A PET/CT procedure is started after 6-12 hours of fasting
2. The patient is allowed to rest for 15 min in lying position to reduce the muscular activity
3. An injection of 5-10 mCi of FDGis given in a vein on one arm of the patient
4. The patient may also be given a contrast agent for CT scan in some cases if required
5. Imaging is done after 40-60 minutes. The patient is allowed to lie on the imaging table of the PET/CT machine with hands kept resting on the sides or above the head
6. The table moves into the gantry and a whole body CT scan is done first, followed by a PET scan. The whole imaging process takes 15-20 minutes.
FDG is the most widely used PET radiopharmaceutical. FDG is glucose labelled with radioactive fluorine and hence has the same metabolism as that of glucose. Glucose the sourse of energy and therefore the fuel for cellular function. FDG is trapped and metabolised inside the cells similar to glucose. Cancer being an uncontrolled proliferation of cells; cancer tissues have intense uptake of FDG. Hence, a PET/CT scan after FDG injection highlights the cancerous tissues in the body. FDG is also used for studying the metabolism in the heart and brain.
SECT is the abbreviation of single-photon emission computerized tomography. It helps doctor to analyze the function of some of your internal organs. It uses radioactive substance ans a special camera to get 3 D pictures,so it can be considered as a nuclear imaging test.
In case of thyroid scan, the person will either swallow or injected a small amount of radioactive iodine. There is a special camera which will measure the amount of iodine taken up by the thyroid. The scan may show the areas within the thyroid without iodine uptake. It called cold spots and can represent cancer. But all cold areas are not cancerous, so a biopsy of these is needed. A whole body scan or check up are very helpful after a diagnosis of cancer is made, I will help to find if the cancer has spread to places the thyroid gland. Blood test, thyroglobulin test are also usually done.
Most of the thyroid nodules or lumps are benign but the risk increases if they occur in people below 30 or above 60. Women have more chance to develop thyroid cancer than men at younger age ( ie 40-50 years old women versus 60-70 men)