Simon P. DiMaio

Needle insertion modeling and simulation

A methodology for estimating the force distribution that occurs along a needle shaft during insertion is described. An experimental system for measuring planar tissue phantom deformation during needle insertions has been developed and is presented. A two-dimensional linear elastostatic material model, discretised using the finite element method, is used to derive contact force information that is not directly measurable. This approach provides a method for quantifying the needle forces and soft tissue deformations that occur during general needle trajectories in multiple dimensions. The needle force distribution is used for graphical and haptic real-time simulations of needle insertion. Since the force displacement relationship is required only along the needle, a condensation technique is shown to achieve very fast interactive simulations. Stiffness matrix changes corresponding to changes in boundary conditions and material coordinate frames are performed using low-rank matrix updates.

Image-guided control of a robot for medical ultrasound

A robot-assisted system for medical diagnostic ultrasound has been developed by the authors. The paper presents the visual servo controller used in this system. While the ultrasound transducer is positioned by a robot, the operator, the robot controller, and an ultrasound image processor have shared control over its motion. Ultrasound image features that can be selected by the operator are recognized and tracked by a variety of techniques. Based on feature tracking, ultrasound image servoing in three axes has been incorporated in the interface and can be enabled to automatically compensate, through robot motions, unwanted motions in the plane of the ultrasound beam. The accuracy of the system is illustrated through a 3-D reconstruction of an ultrasound phantom. An Internet-based robot-assisted teleultrasound system has also been demonstrated.

Interactive simulation of needle insertion models

A novel interactive virtual needle insertion simulation is presented. The simulation models are based on measured planar tissue deformations and needle insertion forces. Since the force-displacement relationship is only of interest along the needle shaft, a condensation technique is shown to reduce the computational complexity of linear simulation models significantly. As the needle penetrates or is withdrawn from the tissue model, the boundary conditions that determine the tissue and needle motion change. Boundary condition and local material coordinate changes are facilitated by fast low-rank matrix updates. A large-strain elastic needle model is coupled to the tissue models to account for needle deflection and bending during simulated insertion. A haptic environment, based on these novel interactive simulation techniques, allows users to manipulate a three-degree-of-freedom virtual needle as it penetrates virtual tissue models, while experiencing steering torques and lateral needle forces through a planar haptic interface.

Needle steering and motion planning in soft tissues

In this work, needle insertion into deformable tissue is formulated as a trajectory planning and control problem. A new concept of needle steering has been developed and a needle manipulation Jacobian defined using numerical needle insertion models that include needle deflection and soft tissue deformation. This concept is used in conjunction with a potential-field-based path planning technique to demonstrate needle tip placement and obstacle avoidance. Results from open loop insertion experiments are provided.

Needle insertion modelling and simulation

A methodology for estimating the force distribution that occurs along a needle shaft during insertion is described. To validate the approach, an experimental system for measuring planar tissue deformation during needle insertions has been developed and is presented. The planar motion of a soft tissue phantom is measured during needle penetration and used in conjunction with a two dimensional linear elastostatic material model, discretised using the finite element method, to derive contact force information that is not directly measurable. This approach provides a method for quantifying the needle forces and soft tissue deformations that occur during general needle trajectories in multiple dimensions. A simulation algorithm that is based upon these results is also described.

Needle Steering and Model-Based Trajectory Planning

Needle insertion for percutaneous therapies is formulated as a trajectory planning and control problem. A new concept of needle steering is developed and a Needle Manipulation Jacobian is defined using numerical needle insertion models that include needle deflection and soft tissue deformation. This concept is used in conjunction with a potential-field-based path planning technique to demonstrate needle tip placement and obstacle avoidance. Results from open loop insertion experiments are provided.

Robot-assisted needle placement in open MRI: System architecture, integration and validation

In prostate cancer treatment, there is a move toward targeted interventions for biopsy and therapy, which has precipitated the need for precise image-guided methods for needle placement. This paper describes an integrated system for planning and performing percutaneous procedures with robotic assistance under MRI guidance. A graphical planning interface allows the physician to specify the set of desired needle trajectories, based on anatomical structures and lesions observed in the patients registered pre-operative and pre-procedural MR images, immediately prior to the intervention in an open-bore MRI scanner. All image-space coordinates are automatically computed, and are used to position a needle guide by means of an MRI-compatible robotic manipulator, thus avoiding the limitations of the traditional fixed needle template. Automatic alignment of real-time intra-operative images aids visualization of the needle as it is manually inserted through the guide. Results from in-scanner phantom experiments are provided.

Transperineal prostate biopsy under magnetic resonance image guidance: A needle placement accuracy study

To quantify needle placement accuracy of magnetic resonance image (MRI)‐guided core needle biopsy of the prostate.

Haptic interface control-design issues and experiments with a planar device

Describes the haptic rendering of a virtual environment by drawing upon concepts developed in the area of teleoperation. A four-channel teleoperation architecture is shown to be an effective means of coordinating the control of a 3-DOF haptic interface with the simulation of a virtual dynamic environment.

Simulated interactive needle insertion

A novel interactive virtual needle insertion simulation is presented. The simulation models are based on planar tissue deformations and forces measured during needle insertion experiments. Users are able to control a three degree-of-freedom virtual needle as it penetrates a linear elastostatic tissue model, while experiencing steering torques and lateral needle forces through a planar haptic interface. Efficient numerical computation techniques permit fast simulation of relatively complex two-dimensional and three-dimensional environments at haptic control rates.