Abstract
Internal organ motion due to breathing is a phenomenon that nullifies the rigidity assumptions in many interventional applications, ranging from image guided needle biopsies to external beam radiation therapy. In this paper, we propose a method to correlate and characterize internal organ motion with the location of skin markers. The method utilizes a MR time sequence along with tracked magnetic marker positions to establish the correlation. We perform a validation study to quantify the degree of the accuracy and the reproducibility of this correlation. The results demonstrate that patient specific correlation of internal motion and skin markers can be established and the target positioning accuracy of better than 15% of the maximum range of the target movement can be achieved.