Home About Clinicians Patients Investors Careers Media Contact Clinicians > About SIRT Selective Internal Radiation Therapy (SIRT), also known as Radioembolization, is a liver-directed therapy for inoperable liver tumors. SIRT is typically a 2-stage process. It requires the involvement of a multi-disciplinary team consisting of representatives from most, if not all of the following specialities: Medical Oncology, Surgical Oncology, Gastroenterology / Hepatology, Nuclear Medicine, Interventional Radiology and Radiation Safety. A microcatheter is used to deliver millions of radioactive microspheres into the hepatic artery, where they are carried into the arterioles and selectively lodge in the tumor microvasculature (for further information see Mode of Action). The SIRT procedure targets liver tumors directly and enables high doses of radiation to the tumor tissue by using the special tumor's blood supply. Healthy liver tissue derives up to 90% of its blood from the portal vein, with only a small amount of the blood coming from the hepatic artery. In contrast, liver tumors derive up to 90% of their blood from the hepatic artery since they need a profuse supply of highly oxygenated blood. The hepatic artery therefore provides an ideal channel for a targeted tumor treatment. Treatment Goals Increase the time to progression Extend overall survival Potentially downsize or downstage tumors for liver resection, ablation, or transplantation Provide palliation of symptoms SIRT can be combined with modern chemotherapy or administered as a monotherapy, either during a chemotherapy-free interval, in a salvage setting or as an alternative to local or systemic treatments. DOORwaY-90 Study International Recommendations FLEXdose Delivery Programme About SIRT About SIR-Spheres microspheres + 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 328-E-0120 This content is intended for healthcare professionals only By clicking "Yes" you are confirming that you are a healthcare professional. If you are not a healthcare professional, then please click "Go to Homepage" which will direct you to the Sirtex homepage. Yes Go to Homepage Effective May 7, 2021, SIR-Spheres will have the following indication for use: SIR-Spheres Y-90 resin microspheres are indicated for the treatment of unresectable hepatocellular carcinoma (HCC) and unresectable metastatic liver tumors from primary colorectal cancer in patients refractory to or intolerant of chemotherapy. Click here to view our Technical Bulletin. Ok