Estimation of Tissue Movement in Needle Insertion Tasks Using an Active Needle

Needle insertion has been used as a minimally invasive technique in many diagnostic or therapeutic procedures such as prostate biopsy or brachytherapy. While the success of these procedures relies on accurate positioning of the needle tip at target positions, the intraoperative movement of the tissue (and consequently the target) has caused physicians some difficulties in acquiring the target. This paper presents a method to estimate tissue movement during a needle insertion task within tissue. The movement of the tissue is valuable information for guidance, navigation, and control of the needle inside tissue towards the target. A needle insertion task was performed using an active needle bending. Ultrasound images were captured at four needle insertion stages of initial needle insertion, bending, unbending, and needle retraction. Ultrasound images were then analyzed to estimate the tissue movement at each stage. The study showed that needle retraction, insertion, bending, and unbending stages correspond to largest to lowest tissue movement, respectively.