Welcome to MRI Safety and Policies

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Welcome to MRI Safetyand Policies Procedures
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Magnet Safety at ALL TIMES

• Outline
• Understanding Magnets
• Your role in MR Safety
• Metallic Screening
• Screening Patients / Colleagues
• Other Safety Considerations
• What to do in Emergencies
• MRI Department Policies and Procedures
• Preview MRI Safety Videotape

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Magnetism / Magnets

• All substances possess some form of magnetism.
• The degree of magnetism exhibited depends on the
  atoms that make-up the substance.
• Magnetic susceptibility is the ability of a
  substance to become magnetized.
• Ferromagnetic substances, such as iron have a
  large magnetic susceptibility, it is easily
  magnetized permanently and becomes a magnet
  itself.
• All magnets have a North and a South pole.
• All magnets have a fringe magnetic field which
  exists in the vicinity surrounding the magnet.

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Magnetic Fringe Fields

• The fringe magnetic field is the magnetic field
  which exists in the vicinity surrounding the
  magnet.
• This field may extend many meters from the magnet
  itself.
• These imaginary lines of force demonstrate the
  pattern of the magnetic field.
• Safety and operational concerns make it necessary
  to contain the fringe field to a small area.
• Magnetic fields are measured in units of Gauss or
  Tesla.
• (1T 10,000G)

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MRI Safety at ALL TIMES

• A STATIC MAGNETIC FIELD IS ALWAYS PRESENT
  24hrs/day, 365 days/yr. EVEN WHEN NOT IN USE.
• ANY PERSON USING THE MAGNET MUST BE CERTIFIED
  AFTER ATTENDING THE MRI SAFETY TRAINING CLASS.
• ONE MUST BE TRAINED ON THE SCANNER INTERFACE
  BEFORE SCANNING.

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What is your role in MR Safety?

• The greatest risk of injury and damage to the
  system results from
• Misuse or abuse of the MR equipment
• Failure to comply with recommended safety
  procedures
• Lack of proper inspection and maintenance of the
  MR equipment

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Who should know MR Safety?

• All in-house personnel that have reason to enter
  the MR suite area should be trained in MR safety
  procedures
• MR technologists, students, researchers,
  transporters and other medical personnel
• Maintenance and janitorial personnel
• All personnel must be thoroughly briefed about
  the potential risks involved and reminded not to
  bring any ferromagnetic items into the magnetic
  field.

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Examples of items in-house personnel may have
that can become projectiles if brought into the
magnetic field
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Who should know MR Safety?

• Public safety forces that may respond to the MR
  suite for an emergency must also know the
  potential hazards of the MR equipment.
• Law enforcement personnel
• Fire department personnel
• A person from the MR site should discuss the
  possible hazards with these people and provide
  them with handouts that will reinforce the
  information.

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Examples of items public safety forces may have
that can become projectiles if brought into the
magnetic field
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MRI Safety - Projectiles

• Projectile effects of metal objects seriously
  compromise safety. The potential harm cannot be
  over emphasized.
• Paper clips, hair pins velocity 40mph _at_ 1.5T.
• Larger objects (scissors, etc.) have higher
  velocities and may be fatal.
• Many types of clinical equipment are
  ferromagnetic and should never be brought into
  the scan room.
• Items may be tested for magnetic susceptibility
  with a hand-held magnet located at each MR
  station.

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Metal Objects Becoming Projectiles
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Fatal Accidents CAN Happen!
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Patient Emergencies

• Should a condition exist where the patient is
  having a medical emergency, all efforts must be
  made to quickly and safely remove the patient
  from the scan room.
• Once the patient is removed from the MR scan
  room, close the door to prevent re-entry.
• Under no circumstances should a code team be
  allowed to enter the scan room without proper
  screening!

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Controlled Access Area

• Although not detectable by the human senses, a
  magnetic field can be dangerous to equipment and
  to people.
• Since a magnet is always at field, safety
  procedures must be followed to prevent accidents.
• For the safety of patients and personnel,
  controlled access areas are established.

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Controlled Access Area

• These areas are established for the safety of
  patients and personnel.
• The area is labeled with the use of warning signs
  and markings to prevent the entry of
  ferromagnetic objects into the controlled access
  area and to limit the access of individuals with
  medical implants near high magnetic fields.
• Public access begins at the 5 gauss line (0.5mT).

