Quantitative T2 mapping is an important tool towards standardization of MRI in clinics and research, whose implementation in 7T MRI will gain SNR and resolution. In this work, we demonstrate a phase-based method with fast 3D spoiled GRE acquisition to estimate T2 and B1 maps in 7T brain imaging. We introduce a new approach employing a dual steady-state with interleaving flip angles - denoted as TWISTARE. This approach is suited to address the RF field inhomogeneity in 7T and can shorten the total scan duration. The new approach was examined using a 3D head-shaped phantom and in human imaging.