# Strontium-89

Source: https://nuclide.cc/isotopes/sr-89/  
Nuclide record `sr-89` (Isotope). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

A radioactive metal that behaves like calcium and is taken up by bone, particularly where cancer has spread there. A single injection can ease bone pain for weeks by irradiating those spots from within.

## Summary

Strontium-89 chloride (Metastron) is a pure beta emitter, decaying by beta-minus emission with a physical half-life of 50.5 days and a single beta energy of 1.463 MeV (100% abundance), giving a maximum tissue range of roughly 8 mm. Because strontium chemically mimics calcium, it is taken up preferentially into bone at sites of increased osteoblastic activity, such as skeletal metastases, and is retained there far longer than in normal bone -- delivering a prolonged local dose from a single injection, used for palliation of painful bone metastases from prostate and breast cancer.

Unlike samarium-153 or radium-223, 89Sr emits essentially no useful gamma photon, so it cannot be imaged with a gamma camera; patient selection instead typically relies on a separate technetium-99m bone scan.

89Sr is produced by thermal-neutron irradiation of an enriched strontium-88 target, 88Sr(n,γ)89Sr, at the DOE's High Flux Isotope Reactor (Oak Ridge National Laboratory) among other sites, yielding radionuclidic purity above 99.8%. As a long-half-life, well-established reactor product, supply has generally been described by the DOE Isotope Program as steady.

## Fields

- Kind: Isotope
- Status: approved
- Last checked: 2026-09-22
- Also known as: 89Sr; Sr-89
- Tags: therapy; pure beta emitter; bone-seeking

## Sources

- FDA label: Metastron (strontium-89 chloride injection): https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/020134s012lbl.pdf
- DOE Isotope Program: Ensuring a steady supply of strontium-89: https://www.isotopes.gov/Ensuring-steady-supply-of-strontium-89
- FDA: comparative physical properties of bone-palliation radiopharmaceuticals (Xofigo NDA review): https://www.accessdata.fda.gov/drugsatfda_docs/nda/2013/203971Orig1s000RiskR.pdf

## Connected records

- terms: [Bone metastases and skeletal-related events](https://nuclide.cc/terms/bone-metastases/), [Flare phenomenon](https://nuclide.cc/terms/flare-phenomenon/)
- isotopes: [Radium-223](https://nuclide.cc/isotopes/ra-223/), [Samarium-153](https://nuclide.cc/isotopes/sm-153/)
- indications: [Bone pain palliation from osteoblastic metastases](https://nuclide.cc/indications/bone-pain-palliation/), [Prostate cancer](https://nuclide.cc/indications/prostate/)
- drugs: [Samarium-153 lexidronam](https://nuclide.cc/drugs/samarium-153-lexidronam/), [Strontium-89 chloride](https://nuclide.cc/drugs/sr-89-chloride/)
- fronts: [Bone-targeted radiopharmaceuticals](https://nuclide.cc/fronts/f-bone-targeted/)

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