Research & Development

Research & Development

Nuclear Medicine

The Therapeutic Applications of Radionuclides

The rationale is that the administration of targeting beta-emitting radionuclides (such as Iodine 131 targeting functional thyroid tissue) or radiopharmaceuticals (such as Yttrium-90 labeled octrotide targeting the somatostatin receptors expressed in neuroendocrine tumors) can deliver high dose radiation to a tumor with limited collateral damage to the neighbouring non tumoral tissues (themagic bullet concept).

The Bordet Institute is a tertiary referral center for treating thyroid cancer patients with high doses of iodine-131. This treatment is given to ablate residual thyroid tissue or to treat recurrent metastatic disease.

Other less frequently performed treatments are Samarium or Strontium targeting painful osteoblastic bone metastasis, I131-MIBG for neuroblastoma and malignant feochromocytoma.

The development of new therapeutic applications of Nuclear Medicine is one of the major focus of research interest of the department. The basic view is a holistic one: new high tech metabolic imaging techniques are performed in parallel with the treatments. The reason for doing so are threefold: (1) for patient selection (eg. Iodine-124 in metastatic thyroid cancer; MAA-SPECT of the arterial hepatic circulation before treatment of liver metastases with Yttrium-90 labeled microspheres); (2) for dosimetry (Zirconium-labeled antibodies against CD20 expressing lymphomas, see higher); and, (3) for metabolic response assessment (using FDG PET-CT).

 

Yttrium-90 labeled microspheres

Yttrium-90 labeled microspheres is an innovative product to treat liver cancer. In cases where it is not possible to surgically remove liver tumours, it can be used to deliver targeted, internal radiation therapy directly to the tumour.
This new therapy is called Selective Internal Radiation Therapy, also know as SIRT. This technique uses millions of tiny polymer (plastic) beads or microspheres which contain a radioactive element yttrium-90. The radiolabeled spheres are very small, approximately 32 microns in size or about one-third the diameter of a strand of hair. This treatment method takes advantage of the fact that approximately 80% of the blood supply to healthy liver tissue flows via the portal vein and only about 20% via the liver arteries. In most cases, the blood supply to the tumours flows primarily via the liver arteries. This treatment method therefore uses the liver arteries to gain direct access to the tumours for radiation, while leaving surrounding healthy liver tissue largely intact.
At the Bordet Institute, a phase III clinical trial is ongoing comparing the therapeutic efficacy of the Y90-microspheres in conjunction with chemotherapy to chemotherapy alone.

 

Yttrium90-labeled monoclonal antibodies against lymphoma

A phase I study is ongoing on the use of Yttrium-90 labeled anti-CD20 antibodies in patients with recurrent, therapy resistant non Hodgkin lymphomas. The efficacy and toxicity profile of this drug will be correlated to the pretherapeutic dosimetry data obtained by PET-CT performed after the administration of the same antibody labeled with a long living positron emitting isotope Zirconium-89 (see higher).

 

Conventional nuclear medicine : SPECT (click here)

- Sentinel Node Scintigraphy
- Multi Drug Resistance

 

Positron Emission Tomography (click here)

- Assesment of the efficacy of a treatment

- Somatostatin Receptor Imaging

- PET-CT based dosimetry for radio-imunotherapy