CT scanner

A CAT scan or a CT scanner machine is a large machine in the shape of a doughnut. The patient is made to lie on a couch. The couch can slide backwards and forwards. The couch slips into the center of the doughnut shaped machine which takes the x-ray images around the body. The actual procedure takes anywhere from half an hour to one and half hours. During the CAT scan procedure, the patient's bodily movement has to be minimal and should remain as still and quiet as possible. This significantly helps to increase the clarity of the x ray images.

Some CAT scans need special preparations before hand. The preparation may vary according to the type of scan taken.

• For abdominal CT scans, the patient is asked not to eat or drink anything after midnight, the night before the scan. A 'contrast medium' has to be drunk or an injection of 'contrast medium' is administered to the patient. Some of this liquid can be taken at home but more of the liquid is taken in the x ray department before the scan. The contrast medium makes the digestive system show more clearly in the scan. This does not have any side effects.
  
• For CT scans of the head, the patient is given an injection of 'contrast medium' dye beforehand to make the scan clearer.
  
• For CT scans of the chest, the injection of 'contrast medium' dye is administered beforehand to show up the tissues in the area containing cancer or blood vessels more clearly.
  
• For pelvic CT scans, the patient is asked not to eat or drink after midnight of the night before the scan. An injection of 'contrast medium' is given before the scan. An injection of a drug to slow down the movement of the pelvis area is given so that there will be distortion during the time of the scan.
  
• For a rectal scan, the patient is given an enema occasionally. This makes the outline of the bowel stand out more during the scan.
  
• In certain detailed scans of the bowel called virtual colonoscopy, the patient is asked not to eat or drink for 36 hours before the study and two doses of a strong laxative the day before the scan is advised.