223
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Radium-223
Medical

Radium-223

Status:

Future

Use:

Targeted alpha therapy

Profile

Radium is a naturally radioactive alkaline-earth metal, famously discovered by Marie Curie in 1898. Radium-223 is a radioisotope used in therapy, with a half-life of about 11.4 days.

Radium-223 is an alpha emitter that is chemically similar to calcium and is drawn to areas of high bone turnover. There it delivers high-energy alpha radiation over a range of less than a tenth of a millimetre, killing cancer cells in bone while largely sparing surrounding healthy marrow and tissue.

Radium-223, as radium-223 dichloride, is an approved targeted alpha therapy for men with castration-resistant prostate cancer that has spread to the bones. It both extends survival and relieves bone pain, and was the first alpha-emitting drug approved for cancer treatment.

Radium-223 is prepared by milking it from a generator containing the longer-lived parent actinium-227, which decays through thorium-227 to radium-223. Actinium-227 is available only from the decay of uranium-235 or from neutron irradiation of radium-226, so parent supply is the key constraint.  

StandardX is developing accelerator-driven production to produce the actinium-227 precursor and secure radium-223 supply.

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