We demonstrate the potential of state-of-the-art high-average power THz-TDS for THz imaging applications, by performing lensless imaging of a 3D-printed mixed polymer probe using a migration algorithm. Images obtained with our 10-mW average power THz-TDS show a clear enhancement of dynamic range, which results in a significantly improved image contrast compared to the same measurements performed using a state-of-the art commercial TDS system with less than 200-Ã,µW of average power. Our result is an important first step towards reflection-mode imaging of dielectric objects with an internal structure, potentially at long distances.