A computer-implemented method of dynamically tracking a target within an anatomical region in order to deliver therapeutic radiation to the target during a motion of the anatomical region, the anatomical region including a plurality of moving skeletal reference structures (230, 232) that move during the motion of the anatomical region, the method comprising: target and the plurality of moving skeletal reference structures (230, 232), as a function of time within a periodic cycle P, and accounts for a non-rigid deformation of the anatomical region during the cycle P, wherein the periodic cycle characterizes periodic motion and deformation of the anatomical region, dynamically tracking the periodic motion of the anatomical region to determine in real time a current point in time within the periodic cycle P; registering one or more near real time images of the plurality of moving skeletal reference structures (230, 232) taken at a point in time within the periodic cycle P with one or more pre-operative images of the plurality of moving skeletal reference structures to determine a 3D location of each of the plurality of moving skeletal reference structures at the point in time within the periodic cycle P; computing a 3D location of the target in real time at the current point in time within the periodic cycle P using the 3D locations of the plurality of moving skeletal reference structures (230, 232) at the point in time within the periodic cycle P, and the relative 3D locations of the target and the plurality of moving skeletal reference structures (230, 232) at the point in time within the periodic cycle P from the 4D mathematical model, wherein computing the 3D location of the target comprises drawing vectors from the 3D locations of the plurality of moving skeletal reference structures to the target; and generating a radiation dose distribution that prescribes an amount of therapeutic radiation to be delivered to the 3D location of the target within the moving anatomical region, the dose distribution accounting for the deformation of the moving anatomical region at the current point in time within the periodic cycle P. target and the plurality of moving skeletal reference structures (230, 232), as a function of time within a periodic cycle P, and accounts for a non-rigid deformation of the anatomical region during the cycle P, wherein the periodic cycle characterizes periodic motion and deformation of the anatomical region, dynamically tracking the periodic motion of the anatomical region to determine in real time a current point in time within the periodic cycle P; registering one or more near real time images of the plurality of moving skeletal reference structures (230, 232) taken at a point in time within the periodic cycle P with one or more pre-operative images of the plurality of moving skeletal reference structures to determine a 3D location of each of the plurality of moving skeletal reference structures at the point in time within the periodic cycle P; computing a 3D location of the target in real time at the current point in time within the periodic cycle P using the 3D locations of the plurality of moving skeletal reference structures (230, 232) at the point in time within the periodic cycle P, and the relative 3D locations of the target and the plurality of moving skeletal reference structures (230, 232) at the point in time within the periodic cycle P from the 4D mathematical model, wherein computing the 3D location of the target comprises drawing vectors from the 3D locations of the plurality of moving skeletal reference structures to the target; and generating a radiation dose distribution that prescribes an amount of therapeutic radiation to be delivered to the 3D location of the target within the moving anatomical region, the dose distribution accounting for the deformation of the moving anatomical region at the current point in time within the periodic cycle P. dynamically tracking the periodic motion of the anatomical region to determine in real time a current point in time within the periodic cycle P; registering one or more near real time images of the plurality of moving skeletal reference structures (230, 232) taken at a point in time within the periodic cycle P with one or more pre-operative images of the plurality of moving skeletal reference structures to determine a 3D location of each of the plurality of moving skeletal reference structures at the point in time within the periodic cycle P; computing a 3D location of the target in real time at the current point in time within the periodic cycle P using the 3D locations of the plurality of moving skeletal reference structures (230, 232) at the point in time within the periodic cycle P, and the relative 3D locations of the target and the plurality of moving skeletal reference structures (230, 232) at the point in time within the periodic cycle P from the 4D mathematical model, wherein computing the 3D location of the target comprises drawing vectors from the 3D locations of the plurality of moving skeletal reference structures to the target; and generating a radiation dose distribution that prescribes an amount of therapeutic radiation to be delivered to the 3D location of the target within the moving anatomical region, the dose distribution accounting for the deformation of the moving anatomical region at the current point in time within the periodic cycle P.