Fig. 3
(1) Through the reconstruction function of the software, the spatial relationship between tumor and markers can be observed. (2) The measurement tool measures the distance between the three models. (3) By rotating the model angle, make sure that the three-line segments are in the same plane. (4) After closing the model, it is more convenient to confirm whether the three-line segments are in the same plane, and each two line segments intersect at one point. A anterior, P posterior, S superior, I inferior, L left, R right