Pet scan: benefits, process procedures & risks

What is a PET Scan?

PET scan is a medical examination performed to detect a certain disease in the body by looking at the function of tissues or organs. PET examination which stands for positron emission tomography The scan has many functions, as reported by the Cleveland Clinic website:

Measuring vital body functions, such as blood flow, oxygen use, and blood sugar (glucose) metabolism.
Detect organs and tissues that are not functioning properly.
Detect tumor or cancer cells to help measure the spread of cancer (metastasis).
Evaluating how well the health care plan is in patients with certain conditions.

This examination can be single or it can be combined with other imaging tests, for example in conjunction with a CT scan or MRI.

Anyone who needs a PET scan?

Not everyone who is sick needs to undergo this medical test. Usually, doctors will recommend a PET scan in patients who are suspected of having the following conditions:

Cancer

Cancer cells have a higher metabolic rate than normal body cells. This abnormal activity can be detected with a PET scan. Usually, the types of cancer that can be detected through this imaging test are brain cancer, cervical cancer, colorectal cancer, esophageal cancer, lung cancer, pancreatic cancer, prostate cancer, and thyroid cancer.

After the test is done, the doctor can determine the following:

Detect cancer and its location.
Clarify whether the cancer has spread or not.
Check the effectiveness of cancer treatment whether it is successful or not.
Detect cancer cells that have been re-grown.
Finding cancer recurrence.

Heart disease

Apart from cancer, PET scans are also used to detect heart disease. Through this medical test, doctors can see which areas of the heart have decreased blood flow. Afterward, your doctor can decide whether you need to undergo heart medication, such as an angioplasty (opening a blocked heart artery) or heart bypass surgery.

Brain disorders

This scanning test can also be used to detect brain disorders, for example seeing the growth of tumors around the brain, Alzheimer's disease, and finding out the cause of seizures.

What is the PET scan procedure?

The stages of the scanning process are divided into three, namely:

Preparation before PET scan

Before you undergo this imaging test, first tell your doctor about the following:

Have had a severe allergic reaction.
History of diabetes.
Take certain medications, vitamins, or supplements.
Pregnant or breastfeeding.
Phobias in confined spaces.

The general rule before undergoing this medical test is to avoid strenuous exercise for a few days. You will also be asked not to eat for several hours in advance. However, you are still allowed to drink water. Also avoid caffeinated drinks at least 24 hours before the test and wear comfortable clothing.

PET scan process

PET scans use radioactive fluid (tracer) to show abnormal activity in the body. The tracer substance can be injected, swallowed or inhaled, depending on which organ or tissue is being observed.

The most commonly used radiotracer is fluorodeoxyglucose (FDG). This radiotracer is radioactive sugar. In people who have cancer cells in their bodies, these cells are very active to grow so they require a lot of energy. After the radiotracer is injected, the cells will take in more of the substance.

If the tracer substance accumulates in a certain area of the body, it indicates higher chemical activity. This means that it is the area of the body that is likely to have problems or have cancer cells.

Following are the steps you will take during the scan test:

You will receive an injection of a tracer substance containing a number of radioactive drugs that are safe for the body.
You need to sit in a chair quietly as the radiotracer moves through your bloodstream. Avoid moving too much as this will interfere with the tracking process. In about an hour, your organs and tissues absorb the radiotracer.
If this test is done at the same time as a CT scan, you may also get an injection of a contrast dye. This dye helps produce a sharper CT image. Then, you need to lie down and enter the scanner.
During scanning, you need to stay still as slight movement can blur the image.
During the process, you will hear a hum and click sound as the scanner takes a picture.
Tell the medical team if being in a confined space makes you anxious. You may need to take a mild sedative to help your body relax during the procedure.

After the PET scan is done

After this medical test is done, you may eat and drink again as usual. The radiation in the tracer is very low. You need to drink lots of water to help make these substances from the body.

As a precaution, you should avoid close contact with pregnant women, babies and young children for 6 hours after the scan. You also should not drive, drink alcohol, operate heavy equipment for 24 hours after the test.

Risk of side effects from PET scans

In general, imaging tests are safe and rarely cause health problems. In some people but rarely, allergies can occur. This can cause sweating, fatigue, or difficulty breathing.

It can also cause bruising on the skin where the needle is inserted. The tracer substance that is injected can also leak out of the vein and this can cause swelling and pain.

In order to avoid the risk of these side effects, people with the following conditions are not allowed or need to be reconsidered for having a PET scan:

Are pregnant or breastfeeding, because it is feared that radiation will have a negative impact on the fetus or flow with breast milk.
People who are allergic to tracer or contrast agents.
Diabetics because the body is not good at absorbing trace substances that contain sugar, so that it can affect test results.

What will the PET scan look like?

This medical imaging test will be combined with a CT scan. The results will show spots that indicate high chemical activity in certain organs or tissues. Understanding the results of this examination will certainly be very difficult if you observe it yourself.

Therefore, the doctor will help you understand it as well as explain the results to you. To get more precise results, your doctor may order an MRI (magnetic resonance imaging).