Forces
A very strong magnetic field to polarize the spin of protons in human tissue, allowing for MR imaging. Typically measured in units of Tesla (T).
What is the static magnetic field (B0)?
Greatest risk of this type of injury associated with radiofrequency energy.
What is thermal injury?
Generated by the switching of gradient fields and requires proper placement of protective gear on patients.
What is acoustic noise?
The two MR zones that are restricted access.
What are Zones 3 and 4?
MRI stands for
What is Magnetic Resonance Imaging?
The forces that ferromagnetic materials are subject to in a magnetic field that try to rotate the object into alignment with the poles of the magnetic field and attract the material to the strongest part of the magnetic field.
What are rotational (torque or twisting) and translational (missile or attractive) forces?
RF power absorbed per unit mass of tissue (Watts/kg)
What is SAR (specific absorption rate)?
Can cause tingling or itchiness sensation in patients during MR exam.
What is peripheral nerve stimulation?
The zone that is freely accessible to the general public.
What is zone 1?
On July 3, 1977, this important event occurred in MR history
When was the first MRI on a live human patient performed?
A conducting object experiencing a change in magnetic field will have current induced that generates a magnetic field resisting that change. Patients may experience a tugging sensation by an implant when moving in and out of the MR scanner.
What are Lenz effects?
Burns that occur from close proximity to the transmitting body coil. Generally seen in larger/obese patients in the lateral shoulders, elbows, or flank.
What are near field effects or proximity burns?
List other potential risks associated with the time-varying magnetic field gradients.
What are induced vibrations in electrically conductive devices?
Zone where screening is often performed, according to the ACR manual.
Zone II
He first described the rotating magnetic field in 1882 and is named for a unit of measurement in MRI.
Who is Nikola Tesla?
Torque effects are greatest at this part of the MRI scanner.
What is isocenter?
Burns most commonly in these areas of the body occur from tissue currents in large caliber body loops induced by RF energy.
What are points of high resistance and skin-to-skin contact -fingers and thighs, medial thighs, medial calves?
Operating mode with lowest level of output in MRI which presents negligible risk to the patient.
Screening with this equipment is recommended prior to entering zone 3 and 4.
What is a ferromagnetic detector (FMD)?
The last week in July is universally recognized as MR Safety Week, which was inspired by the anniversary of the tragic MRI-related death of this 6-year old boy.
Who was Michael Columbini?
The spatial gradient magnetic field is strongest at this part of the MR scanner.
Results in burns when current is induced in elongated conductors within the volume of the RF transmit coil, length of the conductor matches a harmonic of the RF waveform.
What are resonant circuitry (antenna) effects?
This operating mode limits the dB/dt (time-varying magnetic field gradients) to 80% of the peripheral nerve stimulation mean, <45T/s
What is normal operating mode?
These personnel are permitted unaccompanied access throughout zones 3 and 4.
Recently FDA approved GBCA with high T1 relaxivity
What is Gadopiclenol (Vueway or Elucirem)?