MAGNETIC RESONANCE SAFETY
EXPERT (MRSE) EXAM REVIEW
QUESTIONS & VERIFIED ANSWERS
2026/2027 UPDATE
1. According to the IEC 60601-2-33 standard, what is the whole-body SAR limit for the First
Level Controlled Operating Mode?
A. 4.0 W/kg over 6 minutes
B. 2.0 W/kg over 6 minutes
C. 8.0 W/kg over 5 minutes
D. 1.5 W/kg over 15 minutes
Answer: A
Conceptual Explanation: The IEC standard specifies that for the First Level Controlled
Operating Mode, the whole-body SAR limit is 4.0 W/kg averaged over 6 minutes, whereas
the Normal Operating Mode limit is 2.0 W/kg.
2. Which physical phenomenon is responsible for the induction of eddy currents in conductive
implants when exposed to time-varying magnetic field gradients?
A. The Zeeman Effect
B. Larmor Equation
,C. The Lorentz Force
D. Faraday’s Law of Induction
Answer: D
Conceptual Explanation: Faraday’s Law of Induction states that a time-varying magnetic
field (dB/dt) will induce an electromotive force (EMF) in a conductor, resulting in eddy
currents.
3. A patient has a ‘MR Conditional’ implant with a specified spatial field gradient limit of 720
Gauss/cm. If the scanner’s maximum spatial gradient is 30 T/m, what is the correct
assessment?
A. The implant is safe because 30 T/m is less than 720 G/cm.
B. The implant is safe because the limit is 7.2 T/m.
C. Spatial gradient is irrelevant for static implants; only SAR matters.
D. The implant is unsafe because 30 T/m equals 3000 G/cm, exceeding the 720 G/cm limit.
Answer: D
Conceptual Explanation: 1 Tesla/meter (T/m) is equal to 100 Gauss/centimeter (G/cm).
Therefore, 30 T/m is 3000 G/cm, which significantly exceeds the manufacturer’s limit of
720 G/cm.
4. Which of the following describes the ‘Antenna Effect’ in MR safety?
A. The amplification of the B0 field near metallic edges.
, B. The distortion of the image due to susceptibility artifacts.
C. The resonant coupling of RF energy into a conductive lead when its length is a fraction of
the RF wavelength.
D. The displacement force caused by the fringe field.
Answer: C
Conceptual Explanation: The antenna effect occurs when a conductive lead (like a
pacemaker lead) acts as an antenna, coupling with the RF field (B1), leading to
concentrated heating at the tips.
5. In the event of a quench, which gas is released that poses a primary risk of asphyxiation
and pressure buildup?
A. Liquid Nitrogen
B. Hydrogen Gas
C. Carbon Dioxide
D. Gaseous Helium
Answer: D
Conceptual Explanation: Modern superconducting magnets use liquid helium. During a
quench, it rapidly boils into gaseous helium, expanding by a factor of about 700, displacing
oxygen and increasing room pressure if venting fails.
EXPERT (MRSE) EXAM REVIEW
QUESTIONS & VERIFIED ANSWERS
2026/2027 UPDATE
1. According to the IEC 60601-2-33 standard, what is the whole-body SAR limit for the First
Level Controlled Operating Mode?
A. 4.0 W/kg over 6 minutes
B. 2.0 W/kg over 6 minutes
C. 8.0 W/kg over 5 minutes
D. 1.5 W/kg over 15 minutes
Answer: A
Conceptual Explanation: The IEC standard specifies that for the First Level Controlled
Operating Mode, the whole-body SAR limit is 4.0 W/kg averaged over 6 minutes, whereas
the Normal Operating Mode limit is 2.0 W/kg.
2. Which physical phenomenon is responsible for the induction of eddy currents in conductive
implants when exposed to time-varying magnetic field gradients?
A. The Zeeman Effect
B. Larmor Equation
,C. The Lorentz Force
D. Faraday’s Law of Induction
Answer: D
Conceptual Explanation: Faraday’s Law of Induction states that a time-varying magnetic
field (dB/dt) will induce an electromotive force (EMF) in a conductor, resulting in eddy
currents.
3. A patient has a ‘MR Conditional’ implant with a specified spatial field gradient limit of 720
Gauss/cm. If the scanner’s maximum spatial gradient is 30 T/m, what is the correct
assessment?
A. The implant is safe because 30 T/m is less than 720 G/cm.
B. The implant is safe because the limit is 7.2 T/m.
C. Spatial gradient is irrelevant for static implants; only SAR matters.
D. The implant is unsafe because 30 T/m equals 3000 G/cm, exceeding the 720 G/cm limit.
Answer: D
Conceptual Explanation: 1 Tesla/meter (T/m) is equal to 100 Gauss/centimeter (G/cm).
Therefore, 30 T/m is 3000 G/cm, which significantly exceeds the manufacturer’s limit of
720 G/cm.
4. Which of the following describes the ‘Antenna Effect’ in MR safety?
A. The amplification of the B0 field near metallic edges.
, B. The distortion of the image due to susceptibility artifacts.
C. The resonant coupling of RF energy into a conductive lead when its length is a fraction of
the RF wavelength.
D. The displacement force caused by the fringe field.
Answer: C
Conceptual Explanation: The antenna effect occurs when a conductive lead (like a
pacemaker lead) acts as an antenna, coupling with the RF field (B1), leading to
concentrated heating at the tips.
5. In the event of a quench, which gas is released that poses a primary risk of asphyxiation
and pressure buildup?
A. Liquid Nitrogen
B. Hydrogen Gas
C. Carbon Dioxide
D. Gaseous Helium
Answer: D
Conceptual Explanation: Modern superconducting magnets use liquid helium. During a
quench, it rapidly boils into gaseous helium, expanding by a factor of about 700, displacing
oxygen and increasing room pressure if venting fails.
