tokens: Following the standard in 2D/3D registration , the performances of the proposed method and the baseline methods are evaluated with mean target registration error ( mTRE ) , i.e. , the mean distance ( in mm ) between the patient landmarks and the aligned CT landmarks in 3D. The mTRE results are reported in forms of the 50th , 75th , and 95th percentiles to demonstrate the robustness of the compared methods .