“…An important issue in inverse planning is how to formalize the clinical goals to objectively evaluate the figures of merit of different IMRT plans. Despite intense research effort in modelling the clinical decision-making strategies (Amols and Ling 2002, Deasy et al 2002, Earl et al 2003, Hou et al 2003, Lahanas et al 2003, Langer et al 1993, Lee et al 2000, Llacer et al 2001, Mohan et al 1994, Webb 2004, Xing et al 1999, Yan et al 2003, the appropriate form of the objective function remains illusive. Presently, two types of objective functions are widely used: dose or dose-volume histogram (DVH)-based (physical objective functions) (Chen et al 2002, Cho et al 1998, Holmes et al 1995, Hristov et al 2002, Michalski et al 2004, Starkschall et al 2001, Shepard et al 2002, Xing et al 1998 and dose-response-based objective functions (biological objective functions) (Brahme 2001, Kallman et al 1992, Miften et al 2004, Mohan et al 1992, Wang et al 1995, Webb and Nahum 1993.…”