Home About Clinicians Patients Investors Careers Media Contact Clinicians > About SIR-Spheres microspheres SIR-Spheres® Y-90 resin microspheres are a medical device used in Selective Internal Radiation Therapy (SIRT) for liver tumours. SIR-Spheres Y-90 resin microspheres are a permanent implant and for single use only. The biocompatible resin microspheres labelled with yttrium-90 have a median diameter of 32.5 microns (range between 20 and 60 microns). Yttrium-90 is a high-energy beta-emitting isotope with no primary gamma emission. The maximum energy of the beta particles is 2.27MeV with a mean of 0.93MeV. The maximum range of emissions in tissue is 11mm with a mean of 2.5mm. The half-life is 64.1 hours. Following administration, 94% of the radiation is delivered in 11 days. These properties of the SIR-Spheres Y-90 resin microspheres mean that the microspheres lodge preferentially in the microvasculature surrounding the tumour, maximising tumoricidal effects and minimising the effects on healthy liver parenchyma (Also see Mode of Action and Radiation Safety Aspects). DOORwaY-90 Study International Recommendations FLEXdose Delivery Programme About SIRT About SIR-Spheres microspheres Mode of Action How are SIR-Spheres microspheres administered Patient Selection Potential adverse events Radiation Safety Aspects Follow Up Peri-Procedural Medications - mCRC Clinical Studies + HCC Clinical Studies + Ongoing Clinical Studies Customer Support and Training Programs Events Frequently Asked Questions Who we are Sirtex Medical is a global healthcare business with offices in the U.S., Australia, Germany and Singapore, working to improve outcomes in people with cancer. Our current lead product is a targeted radiation therapy for liver cancer called SIR-Spheres® Y-90 resin microspheres. What are SIR-Spheres® Y-90 resin microspheres? SIR-Spheres® Y-90 resin microspheres are a medical device used in Selective Internal Radiation Therapy (SIRT) for treatment of unresectable hepatocellular carcinoma (HCC) and unresectable metastatic liver tumors from primary colorectal cancer in patients refractory to or intolerant of chemotherapy. To view the Technical Bulletin regarding our indication, click here. Contact or follow us Contact Us SIR-Spheres® is a registered trademark of Sirtex SIR-Spheres Pty Ltd. Terms of Use | Privacy Information 892-EUA-1117