The 16 articles in this special issue report cutting-edge research achievements in the field of applications of Networks for Healthcare.

A novel, unobtrusive and wearable, multiparameter ambulatory physiologic monitoring system for space and terrestrial applications, termed LifeGuard, is presented. The core element is a wearable monitor, the crew physiologic observation device (CPOD), that provides the capability to continuously record two standard electrocardiogram leads, respiration rate via impedance plethysmography, heart rate, hemoglobin oxygen saturation, ambient or body temperature, three axes of acceleration, and blood pressure. These parameters can be digitally recorded with high fidelity over a 9-h period with precise time stamps and user-defined event markers. Data can be continuously streamed to a base station using a built-in Bluetooth RF link or stored in 32 MB of on-board flash memory and downloaded to a personal computer using a serial port. The device is powered by two AAA batteries. The design, laboratory, and field testing of the wearable monitors are described.

Real-time surgical simulation often requires computing the deformations of visco-elastic human-body tissue and generating both graphic and haptic renderings. As human users are more sensitive to small haptic discrepancies than visual ones, good force rendering requires a refresh rate of 500 Hz or more, which is far beyond the capabilities of current simulators. Moreover, if the simulator runs on a remote server, limited bandwidth, network latency and variance further compromise the quality of haptic rendering. To address these problems, a new interpolation-extrapolation data structure called the forcegrid is proposed, which makes it possible to approximate forces at rates greater than 500 Hz, regardless of the complexity of the simulated object. The forcegrid is designed for haptic interaction with continuous contact. It is a regular grid defined over the virtual workspace, in which every vertex contains a force. An extrapolation algorithm updates this force at every simulation cycle, while an interpolation algorithm computes the force to be rendered on the haptic device at the desired rate. The forcegrid has been successfully tested on various virtual deformable objects.

Media-rich learning experiences are widely available on the web.Medical schools and other health care organizations maintain extensive websites for learning, reference, and assessment.Continuing medical education on the Internet is one of the most commonly available and widely used services for health care practitioners.These media-based learning environments, though widely available, represent a passive medium of information retrieval by clicking a mouse.We have been investigating the next generation of Internet-based learning technologies: simulation-oriented learning environments that support interaction, collaboration, and active learning.The topics of learning are anatomy and basic surgical manipulations.To support these topics, we have developed three-dimensional visualizations of anatomy and have enriched these anatomical models with biomechanical tissue properties of elasticity and viscosity such that the learner can use appropriate force-feedback tools to feel tissues at the same time that they visualize them.Access to and interaction with these simulation environments have required that we push the envelope of current Internet capabilities, and that we investigate the role of network bandwidth and latency in the performance of these applications.A preliminary version of this work was presented at MedInfo, 2001. 1 BackgroundThe learning of anatomy and surgery involves a visuo-haptic-audio experience.While books, lectures, and multimedia are important routes to this learning, the acts of touching, feeling and cutting are believed to be essential in the training of new physicians and surgeons.Simulated environments that deliver this experience are expected to form the next generation of technology-enhanced learning environments.When this research was begun in 1998, simulators were in development for knee arthroscopy, laparoscopy, endoscopy, epidural needle insertion, and sinus endoscopy.2-10 These were three-dimensional graphical simulations of anatomy, with haptic feedback, to support planning a surgical or clinical procedure.Some included the ability to cut and move tissue.11 Others

Abstract In our experience, mesh‐cutting methods can be distinguished by how their solutions address the following major issues: definition of the cut path, primitive removal and re‐meshing, number of new primitives created, when re‐meshing is performed, and representation of the cutting tool. Many researches have developed schemes for interactive mesh cutting with the goals of reducing the number of new primitives created, creating new primitives with good aspect ratios, avoiding a disconnected mesh structure between primitives in the cut path, and representing the path traversed by the tool as accurately as possible. The goal of this paper is to explain how, by using a very simple framework, one can build a generalized cutting scheme. This method allows for any arbitrary cut to be made within a virtual object, and can simulate cutting surface, layered surface or tetrahedral objects using a virtual scalpel, scissors, or loop cautery tool. This method has been implemented in a real‐time, haptic‐rate surgical simulation system allowing arbitrary cuts to be made on high‐resolution patient‐specific models. Published in 2002 by John Wiley & Sons, Ltd.

Presents algorithms for animating deformable objects in real time. We focus on computing the deformation of an object subject to external forces and detecting collisions among deformable and rigid objects. The targeted application domain is surgical training. This application relies more on visual realism than exact, patient-specific deformation, but requires that computations be performed in real time. This is in contrast with pre-operative surgical planning, where computations may be done offline but must provide accurate results. To achieve real-time performance, the proposed algorithms take advantage of the fact that most deformations are local, human-body tissues are well damped, and motions of surgical instruments are relatively slow. They have been integrated into a virtual reality system for simulating the suturing of small blood vessels (microsurgery).

Animal dissection for the scientific examination of organ subsystems is a delicate procedure. Performing this procedure under the complex environment of microgravity presents additional challenges because of the limited training opportunities available that can recreate the altered gravity environment. Traditional astronaut crew training often occurs several months in advance of experimentation, provides limited realism, and involves complicated logistics. We have developed an interactive virtual environment that can simulate several common tasks performed during animal dissection. In this paper, we describe the imaging modality used to reconstruct the rat, provide an overview of the simulation environment and briefly discuss some of the techniques used to manipulate the virtual rat.

Computer-based surgical simulation promises to provide a broader scope of clinical training through the introduction of anatomic variation, simulation of untoward events, and collection of performance data. We present a haptically-enabled surgical simulator for the most common techniques in diagnostic and operative hysteroscopy-cervical dilation, endometrial resection and ablation, and lesion excision. Engineering tradeoffs in developing a real-time, haptic-rate simulator are discussed.

The paper details the use of a Virtual Environment for Reconstructive Surgery (VERS) in the case of a 17 year-old boy with a severe facial defect, arising from the removal of a soft tissue tumor. Computed tomography (CT) scans were taken of the patient, the data were segmented, a mesh was generated, and this patient-specific mesh was used in a virtual environment by the surgeons for preoperative visualization of the defect, planning of the surgery, and production of a custom surgical template to aid in repairing the defect. The paper details the case of this patient, provides a background on the virtual environment technology used, discusses the difficulties encountered, and describes the lessons learned.