Simplify how cat scan work?

[sweet_gal]

Can anyone simplify or explain the way a cat scan works............

 

Thanks

[nuune]

lol this is one of the most beautiful questions i have ever seen, i love to know the answer, i just can't wait

[Khayr]

Salaamz,

 

" CAT scans take the idea of conventional X-ray imaging to a new level. Instead of finding the outline of bones and organs, a CAT 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."

 

For an illustrated example,

follow this link

http://www.colorado.edu/physics/2000/tomography/

 

and if you were wondering about MRI's

 

The Basic Idea

If you have ever seen an MRI machine, you know that the basic design used in most is a giant cube. The cube in a typical system might be 7 feet tall by 7 feet wide by 10 feet long (2 m by 2 m by 3 m), although new models are rapidly shrinking. There is a horizontal tube running through the magnet from front to back. This tube is known as the bore of the magnet. The patient, lying on his or her back, slides into the bore on a special table. Whether or not the patient goes in head first or feet first, as well as how far in the magnet they will go, is determined by the type of exam to be performed. MRI scanners vary in size and shape, and newer models have some degree of openness around the sides, but the basic design is the same. Once the body part to be scanned is in the exact center or isocenter of the magnetic field, the scan can begin.

In conjunction with radio wave pulses of energy, the MRI scanner can pick out a very small point inside the patient's body and ask it, essentially, "What type of tissue are you?" The point might be a cube that is half a millimeter on each side. The MRI system goes through the patient's body point by point, building up a 2-D or 3-D map of tissue types. It then integrates all of this information together to create 2-D images or 3-D models.

 

MRI provides an unparalleled view inside the human body. The level of detail we can see is extraordinary compared with any other imaging modality. MRI is the method of choice for the diagnosis of many types of injuries and conditions because of the incredible ability to tailor the exam to the particular medical question being asked. By changing exam parameters, the MRI system can cause tissues in the body to take on different appearances. This is very helpful to the radiologist (who reads the MRI) in determining if something seen is normal or not. We know that when we do "A," normal tissue will look like "B" -- if it doesn't, there might be an abnormality. MRI systems can also image flowing blood in virtually any part of the body. This allows us to perform studies that show the arterial system in the body, but not the tissue around it. In many cases, the MRI system can do this without a contrast injection, which is required in vascular radiology.

 

Here is the link

http://health.howstuffworks.com/mri1.htm

 

Did you know that to get Cat Scans and MRI's, you have to wait for months b/c they cost so much. Unless you are a professional or collegiate athelete, then you get them right away.

I'm in need of one real badly b/c of my left knee but have been giving the run around for months and just ordinary x-rays that don't show anything about 'Tissues and Cartildge' but just show BONE.

[sweet_gal]

Thanks khayr......ur so kind....except I printed that out last night....din't really read it though...I guess that'll give me all the information....thanks again

[JIDAAWY]

The Basic Idea

Computerized axial tomography (CAT) scan machines 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. (See How X-Rays Work to find how X-rays do this, as well as how X-ray machines produce X-ray photons).

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. Imagine you are standing in front of a wall, holding a pineapple against your chest with your right hand and a banana out to your side with your left hand. Your friend is looking only at the wall, not at you. If there's a lamp in front of you, your friend will see the outline of you holding the banana, but not the pineapple -- the shadow of your torso blocks the pineapple. If the lamp is to your left, your friend will see the outline of the pineapple, but not the banana.

 

Scanning Procedure

The CAT machine looks like a giant donut 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.

 

find more info at This website.. which is by the way one of my favorite sites

[Oocyte]

CT scans take cross sectional images of the body.

It is used with and without constrast - which is dye injected to the patient and outlines better certain features of the body. Before its discovery, doctors had to operate and do exploratory surgeries for certain conditions.

 

http://radiologyinfo.org/photocat/popup/picbody.jpg

 

This is CT scan of abdomen which is like as if you cut the body in half through abdomen and take pictures from below of upper half of the body.

It shows Liver and gall bladder (left), Spleen (right), Stomach (Upper right - white balloon), upper part of Left kidney ( lower right - adjacent to spleen), Aorta (white ball in center), Vertebra with spinal cord (center -lower part), and Ribs (shiny white spots - 5 on each sides).

 

 

Originally posted by Khayr:

Salaamz,

 

Did you know that to get Cat Scans and MRI's, you have to wait for months b/c they cost so much. Unless you are a professional or collegiate athelete, then you get them right away.

I'm in need of one real badly b/c of my left knee but have been giving the run around for months and just ordinary x-rays that don't show anything about 'Tissues and Cartildge' but just show BONE.

Depending on what part of the world you are at and the underlying condition. In most of developed countries CT scans and MRI are available and used all the time. There is no waiting period and in fact many patients' get during their ER visits( depending on their presentations). Outpatient scanning may be scheduled couple of days later but usually never months long.