ASMIRT - MRI ACCREDITATION EXAM ACTUAL
EXAM 2026 | COMPLETE QUESTIONS AND
CORRECT ANSWERS | VERIFIED ANSWERS |
JUST RELEASED
Mild sensory effects due to static magnetic fields include: ---------
CORRECT ANSWER-----------------• Vertigo
• Nausea
• Taste Sensations
Sensory effects of the static magnetic field increase or decrease with
field strength? ---------CORRECT ANSWER-----------------Sensory effects
are related to the strength of the magnetic field with few symptoms at
1.5T and more appearing approaching a 4T field strength
Explain what t-wave artefact is and why it occurs ---------CORRECT
ANSWER-----------------Any charged particle moving through a magnetic
field will have a current induced via this interaction. As blood, a
conductive fluid flows through a magnetic field it induces an electrical
biopotential. This electrical biopotential can be seen on the ECG
waveform of patients in MRI. It is demonstrated by an increase in the T-
wave amplitude on ECG. This change in T-wave amplitude is directly
proportional to the strength of the Static Filed. It is important that MR
,radiographers are aware of this as elevated T-waves are also associated
with ischemia and myocardial infarction.
What risks does the static magnetic field pose in terms of implants and
objects? ---------CORRECT ANSWER-----------------Static Fields also pose
hazards through the displacement of ferro-magnetic implants and
objects. The static field imparts both a translation (attractive force) and
a torque (twisting force). The strong nature of the Static Field also has
the potential to disrupt the function of Cardiac Pacemakers. Anyone
entering beyond the 5G line should be screened for contraindications
to strong Magnetic Fields. Also be aware of what is being taken over
the 5G line.
What strategies can be employed to reduce the risks of the static
magnetic field impacting on implants and objects? ---------CORRECT
ANSWER-----------------• Ferromagnetic objects may become airborne -
40 km/hr terminal velocity possible at 1.5T
• Test any metal objects with a hand held magnet before allowing them
to enter the room.
• Keep the general public behind the 5G line. •
Possible contra-indications include pacemakers, aneurysm clips, intra-
vascular coils and stents, heart valves, penile implants, cochlear
implants, ocular implants (Fatio eyelid springs), neuro stimulators, bone
growth stimulators, drug infusion pumps.
,What effect do gradient magnetic fields have on patient safety? ---------
CORRECT ANSWER-----------------Faraday's Law dictates that changing
magnetic fields will generate a voltage and a current in a conductor.
The switching of the gradients induces electrical currents in conductive
tissues. Voltage generation will occur during the rise and fall times - ie.
while the field is changing. The largest voltages will be generated at the
periphery where the gradient amplitudes are highest. The most
common result of these voltages is Peripheral Nerve Stimulation (PNS).
Other side-effects are listed below;
• magnetophosphenes - electromagnetically induced flashes of light
• seizures
• tissue heating
• peripheral nerve stimulation
• muscle contractions
• cardiac arrhythmias
• some degree of patient heating has been shown to be a result of
Gradient Magnetic effects. However, this has been shown to be so low
as to be negligible
What strategies can be employed to keep gradient effects to a
minimum? ---------CORRECT ANSWER-----------------In order to keep these
effects to a minimum the following is recommended.
• keep dB/dT less than those required to produce peripheral nerve
stimulation.
, • max limit for dB/dT of 6 Tesla / sec
What is the cause of acoustic noise during an MRI scan? ---------
CORRECT ANSWER-----------------The characteristic noise that is heard
during an MRI scan is the result of the interaction of Lorentz forces
generated by the Gradient Coil when a current is pulsed through them
in the presence of a Static Magnetic Field. The noise results as these
forces are so strong as to twist the coils on their mounts. In some cases
this can be in excess of 100dB particularly when running EPI sequences.
Thus all patients need to be provided hearing protection.
What is the greatest concern in terms of MR safety? ---------CORRECT
ANSWER-----------------RF effects are of the greatest concern in terms of
MR safety. The main effect is the deposition of energy resulting in
tissue heating. Of particular concern are heat sensitive organs such as
the eyes and testes. One of the major concerns is where a patient has a
metallic implant which results in greater heating.
