Strontium-89

Strontium-89 (89
Sr
) is a radioactive isotope of strontium produced by nuclear fission, with a half-life of 50.57 days. It undergoes β⁻ decay into yttrium-89. Strontium-89 has an application in medicine.

Strontium belongs to the same periodic family as calcium (alkaline earth metals), and is metabolised in a similar fashion. ⁸⁹Sr, used in the treatment of osseous (bony) metastases preferentially targets metabolically active regions of the bone. As such, intravenous or intracavity administration of ⁸⁹Sr may be helpful in the palliation of painful bony metastases, as it allows for targeted radiation to metastatic lesions, inducing apoptosis of cells, membrane and protein damage. Subsequently, bone pain resulting from cytokine release at the site of lesions, bone-associated nerve compression and stretching of the periosteum may be reduced. Treatment with ⁸⁹Sr has been particularly effective in patients with hormonally-resistant prostate cancer, often leading to a decreased requirement for opioid analgesics, an increase in time until further radiation, and a decrease in tumour markers.

It is an artificial radioisotope which is used in treatment of bone cancer. In circumstances where cancer patients have widespread and painful bony metastases, the administration of ⁸⁹Sr results in the delivery of beta particles directly to the area of bony problem, where calcium turnover is greatest.

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