In the field of healthcare there have been major advancements in medical
imaging techniques. Their ability to create visual representations of
internal structures and organs of the body allow these imaging techniques that
have major clinical applications. Today, we discuss three of the most commonly
used imaging techniques: the MRI, CT scan and the PET scan. This is Michael. Michael
suffered a knee injury while playing basketball last week. After an
appointment with his doctor Michael finds out he will be needing an MRI scan
to determine if he needs surgery.
Well what exactly is an MRI?
An MRI which
stands for magnetic resonance imaging is a technique used to generate an image of
one's body non-invasively. When undergoing an MRI scan a patient lies on
a moveable bed which is surrounded by the MRI scan and a circular magnet. Radio
waves 10,000 to 30,000 times stronger than the magnetic field of Earth are
sent through the body. As we all know, our bodies are mainly composed of water
which contain hydrogen atoms these waves cause the nuclei of the atoms to change
position. As the nuclei move back into their original positions they emit their
own radio waves which the scanner picks up and ultimately turns into a picture
that is seen on a computer. For the most part this procedure is painless and
risk-free. It should be noted that pregnant women or anyone with a
pacemaker or any sort of metal implant cannot do an MRI scan due to its
powerful magnetic force. After finishing his MRI scan
Michael meets Sarah who just underwent a CT scan for her severe abdominal pain.
A computerized tomography scan produces detailed images of the body mainly
through the use of x-rays. Several beams of x-rays all from different angles are
sent through the body during a CT scan. Each angle provides a picture of a thin
slice of the area being analyzed. The data is saved on a computer which takes
these two-dimensional pictures and creates a 3d cross-sectional picture of
the area. In some CT scans a dye called contrast material is taken by the
patient through injection, solution or inserted rectally.
This dye makes structures and organs easier to see on the pictures. Because of
the extreme accuracy and detail of these pictures CT scans are used for a myriad
of the body's internal situations including internal injuries from trauma,
muscle and bone disorders, detecting lung and liver diseases, and also detecting
different types of cancer. CT scans provide advantages in comparison to an
MRI scan as they provide higher resolution pictures, however they do pose
some risks as well. The ionizing radiation from the x-rays has been
linked to increased risk of cancer, although it is a low possibility.
The most common risk of CT scans is a reaction to the contrast material which
is generally mild and results in hives or itchiness. Similar to MRIs, pregnant
women should not undergo CT scans in order to avoid radiation exposure to the
fetus. Finally, meet Claire. Claire has a history of coronary artery disease so
her doctor advises her to undergo a PET scan. A Positron Emission Tomography scan
is performed by using a special dye that has radioactive tracers. The patient
injects this tracer and it is subsequently absorbed by organs and
tissues in the body. The PET scanner can highlight these traces and see how well
organs and tissues are performing. PET scans can therefore measure blood flow,
oxygen use, and glucose metabolism. A major difference between PET scans and
the two previous scans is the ability of a PET scan to show problems and
complications at a cellular level. The resolution might not be as clear as
an MRI or CT scan, however, it gathers more functional information. To prepare
for a PET scan, the patient must notify their doctor about any medical
conditions and if they are pregnant. In some instances it is advised that the
patient does not eat for 8 hours prior to the scan. Risks associated with a PET
scanner similar to those of a CT scan including exposure to radiation and
allergic reactions to the injected tracer. The MRI, CT scan, and PET
scan are three of the most commonly used techniques for medical imaging.
We learned the benefits associated with each, such as the high-resolution
provided by the CT scan or the functional information given by the PET
scan. Furthermore, we also learned about the disadvantages and risks associated
with these scans such as the possibility of an allergic reaction to the tracers
in a PET scan or the exposure to high radiation in CT scans.
In conclusion, the benefits outweigh the risks in all three of these scans as they provide essential
information for patients and healthcare providers in need of help.
Thank you for watching!
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