strontium

strontium /stron·ti·um/ (stron´she-um) a chemical element, at. no. 38, symbol Sr.

---

strontium 89  a radioactive isotope of strontium having a half-life of 50.55 days and decaying by beta emission; used in the form of the chloride as a radiation source in palliation of bone pain caused by metastatic lesions.

---

stron·ti·um (strnch-m, -t-m, -shm)

n. Symbol Sr

A soft, easily oxidized metallic element that ignites spontaneously in air when finely divided, used in pharmaceuticals and in radioisotope form for bone imaging. Atomic number 38.

---

strontium (Sr)

[stron′sh(ē)əm]

Etymology: Strontian, Scotland

a metallic element. Its atomic number is 38, and its atomic mass is 87.62. Chemically similar to calcium, it is found in bone tissue. Isotopes of strontium are used in radioisotope scanning procedures of bone. Strontium 85 (⁸⁵Sr) and strontium 87 (⁸⁷Sr) mimic calcium metabolism and are used in studies of bone physiologic characteristics and disorders. These radionuclides can be counted with any standard detector or imaged at a very early stage in bone disease, whereas radiographic films of bone without the use of a radioactive tracer can show decreased density only after approximately 50% of bone is decalcified. Most ⁸⁵Sr or ⁸⁷Sr is deposited in bone within 1 hour after injection. Increased deposition of these radionuclides is strongly linked to osteoblastic activity and new bone formation. In addition to 4 naturally occurring isotopes (⁸⁸Sr, ⁸⁷Sr, ⁸⁶Sr, and ⁸⁴Sr), 12 artificial strontium isotopes are produced by nuclear reactions. Strontium 90, the longest-lived, is the most dangerous constituent of fallout from atomic bomb tests. It can replace some of the calcium in food, become concentrated in teeth and bones, and continue to emit electrons that can cause death in the host. Strontium 90 becomes concentrated in cow's milk.

---

strontium (Sr) (stron´chēm),

n a metallic element. Its atomic number is 38 and its atomic weight is 87.62. It is chemically similar to calcium and is found in bone tissue. Isotopes of strontium are used in radioisotope scanning procedures of bone.

---

strontium

a chemical element, atomic number 38, atomic weight 87.62, symbol Sr. See Table 6.

---

strontium-90

is deposited in bones and removed with great difficulty. It has a very long half-life (28.1 years) and if sufficient is ingested it will have the same toxic and teratogenic effects as external irradiation. S-90 plates are used in the treatment of superficial squamous cell carcinomas involving the eye.

strontium chloride

experimental feeding to pigs causes gross bone abnormality and weakness and paralysis.