Rhenium-186 is a radioactive isotope of the element rhenium with a half-life of about 3.72 days. It is used in nuclear medicine for therapeutic purposes, particularly in the treatment of certain types of cancer.
Rhenium-186 is typically used in the form of rhenium-186-labeled compounds, known as radiopharmaceuticals, that can specifically target and deliver radiation to cancer cells. These radiopharmaceuticals are administered to patients either intravenously or directly to the tumor site, where they emit beta radiation that can destroy cancer cells.
One of the main applications of Rhenium-186 is in targeted radionuclide therapy, where the radiation emitted by the isotope is used to treat tumors while sparing surrounding healthy tissues. Rhenium-186 therapy is commonly used in the treatment of various cancers, including liver cancer, bone metastases, and neuroendocrine tumors.
The beta radiation emitted by Rhenium-186 has a therapeutic range in tissue, allowing it to deliver localized radiation to cancer cells and induce cell death. This targeted approach can help shrink tumors, alleviate symptoms, and improve overall survival in patients with certain types of cancer.
Overall, Rhenium-186 is a valuable radioisotope used in nuclear medicine for therapeutic applications, particularly in targeted radionuclide therapy for cancer treatment. Its ability to deliver localized radiation to tumors makes it an important tool in the management of various types of cancer, providing a targeted and effective treatment option for patients with advanced disease.
Properties:
Rhenium-186 (186Re) is a therapeutic radionuclide with a half-life of 3.72 d. It is a low- energy β– emitter (810 keV) with a 28% gamma emission at 137 keV (9%) allowing imaging. 186Re is also an Auger electron emitter. The mean path length is 1.8 mm. Tenth value layer (TVL) is 5.6 mm for concrete and 0.1 mm for lead.
Manufacturing:
186Re is produced by neutron activation of enriched 185Re (natural abundance 26.7%) via the route [185Re(n,γ)186Re]. Obviously 186Re can only be obtained as a carrier-added (low specific activity) radionuclide.
Source and availability:
Major players in the field controlling reactor isotope production are able to supply this radionuclide in smaller amounts. As the market is very small (and will probably not greatly increase), there is and will not be a supply issue in the future. The product is in the POLATOM catalogue.
Derivatives:
186Re is useful for bone pain palliation (186Re-Rhenium-Etidronate/HEDP) and its major application is for radiosynovectomy of mid-sized joints such as ankle and elbow (186Re- Rhenium Sulfide). The average dose used with 186Re-HEDP is around 35–40 mCi.
Price:
The reactor origin, the absence of capacity issue and the limited demand means that this radionuclide remains in the low-price range, i.e., a few tens of Euros per mCi.
Issues:
No special issues are to be reported here, except that so far, no pharmacist has found an interest in this radionuclide beside radiosynovectomy. This radionuclide, like 169Er, may disappear from the nuclear medicine landscape in the next 10 years unless its analogue 188Re develops and needs another gamma emitting equivalent to form a theranostic pair.
Comments:
Rhenium is a metal with similar properties to technetium. Therefore, it is quite easy to transform any technetium-labeled compound into its equivalent rhenium analogue. However, as carrier free 186Re is not available, only a limited number of molecules were developed and beside radiosynoviorthesis and bone pain palliation, no serious attempt was made to develop rhenium-labeled compounds at the clinical level.