An MRI Coil-Mounted Multi-Probe Robotic Positioner for Cryoablation

Abstract

Cryoablation is a percutaneous procedure for treating solid tumors using needle-like instruments. This paper presents an interventional guidance device for faster and more accurate alignment and insertion of multiple probes during cryoablation performed in closed bore magnetic resonance (MR) imaging systems. The device is compact and is intended to be mounted onto a Siemens 110 mm MR loop coil. A cable-driven two-degrees-of-freedom spherical mechanism mimics the wrist motion as it orients the intervention probes about a remote center of motion located 15 mm above the skin. A carriage interfaces with the probes via a thumbscrew-fastened latch to passively release the probes from their tracks, enabling them to be inserted sequentially and freeing them to move with respiration. Small actuator modules containing piezoelectric encoder-based motors are designed to be snap-fit into the device for ease of replacement and sterilization. The robot MRI compatibility was validated with standard cryoablation imaging sequences in 3T MR environment, yielding a maximum of 4% signal to noise ratio during actuator motion. Bench-level device characterization demonstrated a maximum error of 0.78° in the carriage movement. Needle-tip placement experiments for multiple targets in gelatin were performed using our image-guided navigation software, measuring an average targeting error of 2.0 mm.

An overview of systems for CT‐ and MRI‐guided percutaneous needle placement in the thorax and abdomen

“…(d) Robopsy, adapted from (66). (e) Song et al ., adapted from (69), copyright © 2013 by IEEE, reproduced by permission. (f) CT‐Bot, adapted from (72).…”

“…Yet another 2‐DOF manipulator fitted onto an MRI loop coil was developed by Song et al . (69). It contains a needle guide which can be oriented about two axes through manual rotation of two serially stacked rings.…”

“…Targeting of a lesion during an in vivo porcine trial was successfully accomplished using a total of four image scans (67). Wu et al subsequently developed a spherical needle manipulator mounted on an MRI loop coil (68). Piezo stepper motors automate its two DOFs and registration with the imager is performed through six spherical fiducials.…”

Sensors, Actuators, and Robots for Mri-Guided Surgery and Interventions

“…Wu et al 73 described the design of a 2-DOF (pitch and yaw) guidance device for faster and more accurate alignment and insertion of multiple probes during cryoablation and other percutaneous interventions performed in closed-bore MRI. The 3D printed prototype shown in Fig.…”

Body-mounted robotic assistant for MRI-guided low back pain injection

“…A coil-mounted manual device with double ring remote-center-of-motion (RCM) mechanism was designed by Song et al to provide needle insertion angle guidance at the skin entry for MRI-guided liver interventions [28]. Wu et al developed a coil-mounted multi-probe robotic positioner for MRI-guided cryoablation using a cable-driven 2-DOF spherical mechanism and a carriage interface with the probe [29]. These robots have shown promise; however, most are proof-of-concept prototypes, only a few have made it to clinical trials, and none are ongoing to the best of our knowledge.…”