Background: PET/CT simulation in Radioth erapy is one of the moderm technics in cancer treatment. Since 2009, the first time in Vietnam, Center for Nuclear Medicine and Cancer Bach Mai Hospital has conducted successful deployment of simulation taken on PET-CT for radiation treatment planning for patients with accelerated cancer. Objective: Initially an assessment of the results of treatment of esophageal cancer with radiotherapy accelerators incorporate techniques PET/CT simulation. Subjects an methods: Assessed response before and after treatment on 50 patients of esophageal cancer to 9/2010 - 12/2012. Results: In the simulation of radiotherapy of esophageal, PET/CT have a values higher than CT: Detection of damage more precisely and more clearly. Patients were applied of radiotherapy treatment techniques in the simulation by PET/CT is a good response rate to treatment and minimize complications: overall response (complete and partial) with symptoms clinical: 80 percent, response to treatment the tumor of esophagus is: 83 percent, complications are common depletion rate is: 34 percent. Most complications are mild and can be overcome. Conclusion: PET/CT simulation in radiotherapy initially achieved good results.