A numerical simulation has been performed to investigate the precision of a Ti measurement of a Tokamak plasma, via collective Thomson scattering at 385 mu m. The study is based on a parameter and data set referring to an experiment that has been carried out at the TCA Tokamak, using a pulsed D2O laser and a heterodyne receiver system. Apart from limitations due to the signal-to-noise ratio of the detection system, the authors investigate the influence of uncertainties in various plasma parameters required for the Ti evaluation from a scattered spectrum. In the experiment, typical relative errors of +or-25% have already been obtained, but careful optimization of the system, taking into account the results of the study, and further technical improvements should allow a reduction of this limit to about +or-10% for the plasma conditions considered.