Hi Everyone! We decided
to make this post because many of you have doubts about the differences between
some diagnostic exams and medical devices that are frequently performed in
clinical practice.
So, we are going to present to you some characteristics and functions of the CT Scan, the MRI, the PET scan and the X-ray.
Part I: CT SCAN
A
computerised tomography scan take the idea of conventional X-ray imaging to a
new level. Instead of finding the outline of bones and organs, a CT scan machine
forms a full three-dimensional computer model of a patient's insides. Doctors
can even examine the body one narrow slice at a time to pinpoint specific
areas.
The CT scan
combines a series of X-ray views taken from many different angles and computer
processing to create cross-sectional images of the bones and soft tissues
inside your body.
So, a CT
scan machine, produce X-rays, a powerful form of electromagnetic energy. X-ray
photons are basically the same thing as visible light photons, but they have
much more energy. This higher energy level allows X-ray beams to pass straight
through most of the soft material in the human body.
http://www.arimaclinic.com/CT/images/ct-scan-of-the-brain.jpg
A
conventional X-ray image is basically a shadow: You shine a "light"
on one side of the body, and a piece of film on the other side registers the
silhouette of the bones. Shadows give you an incomplete picture of an object's
shape. If a larger bone is directly between the X-ray machine and a smaller
bone, the larger bone may cover the smaller bone on the film. In order to see
the smaller bone, you would have to turn your body or move the X-ray machine.
In a CAT
scan machine, the X-ray beam moves all around the patient, scanning from
hundreds of different angles. The computer takes all this information and puts
together a 3-D image of the body. The CAT
machine looks like a giant doughnut tipped on its side. The patient lies down
on a platform, which slowly moves through the hole in the machine. The X-ray
tube is mounted on a movable ring around the edges of the hole. The ring also
supports an array of X-ray detectors directly opposite the X-ray tube.
A CT Scan
is best suited for viewing bone injuries, diagnosing lung and chest problems,
and detecting cancers. Besides
this, CT scans are widely used in emergency rooms because the scan takes fewer
than 5 minutes.
In addition
to be a very good for imaging bone structures, this exam is important in cases
of some patients who have received certain types of surgical clips, metallic
fragments, cardiac monitors or pacemakers cannot receive an MRI.
(Adapted from: http://science.howstuffworks.com/cat-scan.htm)
https://www.youtube.com/watch?v=tqGmqRrxajQ