Needle steering scheme within limited DOFs for MR-guided breast needle intervention robot

Abstract

The MR-guided needle-based procedure is commonly performed for breast diagnosis and treatment. Accurate needle tip placement is important for the success of the procedure, because misplacement of the needle tip can lead to unsuccessful treatment and misdiagnosis. In addition, developing a needle steering robotic system with high precision and dexterity is required to avoid important organs, minimizing patients trauma. However, due to the strong magnetic field and relatively small MRI bore size, developing a high degrees of freedom (DOFs) robotic system is challenging. This work proposes a needle steering scheme that can be effectively utilized in an MR-guided breast needle intervention robot under limited space of MRI bore with minimizing system size increase. To overcome the space limitation and avoid critical structures in front of the lesion, a pivot is used to change the needle insertion direction. We devise the needle pivoting breast plate to increase needle tips DOFs and an estimation model of the needle deflection with a pivoted super-elastic flexible needle made of Nitinol. This computational model is based on large deflection beam theory and is employed for robot control. Open-loop needle targeting experiments under infrared tracking cameras are performed to verify the proposed scheme. The average targeting error and the standard deviation is 4.42 ± 2.58 mm.