PET Scan: FAQ
1. What is PET Scan?
Positron Emission Tomography is a non-invasive imaging technique that reports the functional activity, constitution and physiology of cells in the human body. PET scans are accurate and help in diagnosing diseases including cancer at early stages. The process completes and confirms the finding of all other scans that are being used to study body internal structures.
2. Why is PET Scan performed?
PET Scan is performed to understand the factors at the cellular level that are contributing to a disease or abnormal condition. What a single PET scan can achieve would otherwise be known through several tests and, if required, a surgery. In most cases, PET scans are prescribed to detect and monitor cancer which has been disseminated to various body parts. Causes of heart disease, epilepsy, cancer, etc. are found using PET scans. PET scan is also used extensively in medical research.
3. Types of PET Scan?
The different types of PET scan seen in the medical world today are targeted towards different parts of the body and may use specific chemicals. They are as follows:
- Fluorodeoxyglucose FDG PET: Fluorodeoxyglucose, also called FDG is used as a radiopharmaceutical in PET procedure. It is a sugar like substance that carries the radioactive element in it. We all know that tumours need sugars to proliferate. FDG PET is used to image almost all types of tumours in any part of the human body. Specifically, it is useful in creating exact functional images of inflammation, brain function and infection.
- DOTA-NOC and DOTA-TATE (GaTate) PET: This procedure is mainly used for creating images of phaeochromycytoma , paraganglioma, neuroendocrine tumours, or neuroblastoma.
- Fluoride bone PET: This procedure is used to create the scans of bones.
- FLT PET: This procedure uses Fluorothymidine , also known as FLT to create images for fast replicating cells. Currently this procedure is widely used to image bone marrow function, clinical trials, and brain tumours.
- FCH PET: Fluorocholine (FCH) is used in this procedure to image prostate cancer.
- FET PET: This procedure uses Fluoroethyltyrosine (FET) and is used to image brain tumours.
4. Preparation for PET Scan?
FDG Pet scans rely on the activity of the radioactive sugar that enters the body. To maintain correct levels at the time of the scan, natural sugar content in the blood needs to be controlled by fasting for six hours before the scheduled scan time. This lowers the natural sugar levels and the radioactive sugar when injected can work without hindrance. Diabetic patients need to pay extra attention in this regard and must notify their PET centre if they have a blood sugar level of more than ten millimoles per litre.
The patient needs to drink a minimum of 500ml of plain water without any mix in the time duration before the PET scan appointment. Preparation differs from case to case beyond these two measures. A personalized instruction sheet is drafted to meet the preparation requirements for each patient and is determined by the area being scanned.
5. What happens during a PET Scan?
PET scan utilizes a radioactive sugar chemical that is injected in your body. The cancerous tumour cells take up this radioactive element easily. You are required to rest for an hour or more while the chemical circulates through different parts of your body. The sugar is also absorbed by active muscle cells.
Therefore, lying down and avoiding any movement will avoid muscle cells taking up the radioactive elements. Thus, the chemicals will be able to reach other tumour cells. After an hour’s rest, you will be transferred to a radiochemistry lab room wherein pictures are taken of the target body part. The time duration of picture taking phase is roughly around fifteen to thirty minutes.
6. How long does PET Scan take?
PET scan takes around two to three hours in totality. If the patient wants to rest for a certain amount of time after the procedure, or the chemical uptake in the body is slow, then this time approximation changes.
7. What happens after the PET Scan?
The patient is allowed to leave the PET centre immediately unless he is feeling tired after fasting so long. The patient must drink loads of water throughout the day to flush out the radioactive chemical from within the body. Other fluids can also be taken.
8. What are the possible risks of PET Scan?
There are no possible risks of PET Scan since the radiation dose used is minimal and usually exits the body by the end of the day. No isolation is required in the procedure and other than weakness due to fasting; the patient does not experience any abnormality. In case the patient is breast feeding or pregnant, the technologist must be notified beforehand.
9. Cost of PET Scan?
PET Scan procedures may be free in select centres of health. Average cost of a PET Scan procedure is INR 6000. It might range from INR 2000 to INR 10000. If one wants to undertake complete body PET Scan, then he might pay a cost between INR 15000 to INR 27000. Exact prices are determined by body part being targeted, type of PET Scan ultimately used and scanning protocol used.
10. Alternative Names?
Alternate names for PET Scan are PET CT, FDG PET, FET PET, DOTA-NOC, DOTA-TATE, FCH PET and GaTate PET.