Percutaneous needle insertions are commonly performed for diagnostic and therapeutic purposes as an effective alternative to more invasive surgical procedures. However, the outcome of needle-based approaches relies heavily on the accuracy of needle placement, which remains a challenge even with robot assistance and medical imaging guidance due to needle deflection caused by contact with soft tissues. In this paper, we present a novel mechanics-based 2D bevel-tip needle model that can account for the effect of nonlinear strain-dependent behavior of biological soft tissues under compression. Real-time finite element simulation allows multiple control inputs along the length of the needle with full three-degree-of-freedom (DOF) planar needle motions. Cross-validation studies using custom-designed multi-layer tissue phantoms as well as heterogeneous chicken breast tissues result in less than 1mm in-plane errors for insertions reaching depths of up to 61 mm, demonstrating the validity and generalizability of the proposed method.

Needle-guiding templates are used for a variety of minimally invasive medical interventions. While physically supporting needle placement with a grid of holes, they lack integrated information where needles need to be inserted. Physicians must manually determine the correct holes based on the output of planning software - a workflow that is error-prone and lengthy. We address these issues by embedding a display into the template using electroluminescence (EL) screen printing. The EL display is connected to planning software and illuminates the correct hole. In an empirical evaluation with physicians and researchers from the medical domain, we compare the illuminated against the conventional template as used in magnetic resonance imaging (MRI) guided prostate biopsies. Our results show that the EL display significantly improves task completion time by 51%, task load by 47% and usability by 30%.

This paper undertakes the modular design and development of a minimally invasive surgical manipulator for MRI-guided transperineal prostate interventions. Severe constraints for the MRI-compatibility to hold the minimum artifact on the image quality and dimensions restraint of the bore scanner shadow the design procedure. Regarding the constructive design, the manipulator kinematics has been optimized and the effective analytical needle workspace is developed and followed by proposing the workflow for the manual needle insertion. A study of the finite element analysis is established and utilized to improve the mechanism weaknesses under some inevitable external forces to ensure the minimum structure deformation. The procedure for attaching a sterile plastic drape on the robot manipulator is discussed. The introduced robotic manipulator herein is aimed for the clinically prostate biopsy and brachytherapy applications.

MRI-guided percutaneous liver interventions have been investigated by researchers as an alternative to CT-guided procedures as it is non-invasive and provides greater soft tissue details. In practice, however, repeated needle insertion is still required to reach desired positions on trial-and-error basis. To minimize the needle attempt and procedural time, we designed a robotic needle guidance device that provides needle insertion angle guidance at skin entry using two rotational joints structured for remote-center-of-motion manipulation. To evaluate the mechanism and clinical feasibility, we fabricated a proof-of-concept prototype that can be manually operated. As preliminary design evaluation, we conducted a retrospective clinical study of 13 MRI-guided abdominal biopsies to determine if the proposed mechanism and device can provide necessary needle insertion angles in MRI-guided liver biopsy procedures. The number of needle insertion attempts per biopsy was also measured. To confirm the kinematic design of the double ring remote-center-of-motion mechanism and to identify any procedural difficulties, we conducted a phantom targeting experiment. The retrospective clinical study showed that the 80 degree insertion angle coverage of the device is sufficient for clinical cases, and an average of five needle insertion attempts per biopsy in conventional MRI-guided biopsy can be reduced by the proposed device. A phantom targeting experiment confirmed that the unique kinematic design was successfully implementation in the targeting.

Magnetic Resonance Imaging (MRI) has potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. The strong magnetic field prevents the use of conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intra-prostatic needle placement inside closed high-field MRI scanners. The robot performs needle insertion under real-time 3T MR image guidance; workspace requirements, MR compatibility, and workflow have been evaluated on phantoms. The paper explains the robot mechanism and controller design and presents results of preliminary evaluation of the system.

Prostate cancer biopsy is a routine medical procedure, yet conventional techniques suffer from low sensitivity attributed to suboptimal image guidance and needle placement. Targeting small lesions and foci (5 mm in diameter) is particularly prone to errors. We developed an integrated system to perform robot-assisted transperineal needle insertions into the prostate, under Magnetic Resonance Imaging (MRI) guidance. The system provides arbitrary needle trajectories and allows for simultaneous surveillance and correction of the needle path, based on intra-operative MRI. System functionality and data transfer and processing tests were conducted. Five lesions embedded in the gel phantom were targeted successfully, while communication delays (due to higher image frame rates) had no adverse affect on robot-software communication. The system was sufficiently resistant to high network loads and performed with an acceptable transfer rate.

Searching for optimal needle insertion path by intraoperative magnetic resonance imaging (MRI) is complex and time-consuming task in MR-guided microwave thermotherapy of liver tumor. This paper reports the semi-active needle-guiding robot for MR-guided therapy by which a surgeon can freely selects needle insertion path while maintaining the remote center of motion at the pre-defined tumor site. The robot consists of three-degree-of-freedom active XYZ base stage with ultrasonic motors and passive needle holder with unconstrained two-degree-of-freedom rotation measured by optical fiber sensor with aluminum die cast. Once the target point on the tumor is defined in volumetric MR images, the base stage keeps the remote-center-of-motion at the target point, while physician can interactively selects the orientation of the needle path with continuous single slice MR imaging. Experiments to test the accuracy of remote-center-of-motion indicated that the robot can keep the needle tip with an average error of 0.7 ∼ 0.3 mm in the compatibility test showed the robot can be safely used in MR axial plane, and 1.0-0.4 mm in the sagittal plane. Unlike related studies published elsewhere where the MR compatible robot autonomously brings the tools to predefined location, the proposed approach is fit to use in microwave thermotherapy of liver cancer.