A Computer Tomography scan can assist doctors in detecting cancer. It can also help in identifying the shape and size of the tumor. Most CT scans are usually carried out as an outpatient procedure which is painless and takes about 10 to 30 minutes. CT scans show a cross-section of the body including the organs, bones and soft tissues more clearly than standard X-rays.
CT scans can show the location, size and shape, and even the blood vessels that feed the tumor.
Doctors use CT scans to help them guide a needle in removing a small piece of tissue (CT-guided biopsy). They can also be used to guide needles for cancer treatments such as radiofrequency ablation (RFA) which uses heat to destroy a tumor. CT scans are like standard X-ray tests in a way. While an X-ray uses a beam of radiation from one angle, a CT scan uses a pencil-thin beam to create a series of pictures from different angles.
- When preparing for a CT scan, you put on a robe and remove any jewelry, underwire bars or metal objects which can affect the CT pictures.
- Ensure that the doctor knows if you have any implanted medical devices like infusion ports or pacemakers.
- The CT scanner is a doughnut-shaped machine where you lie on a flat table that slides back and forth inside the hole that is in the middle of the scanner.
- As the table moves to the opening, an x-ray tube rotates with the scanner and sends out many tiny beams of X-ray at precise angles.
- The beams pass through your body and are detected on the other side of the scanner. During this process, you may hear clicking and buzzing as the scanner switches on and off. The technologist will be able to hear, see and talk to you as you undergo the scan.
- A CT scan, though painless, is uncomfortable to hold still in certain positions for minutes at a time. Sometimes you’ll be asked to hold your breath because the chest movement can affect the image.
- Your head may be held still in a special device during a CT head scan. In a CT colonography, air is pumped into the colon to help see the inner surface of the bowel, which is uncomfortable.
Layering image pieces on top of each other creates a 3-dimensional view which can be rotated on the screen to look at different angles. Doctors now use CT scan in a technique called virtual endoscopy to look inside organ surfaces such as lungs (virtual bronchoscopy) or colon (CT colonography or virtual colonoscopy) without having to put scopes in the body. Depending on the part of the body being scanned, you will need to get a contrast enema or drink a contrast liquid before the test.