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 conside ...

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

strontium Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to ...

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 radioactiv ...

, with a

half-life Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * ''Half Life: ...

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

History

Strontium-89 was first synthesized in 1937 by D. W. Stewart et al. at the

University of Michigan The University of Michigan (U-M, U of M, or Michigan) is a public university, public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Mi ...

; it was synthesized via irradiation of stable strontium (⁸⁸Sr) with

deuteron Deuterium (hydrogen-2, symbol H or D, also known as heavy hydrogen) is one of two Stable isotope ratio, stable isotopes of hydrogen; the other is protium, or hydrogen-1, H. The deuterium atomic nucleus, nucleus (deuteron) contains one proton and ...

s. Biological properties and applications of strontium-89 were studied for the first time by Belgian scientist

Charles Pecher Charles Pecher (26 November 1913 – 28 August 1941) was a Belgian pioneer in nuclear medicine. He discovered and introduced strontium-89 in medical therapeutic procedures in 1939. He was the first to report a possible therapeutic role for the b ...

. 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, exce ...

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; it has 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 it ...

(

alkaline earth metal The alkaline earth metals are six chemical elements in group (periodic table), 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 p ...

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 spreading 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, ...

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

. In circumstances where cancer patients have widespread and painful bony metastases, the administration of ⁸⁹Sr results in the delivery of

beta particle A beta particle, also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus, known as beta decay. There are two forms of beta decay, β− decay and � ...

s 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 ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...

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 produced by a broad range of cells, including immune cells like macrophages, B cell, B lymphocytes, T cell, T lymphocytes ...

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. (At the joints of long bones the bone's outer surface is lined with "articular cartila ...

may be reduced. Treatment with ⁸⁹Sr has been particularly effective in patients with hormonally-resistant

prostate cancer Prostate cancer is the neoplasm, uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Abnormal growth of the prostate tissue is usually detected through Screening (medicine), screening tests, ...

, often leading to a decreased requirement for

opioid analgesic Opioids are a class of drugs that derive from, or mimic, natural substances found in the opium poppy plant. Opioids work on opioid receptors in the brain and other organs to produce a variety of morphine-like effects, including pain relief. Th ...

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

References

{{Therapeutic radiopharmaceuticals Strontium-089 Medical isotopes

History

Physiological effects and medical use

See also

References