The purpose of this study was to develop a methodology for the construction of models of interest to improve the choice of areas to radiate in the use of brachytherapy (BT). This work aims to propose a principal component model which is constructed from the data of different patients including medical images of arbitrary resolution and modality supplemented with delineations of radiation target (HR-CTV) structure, reconstructed applicator structure and eventual organs at risk (OAR) structures. The principal component model provides information about the spatial variability described by only a few parameters. It can be used to predict specific extreme situations in the scope of sufficient applicator radiation dose coverage in the target structure as well as radiation dose avoidance in OAR structures.