Techniques and systems are disclosed for implement real-time volumetric image reconstruction and 3D tumor localization based on a single x-ray projection image for lung cancer radiotherapy. In one aspect, a method includes performing deformable image registration between a reference phase and remaining N-1 phases for a set of volumetric images of a patient at N breathing phases to obtain a set of N-1 deformation vector fields (DVFs). The set of DVFs can be represented efficiently by a few eigenvectors and coefficients obtained from PCA. Additionally, the PCA coefficients are varied to generate new DVFs, which, when applied on a reference image, lead to new volumetric images.
展开▼