According to the World Health Organization, Breast Cancer is the most common type of cancer among women and the deadliest one in Mexico. The Mexican Institute of Social Security (Instituto Mexicano del Seguro Social) proposes radiotherapy (RT) as the main treatment or coadjuvant treatment due to its effectiveness in reducing relapse of cancer with minimal side effects. Additionally, breast cancer treatments with radiotherapy over chemotherapy are predominant in the United States regardless cancer’s stage. The present work proposes the design of a basic electron Linear Accelerator (eLINAC) aimed at treating breast cancer.