How is a PET/CT scan different from a CT and MRI scan?

The article is professionally consulted by Master, Doctor Nguyen Quang Duc - Doctor of Nuclear Medicine - Department of Diagnostic Imaging and Nuclear Medicine - Vinmec Times City International General Hospital.

Positron emission tomography (PET) provides information about blood flow and how your body uses oxygen and sugar. This can give important clues about how a disease is going in the body.
During a PET scan, your doctor will first give you a substance called a radioactive substance. The monitor emits radiation that the PET scanner captures. The images received will show where the carrier is going in the body. If it builds up in certain areas, it could be a sign of disease.

PET scans can help doctors check for disease, prepare for surgery, and evaluate whether treatments are working. You may be ordered to have a PET scan for many other reasons, but it is more commonly used in cancer, heart disease, and brain disease.
Doctors can use PET scans to:
● Find cancer;
● See if the cancer has spread;
● Evaluate the effectiveness of cancer treatment regimens;
● Evaluate the effectiveness of cancer after treatment.
When you have heart disease, your doctor may use a PET scan to:
● Assess myocardial perfusion;
● Guide to the best treatment regimen for clogged arteries;
Identify the consequences of a heart attack.
Can also be used to assess brain conditions such as:
● Alzheimer's disease;
Parkinson's disease ;
Seizures ;
Stroke ;
● Tumor.

Doctors use different types of imaging techniques for different reasons. Usually, you start with an X-ray because it's a quick way to get basic information. But if the doctor needs more finer details, the patient will be ordered to have other diagnostic techniques, possibly CT or MRI.
Many doctors use a combination of imaging techniques, eg PET/MRI and CT/PET scans, which combine the two in one scan. This allows doctors to perform a CT or MRI scan in conjunction with a PET scan at the same time.
PET scans can allow assessment of metabolic function in your cells. One reason is important that PET scans can detect some diseases at an early stage that other diagnostic techniques don't, like MRI or CT scans.

First, you need to tell your doctor about any of the following:
● Health conditions such as diabetes or any illness you have had recently;
● Medicines, herbs and functional foods;
If you are a woman, tell your doctor if you are:
● Breastfeeding
● Pregnant or think you may be pregnant, because radiopharmaceuticals may affect your baby.

Your doctor will give you specific instructions to prepare for the scan. Usually you will need:
Avoid vigorous physical activity for 24 hours before the scan;
● Drink only water and avoid eating for a few hours before the scan;
● Leave at home or remove all jewelry and metal objects in the body.
The PET scan depends on where and why you have it, but you will typically:
● Change into a hospital gown; go to the bathroom.
● Inject radiopharmaceuticals into your body intravenously.
● Wait 30 minutes to an hour for your body to absorb the radiopharmaceuticals;
● During the shoot, you will lie on your back. Be careful not to move or talk during the scan and this can take up to an hour.
After the scan, you should drink plenty of water to help remove the radioactive material from your body. Your doctor may suggest that you avoid close contact with pregnant women, children or babies for several hours
If there is an abnormality on the PET scan that indicates increased uptake of radiopharmaceuticals.

To get a more complete picture of what's going on, your doctor may compare the PET scan with results from other imaging techniques you've had.
Currently, Vinmec International General Hospital has become a leading prestigious address in disease screening with modern techniques, proud to be the first private hospital in Vietnam to deploy this technique. Modern and accurate diagnosis with the most modern 128-sequence PET/CT system in Southeast Asia, for accurate images and short imaging time, the team of doctors are leading experts with high expertise and rich experience. Experience creates trust for customers when experiencing medical examination and treatment services at Vinmec.
German doctor has more than 12 years of experience in the field of Diagnostic Imaging. Recently, the Doctor has been assigned to specialize in the field of Nuclear Medicine. Currently, the doctor is studying an intensive course in Nuclear Medicine at Stanford Hospital, USA

Reference source: webmd.com