Optimization techniques play a vital role in cancer treatment through irradiation. Complex system such as IMRT equipment involves beam angle optimization for fixed rotation of gantry to deliver radiation beams to the tumor target avoiding the healthy tissues and vital organs. Fluence- map optimization enables non-uniform distribution of radiation aided by Multi-leaf Collimator (MLC) of IMRT to shrink the target with high intensity, maintaining low intensity for organ at risk. Therefore beam shaping with respect to the geometry of the tumor region satisfying the mechanical constraints of MLC is addressed in this paper. The MLC can be represented in Matrix to synchronize with the tumor geometry. This matrix is converted to weighted directed graph to which Bellman-Ford algorithm is applied to find the optimal aperture to irradiate the large area of tumor region. © 2017, Indian Journal of Public Health Research and Development. All rights reserved.