Fredrik Carlsson

A conjugate-gradient based approach for approximate solutions of quadratic programs

  • Fredrik Carlsson
  • Anders Forsgren
    • Categories Biomedical Applications, Quadratic Programming Tags , , ,

    This paper deals with numerical behaviour and convergence properties of a recently presented column generation approach for optimization of so called step-and-shoot radiotherapy treatment plans. The approach and variants of it have been reported to be efficient in practice, finding near-optimal solutions by generating only a low number of columns. The impact of different restrictions … Read more

    Combining segment generation with direct step-and-shoot optimization in intensity-modulated radiation therapy

  • Fredrik Carlsson
    • Categories Biomedical Applications, Constrained Nonlinear Optimization Tags , , ,

    A method for generating a sequence of intensity-modulated radiation therapy step-and-shoot plans with increasing number of segments is presented. The objectives are to generate high-quality plans with few, large and regular segments, and to make the planning process more intuitive. The proposed method combines segment generation with direct step-and-shoot optimization, where leaf positions and segment … Read more