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Equipment / Personal Items

• The magnetic field can seriously damage or impair
  the operation of equipment or personal items such
  as
• Oscilloscopes (slow moving electron beams)
• Camera
• Watches
• Credit / Bank cards
• Hearing Aids
• Hair Accessories, Belt Buckles, Shoes

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Screening Procedures

• At least one MR operator must screen the patient
  for possible contraindications that could affect
  the MR scan. See Patient History and Safety
  Screening form.
• Check implanted devices in the Reference Manual
  for Magnetic Resonance Safety by Frank Shellock,
  Ph.D. or by using MRIsafety.com

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Example of MRI Metal Screening Sheet
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Screening Procedures

• Static magnetic fields can alter the operation of
  electrically and mechanically operated implants
  and must remain outside the 5 gauss line.
• Pregnant medical personnel should take
  precautions and remain outside of the magnet room
  during scanning.
• Questions about implants not found in reference
  material should be discussed with a licensed, MRI
  technologist or a radiologist before allowing the
  patient to be scanned.

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Absolute Contraindications

• Cardiac Pacemakers (except in rare, controlled
  environments)
• Cochlear (inner ear) implants
• Swan-Ganz catheters with thermodilution tips
• Ferromagnetic or unidentifiable aneurysm clips of
  the brain
• Implanted neuro stimulators
• Metal or unidentifiable foreign bodies in the
  eyes
• Shrapnel near a vital organ

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Bioeffects

• There is no conclusive evidence for irreversible
  or harmful bioeffects in humans below 3.0T.
• Reversible abnormalities may include but are not
  limited to
• Localized tissue and core body temperature
  heating
• Cutaneous sensations (tingling)
• Peripheral nerve stimulation (involuntary muscle
  contractions)
• Burn hazards

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Bioeffects

• Burn Hazards are caused by damaged hardware or by
  electrical currents produced in conductive loops
  of material.
• Localized heating is caused by RF irradiation
  energy absorption to a volume of tissue.
• Dissipation of the absorbed RF energy is
  described in terms of Specific Absorption Rate
  (SAR), measured in watts/kg.
• SAR is calculated by the patients weight and the
  expected increase in body temperature for each
  imaging pulse sequence.
• Patients with poor thermo-regulatory systems must
  be carefully monitored.

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Bioeffects

• Acoustic Noise
• The MR scanner can produce very high acoustic
  noise levels.
• Some patients may experience discomfort from the
  associated noise of the scanner.
• Prior to scanning, it is strongly recommended
  that earplugs be provided to the patient to
  reduce the noise level by at least 25dB.

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Operating Safely

• When operating the MR equipment, be attentive to
  the following abnormal conditions
• Louder-than-normal motor noises
• Sparks
• Components overheating
• Smoke or odors coming from the electronic
  equipment or from within the scan room.
• Do not operate equipment with protective panels
  opened or removed, there is risk of electric
  shock and can cause image artifacts.

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Magnetic Field / Scan RoomEmergencies

• If an emergency situation arises, you may need to
  quickly bring down the patient systems and remove
  power from the MR system.
• The nature of the emergency will dictate which
  procedure you follow. Each procedure has a
  distinct and specific purpose.

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Magnetic Field / Scan RoomEmergencies

• Each magnet is equipped with two emergency
  buttons
• Emergency Stop / Shut Off
• Turns off all incoming electrical power to the
  magnet Power Distribution Unit (PDU)
• Quench or Emergency Run Down
• Causes immediate collapse of the superconductive
  magnetic field within minutes
• FAMILIARIZE YOURSELF WITH THESE BUTTONS. KNOW
  THE DIFFERENCE!

