This is usually the best initial test if you are worried about pancreatic cancer and is considered the single most useful imaging technique. Since a CT scan visualizes all of the abdominal organs, it is also very useful in detecting any spread of the cancer to the liver or nearby lymph nodes. A CT is often performed to monitor patients after treatment to determine whether the cancer has recurred (typically as a "metastasis" to the liver) or is changing in size.There are different variations of the CT technique:

Using this method, once the patient is positioned, the X-ray beam is turned on for approximately 1-2 seconds and then turned off. The table is then moved to the next position or increment and the X-ray is turned on again. Because this method is relatively slow, the timing may not coincide with when the dye is optimal for imaging. The resulting image may not be adequate

• A conventional CT will visualize approximately 9 out of 10 pancreatic cancers.

• The primary limitation of CT scanning is its resolution, approximately 1 centimeter. A cancer smaller than this cannot be easily detected using this technique. However, recently developed scanners such as "helical" and "spiral" CT scanners are able to detect smaller masses. (see below)

• Duration of scan vs. duration of dye- The optimal scanning time lasts for about 20 seconds. If the scanning proceeds slowly, as with conventional CT, the dye can sometimes wear off before the scanning is complete.

• The optimal time to image the pancreas after intravenous injection of the dye is not the same as for the liver. This can account for some inaccuracies with conventional CT.

Small fluid collections may be seen in the abdominal cavity through CT imaging. This may indicate the presence of metastatic disease.

Occasionally, the head of the pancreas appears enlarged on a CT but shows no other visible abnormalities. This is also cause for concern. If the patient has pre-existing pancreatitis (inflammation of the pancreas), it can be difficult to determine by imaging alone whether cancer is also present.

A mass detected in the pancreas is not necessarily a cancer, so imaging is usually followed up with a fine needle biopsy (FNA). During this procedure a tissue sample is obtained and tested to confirm a diagnosis of pancreatic cancer.

The level of radiation received during a CT scan is modest. Apart from the minute risk (much less than 1% of patients) of an allergic reaction to the contrast dye, a CT scan is without complication. It is always advisable to inform your doctor of any allergies you have.