Transcript MRISC

MRISC Organizational Chart
Research and Graduate Studies
Dr. James Tracy
College of Medicine
Fred de Beer, M.D.
Director
Dr. Charlie Smith
Administrative Staff
Officer
Nancy Bailey
MRI
Technologist
Beverly Meacham
Faculty Support
(Primary in Academic Depts)
Anders Andersen, Ph.D.
Anatomy & Neurobiology
Peter Hardy, Ph.D.
Radiology
David Powell, Ph.D.
Biomedical
Engineering
MRISC Users
MRI Terminology
1. Ferrous- Objects made of metal that are highly
attracted to the MRI machine
examples: Cast Iron, Steel, Wrought Iron
2. Nonferrous- Objects made of metal that are not
attracted to the MRI machine
examples: Titanium, Copper, Aluminum
MRI Terminology
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Tesla or Gauss- Magnetic field strength is measured
in one of these two units
1Tesla = 10KG=10,000 Gauss
Tesla is used to measure higher magnetic field strengths
Gauss is used to measure lower magnetic field strengths
example: Earth’s magnetic field is 0.6Gauss
MRI Terminology
5 Gauss Line- inside the MRI room
****Electronic devices and ferromagnetic objects
inside the 5 Gauss line are strictly prohibited****
MRI Terminology
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Missile Effect- Ferromagnetic metal objects such as an oxygen
tank can become airborne as a projectile in the presence of a
strong magnetic field.
MRI Terminology
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Fringe Field- stray magnetic field outside of the bore of the
magnet
MRI Terminology
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Static Magnetic Field- is the non-fluctuating main
magnetic field
Bioeffects: Static Magnetic Field
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There is a great deal of information about the possible
bioeffects of static magnetic fields.
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Many effects cannot be reproduced consistently in a
controlled environment.
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Most studies conclude that static magnetic fields below
2 Tesla produce no substantial harmful bioeffects.
Bioeffects: Static Magnetic Fields
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Fields above 2 Tesla can
cause the following side
effects:
Nausea
Vomiting
Dizziness
Magnetophospenes
Bioeffects: Static Magnetic Field
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Magnetophosphenes
Defined as flashes of light
Caused by the induction of
the electricity within the optic
nerves
Bioeffects: Static Magnetic Field
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Other biological effects at fields above 2T include:
Fatigue
Headaches
Hypotension
Irritability
Bioeffects: Static Magnetic Field
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The FDA limits clinical
magnets to 8.0 Tesla.
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Most common clinical field
strengths between .3 Tesla
and 1.5 Tesla.
MRI Safety
Magnet Safety
THE INVISIBLE FORCE
Safety: Missile Effect
Safety: Projectiles
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Small objects such as a paperclip can
travel up to 60 mph when pulled into a
3Tesla Magnet.
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The amount of force on a projectile
depends on the following:
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The strength of the magnetic field
The mass of the object
The distance from the magnet
The orientation to the magnetic field
Magnet Safety
Equipment safe for MRI room:
MRI Wheelchairs
MRI Stretchers
MRI Monitoring equipment
**Equipment will be identified as MR safe**
(The equipment is made of nonferrous material)
***Absolutely NO outside stretchers/wheelchairs
allowed in the MR Room
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Video- #1
Chair gets stuck in an MRI machine
27 secs
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Video #2
MRI oxygen bottle
9sec
Video #3
Oxygen cylinder in MR scan room
 2:01 min
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Video #4
Gurney let loose in MR scan room
1:28 min
Screening
Safety: Pregnancy Screening
Possible Pregnancy
There are no known biological
effects of MRI on fetuses.
Many of the mechanisms could
potentially cause adverse affects in
developing fetuses
FDA requires labeling of MR
systems to indicate the safety when
imaging a fetus or infant.
Benefit should out weight the risk
and caution should be used within the
first trimester.
Safety: Pregnant Employees
Pregnant Employees
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No known effects
Should avoid RF and
gradient magnetic fields.
Make your own decision
Subject Screening
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The MRI subject questionnaire should
include the following:
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Subject history related to problem
Previous surgeries
Metallic foreign bodies
Possible Pregnancy
Biomedical Implants
 Pacemaker
 Aneurysm Clips
Subject Screening
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All subjects will have a
screening form completed
Forms are filed in the Study
Binder kept in the MRI
console area.
