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Institutes/ Institute of biomedical imaging (I²BM)/ Departments/ Frédéric Joliot Hospital Service (SHFJ)/ Research Groups and Laboratories/ Clinical investigation group

Clinical investigation group


Scintigraphic imaging, today multimodal, for coupled with radiological systems, is a technique of exceptional sensitivity, which allows to obtain extremely precise functional information on normal or pathological cellular metabolism. This performance makes of this technique a true molecular imaging method. It has stood out these last years in the field of oncology as a key parameter in early diagnostics, therapeutic choice and patient follow up. It has also allowed for much progress in the fields of neurological, psychiatric and cardiovascular pathologies.

Irrespective which of its isotopic imaging modalities, PET or SPECT, nuclear medicine is basically about the administration, chiefly intravenously, of a molecule labelled with a radioactive element, which makes it possible to follow the function of a tissue or a group of cells in the organism. The labelled molecules have the same biological behaviour as their non-radioactive counterparts and emit a physical signal detectable outside the organism, thus in a non-invasive way.

Biograph imager (PET-CT) of the SHFJ

Biograph imager (PET-CT) of the SHFJ

PET-CT camera. This new camera, which combines positron emission tomography and tomographic X-ray scanning, represents a major development in imaging of the last years and in particular for the management of oncological patients. This camera is at the service of patients of the hospital group Orsay-Longjumeau and of its corresponding territory.

The SHFJ is a support centre for the clinical activities of the hospital group Orsay-Longjumeau. It houses a clinical section with eleven beds for hosting outpatients, adults and children. The examinations carried out are of the conventional nuclear medicine type. The diagnostic activity of the SHFJ comprises nuclear cardiology and bone scintigraphy. Pulmonary, thyroid, renal and cerebral scintigraphies as well as sentinel node detection are equally practiced.

18F-FDG is a glucose analogue in which one of the hydroxyl groups has been replaced by a radioactive isotope of fluorine, fluorine-18, without consequences for the biochemical transport mechanisms of the molecule. Its use as a marker of cancer cells is based on the special nature of cellular tumour metabolism, known since 1930, which consists in an increased glucose consumption. The 18F-FDG will therefore be taken up preferentially in the cancer cells. Endowed with a great sensitivity of detection, this technique enables a visualization of the entire organism in a one and only examination, replacing in fact various examinations by a single one.

An early diagnosis and a complete view of disease spreading allow oncologists to improve the management of the patient, avoiding unnecessary examinations and inappropriate therapeutic choices. The short half life (110 min) of fluorine-18 limits the radiation dose to the patient, which remains comparable to that of a bone scintigraphy and slightly below that of an X-ray scanner (about 5 mSv).

Some types of examinations performed:

  • use of PET in the physiopathological study, the diagnosis and the follow up of neurodegenerative pathologies and of epilepsy in children and adults. These studies are realized not only with 18F-FDG but also with other tracers such as those for the dopaminergic system or for the benzodiazepine receptors.
  • evaluation of brain metabolism using 18F-FDG in autoimmune disease with implication of the brain.
  • use of PET in the diagnosis of hyperinsulism in children.
  • use of PET in the diagnosis and follow up of neuroendocrine pathologies.
  • in vivo quantification of muscarinic and b-adrenergic receptors of the myocardium using specific ligands labelled with carbon-11 for the study of physiopathological mechanisms in various cardiac diseases.

Example : the unfolding of an oncology examination.

Image acquisition generally begins 45-60 minutes after the intravenous injection of 150 to 370 MBq/70kg of 18F-FDG. The data acquisition takes 20 to 60 minutes, during which immobility of the subject is mandatory. An oncological examination requires the acquisition of several series of images, the number of which depends on the camera that is used and the extent of the areas to be studied. Thus the examination time depends directly on the number of acquisitions needed and on the type of PET camera.

The team is headed by Serge Desarnaud and includes the following members :