摘要： Objective To increase the accuracy of beam targeting and improve the dose distributions in radiotherapy using a
robust image registration algorithm based on control volumes. Methods Control volume mapping and thin-plate spline
deformable transformation were combined. The use of the control volumes increased the accuracy for the deformable
registration. A bi-directional mapping method was also employed to correctly match the control volumes. Results The clinical
images were simulated using the proposed two-step image registration algorithm. The simulation results indicated that the
registration algorithm was robust and universal, even in cases of obvious deformation. Conclusions The algorithm provides a
more convenient and robust resolution as compared to manual landmark-based methods and single-step deformable
transformations, and may help in automatic image registration in radiation therapy.