Strontium-89 () is a

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consi ...

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) ...

of strontium produced by

nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radio ...

, with a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

of 50.57 days. It undergoes β⁻ decay into yttrium-89. Strontium-89 has an application in medicine.

History

It was used for the first time by Belgian scientist Charles Pecher. Pecher filed a patent in May 1941 for the synthesis of strontium-89 and

yttrium-86 Natural yttrium (39Y) is composed of a single isotope yttrium-89. The most stable radioisotopes are 88Y, which has a half-life of 106.6 days and 91Y with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except ...

using cyclotrons, and described the therapeutic use of strontium.

Physiological effects and medical use

Strontium belongs to the same periodic family as

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

(

alkaline earth metal The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are al ...

s), and is metabolised in a similar fashion, preferentially targeting metabolically active regions of the bone. ⁸⁹Sr is an artificial radioisotope used in the treatment of osseous (bony)

metastases Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then ...

bone cancer A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body such as from lung, breast, thy ...

. 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. Consequently intravenous or intracavity administration of ⁸⁹Sr may be helpful in the palliation of painful bony metastases, as it allows radiation to be targeted at metastatic lesions, inducing

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

of cells, membrane and protein damage. Subsequently, bone pain resulting from

cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...

release at the site of lesions, bone-associated nerve compression and stretching of the

periosteum The periosteum is a membrane that covers the outer surface of all bones, except at the articular surfaces (i.e. the parts within a joint space) of long bones. Endosteum lines the inner surface of the medullary cavity of all long bones. Structu ...

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 analgesic Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...

s, an increase in time until further radiation is needed, and a decrease in tumour markers.

References

{{Therapeutic radiopharmaceuticals Strontium-089 Radiopharmaceuticals

History

Physiological effects and medical use

See also

References