How to prepare for a PET-CT scan

A PET-CT scan is a powerful imaging method that combines the efficiency of Positron Emission Tomography and Computed Tomography technologies in a single modality. It provides highly detailed three-dimensional images for a more accurate diagnosis of the disease. The imaging method helps in visualizing the biochemical changes taking place in the body. It allows a doctor to diagnose a disease, plan treatment, know about how an existing condition is developing and check the effectiveness of a treatment.


A PET-CT scan can distinguish between benign and malignant lesions which is not possible in the case of CT and MRI. It is most often used by oncologists, neurologists, cardiologists and neurosurgeons. With the rapid advancement in technologies, PET-CT technology holds great promise in diagnosing many diseases, particularly cancer. 


How does PET-CT work?


A PET-CT scan uses a small amount of radioactive glucose (FDG) to look for diseases inside the body. The radioactive material is injected into a vein in your hand or arm. By evaluating where the tracer builds, it becomes easy to find out how certain body functions are working. Using FDG in the body’s tissues can help determine cancerous cells since they use glucose at a much faster rate than normal cells. The scan takes somewhere between 15-20 minutes. 


How do you prepare for a PET-CT scan?


Based on the type of PET-CT scan you are undergoing, you will receive specific instructions. If you are pregnant or are breastfeeding, do let the radiology staff know about this. The special preparations may include stopping breastfeeding for a short duration and to avoid close contact with small children. This is a precautionary measure in response to the fact that your body may release a small amount of radioactivity for a while after the test. During the time of the test, you should bring your medical records including X-ray or radiology images. Before the test, drinking water is acceptable, but you will be asked to not eat anything for several hours, since it may alter the sugar metabolism and affect the quality of your images. 


Why PET-Scans are used? 


  • To detect cancer
  • To find out how far cancer has spread
  • To check whether a cancer treatment is working
  • To find a cancer recurrence
  • To manage epilepsy
  • Assess tissue metabolism and viability
  • Find out the effects of a heart attack on areas of the heart
  • Evaluate brain abnormalities, such as tumors, memory disorders and seizures


How is a PET scan performed?


Before the scan, you will receive an intravenous (IV) injection of a safe amount of a radioactive drug. It can take around one hour for the radiotracer to accumulate in the area of interest. The time it takes for the radiotracer to get absorbed will depend on the area of the body being scanned. The PET machine looks like giant letter “O” and you will be lying on a narrow table attached to a PET machine. The table slides slowly to perform the scan. During the test, you may need to stay still and may need to hold your breath for several seconds. As the scanner takes images, you'll hear buzzing and clicking sounds.


A PET/CT scan is a painless imaging modality that is revolutionizing cancer diagnosis, staging, and therapy monitoring. It notably offers a higher level of accuracy and greater convenience for the patients.

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