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Emergency Stop / Shut Off Button

• Shutting power to the PDU may be required for
  life threatening situations such as
• Fire in the computer room
• Fire, sparks, loud noises emanating from the scan
  room
• Flooding or sprinkling system goes off
• Catastrophic equipment failure
• Keep in mind that when this button is pushed,
  it does not initiate a quench, the magnet remains
  at field. Exercise caution, make sure that all
  ferromagnetic materials remain outside of the
  scan room

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Quench / Emergency Run Down Button

• The following situation is THE ONLY TIME that may
  require quenching of the magnet
• Large magnetic object pins or impales a person
  against the magnet and no other method can
  prevent further injury or free the person.
• Do not attempt to pull large magnetic objects
  (oxygen tanks) from a magnet field. The object
  may change its magnetic polarity and re-align
  itself on the magnet and become a projectile,
  causing a serious or fatal injury.
• Do not touch a quenched magnet. Under certain
  conditions, an electrical potential of gt1,000
  volts could exist on the surface of the magnet.

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Quenching

• Definition a loss of superconductivity of the
  magnet coil due to a local temperature increase
  in the magnet as it becomes resistive, resulting
  in rapid evaporation of liquid helium in the
  cryostat and quickly reducing the magnetic field
  strength.
• A quench may happen spontaneously or can be
  manually instigated in case of an emergency.
• Quenching may cause severe and irreparable damage
  to the superconducting coils (magnet).
• A magnet quench will result in several days
  downtime, so do not press the button except in a
  true emergency.
• Do not attempt to test this button!

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Emergency Buttons _at_ MR1Univ. of Utah Hospital

• QUENCH BUTTON
• Button is located on the east wall (with window).
• E-STOP BUTTON
• Button is located behind the door as you enter
  the scan room (on the right).

OXYGEN SENSOR
QUENCH
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Emergency Buttons _at_ MR2Univ. of Utah Hospital

• QUENCH BUTTON
• Button is located on the southeast wall (across
  from the door to enter the scan room).
• E-STOP BUTTON
• Button is located to the right as you enter the
  scan room (south wall).

OXYGEN SENSOR
QUENCH
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Emergency Buttons _at_ MR2Univ. of Utah Hospital
OXYGEN SENSOR
E-STOP
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Emergency Buttons _at_ MR3CAMT Building, Research
Park

• QUENCH BUTTON
• Button is located on the east wall (behind the
  door to enter the scan room).
• E-STOP BUTTON
• Button is located outside the door used to enter
  the scan room on the left side (north wall).

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Emergency Buttons _at_ MR3CAMT Building, Research
Park
QUENCH
E-STOP
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Emergency Buttons _at_ MR4CAMT Building, Research
Park

• QUENCH BUTTON
• One button is located above the scanner
  workstations (west wall).
• One button is located inside the scan room on the
  left (south wall).
• E-STOP BUTTON
• One button is located under the cupboard by the
  console (west wall).
• One button is located inside the scan room on the
  left (south wall).

QUENCH
E-STOP
E-STOP
QUENCH
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Emergency Buttons _at_ MR4CAMT Building, Research
Park
QUENCH
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Emergency Buttons _at_ MRHHuntsman Cancer Hospital
QUENCH

• QUENCH BUTTON
• One button is located above the scanner
  workstations (east wall).
• One button is located at the hand washing station
  just outside the scan room door.
• E-STOP BUTTON
• Button is located at the hand washing station
  just outside the scan room door.

E-STOP
QUENCH
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Emergency Buttons _at_ MRHHuntsman Cancer Hospital
E-STOP
QUENCH
QUENCH
E-STOP
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University of Utah Hospital and ClinicsMRI
Department Policies and Procedures

• This manual is available at all sites having a
  MRI scanner. Detail of all departmental
  situations can be reviewed. The following safety
  considerations are further highlighted
• Cryogen Safety Oxygen Monitors
• Metallic Screening Pregnancy / Nursing
• Magnet Quench Medical Emergencies
• Magnetic Field / Scan Room Emergencies

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Summary

• MRI scanners are powerful magnets with the
  ability to attract ferromagnetic objects.
• Any personnel around the MRI suite must be
  adequately screened for metallic implants and
  personal items before entering the scan room.
• Patients in the scanner must be carefully
  monitored for reversible bioeffects caused by the
  magnets hardware.
• Become familiarized with E-Stop vs. Quench
  buttons at each scanner.
• Review Policies and Procedures Manual

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Congratulations!

• You have completed the University of Utah
  Hospital and Clinics MRI Safety Training course!
  
• Please review a safety video that demonstrates
  the powerful forces of MRI magnets.
• Following written certification, you will be
  authorized to aid or assist an MRI technologist
  with patient examination procedures.