ON THE FULLY DISCRETIZED MODEL FOR THE INVERSE PROBLEM OF RADIATION THERAPY TREATMENT PLANNING.

Radiation therapy treatment planning (RTTP) involves a forward problem and an inverse problem. Since there exists no analytic closed-form mathematical formulation of the forward operator, the inverse problem actually calls for computerized inversion of data. This is achieved in this study by construction of a fully discretized model leading to a system of linear inequalities. The inequalities are solved either by a row-action method or a block-Cimmino algorithm which allows the assignment of weights within each block of inequalities. Consequences and limitations of this approach are discussed.