PET/CT

A PET/CT examination consists of the merging of two methods of medical imaging in order to obtain images of the anatomy (through the CT portion of the exam) and of the metabolic activity of the body cells (through the PET portion of the examination).

To perform a PET/CT scan, a glucose-based radioactive substance (FDG-F18) is injected through intravenous route. Since body cells use glucose as their main energy source, they will absorb the injected FDG-F18. Therefore, the cancerous cells which have an increased metabolism will accumulate a greater quantity of FDG-F18 than the healthy cells. One hour after the injection, images are obtained: first a CT, immediately followed by PET images. Both series of images are then fused to allow the accurate localization of FDG-F18 hyperfixation areas.

PET in Oncology

Although several doctors rarely recommend it to their patient, the PET/CT examination is recognized in the medical guidelines and is a very helpful tool in the field of oncology. In fact, it is a very efficient way to obtain:

• characterization of indeterminate solitary pulmonary nodules;
• preoperative staging to evaluate mediastinal and distant metastasis of non-small cell lung cancers;
• staging of colorectal cancers;
• staging of Hodgkin’s disease and non-Hodgkin lymphomas;
• an evaluation of the presence of metastasis in cases of melanoma;
• an evaluation of the extent of loco-regional recurrence and distant metastasis, as well as of the treatment response in cases of breast cancer;
• staging of head and neck cancers, and esophagus cancers;
• staging of well differentiated thyroid gland cancers characterized by a positive thyroglobulin and negative Iodine-131 scan;
• differentiation between the recurrence of a brain tumour and radiation necrosis due to previous radiation treatment.

PET/CT can detect tumors, assess the aggressiveness of a cancer, and determine the stage of cancers. The treating physician will use the results obtained to determine the most appropriate treatment. Also, in 15% of cases, the PET/CT examination leads to the detection of new metastasis. In such cases, the treatment can be modified in a way that corresponds more closely to the patient’s actual condition.

Preparation for the examination >>>

PET in Neurology

A PET/CT scan also allows the early diagnosis of Alzheimer’s disease and the detection of other types of dementia. In addition, this examination is useful for the localization of a focus of epilepsy in cases where usual medication does not allow for the proper control of the disease and where surgery is considered.

Preparation for the examination >>>

PET in Cardiology

A PET/CT scan can also be used to assess myocardial viability in order to determine if a revascularization could be beneficial for the patient.

Preparation for the examination >>>

top of page