The PET-Scan, whose name comes from the English "positron emission tomography," is a nuclear medicine exam often called PET or positron emission tomography. Like scintigraphy, it consists of analyzing the functioning of an organ or a structure of the body using a contrast product injected into the patient. The radiotracer reacts in a certain way by meeting the organs and in the presence of an anomaly.
Images of these reactions are captured by a machine and reproduced on a computer screen. The three-dimensional reconstruction makes it possible to visualize the zones of high concentration of the tracer (zones in red). The doctor can identify an abnormality or pathology. The main advantage of PET-Scan is that it allows obtaining 3D cuts, which is not the case of scintigraphy. This technique is particularly useful in oncology for detecting or monitoring a tumor.
Why prescribe a tomography?
PET CT scan is mainly prescribed:
- In oncology to detect metastases, to know the effectiveness of treatment put in place or to confirm a tumor recurrence when a blood test revealed an increase in tumor markers.
- In cardiology to study the functioning of the myocardium (for example after a heart attack) or coronary arteries
- In neurology to confirm the presence of brain damage and degenerative disease such as Alzheimer's or Parkinson's disease.
There are several tracers. The choice of doctor depends on the pathology sought or the type of tumor.
How does a PET scan work?
In total, the PET scan takes about two hours. Intravenous injection of the radioactive substance is the first step. The patient remains to lie down, usually one hour. This is the time normally required for the contrast material to enter the body and reach the organs to be examined. The patient, still lying on his back, is then placed for about twenty minutes in a machine equipped with a ring-shaped opening. That's when PET images are made. The results cannot be communicated immediately after the examination because the study of the images takes a certain time.
According to the results of the PET CT examination is determined:
- The presence and nature of tumor lesions, recurrence of the disease or metastasis of cancer at an early stage;
- The presence of vascular disorders, post-traumatic changes, foci of epilepsy and Parkinsonism in the brain, as well as causes of dementia;
- The viability of the myocardium (heart muscle) in ischemic heart disease, congenital heart defects.
What are the risks of PET CT scan?
PET-Scan is a reliable test that has no adverse effect on health. Some mild allergic reactions are sometimes observed at the injection site. It can be achieved during pregnancy. As a precaution, breastfeeding should be stopped for the next 12 hours if the tracer used is 18F-fluorinated fluorodeoxyglucose (18F-FDG).
Is PET-Scan painful?
No, PET-Scan is an entirely painless test except for the bite that can cause temporary itching. Positron emission tomography is the most informative methods used in the diagnosis of malignant and benign tumors, as well as other problems, accompanied by a violation of biochemical processes in various organs and tissues. Today, most cancer centers use a more informative version of the study of PET CT.