18F-fluorodeoxyglucose (FDG) is the most widely used contrast agent in PET. FDG is a compound in which the radioactive isotope fluorine-18 is attached to a molecule of glucose, or sugar. Once in the body, the FDG is absorbed by various tissues and detected by a PET scanner. Images show how the FDG radiotracer is distributed within the body, which help physicians assess how well the body is functioning and diagnose various medical conditions.

Molecular Imaging

Molecular imaging is the use of imaging technologies to assess biological activity in the body and is a valuable way to obtain medical information that may otherwise require exploratory surgery or more expensive diagnostic tests.

Molecular Nuclear Diagnostics (MND)

MND employs a variety of imaging devices and uses radiopharmaceuticals that enable physicians to detect different types of diseases in their early stages.

Molecular Nuclear Medicine (MNM)

MNM is a medical specialty using trace amounts of active substances, called radiopharmaceuticals, to create images of organs and lesions and to treat various diseases, including cancer. The technique works by injecting into the patient’s body targeted radiopharmaceuticals that accumulate in the organs or lesions and reveal specific biochemical processes.

Molecular Nuclear Therapy (MNT)

MNT uses radiopharmaceuticals that emit electrons, the same particles used in radiotherapy. These electrons are emitted locally for a short period of time and destroy unhealthy tissues whilst sparing surrounding healthy tissues.

Positron Emission Tomography (PET)

PET is a nuclear medicine imaging technique used in diagnosis and biomedical research. In PET, a chemical compound labelled with a shortlived positron-emitting radionuclide of carbon, oxygen, nitrogen, or fluorine is injected into the body. The activity of such a radiopharmaceutical is quantitatively measured throughout the target organs. Data are analysed and reconstructed by means of a computer to produce images of the organs being scanned.

Radioactive decay

A radioactive isotope is an unstable atom that spontaneously loses energy by emitting ionizing particles and radiation in a process called radioactive decay. By losing energy the nucleus reaches a stable state. The time taken to halve the radioactivity produced is called half-life and it is a property of each radioactive species.


A radiopharmaceutical is a radioactive drug. Radiopharmaceuticals are used in the field of nuclear medicine as tracers in the diagnosis and treatment of many diseases. The most commonly used PET radiopharmaceutical is FDG.

Single Photon Emission Tomography (SPECT)

SPECT is a nuclear medicine imaging technique used in diagnosis and biomedical research. In SPECT radioisotopes, typically iodine-123, technetium-99m, xenon-133, thallium-201 and fluorine-18, are injected into the body. These radioactive forms of natural elements pass through the body and can be detected by a scanner. The test differs from a PET scan in that the tracer stays in the blood stream rather than being absorbed by surrounding tissues, thereby limiting the images to areas where blood flows.