RF field safety concerns increase or decrease with increasing field
strength> ---------CORRECT ANSWER-----------------The amount of energy
absorbed will increase with frequency of the RF field delivered and is
therefore greater at higher field strengths
EXAM 2026 | COMPLETE QUESTIONS AND
CORRECT ANSWERS | VERIFIED ANSWERS |
JUST RELEASED
Mild sensory effects due to static magnetic fields include: ---------
CORRECT ANSWER-----------------• Vertigo
• Nausea
• Taste Sensations
Sensory effects of the static magnetic field increase or decrease with
field strength? ---------CORRECT ANSWER-----------------Sensory effects
are related to the strength of the magnetic field with few symptoms at
1.5T and more appearing approaching a 4T field strength
Explain what t-wave artefact is and why it occurs ---------CORRECT
ANSWER-----------------Any charged particle moving through a magnetic
field will have a current induced via this interaction. As blood, a
conductive fluid flows through a magnetic field it induces an electrical
biopotential. This electrical biopotential can be seen on the ECG
waveform of patients in MRI. It is demonstrated by an increase in the T-
wave amplitude on ECG. This change in T-wave amplitude is directly
proportional to the strength of the Static Filed. It is important that MR
,radiographers are aware of this as elevated T-waves are also associated
with ischemia and myocardial infarction.
What risks does the static magnetic field pose in terms of implants and
objects? ---------CORRECT ANSWER-----------------Static Fields also pose
hazards through the displacement of ferro-magnetic implants and
objects. The static field imparts both a translation (attractive force) and
a torque (twisting force). The strong nature of the Static Field also has
the potential to disrupt the function of Cardiac Pacemakers. Anyone
entering beyond the 5G line should be screened for contraindications
to strong Magnetic Fields. Also be aware of what is being taken over
the 5G line.
What strategies can be employed to reduce the risks of the static
magnetic field impacting on implants and objects? ---------CORRECT
ANSWER-----------------• Ferromagnetic objects may become airborne -
40 km/hr terminal velocity possible at 1.5T
• Test any metal objects with a hand held magnet before allowing them
to enter the room.
• Keep the general public behind the 5G line. •
Possible contra-indications include pacemakers, aneurysm clips, intra-
vascular coils and stents, heart valves, penile implants, cochlear
implants, ocular implants (Fatio eyelid springs), neuro stimulators, bone
growth stimulators, drug infusion pumps.
,What effect do gradient magnetic fields have on patient safety? ---------
CORRECT ANSWER-----------------Faraday's Law dictates that changing
magnetic fields will generate a voltage and a current in a conductor.
The switching of the gradients induces electrical currents in conductive
tissues. Voltage generation will occur during the rise and fall times - ie.
while the field is changing. The largest voltages will be generated at the
periphery where the gradient amplitudes are highest. The most
common result of these voltages is Peripheral Nerve Stimulation (PNS).
Other side-effects are listed below;
• magnetophosphenes - electromagnetically induced flashes of light
• seizures
• tissue heating
• peripheral nerve stimulation
• muscle contractions
• cardiac arrhythmias
• some degree of patient heating has been shown to be a result of
Gradient Magnetic effects. However, this has been shown to be so low
as to be negligible
What strategies can be employed to keep gradient effects to a
minimum? ---------CORRECT ANSWER-----------------In order to keep these
effects to a minimum the following is recommended.
• keep dB/dT less than those required to produce peripheral nerve
stimulation.
, • max limit for dB/dT of 6 Tesla / sec
What is the cause of acoustic noise during an MRI scan? ---------
CORRECT ANSWER-----------------The characteristic noise that is heard
during an MRI scan is the result of the interaction of Lorentz forces
generated by the Gradient Coil when a current is pulsed through them
in the presence of a Static Magnetic Field. The noise results as these
forces are so strong as to twist the coils on their mounts. In some cases
this can be in excess of 100dB particularly when running EPI sequences.
Thus all patients need to be provided hearing protection.
What is the greatest concern in terms of MR safety? ---------CORRECT
ANSWER-----------------RF effects are of the greatest concern in terms of
MR safety. The main effect is the deposition of energy resulting in
tissue heating. Of particular concern are heat sensitive organs such as
the eyes and testes. One of the major concerns is where a patient has a
metallic implant which results in greater heating.
RF field safety concerns increase or decrease with increasing field
strength> ---------CORRECT ANSWER-----------------The amount of energy
absorbed will increase with frequency of the RF field delivered and is
therefore greater at higher field strengths
