Yttrium-90, 90
Y
, is a medically significant isotope of yttrium. Yttrium-90 has a wide and valuable use in radiation therapy to treat cancer.
Contents
Decay
90
Y
undergoes β− decay to zirconium-90 with a half-life of 64.1 hours and a decay energy of 2.28 MeV. It also produces 0.01% 1.7 MeV photons along the way. Interaction of the emitted electrons with matter can lead to Bremsstrahlung radiation.
Production
Yttrium-90 is a decay product of strontium-90 which makes up about 5% of the nuclear daughter isotopes when uranium is fissioned. Yttrium-90 is produced by chemical high-purity separation from strontium-90, a fission product of uranium in nuclear reactors.
Clinical Application
90Y plays a significant role in the treatment of hepatocellular carcinoma (HCC) and other liver cancers. Trans-arterial radioembolization is a procedure performed by interventional radiologists in which microspheres are impregnated with 90Y and injected into the arteries supplying the tumor. Radioembolization with 90Y significantly increases time-to-progression (TTP) of HCC, has a tolerable adverse event profile, and improves patient quality of life more than do similar therapies.