Transcript intro.phys.psu.edu

Exploding Tattoos
Carissa Ferraro
Sarah Fiorelli
Anne Adams
The Myth
Tattoos are reported to "explode" when put
inside an MRI scanner, because of the
strength of the magnetic field within the MRI
machine. The claim is that trace metal
filaments in tattoo ink are attracted to the
magnets within the machine (which are 20
times stronger than the Earth's magnetic
field), making them explode off the patient's
skin.
Part of an MRI machine
Magnetic Resonance Imaging:
Primary Magnet- this is the main part of the MRI
machine. This magnet creates the magnetic field.
•
•
•
Gradient Magnets- these are the fine tuning part of the
machine. This allows the machine to focus on specific
parts of the body.
The Coil- emits a radio frequency waves into the
patient's body. There are different coils for different
parts of the body. It detects the energy given off by the
magnetic induction from the processing of atoms.
How it Works?
•
•
•
•
•
•
Moving a magnet near a wire will create a current
flowing in the wire.
The MRI machine is made up of one big coil/loop
with a magnet.
Changing a magnetic field (induction) inside the
loop creates a current that can produce the
magnetic resonance imaging
The current makes an electromagnetic field
Before a patient enters the MRI machine the
hydrogen atoms in their body all pointing in all
different directions
When the patient enters the MRI machine the
atoms line up in the direction of the magnetic field.
How it Works? (continued)
•
•
•
•
The magnetic field runs straight down the center of
the machine.
This then makes the hydrogen protons line up in the
direction of this magnetic field, pointing towards
the patient's head or feet.
Half the protons point towards the patient's feet
and the other half point towards to the head. This
makes many of the protons cancel each other out
because for every proton pointing in one direction
there is an atom pointing in that same direction.
Only a couple protons out of every million aren't
cancelled out, the protons that are not cancelled out
give us a detailed MRI.
How it Works?(continued)
• Now the MRI machine emits a radio frequency
•
•
•
•
pulse that is specific to the hydrogen
The MRI machine emits this pulse towards the area
of the body that needs examination
Unmatched protons absorb this energy, and then
gradient magnets turn on and off altering the
magnetic field.
When the RF pulse is turned off the hydrogen
protons slowly return to their natural state, and
release the previously absorbed energy that is
detected by the coils, and sent to the computer
system
Once they are sent to the computer, the image is
created for a doctor to further examine.
MRI Machine
Components of Tattoo Ink
Many people are under the impression that
tattoos are composed of different colored
ink, when actually they consist of two main
components: pigments and carriers.
Composition of Pigments
The pigment of tattoos is composed of different
elements to form the different colored "inks".
Blue: Calcium Copper Silicate
Red: Iron Oxide
Green: Chromium Oxide
Yellow: Curcuma
Black: Carbon
White: Zinc Oxide
•
•
•
•
•
•
Carriers
Carriers are an essential component to tattoo
"ink". They are the liquids that deliver the
pigments beneath the skin.
Commonly Used Liquid Carriers:
Listerine
Witch Hazel
Purified Water
Propylene Glycol
Vodka
•
•
•
•
•
Validity
The only ink that has the potential to react with
the magnetic field is red ink (made from iron
oxide). Even so, the amounts of iron in the
skin are too small to make a tattoo "explode"
when under the MRI scanner. There have
been some reports of redness or irritation at
the tattoo site, but no explosions.
Prison Tattoos?
An objection to the debunking of the myth is
that it doesn't account for tattoos
administered in prison. These tattoos aren't
administered with sterile needles, but often
with whatever is available -- mechanical
pencils, paper clips, staples, or guitar strings.
The ink can be comprised of whatever the
artist can get, mostly melted plastics and pen
ink. Still, the amount of iron found in the
prison tattoos are most likely not enough to
make the tattoo explode.
Historical Validity
Patients who received tattoos years ago have
reported slight to severe pain when
undergoing a scan. This may be because
tattooing has only recently been strictly
regulated for health concerns, and pigments
used to contain metal fragments in larger
proportions than they do today. While pain is
still a serious side effect, tattoos can't
"explode" in an MRI scanner.
What We've Learned
While the magnetic field in an MRI machine is
quite strong, the metal found in tattoos isn't
enough to make it explode (although the field
is strong enough to injure patients who wear
metal jewelry, etc.).
Also, none of us will ever get a tattoo.
Bibliography
http://orthopedics.about.com/cs/sportsmedicine/a/mri.htm
http://www.bellaonline.com/articles/art57596.asp
http://tattoo.about.com/cs/tatfaq/a/mri_scan.htm
http://tattoos.lovetoknow.com/Tattoo_Ink
http://science.howstuffworks.com/mri.htm
http://www.convictedartist.com/prison_tattoos.html