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How Does a CT Scan Work?

September 25, 2020

What is a CT Scan?

A CT scan (computed tomography) is a medical imaging device used all around the world. It is used to diagnose diseases, monitor disease progression, and to screen for diseases.

In the US alone, approximately 80 million CT scans are done each year. This is a stark contrast to 1980 when only 3 million CT scans were performed. As you can see, the demand for CT scans has skyrocketed in the last 40 years or so. To learn more about the history of CT scans read the article by the International Society for Computed Tomography.

The CT scan machine emits x-ray beams from various positions around the patient. Then image slices can be patched together using the computer system to create 2D or 3D images of the target region. This way the bodily structures can be clearly visualized with the CT scan.

Many body parts, including the heart, lungs, bones, and much more can be visualized with a CT scan. The CT scan is helpful because it can highlight broken bones, restricted blood flow, tumors, and organ damage.

The patient’s treatment will be decided depending on the CT scan images, so it’s an important piece of equipment, to say the least.

The CT Scan Procedure

You will need to remove any metal items from your body including jewelry or clothing with metal pieces because it can interfere with the CT scan. You will be given a gown to wear for the CT scan or you may be allowed to wear your own clothing if it is loose.

For the CT scan, you may need to have contrast materials. Contrast materials are used to make the bodily structures easily visible. Contrast materials can be injected, ingested with a drink, or administered by enema. Contrast materials are safe; they are only used to make the images clearer.

You might be asked to fast for your CT scan if you need to use a certain contrast material. Your doctor will let you know in advance if you need to fast or not.

During the scan, you might be asked to lie on the table facing upwards, downwards, or sideways depending on the imaging region.

The imaging technician will leave the room and begin the scan from an adjacent room called the control room. The imaging technician will be able to see and hear you through the glass window and intercom.

You will then be passed through a donut-shaped machine (this is the CT scan machine). It is important that you remain calm and lay still so that the images don’t come out blurry. Be aware that the imaging technician may ask you to hold your breath at some point during the CT scan, so keep an ear out.

The whole process of taking images with the CT scan should only take 10 to 20 minutes but may take longer in some circumstances.

After the scan, you might be asked to wait an hour or so if you used contrast materials. This is to ensure you don’t experience any adverse side effects related to the contrast materials.

The contrast material will not permanently stain your organs; it will be absorbed by the body or will leave your system hours later through urine. Drinking 6-8 glasses of water may help to flush it out of your system.

The imaging technician will send your results to your doctor. Then at your next appointment, your doctor will explain the scan results to you and the next steps required for your treatment.  

Are there any side effects?

CT scans are very quick and easy to do. Each year millions of people in the US have a CT scan because the benefits outweigh the risks. As with any medical equipment, there are side effects associated with CT scans. It is quite a safe piece of equipment, but it is important to remember that there is a small radiation risk.

Some patients have reported side effects from the contrast reagent including a rash, flushing, nausea, and vomiting. These adverse reactions are more likely to occur if you have health conditions like asthma or cystic fibrosis, a gastrointestinal blockage, or if you are dehydrated.  

Furthermore, kidney complications may happen because of the contrast material in individuals with pre-existing kidney conditions. Therefore, individuals with kidney conditions will have a special assessment prior to the CT scan.

Unfortunately, CT scans may slightly increase the risk of cancer. The risk is less than 1 in 2000 of getting cancer from the CT scan. So, the risk is fairly low but it does depend on other factors.

Can I have a CT Scan?

Pregnant women won’t be recommended CT scans because there is a small risk to the baby. Therefore, alternatives will be sought out unless there is a substantial need that outweighs the potential risks.

Those that are allergic to contrast material should notify the medical staff immediately.

Breastfeeding mothers that require contrast materials for their CT scan should not breastfeed for at least 24 hours. This is to ensure the contrast material is not in the breast milk and potentially passed onto the child.

Individuals with pre-existing kidney conditions may be at risk of contrast-induced nephropathy due to the use of iodine-based contrast materials. Due to this, they should talk to their specialist and explore the options together.

Old CT Scanner?

Do you have a CT scanner that you need removed or sold? Mazree specializes in helping hospitals sell, deinstall, and remove your old CT scanner. Contact us today.

Image by David Mark from Pixabay