: The device is safe for MRI only under specific conditions
(e.g., field strength, gradient, SAR).
12.What does "MR Safe" imply?
Correct Answer: The item is non-metallic, non-conductive, and non-
paramagnetic, posing no hazard in any MRI environment.
13.Which ASTM symbol is a red circle with a diagonal bar?
Correct Answer: MR Unsafe.
14.What is the "5 Gauss Line"?
Correct Answer: The perimeter where the fringe field is strong enough
to interfere with pacemakers or other medical devices.
15.What is the primary danger of a "Quench"?
Correct Answer: The release of helium gas, which can displace oxygen
and cause asphyxiation.
16.What is the "Oxygen Depletion Alarm"?
Correct Answer: A sensor that triggers an alarm if oxygen levels in the
scan room drop below a safe threshold (typically 19.5%).
17.Why should patients not touch the bore walls during a scan?
Correct Answer: To prevent RF-induced thermal burns from the
"antenna effect" or conductive loops.
18.What is the "Specific Absorption Rate" (SAR)?
Correct Answer: A measure of the rate at which energy is absorbed by
the body when exposed to a radiofrequency (RF) electromagnetic field.
19.Which patient population is at the highest risk for thermal regulation
issues during MRI?
Correct Answer: Neonates, the elderly, and patients with fever or
impaired sweating.
20.What is the "B1+rms" value?
Correct Answer: The root-mean-square of the RF magnetic field, used as
a more precise heating metric than SAR for certain implants.
21.What is the first thing an MRSO should do if a person is pinned by a
ferromagnetic object?