What is a CT scan?
A computerized axial tomography, also known as a CT scan, uses a series of X-rays to provide cross-sectional views of your organs, soft tissues and bones. A computer is used to combine these detailed pictures of your body into a batch or group, depicting many separate “slices” of areas in the body. CT scans allow your physician to create three-dimensional images, making CT scans a superior diagnostic test to traditional X-rays.
Doctors order a CT scan to determine the likelihood and severity of many conditions and illnesses. For example, in the case of cancer, a CT scan can show physicians where in the body the cancer exists. CT scans are also used to detect:
- Tumors, cysts, abscesses and aneurysms
- Infections and blockages
- Kidney and bladder stones
- Internal bleeding and inflammation
- Extent of injuries
- Cause of conditions like jaundice
CT scans are also used to guide radiation therapy. During a biopsy, CT scans help to ensure that the surgical instrument is correctly inserted into the body.
What to expect during a CT scan
Preparing for your procedure
Do not eat or drink anything for at least four hours prior to your CT scan. Check with your physician to determine if any of your medications should be avoided for the days leading up to your scheduled test. Make sure to bring all of your medications, as well as any herbal or dietary supplements and over-the-counter medications, to the test with you. Your doctor will also check your kidney function prior to the CT scan.
Before your CT scan begins, a type of dye known as a contrast agent may be administered using an IV injection in your arm or hand. Other types of contrast agents can be given by swallowing an oral drink, a rectal enema or through gas inhalation. The contrast agent enhances the clarity of your organs, bones and tissues and is naturally eliminated by the body after the procedure. Typical contrasting agents include iodine, barium and barium sulfate.
During your procedure
For your CT scan, you will lie on a table that slides into a doughnut-shaped machine and a specialized scanner will rotate around you. CT scans are not painful, although you may be asked to briefly hold your breath or remain motionless. Soft straps are often used to hold areas of the body still, and the machine may tilt during the procedure. You also may hear strange clicking sounds during your scan that are normal operations of the machine. If you are uncomfortable or need assistance during the scan, you will be able to communicate with the technician to ask for help.
After your procedure
No special care is required after a CT scan. You should be able to resume your normal activities unless your doctor tells you differently. You will be instructed to drink water after your CT scan to help clear the dye from your body.