Strontium SR-89 is a radioactive isotope of strontium. Strontium-89 decays by beta emission with a half-life of 50.5 days. Beta-particles produced by radioactive decay penetrate tissues at a range of approximately 8 mm. Strontium SR-89 is used in medicine for the relief of bone pain in patients with painful skeletal metastases. Following intravenous injection, soluble strontium compounds behave like their calcium analogs, clearing rapidly from the blood and selectively localizing in bone mineral. Uptake of strontium by bone occurs preferentially in sites of active osteogenesis; thus primary bone tumors and areas of metastatic involvement (blastic lesions) can accumulate significantly greater concentrations of strontium than surrounding normal bone.

Strontium SR-89 is a radioactive isotope of strontium. Strontium-89 decays by beta emission with a half-life of 50.5 days. Beta-particles produced by radioactive decay penetrate tissues at a range of approximately 8 mm. Strontium SR-89 is used in medicine for the relief of bone pain in patients with painful skeletal metastases. Following intravenous injection, soluble strontium compounds behave like their calcium analogs, clearing rapidly from the blood and selectively localizing in bone mineral. Uptake of strontium by bone occurs preferentially in sites of active osteogenesis; thus primary bone tumors and areas of metastatic involvement (blastic lesions) can accumulate significantly greater concentrations of strontium than surrounding normal bone.

Samarium SM-153 lexidronam is a chelated complex of a radioisotope of the element samarium with ethylenediamine tetra(methylene phosphonic acid) (EDTMP). Samarium Sm-153 EDTMP has an affinity for bone and concentrates in areas of bone turnover in association with hydroxyapatite. In clinical studies employing planar imaging techniques, more Samarium (153Sm) lexidronam accumulates in osteoblastic lesions than in normal bone with a lesion-to-normal bone ratio of approximately 5. It is indicated for the relief of pain in patients with confirmed osteoblastic metastatic bone lesions that enhance on radionuclide bone scan. It should not be given concurrently with chemotherapy or external beam radiation therapy unless the benefit outweighs the risks. The most common adverse events are: nausea and vomiting, hemoglobin decrease, myasthenia, paresthesia, thrombocytopenia and abdominal pain.