Sirtex

SIRTEX SIR-Spheres microspheres are tiny resin microspheres that are loaded with yttrium-90, a radioisotope that emits pure beta radiation. Yttrium-90 has a "half life" of about 64 hours. The radiation from yttium-90 is largely confined to a tissue depth of 2-3 mm. After injection into the artery supplying blood to the tumours, the spheres are trapped in the tumour's vascular bed, where they destroy the tumour cells by delivering the beta radiation. The radiation is targeted and contained within the patient's body and after 14 days the majority of the radiation effect has occurred. SIR-Spheres microspheres are considered a regional treatment as the radiation is directed to the liver and does not affect other organs in the body.