Optimal IMRT treatment planning with prescribed trapezoidal fuzzy target dose

Clinical observations in intensity-modulated radiation therapy (IMRT) planning have suggested that a prescribed target dose in the form of a trapezoidal fuzzy number is more aligned with oncologist goals. Our investigations have revealed a lack of prior work in this area. In this article, we propose a fluence map optimization for the IMRT procedure based on trapezoidal fuzzy numbers. First, the problem is formulated as a fuzzy optimization problem due to the properties of a trapezoidal fuzzy dose vector. Then, it is converted to a nonfuzzy optimization problem. After that, the optimal solution is reached based on the gradient method and using the projection operation. We utilize the computational environment for radiotherapy research (CERR) planning system to generate patient information and dose data for treatment planning. Numerical results for two typical clinical examples, prostate and head-and-neck cancers, in the format of dose–volume histograms, are also represented, interpreted, and compared with two other methods. These results show that the treatment planning we provided, based on the trapezoidal fuzzy target dose, is in better agreement with the goals prescribed by oncologists compared to the triangular fuzzy state (our previous study) and the method used in CERR.