Safety: Subject Screening
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Evaluating Implants
 Determine type and location
 Use published implant list
 Call surgeon
 Call manufacturer
Safety: Subject Screening
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Evaluating Metallic Foreign
Bodies:
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Determine type, location, and size
Use X-ray to evaluate
Use CT to evaluate orbital objects
Safety: Subject Screening
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Protecting From Missile Effect
(Projectiles)
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Remove any and all metal (lockers
available)
Dress subject in gown or scrubs if
required
Check all metallic items with bar
magnet
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Wheelchair, Patient Beds, Oxygen
tanks
Safety: Subject Screening
MRI complications with Tattoos:
Rarely, tattoos or permanent makeup might
cause swelling or burning in the affected areas
during MRI exams.
In some cases, tattoo pigments can interfere with
the quality of the image — such as when a
person who has permanent eyeliner has an MRI
of the eye.
Safety: Auditory Effects
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MRI is a noisy procedure.
Various noises come from gradients,
cryogen pumps, and monitors.
Gradient noise is the most potentially
harmful.
Caused by vibrations of the gradient
coils within their fiberglass casing.
Safety Auditory Effects
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Effects can include the following:
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Annoyance
Decreased ability to communicate
Increased anxiety
Potential temporary hearing loss
Potential permanent hearing loss
Safety: Auditory Effects
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Techniques used to reduce the risk of
hearing loss during the MRI procedure
include the following:
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Ear plugs /Ear muffs
Active noise cancellation
Safety: Subject Monitoring
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Who should be monitored?
 Sedated subjects
 Subjects with communication
difficulties
 Subjects with weak voices or
impaired hearing
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All Subjects should be monitored
visually and verbally.
Give Subjects emergency squeeze ball
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Safety: Subject Monitoring
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Problems with subject monitoring
include the following:
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Monitors attracted to the magnet (8ft)
RF distorts monitor readings (Shielding)
Monitor causes artifacts on MRI images
Monitor wires may cause subject burns
(fiber optic)
Safety: Subject Monitoring
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Techniques used to reduce the potential
for subject burns from monitors include
the following:
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Straighten looped cords
Eliminate direct subject contact
where possible
Use only tested MRI safe devices
Safety: Subject Monitoring
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Commonly used MRI subject monitoring techniques include
the following:
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EKG
Capnography
Blood Pressure
Pulse Oximetry
Ventiltor
Safety: Subject Monitoring
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EKG monitor monitors
the heart rate.
Safety: Subject Monitoring
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Pulse Oximeter measures the
oxygen level of the blood.
Safety: Subject Monitoring
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Ventilator breaths for heavily
sedated subjects that cannot
breath on their own.
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The monitors used in MRI
are MRI safe and only
used in the MRI suite.
Subject Management
Subject Management Claustrophobia
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Claustrophobia is defined as an
anxiety disorder that involves the
fear of enclosed or confined
spaces.
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Subjects that experience
claustrophobia can have panic
attacks.
Subject Management Claustrophobia
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Ways to manage claustrophobia include:
 Educate the patient
 Ensure sufficient air flow
 Provide light within the bore
 Cover eyes or use mirrors
 Communicate often with patient
Emergency Procedures
Quench
A quench is the spontaneous release of
the liquid gasses that maintain the
superconductive magnetic field
All systems are built with a "quench
button". The primary use for the button is to
render the unit non-magnetic in case of an
emergency (object projectile into the
magnet, etc), but isalso utilized to
"quench" when the magnet (MRI) is being
taken out of service.
Quench
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What to do if a quench occurs
Evacuate the room
Stay low to the ground, Oxygen
will be low
Asphyxiation/Frostbite/Hearing
Loss can occur
Quench Video
http://www.youtube.com/watch?v=uZWMWJwYcZk
Quench Video
http://www.mrisafetyvideo.com/kch_quenc
h_insideSo.htm
Emergency Procedure
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***Only Quench the Magnet if it is life or death**
Do not quench: If metal is stuck in the magnet
ie buffer, O2 tank
Emergency Procedure
Medical Distress:
1. Cardiac Arrest
2. Respiratory Distress
3. Seizure
***Call 911, Remove Subject from Magnet ASAP--Shut Magnet Door
Begin CPR (if indicated)…..outside of MRI room
Crash Cart located next to subject lockers
***NEVER Bring Crash Cart into Magnet Room***
Do not allow anyone into Magnet room
Emergency Procedure
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Emergency Electrical Shutdown Button
Located: In MRI Console area
Used to shut down electrical power to unit
ie. Fire/smoke
**This does not Quench the Magnet, Emergency Personnel do not enter
MRI room unless they remove all metal**