Planning system for adaptive radiation therapy

Abstract

The invention relates to the planning of a radiation therapy treatment of at least one structure in a region of a patient body. A planning unit obtains a first treatment plan generated on the basis of a planning image of the body region and on the basis of dose objectives. Moreover, the planning unit receives a further image of the body region of the patient body, determines a transformation for generating an adapted treatment plan from the first treatment plan and/or for generating an adapted dose distribution from the dose distribution corresponding to the first treatment plan on the basis of the further image and determines an adapted treatment plan on the basis of the transformation and/or the adapted dose distribution. In accordance with the invention, the transformation on the basis of the dose objectives.

1 . System for planning a radiation therapy treatment of at least one structure in a region of a patient body, the system comprising a planning unit configured to:
 obtain a first treatment plan generated on the basis of a planning image of the region of the patient body and on the basis of dose objectives with respect to the region of the patient body, the first treatment plan corresponding to a first dose distribution in the region of the patient body,   receive a further image of the region of the patient body,   determine a transformation for generating an adapted treatment plan from the first treatment plan and/or for generating an adapted dose distribution from the first dose distribution on the basis of the further image, and   determine an adapted treatment plan for controlling the radiation therapy treatment on the basis of the transformation and/or the adapted dose distribution,   wherein the planning unit is configured to determine the transformation on the basis of the dose objectives.   
     
     
         2 . The system as defined in  claim 1 , wherein the transformation is a rigid transformation consisting of a rotation and/or a translation. 
     
     
         3 . The system as defined in  claim 1 , wherein the first treatment plan is generated on the basis a first delineation of the at least one structure determined on the basis of the planning image and wherein the planning unit is configured to generate the transformation on the basis of a second delineation of the at least one structure determined on the basis of the further image. 
     
     
         4 . The system as defined in  claim 3 , wherein the planning unit is configured to determine the transformation by optimizing an objective functional generated on the basis of the dose objectives evaluated for a dose distribution resulting from the first treatment plan and a patient anatomy as represented by a transformed second image and for a transformed second delineation of the at least one structure, the objective function being optimized with respect to the transformation for generating the transformed second image and the transformed second delineation. 
     
     
         5 . The system as defined in  claim 3 , wherein the planning unit is configured to determine the transformation such that an objective functional O(T) of a transformation T of the form O(T)=F(d(p 1 ,T*I 2 ),T*s 2 ) is at least approximately optimized when the transformation T corresponds to the determined transformation, where F is a functional generated on the basis of the dose objectives, d is a dose distribution in the region of the patient body, p 1  is first treatment plan, I 2  is the second image, T*I 2  is a transform of the second image generated using the transformation T, s 2  is the second delineation of the target structure and T*s 2  is a transform of the second delineation generated based on the transformation T. 
     
     
         6 . The system as defined in  claim 4 , wherein the planning unit is configured to:
 obtain a plurality of first treatment plans generated on the basis of the dose objectives,   at least approximately optimize the objective functional for each of the first treatment plans and to compare the optima of the objective function determined for the treatment plan, and   determine an adapted treatment for controlling the radiation therapy treatment on the basis of the result of the comparison.   
     
     
         7 . The system as defined in  claim 6 , wherein the planning unit is configured to select one of the first treatment plans on the basis of the comparison and to adapt the treatment on the basis of the transformation determined by optimizing the objective function for the selected treatment plan. 
     
     
         8 . The system as defined in  claim 6 , wherein the planning unit is configured to determine a combined treatment plan on the basis of the first treatment plans on the basis of the comparison and to adapt the combined treatment plan on the basis of the transformations determined by optimizing the objective functionals for the treatment plans. 
     
     
         9 . The system as defined in  claim 3 , wherein the planning unit is configured to generate the second delineation from the first delineation using an image transformation, the image transformation being determined on the basis of an image registration procedure between the further image and the planning image. 
     
     
         10 . The system as defined in  claim 9 , wherein the image registration procedure is a deformable image registration procedure. 
     
     
         11 . The system as defined in  claim 1  further comprising an imaging unit for acquiring the further image of the region of the patient body and wherein the planning unit is configured to receive the further image from the imaging unit. 
     
     
         12 . A method for planning a radiation therapy treatment of at least one structure in a region of a patient body, the method comprising:
 obtaining a first treatment plan generated on the basis of a planning image of the region of the patient body and on the basis of dose objectives with respect to the region of the patient body, the first treatment plan corresponding to a first dose distribution in the region of the patient body,   receiving a further image of the region of the patient body,   determining a transformation for generating an adapted dose distribution from the first dose distribution on the basis of the further image and the planning image, and   determining an adapted treatment plan for controlling the radiation therapy treatment on the basis of the transformation and/or the adapted dose distribution,   wherein the transformation is determined on the basis of the dose objectives.   
     
     
         13 . A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of  claim 12 .