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How CT Scan Works

CT scan stands for Computerized Axial Tomography. It's a way of using a spinning Xray and computer to make high resolution images of the inside of your body. You lie flat on a table which slides through this machine and takes many circular pictures which are put together by a computer algorithm into a final sequential film.

ct scan cartoon

How a CT Scan Works

Any part of your body can be captured and a technologist instructs the CT scan where to begin and end taking pictures. To enhance difficult to make out areas, some CT scans are done after injecting you with a special contrast dye to clarify indistinct areas of tissue.

CT brain


The above picture shows a brain CT scan of a twenty year old with weakness on his right side. The red dots show that he's weak because there's damaged brain tissue on that side - the black areas. The bones of the skull look like a white halo and normal brain tissues looks speckled gray. Below is a picture of an actual CT scan machine:

CT scanner

Risk CT Scan, CT Scan Danger

Risks from taking a modern CT scan are low. A single CT scan is equivalent to about 8 months of natural outdoor cosmic radiation. Obviously risk becomes more significant with multiple repeated CT scans as radiation exposure is additive. This is why radiographers who are potentially exposed to radiation for many hours everyday wear lead protected vests or stand behind a protective wall when firing their CT scanners.

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    Last Updated:
    April 22 2016
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