AIM:To evaluate the long-term natural history of the gastroduodenal lesions secondary to extrahepatic embolization with Ytrium 90(90 Y) spheres.METHODS:From September 2003 to January 2012,379 procedures of liver radioembolization(RE) using resin microspheres loaded with 90 Y were performed in our center.We have retrospectively compiled the data from 379 RE procedures performed in our center.We report a comprehensive clinical,analytical,endoscopic and histologic long-term follow-up of a series of patients who developed gastroduodenal lesions after the treatment.RESULTS:Six patients(1.5%) developed gastrointestinal symptoms and had gastrointestinal lesions as shown by upper endoscopy in the next 12 wk after RE.The mean time between RE and the appearance of symptoms was 5 wk.Only one patient required endoscopic and surgical treatment.The incidence of gastrointestinal ulcerations was 3.75%(3/80) when only planar images were used for the pre-treatment evaluation.It was reduced to 1%(3/299) when singlephoton emission computed tomography(SPECT) images were also performed.The symptoms that lasted for a longer time were nausea and vomiting,until 25 mo after the treatment.CONCLUSION:All patients were free from severe symptoms at the end of follow-up.The routine use of SPECT has decreased the incidence of gastrointestinal lesions due to unintended deployment of 90 Y particles. AIM: To evaluate the long-term natural history of the gastroduodenal lesions secondary to extrahepatic embolization with Ytrium 90 (90 Y) spheres. METHODS: From September 2003 to January 2012, 379 procedures of liver radioembolization (RE) using resin microspheres loaded with 90 Y were performed in our center. We have retrospectively compiled the data from 379 RE procedures performed in our center.We report a comprehensive clinical, analytical, endoscopic and histologic long-term follow-up of a series of patients who developed gastroduodenal lesions after the treatment .RESULTS: Six patients (1.5%) developed gastrointestinal symptoms and had gastrointestinal lesions as shown by upper endoscopy in the next 12 wk after RE. the mean time between RE and the appearance of symptoms was 5 wk. Only one patient required endoscopic and surgical treatment. The incidence of gastrointestinal ulcerations was 3.75% (3/80) when only planar images were used for the pre-treatment evaluation. It was reduced to 1% (3/299) when singlephoton emission computed tomography (SPECT) images were also performed. These symptoms that lasted for a longer time were nausea and vomiting, until 25 months after the treatment. CONCLUSION: All patients were from severe symptoms at the end of follow-up. The routine use of SPECT has decreased the incidence of gastrointestinal lesions due to unintended deployment of 90 Y particles.