QUALITY CONTROL OF LINEAR ACCELERATOR OF NOUAKCHOTT.

At the National Center of Oncology of Nouakchott, the external radiotherapy treatments are performed using a linear accelerator particles of two energies 6 MV and 18 MV. This particle accelerator is originally set to deliver a dose under reference conditions. It is essential that the measured data on the particle accelerator be consistent with the data calculated by the Treatment Planning System (TPS). The purpose of this work is to perform a general quality control of this accelerator, and to compare the results obtained by two ionization chambers (PTW 0.125 cm3 and PTW 0.6 cm 3). This control is based on the measure of percentage depth dose (PDD) and beam profiles (BP) and the comparison of these measurements with the same results performed by TPS calculations for different field sizes. In general, the results measured are in good concordance with the results calculated by TPS. Regarding comparison between the two ionizations chambers, we notice that the light difference between the percentage depth doses measured by the two ionizations is related to the energy and to the field size of the incident photons beam.