The Electronic Portal Imaging Device (EPID) is a valuable imaging tool for verifying radiotherapy treatments. The treatment cannot be carried out without being sure of the patient's position and the associated deviations, so it is essential that its reliability must be as high as possible. In this work, it was explored real failure data in order to determine the reliability behavior of such devices and identify in which life stage the device is operating. With the analysis developed it was possible to identify the probability of failure of the EPID related to the number of treatments performed and based on that to have a sustainable decision- making process regarding the operation and maintenance of the EPID.