[en] Objective: to determine the influence of acquisition parameters and reconstruction of dose and the image quality in multi detectors T.D.M. for protocols optimization. conclusion: the optimization allowed to reduce in average, the C.T.D.I.vol (weighted computed tomography dose index) of 20% via the pitch increase, the use of a collimation as broad as possible and/or the use of a retrospectively construction (factor zoom and/or increased size of matrix) without degrading the performances of noise and:or resolution of more than 10%. (N.C.)