Taking into account positioning errors during a three dimensional conformal radiotherapy for a non at small cells lung cancer

Purpose: According to the report 62 of the International commission on radiation units and measurements (ICRU), the estimated target volume adds to the internal margin that takes into account the movements of the target volume during breathing, an external margin that takes into account the uncertainties of beams positioning. Our objective was to describe a method of estimated target volume calculation taking into account the technique of irradiation chosen in the service. (N.C.)