Smart Image-guided Needle Insertion For Tissue Biopsy

Abstract

Motivation: Various needle-based procedures have been practiced in cancer interventions in recent years. Needle insertion as one of the most popular techniques could facilitate minimally invasive surgeries such as biopsy and brachytherapy to extract or kill the cancer locally, respectively. Needle insertion process may become more challenging and complicated due to several difficulties in needle navigation and targeting accuracy. To resolve this issue and for effective control during the needle insertion tasks, active flexible needles are proposed in this work to replace passive rigid needles in medical practice. Utilizing active needles in minimally invasive procedures enhances the needles’ maneuverability under actuation forces, and thereby facilitates needle steering within the biological tissue. This work presents three novel active needle designs to enable needle deflection in three directions. Needle steering is visualized and tracked via an imaging system with a 2D transducer connected to an ultrasound machine positioned on the tissue surface. Needle insertion and ultrasound probe displacement are automatically operated. Methods: The design of the three steerable active needles and the fabrication process are discussed. The active needles are tested in air and in a tissue-mimicking phantom. A motorized system is developed to control the needle insertion, via axial movement and rotation of the needle, and planar movement of the ultrasound transducer. An ultrasound image-guided procedure to visualize and track the needle tip inside a tissue-mimicking phantom in order to reaching target location is fully described. The phantom preparation based on a low-cost and high-quality experimental method is explained as well. Result: Three active needles were designed, fabricated, and tested in air and tissue-mimicking phantom to realize angular deflection of needle tip in three-dimensional directions. All needles were modeled in SOLIDWORKS. A setup was developed to pull the wires with three programmable stepper motors. To show the needle deflection in air, two cameras were positioned to capture and record top and side views for angular deflection. Tracking was also done by an ultrasound probe when the needle is inserted in tissue. Furthermore, an insertion setup was developed to simultaneously control needle insertion and rotation (if needed). The setup includes a motorized stage attached to the ultrasound probe for planar movement to allow needle tip tracking and guidance inside the tissue. The probe was placed perpendicular to the tissue surface and was attached to a Doppler ultrasound machine. Captured images were transferred to a computer for analysis. Experimental observations validate a reasonable amount of needle angular deflection equal to 11.49° and 11.06° in air and tissue, respectively. Conclusion: This experimental study demonstrated the capability of three novel active flexible needles to steer inside the tissue via control and actuation. Needle navigation was improved via enhanced flexibility of the active needles and their active 3D deflection. Needle tracking was also improved via utilization of an ultrasound imaging device. The modulus of the needle insertion system developed in this work is expected to assist in precise needle placement at target positions via a curvilinear approach, while avoiding anatomical obstacles. This approach is also advantageous in minimally invasive procedures such as lumpectomy, biopsy and brachytherapy.