Robot-assisted ultrasound-guided biopsy on MR-detected breast lesions

One out of eight women will get breast cancer during their lifetime. A biopsy, a procedure in which a tissue sample is acquired from the lesion, is required to confirm the diagnosis. A biopsy is preferably executed under ultrasound (US) guidance because it is simple, fast, and cheap, gives real-time image feedback and causes little patient discomfort. However, Magnetic Resonance (MR)-detected lesions may be barely or not visible on US and difficult to find due to deformations of the breast. This paper presents a robotic setup and workflow that assists the radiologist in targeting MR-detected breast lesions under US guidance, taking into account deformations and giving the radiologist robotic accuracy. The setup consists of a seven degree-of-freedom robotic serial manipulator equipped with an end-effector carrying a US transducer and a three degree-of-freedom actuated needle guide. During probe positioning, the US probe is positioned on the patient's skin while the system tracks skin contact and tissue deformation. During the intervention phase, the radiologist inserts the needle through the actuated guide. During insertion, the tissue deformation is tracked and the needle path is adjusted accordingly. The workflow is demonstrated on a breast phantom. It is shown that lesions with a radius down to 2.9 mm can be targeted. While MRI is becoming more important in breast cancer detection, the presented robot-assisted approach helps the radiologist to effectively and accurately confirm the diagnosis utilizing the preferred US-guided method.