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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: Safety margin in irradiation of colorectal liver metastases: assessment of the control dose of micrometastases. | Seidensticker et al. Radiation Oncology 2010 5 24 http www.ro-journal.eom content 5 1 24 RADIATION ONCOLOGY RESEARCH Open Access Safety margin in irradiation of colorectal liver metastases assessment of the control dose of micrometastases Max Seidensticker 1 Peter Wust2 Ricarda Ruhl1 Konrad Mohnike1 Maciej Pech1 Gero Wieners1 Gunther Gademann3 and Jens Ricke1 Abstract Backround Micrometastases of colorectal liver metastases are present in up to 50 of lesions. In this study we sought to determine the threshold dose for local control of occult micrometastases in patients undergoing CT computed tomography -guided brachytherapy of colorectal liver metastases. Materials and methods Nineteen patients demonstrated 34 local tumor recurrences originating from micrometastases after CT-guided brachytherapy of 27 colorectal liver metastases. We considered a local tumor recurrence as originating from a micrometastasis if tumor regrowth occurred adjacent to a formerly irradiated lesion and the distance of the 3D isocenter of the new lesion was 23.5 mm from the previous tumor margin. Follow-up MRI was fused with the planning-CT and dosimetry data. Two reviewers independently indicated the dose exposure at the isocenter of the micrometastases. Statistical analysis included an analysis of variance ANOVA using backward selection. 95 tolerance intervals with coverage of 87.5 and 75 of the data of the normal distribution were calculated. Results The median distance of the micrometastases to the margin of the originating colorectal metastases was 8.75 mm 1-21 mm . Dose exposure at the isocenter was 12.25 Gy 7-19.8 in median. We stratified according to the distance from the isocenter to the initial tumor margin 9 mm 9-15 mm and 15 mm. The median dose in the according isocenters was 13.18 11.6 and 11.85 Gy. The threshold dose failing to prevent micrometastasis growth was sigificantly higher in a subgroup of lesions with 9 mm distance as compared to 15 mm 13.18 vs 11.85 Gy . Adjuvant .
