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Guidewire insertion is an imperative task of minimally invasive medical procedures. During the procedure, surgeons need to steer long flexible thin wires through patient's blood vessels to reach a clinical target. In this paper, we present a novel approach to model haptics of guidewire insertion process for training simulation. The algorithm also allows for the analysis of the insertion process through subtle physical behaviours of guidewires via force feedbacks. The method includes a 6-DoF dynamic coupling between a rigid body, i.e. the virtual tool and the deformation of the wire simulated as an elastic rod. Instead of using the frictional contact force or the acceleration of the guidewire tip for haptic feedbacks, we compute constrained forces by directly connecting the virtual tool to the end of the guidewire. Therefore, the coupling scheme transmits haptic interactions through constrained dynamics between the virtual tool and the guidewire. Both positional and rotational control modes are implemented and evaluated with respect to the dynamics of the guidewire, user inputs and feedback forces. Experiments highlight the usability of our algorithm for an insertion procedure simulation with complex blood vessel structures. Copyright © 2011 John Wiley & Sons, Ltd.

The medical domain provides excellent opportunities for the application of computer graphics, visualization and virtual environments, with the potential to help improve healthcare and bring benefits to patients. This survey paper provides a comprehensive overview of the state-of-the-art in this exciting field. It has been written from the perspective of both computer scientists and practising clinicians and documents past and current successes together with the challenges that lie ahead. The article begins with a description of the software algorithms and techniques that allow visualization of and interaction with medical data. Example applications from research projects and commercially available products are listed, including educational tools; diagnostic aids; virtual endoscopy; planning aids; guidance aids; skills training; computer augmented reality and use of high performance computing. The final section of the paper summarizes the current issues and looks ahead to future developments.

If we were to have a Grid infrastructure for visualization, what technologies would be needed to build such an infrastructure, what kind of applications would benefit from it, and what challenges are we facing in order to accomplish this goal? In this survey paper, we make use of the term ‘visual supercomputing’ to encapsulate a subject domain concerning the infrastructural technology for visualization. We consider a broad range of scientific and technological advances in computer graphics and visualization, which are relevant to visual supercomputing. We identify the state-of-the-art technologies that have prepared us for building such an infrastructure. We examine a collection of applications that would benefit enormously from such an infrastructure, and discuss their technical requirements. We propose a set of challenges that may guide our strategic efforts in the coming years.

Purpose: We previously proposed to compute the X‐ray attenuation from polygons directly on the GPU, using OpenGL, to significantly increase performance without loss of accuracy. The method has been deployed into a training simulator for percutaneous transhepatic cholangiography. The simulations were however restricted to monochromatic X‐rays using a point source. They now take into account both the geometrical blur and polychromatic X‐rays. Method and Materials: To implement the Beer‐Lambert law with a polychromatic beam, additional loops have been included in the simulation pipeline. It is split into rendering passes and uses frame buffer objects to store intermediate results. The source shape is modeled using a variable number of point sources and the incident beam is split into discrete energy channels. The respiration model is composed of ribs, spine, lungs,liver, diaphragm and the external skin. The organ motion simulation is based on anatomical and physiological studies: the model is monitored by two independent active components: the ribs with a kinematics law and the diaphragm tendon with an up and down translation. Other soft‐tissue components are passively deformed using a 3D extension of the ChainMail algorithm. The respiration rate is also tunable to modify the respiratory profile. Results: We have extended the simulation pipeline to take into account focal spots that cause geometric unsharpness and polychromatic X‐rays, and dynamic polygon meshes of a breathing patient can be used as input data. Conclusions: X‐ray transmission images can be fully simulated on the GPU, by using the Beer‐Lambert law with polychromatism and taking into account the shape of the source. The respiration of the patient can be modeled to produce dynamic meshes. This is a useful development to improve the level of realism in simulations, when it is needed to retain both speed and accuracy.

One of the ways in which computer animation can be generated is to use interactive graphics systems. In this paper we describe Controller, an animation system of this type. We concentrate on the operation of Controller and detail how an animator can plan and choreograph the motion of objects and cameras. We have intended to provide a system that gives the animator as much control as possible subject to keeping die interface simple to operate.