Deformable registration of abdominal CT images: tissue stiffness constraints using B-Splines

摘要

One method of modelling respiratory motion of the abdomen is to acquire CT images at different points in the respiratory cycle and develop a deformation model that gives a mapping between corresponding anatomical points in the images. In this work, we use such a method, and the target application is radiosurgery, specifically radiosurgical treatment of lesions that move during respiration, for example those in the liver, lung, or pancreas. In order to accurately calculate the treatment dose, it is necessary to have a good deformation map both globally and locally (in the vicinity of the treatment target). We use a dual-resolution method in order to allow a more accurate deformation model to be computed in the region of interest. We also introduce a tissue stiffness constraint, along with an application of matrix algebra that allows this constraint to be applied in an effective way with respect to the control point values.