Positron Emission Tomography (PET) Scans
A positron emission tomography (PET) scanner is a type of imaging which uses low doses of radioactive substances linked to compounds used by the body's cells or compounds that attach to tumor cells. Using special detection equipment, the radioactive substances can be traced in the body to see where and when they concentrate.
PET scans may play a role in determining whether a mass is cancerous. However, PET scans are more accurate in detecting larger and more aggressive tumors than they are in locating tumors that are smaller than 8 mm and/or less aggressive. They may also detect cancer when other imaging techniques show normal results. PET scans may be helpful in evaluating and staging recurrent disease (cancer that has come back). PET scans are beginning to be used to check if a treatment is working - if a tumor cells are dying and thus using less sugar.
How A Pet Scan Is Given
Generally you will be asked to fast before the test. (Diabetics receive special instructions).
A PET scan appointment generally lasts from 2 to 4 hours. Generally the scan itself does not hurt.
Typically, the patient is given an injection of a substance that consists of a combination of a sugar and a small amount of radioactively labeled sugar. The radioactive sugar can help in locating a tumor, because cancer cells take up or absorb sugar more avidly than other tissues in the body. The PET scanner is used to detect the distribution of the sugar in the tumor and in the body.
After receiving the radioactive sugar, the patient lies still for about 60 minutes while the radioactively labeled sugar circulates throughout the body. If a tumor is present, the radioactive sugar will accumulate in the tumor.
The patient is then ushered into the room where the PET scanner is and lies on a table. The table gradually moves through the PET scanner 6 to 7 times during a 45-60-minute period. This process is painless, but can be uncomfortable.
A computer translates this information into the images that are interpreted by a radiologist. The findings are given to your doctor, who will then tell you the results.
You will be able to resume all normal activities immediately after the test.
NOTE: It is advisable to get a copy of the radiologists findings to keep with your copy of your Medical Records. Yes, it is advisable to keep your own copy of your medical records.
By the combined matching of a CT scan with PET images, there is an improved capacity to discriminate normal from abnormal tissues.