What happens when you are given a radiopharmaceutical? The scientific explanation

If you have been referred for a PET/CT examination, you may have been told that you will receive an injection of radioactive drug. Understandably, this may sound alarming. But once you understand what it actually is, how it's made, and what's going on inside your body, most people find it much less unsettling and quite exciting.

A radiopharmaceutical is simply a drug that contains a small amount of radioactive material. In PET/CT, the most common radiotracer is 18F-FDG (fluorodeoxyglucose), a glucose molecule (the same sugar your body uses for energy) with a radioactive fluorine-18 atom. This allows the imaging of metabolic activities by cells that take up amounts of glucose.

The radiopharmaceutical is administered intravenously and travels through your bloodstream and is taken up by cells and tissues that need greater glucose consumption, especially:

•Cancer cells, which have very high metabolic activity

•Active signs of infection or inflammation

• Active brain areas

This creates "bright" areas in the PET/CT examination and allows doctors to be able to see which foci are taking in more glucose, manifesting greater metabolic activity and as a result identify problem areas.

This is one of the places that patients find most surprising. The 18F-FDG used in PET/CT has a short half-life of 110 minutes, so it is produced on the same day, at the Positron Diagnostics facility, a few hours before your appointment.

1.Fluorine-18 (F18) Production: The radioactive isotope fluorine-18 (F18) is produced through a particle accelerator, known as the cyclotron, by bombarding an aqueous target (oxygen-enriched water-18) with high-energy protons. At Positron Diagnostics we operate a newer and latest version of cyclotron that is fully automated with improved stability and increased reliability.

2.Radiopharmaceutical Synthesis: F18 is then joined through chemical reactions to a tracer (eg. FDG) for the synthesis of the radiopharmaceutical (18F-FDG). This will allow the drug product to be effectively distributed in the body and taken up by the areas of interest. At Positron Diagnostics, this process is carried out in sterile, controlled areas under GMP (Good Manufacturing Practice) standards, ensuring product quality and safety.

3.Quality Control (QC): Before the radiopharmaceutical is administered to the patient, strict quality control is carried out to confirm the identity, quality and purity of the radiopharmaceutical. Only then, it is made available for administration to the patient by our trained nursing staff.

18F-FDG is administered intravenously where it travels through your bloodstream and is absorbed by cells that need glucose consumption,

Then rest quietly for about 45-60 minutes. This "uptake period" allows the radiopharmaceuticals to be distributed throughout the body and concentrated in the target tissues. You will be asked to remain still and relaxed as the movement activates the muscles, which would take up the FDG and create unwanted "noise" in the image.

After the "intake period", you lie down on the PET/CT bed for your examination which lasts about 15-20 minutes.

The radiation from 18F-FDG is short-lived and leaves your body naturally. Because fluorine-18 has a half-life of 110 minutes, the vast majority of radioactivity is broken down within a few hours. Staying well hydrated after scanning helps your kidneys clear the remaining tracer through urine, so we recommend drinking plenty of water afterward.

For the rest of the day, we ask patients to avoid close prolonged contact with pregnant women and young children as a precaution and not as an emergency. By the next morning, the radiopharmaceuticals are gone from your body.

Our team is always happy to guide you through the process before your appointment. No question is too small, and by understanding your exam, it helps you feel comfortable and get the best possible result.

Contact Phone: +357 22 053 555

Address: 215 Spyrou Kyprianou Avenue, 2047 Strovolos, Nicosia