Agents
The microspheres themselves are made of glass or resin. Inside the microspheres is the isotope yttrium-90, which has beta-emission with a half-life of 2.6 days. Currently there are 2 types of microspheres: TheraSphere and SIR-Spheres, which differ in their radioactivity per sphere and embolic effect.
| Parameter | Resin | Glass |
|---|---|---|
| Trade name | SIR-Spheres | Therapheres |
| Manufacturer and location | Sirtex Medical, Lane Cover, Australia | MDS Nordion, Kanata, Canada |
| Diameter | 20-60 µm | 20-30 µm |
| Specific gravity | 1.6 g/dL | 3.6 g/dL |
| Activity per particle | 50 Bq | 2500 Bq |
| Number of microspheres per 3 GBq vial | 40-80 million | 1.2 million |
| Material | resin with bound yttrium | glass with yttrium in matrix |
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Read more about this topic: Selective Internal Radiation Therapy
Famous quotes containing the word agents:
“Modern man’s capacity for destruction is quixotic evidence of humanity’s capacity for reconstruction. The powerful technological agents we have unleashed against the environment include many of the agents we require for its reconstruction.”
—George F. Will (b. 1941)
“Even though fathers, grandparents, siblings, memories of ancestors are important agents of socialization, our society focuses on the attributes and characteristics of mothers and teachers and gives them the ultimate responsibility for the child’s life chances.”
—Sara Lawrence Lightfoot (20th century)
“Luckless is the country in which the symbols of procreation are the objects of shame, while the agents of destruction are honored! And yet you call that member your pudendum, or shameful part, as if there were anything more glorious than creating life, or anything more atrocious than taking it away.”
—Savinien Cyrano De Bergerac (1619–1655)