“…Dai et al [ 12 ] divides the brachytherapy robotic system into four categories with respect to the imaging method used: ultrasound (US)-guided systems [ 13 , 14 , 15 , 16 ], MRI-guided systems [ 17 , 18 , 19 ], CT-guided systems [ 20 , 21 , 22 , 23 ] and additional image-guided systems [ 24 , 25 , 26 , 27 ]. Lin et al [ 28 ] proposes a multi-DoF (Degrees of Freedom) robotic system for liver brachytherapy.…”