Download Dangers in and around the scanner

Overview
 The scanner
 Dangers in around the scanner
 In case of an emergency
 Emergency numbers
 Emergency procedure
 Reporting adverse events
 Safety checklists
The scanner
Dangers in and around the scanner
 Static magnetic field
 Gradient fields
 Highfrequency fields
 Laser-light
 Helium discharge
 Phantom leakage
Static magnetic field
 The static magnetic field is ALWAYS on even when the
scanner is not in use!!!
 projectile effect
 everything that is ferromagnetic becomes a projectile
when brought into the scanner room
 torsion and translation forces: ferromagnetic objects will
attempt to align with the magnetic field
Metal objects becoming projectiles!!!
Melon in the Scanner
Static magnetic field
 magnetohydrodynamic effect
 phenomena arising from the motion of electrically
conducting fluids in the presence of electric and magnetic
fields
 vertigo, nausea and phosphenes may relate to this
 prevent this by restricting quick and side to side movement
of the head when in the magnetic field
Static magnetic field
 To ensure safety of participants:
 MRI safety checklist has to be filled in and signed for
each and every measurement
 NO RISKS (www.mrisafety.com)
 Less familiar exclusion criteria:
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transdermal medication patches (often contain a metallic
layer)
make-up containing metal
Static magnetic field
 To ensure safety of participants:
 before you start working at the scanner make sure that
you take off everything that contains metal
 before entering the scanner room make sure that the
subject has taken off everything that contains metal
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mention examples explicitly: glasses, belt, keys, money, mobile
phone
watch them carefully and let them take everything out of their
pockets
let them take off their shoes (outside the scanner room)
 when entering the scanner room let the subject enter
first (you have to be perfectly sure that you have no
metal on you)
Dangers in and around the scanner
 Static magnetic field
 Gradient fields
 Highfrequency fields
 Laser-light
 Helium discharge
 Phantom leakage
Gradient fields
 peripheral nerve stimulation
 momentary magnetic field gradients can induce
currents in conductive material including nerve or
muscle tissue
 it is possible to induce currents sufficient to influence
cardiac function
 researchers have to monitor the subject and stop
scanning immediately if peripheral nerve stimulation is
reported
Gradient fields
 peripheral nerve stimulation
 when positioning the subject in the scanner avoid any
closed loops with their extremities
 instruct subjects not to clasp their hands or cross their
legs
Gradient fields
 acoustic noise
 EPI sequences are especially loud
 participants have to wear hearing protection: earplugs
+ headphones
 earplugs have to decrease noise by 30 dB
Dangers in and around the scanner
 Static magnetic field
 Gradient fields
 Highfrequency fields
 Laser-light
 Helium discharge
 Phantom leakage
Highfrequency fields
 tissue heating and burns
 absorbtion of radio frequency power by the tissue is
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described in terms of Specific Absorption Rate (SAR,
Watts/kg)
guideline: less than 1°C change in tissue temperature;
SAR < 4 Watts/kg for any 15min period
scanner calculates SAR and stops scanning if too high
especially dangerous with tatoos containing iron oxide,
or transdermal medication patches
no use of synthetic blankets in the scanner
Dangers in and around the scanner
 Static magnetic field
 Gradient fields
 Highfrequency fields
 Laser-light
 Helium discharge
 Phantom leakage
Laser-light
 damage to the eyes
 instruct participant to close the eyes during positioning
with the laser light
 make sure to report if the laser-light does not show a cross
any longer but only a point
Dangers in and around the scanner
 Static magnetic field
 Gradient fields
 Highfrequency fields
 Laser-light
 Helium discharge
 Phantom leakage
Helium discharge
 risk of frostbites
 helium is odorless, not flammable, not toxic but
extremely cold!!!
 contact causes freezes
 if you come into contact:

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do not rub frozen body parts
remove clothes
rinse with cold water
cover body parts with sterile bandage
contact physician immediately
Dangers in and around the scanner
 Static magnetic field
 Gradient fields
 Highfrequency fields
 Laser-light
 Helium discharge
 Phantom leakage
Phantom leakage
 nickel containing aerosols
 can cause cancer
 therefore do not use leaking phantoms
 avoid skin contact with the leaking substances
In case of emergency
 Participant STOP
 Participant is wedged in the bore
 Fire or voltage accidents
 Quench: life threatening danger
 Earthquake or explosion
In case of emergency
 participants get an emergency ball to signal any problem
during scanning
 when an individual becomes ill or injured he/she must be
removed immediately from the magnetic environment
In case of emergency
 Participant STOP
 Participant is wedged in the bore
 Fire or voltage accidents
 Quench: life threatening danger
 Earthquake or explosion
In case of emergency
 participant is wedged in the magnet bore (risk of
crushes)
 press the stretcher – STOP button
 to the right and left of the scanner
 at the communication system
 the automatic brake of the patient table has to be released
then you can pull the patient table out manually (handle is
at the bottom of the patient table)
In case of emergency
 participant is wedged in the magnet bore (risk of
crushes)
 if you are sure there is no risk anymore you have to restart
the patient table mechanism by pushing the in and out
button after one another
In case of emergency
 Participant STOP
 Participant is wedged in the bore
 Fire or voltage accidents
 Quench: life threatening danger
 Earthquake or explosion
In case of emergency
 fire or voltage accidents
 push the emergency-off button
 this only stops the electricity not the magnet!!!
In case of emergency
 Participant STOP
 Participant is wedged in the bore
 Fire or voltage accidents
 Quench: life threatening danger
 Earthquake or explosion
In case of emergency
 life threatening danger due to magnet or fire
 if a participant is restrained by a ferrous object assess
if the situation is life threatening if YES quench the
magnet
Metal objects becoming projectiles!!!
Here you do NOT need to quench!!! No life in danger.
In case of emergency
 life threatening danger due to magnet or fire
 quenching costs around 50.000 €
 decrease of field to 20mT in 20 seconds (elec. implants are
still disturbed from 0.5mT)
 sudden loss of the magnetic field can cause freezing gases to
enter the room, loud noise
 Normally there is no helium leakage in the magnet room
In case of emergency
 Participant STOP
 Participant is wedged in the bore
 Fire or voltage accidents
 Quench: life threatening danger
 Earthquake or explosion
In case of emergency
 earthquake or explosion
 might lead to an uncontrolled quench: increased risk of
helium leakage (DANGER)
 oxygen level in the magnet room may decrease and may
make breathing difficult (risk of suffocation)
 during quenching condensation occurs therefore do not
walk under the exhaust pipe lines
Emergency numbers
 Fire 88 (don‘t use fire extinguisher!)
 All other medical emergencies: 81
What to do in case of emergency?
(e.g. Participant is unconscious)
1. Get participant out of the scanner (use bed)
& call 81 (simultaneously)
2. Say on the phone:
1.
2.
3.
4.
Where you are: MR dwarsgebouw Links (tussen B1
& B2/between B1 & B2)
What’s going on: ‘e.g. participant unconscious’
Your name
Your internal number: 21240
3. Open all the exit doors for easy access
Reporting adverse events
 accidents and injuries are to be reported
 also near accidents should be reported so we can take
precautions
 report to: Pieter Vandemaele
mail: [email protected]
tel: 09 332 4820
MR safety checklist
 please fill in now
Demonstrations
 Emergency materials
 Emergency procedure:
 Emergency stop:
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Participant stop
Operator stop
 Phonecall & getting participant out
 Opening the doors