In this paper, we have investigated the impact of the personalized physiological lung pressure/volume relationship (compliance) and its comparison with a linear pressure/volume function for lung tumor motion estimation. Using biomechanical model, this comparison has been carried out on five selected patients from DIR-Lab data set, with small and large breathing amplitudes (P1=10.9 mm, P4=18.1 mm, P6=27.2 mm, P9=15.5 mm and P10=26.06mm). We have compared the finite element simulation results with ground truth (4D CT images) at each intermediate respiratory state (10 phases). The results show that the use of personalized lung compliance provides more accuracy and gives better results when comparing with linear compliance. This could help radiation oncologists and medical physicians to better adjust the radiation treatment and to reduce the safety margins used to prevent normal tissues damages for radiation therapy.