A Motion Tracking and Sensor Fusion Module for Medical Simulation.

Here we introduce a motion tracking or navigation module for medical simulation systems. Our main contribution is a sensor fusion method for proximity or distance sensors integrated with inertial measurement unit (IMU). Since IMU rotation tracking has been widely studied, we focus on the position or trajectory tracking of the instrument moving freely within a given boundary.

A New Design for Airway Management Training with Mixed Reality and High Fidelity Modeling.

Restoring airway function is a vital task in many medical scenarios. Although various simulation tools have been available for learning such skills, recent research indicated that fidelity in simulating airway management deserves further improvements. In this study, we designed and implemented a new prototype for practicing relevant tasks including laryngoscopy, intubation and cricothyrotomy.

Virtual trainer for intra-detrusor injection of botulinum toxin to treat urinary incontinence.

Here we introduce a new virtual reality (VR) based simulation system for training the urological procedure of intra-detrusor botulinum toxin (Botox®) injections into the bladder. 6 cases with different bladder anatomy and 3 subtasks are included in the curriculum; this design is guided by several expert urologists according to clinical needs and experience. These virtual bladder models can be deformed by a cystoscope model or penetrated by a needle model.

Sparse Representation of Deformable 3D Organs with Spherical Harmonics and Structured Dictionary.

This paper proposed a novel algorithm to sparsely represent a deformable surface (SRDS) with low dimensionality based on spherical harmonic decomposition (SHD) and orthogonal subspace pursuit (OSP). The key idea in SRDS method is to identify the subspaces from a training data set in the transformed spherical harmonic domain and then cluster each deformation into the best-fit subspace for fast and accurate representation. This algorithm is also generalized into applications of organs with both interior and exterior surfaces.

Phenomenological model of laser-tissue interaction with application to Benign Prostatic Hyperplasia (BPH) simulation.

Laser-tissue interaction is a multi-physics phenomenon not yet mathematically describable and computationally predictable. It is a challenge to model the laser-tissue interaction for real time laser Benign Prostatic Hyperplasia (BPH) simulation which requires the laser-tissue interaction model to be computationally efficient and accurate. Under the consideration and enforcement of the thermodynamic first law and treating the laser-tissue interaction as a gray-box, utilizing the sensitivity analysis of some key parameters that will affect the laser intensity on the tissue surface with respect to the tissue vaporization rate, a phenomenological model of laser-tissue interaction is developed.

Laser surgery simulation platform: toward full-procedure training and rehearsal for benign prostatic hyperplasia (BPH) therapy.

Recently, photo-selective vaporization of the prostate (PVP) has been a popular alternative to the standard electrocautery - transurethral resection of prostate (TURP). Here we introduce a new training system for practicing the laser therapy by using a virtual reality (VR) simulator. To interactively and realistically simulate PVP on a virtual organ with an order of a quarter million elements, a few novel and practical solutions have been applied to handle the challenges in modeling tissue ablation, contact/collision and deformation; endoscopic instruments tracking, haptic rendering and a web/database curriculum management module are integrated into the system.

The Minnesota pelvic trainer: a hybrid VR/physical pelvis for providing virtual mentorship.

Obtaining accurate understanding of three dimensional structures and their relationships is important in learning human anatomy. To leverage the learning advantages of using both physical and virtual models, we built a hybrid platform consisting of virtual and mannequin pelvis, motion tracking interface, anatomy and pathology knowledge base. The virtual mentorship concept is to allow learners to conveniently manipulate and explore the virtual pelvic structures through the mannequin model and VR interface, and practice on anatomy identification tasks and pathology quizzes more intuitively and interactively than in a traditional self-study classroom, and to reduce the demands of access to dissection lab or wet lab.

Volumetric modeling in laser BPH therapy simulation.

In this paper, we introduce a novel application of volume modeling techniques on laser Benign Prostatic Hyperplasia (BPH) therapy simulation. The core technique in our system is an algorithm for simulating the tissue vaporization process by laser heating. Different from classical volume CSG operations, our technique takes experimental data as the guidance to determine the vaporization amount so that only a specified amount of tissue is vaporized in each time.

A discrete mechanics framework for real time virtual surgical simulations with application to virtual laparoscopic nephrectomy.

The inability to render realistic soft-tissue behavior in real time has remained a barrier to face and content aspects of validity for many virtual reality surgical training systems. Biophysically based models are not only suitable for training purposes but also for patient-specific clinical applications, physiological modeling and surgical planning. When considering the existing approaches for modeling soft tissue for virtual reality surgical simulation, the computer graphics-based approach lacks predictive capability; the mass-spring model (MSM) based approach lacks biophysically realistic soft-tissue dynamic behavior; and the finite element method (FEM) approaches fail to meet the real-time requirement.

Task deconstruction facilitates acquisition of transurethral resection of prostate skills on a virtual reality trainer.

Aim: To determine whether task deconstruction is superior to full-task training for the acquisition of transurethral resection skills on a transurethral resection of prostate (TURP) virtual reality trainer previously validated for use in residency training.

Methods: Eighteen first- and second-year medical students with no previous exposure to TURP in the operating room participated in the study. The subjects were randomized to two treatment arms: full-task TURP training versus task deconstruction training.

Realistic soft tissue deformation strategies for real time surgery simulation.

A volume-preserving deformation method (VPDM) is developed in complement with the mass-spring method (MSM) to improve the deformation quality of the MSM to model soft tissue in surgical simulation. This method can also be implemented as a stand-alone model. The proposed VPDM satisfies the Newton's laws of motion by obtaining the resultant vectors form an equilibrium condition.

A novel laparoscopic mesh placement part task trainer.

Background: We present a surgical simulator, developed for the training of a laparoscopic surgery and in particular for mesh placement during an inguinal herniorrhaphy.

Methods: Major technical issues related to virtual surgery training systems include virtual patient modelling, collision detection and collision response, haptic and graphic rendering, 3-D motion tracking and some special effects, such as bleeding, cauterizing and so on. Among these problems, real-time deformation modelling and collision detection are the most challenging research topics.

Physically accurate mesh simulation in a laparoscopic hernia surgery simulator.

In this paper we use the 2D angular spring based mass-spring-damper (AMSD) model to simulate the plastic mesh in a laparoscopic hernia surgery simulator. We propose a physically based method to systematically derive the optimal parameters of the 2D AMSD model. While the traditional 2D MSD model lacks resistance against bending, the 2D AMSD model with optimized parameters can provide correct bending resistance as well as stretching resistance.

Selective tessellation algorithm for modeling interactions between surgical instruments and tissues.

We present a selective spatial tessellation algorithm that is specifically optimized for instrument-to-tissue and instrument-to-instrument collision detection cases, which are the essential part of interaction modeling in surgery simulation with haptic feedback. Virtual surgeries demand haptic rate collision solutions only when instruments are involved in collisions. Other collision cases can be processed at slower rates.

Haptic herniorrhaphy simulation with robust and fast collision detection algorithm.

Collision detection and soft tissue deformation are two major research challenges in real time VR based simulation, especially when haptic feedback is required. We have developed a real time collision detection algorithm for a prototype laparoscopic surgery trainer. However, this algorithm makes no assumptions about its applications and thus can be a generic solution to complicated collision detection problems.