2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/132498A dynamical system model for tumor -- immune system interaction together with a method to mimic radiation therapy are proposed. A large population of virtual patients is simulated following an ideal radiation treatment. A characteristic parameter, the Immune System -- Tumor Efficiency Rate (ISTER), is introduced. ISTER dependence of treatment success and other features is studied. Statistical results allow us to give a patient classification scheme. Radiotherapy treatment biological effective dose (BED) is thus optimized based on the patient physical condition, following the ALARA (As Low As Reasonably Achievable) criterion.10 pages, 3 figuresPopulations and EvolutionImmune System -- Tumor Efficiency Rate as a new Oncological Index for Radiotherapy Treatment Optimizationtext