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PET stands for positron emission tomography and is a type of nuclear medicine imaging. Nuclear medicine uses radiotracers, molecules that are labeled with radioactive material, to pinpoint molecular activity. It not only can show the structure of the organs but also highlight bodily functions.
In PET, the radiotracer is injected into the human body, and its decay produces positrons. A positron is a small particle with roughly the same mass as an electron but positively charged (opposite to an electron). They react with electrons in the body, combining with and annihilating each other, producing energy in the form of 2 photons that eject in opposite directions. The detectors in the PET scanner measure these photons and create images of internal organs.
With the help of suitable radiotracers, PET can measure vital functions, such as perfusion (blood and oxygen flow) and glucose metabolism. One of the most commonly used radiotracers in PET scans is fluorodeoxyglucose (FDG), which is a glucose analog, that can be taken up by body cells as the main source of energy for metabolic activities. Abnormal cells may have a different rate of glucose uptake than normal cells.
One of the major applications of the PET scan is to diagnose cancer, determine if it has spread in the body (metastasis), assess the effectiveness of treatment and detect any recurrence. By observing the build-up of FDG in cancerous cells, which consume glucose at a much higher rate than normal cells, PET scans detect the tumor and its metastasis (if any) accurately.
PET scan can diagnose neurological conditions such as
PET can also evaluate brain functions after trauma by detecting blood clots, bleeding and perfusion of the brain tissue.
PET scan can reveal areas of decreased blood flow, therefore observe:
The results may help the planning of surgical procedures, e.g. whether angioplasty or coronary artery bypass surgery is more suitable.
Sometimes, radiologists will combine the use of PET with CT or MRI to obtain a more detailed assessment. PET-CT is commonly used in cancer diagnosis.
You should inform your doctors if you are:
Your doctors will give you detailed instructions, but usually, you will need to:
If you are having a PET-CT or a PET-MRI scan, you may also need to observe the precautions of CT and MRI scans, i.e. remove any metal or magnetic materials on you.
Drink plenty of water to help expel the radiotracer. You may be advised to avoid close contact with pregnant women, babies or young children for a few hours as you are still radioactive. After a few hours or days, the radioactive material will decay and be passed out of your body.
Except for IV injection, most procedures of a PET scan are non-invasive and painless. There may be slight pain or redness at the injection site, but they should resolve quickly.
The amount of radiation you are exposed to in the radiotracer is small, so the risk of causing cancer from the damage to tissues by radiation is minimal.
Allergic reactions to the radiotracer are rare and usually mild.
PET examinations are classified as private services in the public healthcare system and range in price from HK$2,560 to $19,850, depending on the body parts involved and whether it is combined with CT. Keep in mind that waiting times in the public sector can be extremely long.
In the private sector, you may visit any of the 13 private hospitals in Hong Kong, private clinics or imaging centers for a PET scan. Based on our research, the cost can range from HK$10,000 to over $26,000 per examination, depending on the body parts involved. Please contact your service provider for the exact pricing and appointments.
PET scan costs are reimbursed in Hong Kong when prescribed by a medical doctor and used to make a diagnosis for treatment. That being said, most standard local plans in Hong Kong impose an annual limit and depending on how high the costs are, you may have to pay any outstanding amount out-of-pocket. As for high-end medical plans, most cover PET scan costs in full without any sub-limit. When reading your health insurance table of benefits, look for the following categories: Diagnostic scans and tests, Brain and Body scans, Diagnostics, or Advanced Medical Imaging. If you have any health insurance questions, contact an Alea advisor at [email protected].
PET scan can diagnose cancer, heart disease and brain disorders.
The PET scan itself isn’t painful, but if the radiotracer is injected intravenously, it may hurt a little.
One of the most commonly used radiotracers in PET scans is fluorodeoxyglucose (FDG), which is used by the body in a way similar to glucose and thus may not produce accurate results when used on diabetic patients.
This article was independently written by Healthy Matters. It is informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be relied upon for specific medical advice.
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