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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Radiation Oncology cung cấp cho các bạn kiến thức về ngành y đề tài: SemiHypofractionated radiotherapy for lung tumors with online cone beam CT guidance and active breathing control. | Shen et al. Radiation Oncology 2010 5 19 http www.ro-journal.eom content 5 1 19 RADIATION ONCOLOGY RESEARCH Open Access Hypofractionated radiotherapy for lung tumors with online cone beam CT guidance and active breathing control Yali Shen1 Hong Zhang1 Jin Wang1 Renming Zhong2 Xiaoqing Jiang2 Qinfeng Xu2 Xin Wang1 Sen Bai2 Feng Xu1 Abstract Background To study the set-up errors PTV margin and toxicity of cone beam CT CBCT guided hypofractionated radiotherapy with active breathing control ABC for patients with non-small cell lung cancer NSCLC or metastatic tumors in lung. Methods 32 tumors in 20 patients were treated. Based on the location of tumor dose per fraction given to tumor was divided into three groups 12 Gy 8 Gy and 6 Gy. ABC is applied for every patient. During each treatment patients receive CBCT scan for online set-up correction. The pre- and post-correction setup errors between fractions the interfractional and intrafractional set-up errors PTV margin as well as toxicity are analyzed. Results The pre-correction systematic and random errors in the left-right LR superior-inferior SI anterior-posterior AP directions were 3.7 mm and 5.3 mm 3.1 mm and 2.1 mm 3.7 mm and 2.8 mm respectively while the post-correction residual errors were 0.6 mm and 0.8 mm 0.8 mm and 0.8 mm 1.2 mm and 1.3 mm respectively. There was an obvious intrafractional shift of tumor position. The pre-correction PTV margin was 9.5 mm in LR 14.1 mm in SI and 8.2 mm in AP direction. After CBCT guided online correction the PTV margin was markedly reduced in all three directions. The post-correction margins ranged 1.5 to 2.1 mm. The treatment was well tolerated by patients of whom there were 4 20 grade1-2 acute pneumonitis 3 15 grade1 acute esophagitis 2 10 grade1 late pneumonitis and 1 5 grade 1 late esophagitis. Conclusion The positioning errors for lung SBRT using ABC were significant. Online correction with CBCT image guidance should be applied to reduce setup errors and PTV margin which .
