During the Procedure 

While the CT procedure itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly in the case of a recent injury or invasive procedure such as surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

The CT scanner is a large machine with a hole, or tunnel, in the center. You will lie on a table that slides into and out of this donut-shaped hole or tunnel. Your caregiver will sit behind a window during the CT scan; however, your caregiver will be able to see, hear, and speak with you at all times. You may be asked to change
into a hospital gown and to remove all jewelry, earrings, or other metal objects.

Caregivers will help you lie down on the CT scan table.
The body part being tested may be kept in place with a cradle or straps to hold it very still. Special lights may be used to make sure that you are properly positioned. You will be asked to hold your breath during the scanning. You must lie very still during the scan. If you move, the CT scan pictures may not be clear.
A chest CT may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your physician's practices.

Generally, the CT scan follows this process:

1. You will be asked to remove any clothing, jewelry, or other objects that may interfere with the procedure. 
2. If you are asked to remove clothing, you will be given a gown to wear.
3. If you are to have a procedure done with contrast, an intravenous (IV) line will be started in the hand or arm for injection of the contrast dye. For oral contrast, you will be given a liquid contrast preparation to swallow. 

4. You will lie on your back with your arms above your head on a scan table that slides into a large, circular opening of the scanning machine. Pillows and straps may be used to prevent movement during the procedure.
   
5. The technologist will be in another room where the scanner controls are located. However, you will be in constant sight of the technologist through a window. Speakers inside the scanner will enable the technologist to communicate with and hear you. You will have a call button so that you can let the technologist know if you have any problems during the procedure. The technologist will be watching you at all times and will be in constant communication. 

6. As the scanner begins to rotate around you, low-dosage x-rays will pass through the body for short amounts of time. You will hear clicking sounds, which are normal. 

7. The x-rays absorbed by the body's tissues will be detected by the scanner and transmitted to the computer. The computer will transform the information into an image to be interpreted by the radiologist. 

8. It will be important that you remain very still during the procedure. 

9. If contrast dye is used for your procedure, you will be removed from the scanner after the first set of scans has been completed. A second set of scans will be taken after the contrast dye has been administered. 

10. If contrast dye is used for your procedure, you may feel some effects when the dye is injected into the IV line. These effects include a flushing sensation, a salty or metallic taste in the mouth, a brief headache, or nausea and/or vomiting. These effects usually last for a few moments. 

11. You should notify the technologist if you feel any breathing difficulties, sweating, numbness, or heart palpitations. 

12. When the procedure has been completed, you will be removed from the scanner. 

13. If an IV line was inserted for contrast administration, the line will be removed. 

14. You may be asked to wait for a short period of time while the radiologist examines the scans to make sure they are clear.