tailieunhanh - Báo cáo khoa học: "Independent position correction on tumor and lymph nodes; consequences for bladder cancer irradiation with two combined IMRT plan"

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: Independent position correction on tumor and lymph nodes; consequences for bladder cancer irradiation with two combined IMRT plans. | van Rooijen et al. Radiation Oncology 2010 5 53 http content 5 1 53 RADIATION ONCOLOGY RESEARCH Open Access Independent position correction on tumor and lymph nodes consequences for bladder cancer irradiation with two combined IMRT plans Dominique C van Rooijen René Pool Jeroen B van de Kamer Maarten CCM Hulshof Caro CE Koning and Arjan Bel Abstract Background The application of lipiodol injections as markers around bladder tumors combined with the use of CBCT for image guidance enables daily on-line position correction based on the position of the bladder tumor. However this might introduce the risk of underdosing the pelvic lymph nodes. In this study several correction strategies were compared. Methods For this study set-up errors and tumor displacements for ten complete treatments were generated both were based on the data of 10 bladder cancer patients. Besides two IMRT plans were made for 20 patients one for the elective field and a boost plan for the tumor. For each patient 10 complete treatments were simulated. For each treatment the dose was calculated without position correction option 1 correction on bony anatomy option 2 on tumor only option 3 and separately on bone for the elective field option 4 . For each method we analyzed the D99 for the tumor bladder and lymph nodes and the V95 for the small intestines rectum healthy part of the bladder and femoral heads. Results CTV coverage was significantly lower with options 1 and 2. With option 3 the tumor coverage was not significantly different from the treatment plan. The AD99 D option n - D treatment plan for option 4 was small but significant. For the lymph nodes the results from option 1 differed not significantly from the treatment plan. The median AD99 of the other options were small but significant. AD99 for PTVbladder was small for options 1 2 and 4 but decreased up to Gy when option 3 was applied. Option 4 is the only method where the difference with the treatment plan never .