tailieunhanh - Báo cáo khoa học: "Treatment planning using MRI data: an analysis of the dose calculation accuracy for different treatment regions"

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: Treatment planning using MRI data: an analysis of the dose calculation accuracy for different treatment regions. | Jonsson et al. Radiation Oncology 2010 5 62 http content 5 1 62 RADIATION ONCOLOGY RESEARCH Open Access Treatment planning using MRI data an analysis of the dose calculation accuracy for different treatment regions Joakim H Jonsson 2 Magnus G Karlsson1 Mikael Karlsson2 Tufve Nyholm3 Abstract Background Because of superior soft tissue contrast the use of magnetic resonance imaging MRI as a complement to computed tomography CT in the target definition procedure for radiotherapy is increasing. To keep the workflow simple and cost effective and to reduce patient dose it is natural to strive for a treatment planning procedure based entirely on MRI. In the present study we investigate the dose calculation accuracy for different treatment regions when using bulk density assignments on MRI data and compare it to treatment planning that uses CT data. Methods MR and CT data were collected retrospectively for 40 patients with prostate lung head and neck or brain cancers. Comparisons were made between calculations on CT data with and without inhomogeneity corrections and on MRI or CT data with bulk density assignments. The bulk densities were assigned using manual segmentation of tissue bone lung and air cavities. Results The deviations between calculations on CT data with inhomogeneity correction and on bulk density assigned MR data were small. The maximum difference in the number of monitor units required to reach the prescribed dose was . This result also includes effects of possible geometrical distortions. Conclusions The dose calculation accuracy at the investigated treatment sites is not significantly compromised when using MRI data when adequate bulk density assignments are made. With respect to treatment planning MRI can replace CT in all steps of the treatment workflow reducing the radiation exposure to the patient removing any systematic registration errors that may occur when combining MR and CT and decreasing time and cost for the extra CT .