Sintigraphic images are obtained after a radiotracer is administered to the patient. The radiotracer is a molecule labelled with a radioisope. They are many radiotracers, each one being specific to target a specific function of the body. For instance, the deoxyglucose labelled with Fluorine-18 is commonly used for cancer imaging, as is accumulates in tumors.
Labelling of a tracer with a radioisotope makes it possible to obtain images of the tracer distribution using specific detection devices, known as gamma camera or tomograph.
The images provided by these devices are currently used a lot to detect abnormalities of the tracer distribution in the body. For instance, a focal increased uptake of fluoro-deoxyglucose can reveal a tumor:
We are developping methods that should allow us to extract more information from the images than just detecting abnormal uptake. For instance, additional information concerning the precise amount of tracer in a tumor could help determine whether the tumor is benign or malignant. Other quantitative parameters such as wash-out rates are also of interest to make a more precise diagnosis from the images. This process of "quantification" of the images should help make the most of them for a better characterization of the diseases and for patient follow-up, by repeating quantitative imaging at different times during treatment.