Based on the use of CAT images of the patient in the same position in which the treatment is performed. The images obtained are reconstructed in three dimensions (3D). Powerful computers simulate the treatment and suggest the most suitable combination of beams for each location to ensure compliance with the doses established by the physicians for suitable treatment of the patient. These computers, together with the series of associated programs, are called simulators and execute complex algorithms to calculate the dosimetric distribution which is displayed in three-dimensions on the computer screens. The result is a Dosimetric Report which, among others aspects, shows the variables for placement of the treatment units as well as the dose in the different risk organs and the Monitor Units (MU) delivered by the apparatus during the treatment.