PET CT Scan For Cancer

What Is A PET Scan

A positron emission tomography (PET) scan is an imaging test that can help reveal the metabolic or biochemical function of your tissues and organs. In PET scans radioactive drug (tracer) is used to show both normal and abnormal metabolic activity. A PET scan can often detect the abnormal metabolism of the tracer in diseases before the disease shows up on other imaging tests, such as computerized tomography (CT) and magnetic resonance imaging (MRI).The PET images are typically combined with CT or MRI and are called PET-CT or PET-MRI scans.The machine looks similar to a CT scan machine.

How Does A PET-CT Scan Work?

Before your PET-CT scan, you will get an injection of a small amount of a radioactive sugar called fluorodeoxyglucose-18. This substance is sometimes called FGD-18, radioactive glucose, or a tracer. The cells in your body absorb sugar. Areas that use more energy pick up more of the sugar. Cancer cells tend to use more energy than healthy cells. The PET scan shows where the radioactive tracer is in your body. The CT scan takes x-rays of your body from different angles. You might get a shot of dye before the x-rays. This helps some of the details show up better. Finally, a computer combines the PET and CT images. With a detailed 3-D result, it helps to show anything abnormal, including tumors.

Reasons For Doing A PET Scan?

A PET scan is advised to identify a variety of conditions, including cancer, heart disease and brain disorders.

PET scan for Cancer

Cancer cells show up as bright spots on PET scans because they have a higher metabolic rate than do normal cells. PET scans may be useful in:

  • Detecting cancer.
  • Revealing whether your cancer has spread.
  • Checking whether a cancer treatment is working.
  • Finding a cancer recurrence.
  • In addition to learning your cancer stage, a PET-CT scan can help us.

  • Find the right place for a biopsy.
  • Plan radiation treatment in certain cases.

PET scans must be interpreted carefully because noncancerous conditions can look like cancer, and some cancers do not appear on PET scans. Many types of solid tumors can be detected by PET-CT and PET-MRI scans, including:

  • Brain
  • Breast
  • Cervical
  • Colorectal
  • Esophageal
  • Head and neck
  • Lung
  • Lymphatic system
  • Pancreatic
  • Prostate
  • Skin
  • Thyroid

PET scans can be used to evaluate in non cancerous conditions like in certain brain disorders, such as tumors, Alzheimer's disease and seizures and other central nervous system disorders.. PET scans can reveal areas of decreased blood flow in the heart. This information can help you and your doctor decide, for example, whether you might benefit from a procedure to open clogged heart arteries (angioplasty) or coronary artery bypass surgery.

How to prepare yourself for a PET CT scan?

A PET scan is usually an outpatient procedure. Typically, you should not consume any food for at least 4 to 6 hours before the scan, but it is advised that you drink plenty of water before the scan.

In most cases, a small amount of radiotracer is injected into a vein. Depending on which organ is involved, it may take upto 30 to 60 minutes for the radiotracer to reach the targeted part of the body.

The scan will take place in a special designated room, where you will be made to lie down on a cushioned examination table. You will probably need to wear a gown and remove any jewelry that you are wearing. During the procedure you are supposed to stay still and not talk. The table slides into a large hole to surround the person with the machine. During the scan, the machine takes images.

How long does it take?

Depending on which part of the body the machine needs to scan, a PET scan should take about 30 to 60 minutes. The scan is not painful. At any given point during the procedure if you feel unwell, you can press a buzzer to alert the staff. You will be monitored throughout by qualified personnel.

Most people can go home as soon as the scan is finished. It is important to consume plenty of liquid to flush the radioactive drugs out of the body’s system more quickly.

Are PET-CT scans safe?

PET-CT scans do carry a risk of radiation, however this low dose of radiation has not been shown to cause harm. The benefits of these tests outweigh the risks.This type of scan uses some radiation from x-rays, the substance used in the PET scan, or both. Scanning a smaller body area means less radiation. So does a CT without the dye that helps show details.

Always get a PET CT scan as advised and instructed by your doctor.