Importance of daily verification of radiation beams in a linear accelerator for clinical use as part of a program for quality control

Prescriptions in radiotherapy has her basis in the commitment between the possibility of tumoral control and the probability of induced complications variation of 5% in deposited dose will produce a change of 10% either in tumoral control or in produced complications by treatment. For this reason the 'International Commission on Radiation Units and Measurements' (ICRU) has recommended a global precision of ± 5% in what absorbed doses concern. The electronic fluctuation inherent to running of every linear accelerator, made extremely important, provided the required deposition of doses, the verification in a daily basis, the constancy of absorbed doses per monitored unit in the central axis, with respect to the last complete calibration and the symmetry and flattening of radiation beam, at least a time a weak, the above to fulfill satisfactorily with the international schemes of quality control in accelerators of clinical use. In this work how this practice is carry out in our institution is shown. (Author)