SIR-Spheres® Y-90 resin microspheres are tiny radioactive ‘beads’ used in selective internal radiation therapy (SIRT), sometimes referred to as Y-90 radioembolization, and are used for the treatment of stage IV colon cancer that has spread to the liver and can’t be surgically removed.

SIR-Spheres Y-90 resin microspheres are much smaller than the width of a human hair and contain the radioactive component yttrium-90 (Y-90).

Vial with spheres

SIR-Spheres Y-90 resin microspheres vial and microscopic view of the microspheres

The microspheres are injected by the millions directly to the liver tumors via the tumor’s main blood supply, where they become stuck in the small blood vessels that are in and around the tumors.

Spheres entering tumor
SIR-Spheres Y-90 resin microspheres are delivered directly to the liver tumor

The microspheres emit high doses of radiation to the tumor cells to destroy them.   This targeted nature of the procedure enables doctors to deliver up to 40 times more radiation to the liver tumors than would be possible using normal radiation therapy, while sparing the surrounding healthy liver tissue.

Radiation on tumor
SIR-Spheres Y-90 resin microspheres emit radiation to kill the tumor

The radiation decreases over time and after 2 weeks most of the radiation is gone and the microspheres harmlessly remain in the liver.

SIR-Spheres Y-90 resin microspheres therapy is a minimally invasive outpatient procedure and patients usually go home hours after the procedure is completed.

SIR-Spheres Y-90 resin microspheres are the only fully FDA approved microsphere radiation therapy in the United States for the treatment of colorectal cancer that has spread to the liver. See Important Safety Information.

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How do SIR-Spheres Y-90 resin microspheres work?

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