Feb 8, 2015

Comparison: Medical Imaging Using Different Techniques - CT Scan

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