The way in which healthcare is delivered is changing, that is there are forces within medicine and external to the field that are bringing about change

Medical Applications Involving Virtual Environments

New Jersey Institute Of Technology

CIS 732

Eric Antonelli

December 17, 2001

Table of Contents

I. Abstract

II. Introduction

Historical perspective 1

Current Information Systems 2

III. Virtual Environments

Media-spaces systems 3

Video-conferencing systems 4

Collaborative virtual environments 5

Avatars 5

System examples 6

Telepresence systems 7

Collaborative augmented environments 8

Transportation and artificiality 9

Spatial representations 9

IV. Medical Applications and Virtual Environments

Computer Integrated dexterous work 10

Medical Simulations 11

V. Current Surgical Aspects

Image-guided surgery 12

Preoperative planning 13

Telemedicine 13

VI. Medical Education

Considerations 14

Anatomical simulations 16

Surgical Simulations 17

VII. Collaborative Medical Environments 18

VIII. Conclusion 19

IX. Figures

X. References

Abstract

As medicine enters the twenty-first century it is apparent that computer technology will change the delivery of healthcare. In particular, the use of virtual environments represent a future where virtual worlds mix with actual patient data to form an augmented reality system where complicated medical procedures are simplified leading to improved patient care and reduced cost. There are five basic types of virtual reality categories these are media-spaces, spatial video-conferencing, collaborative virtual environments, telepresence systems and collaborative augmented environments. Each possesses unique features and functions that allow for degrees of artificiality, spatiality and user transportation. Medical education has made use of virtual environment simulations to train healthcare professionals using computer generated anatomical models thus allowing for medical procedure training and the improvement of user hand eye coordination. Virtual environments have also made advances possible in preoperative planning, image-guided surgery and in computer mediated communication as a means to enhance collaboration and to change and extend the medical knowledge base.

Introduction

The way in which healthcare is delivered is changing, that is there are forces within medicine and external to the field that are bringing about change. For instance, managed care, a means of limiting the cost of medical treatment, initiated by the insurance industry has pressured the healthcare industry to rethink doctor-patient interactions and medical procedures.

There have been major strides in the treatment disease, however, there are aspects of medicine that have changed little since the time of the Egyptians or Greeks. Since the time of Hippocratus, doctor-patient interaction has changed little. There are still interpersonal interactions allowing the physician to unravel a patient's aliment. On the other hand, technological advances can be seen in all disciplines of medicine. These include the development of antibiotics and vaccinations enabling many scourges of man such as syphilis or smallpox to be controlled or eradicated. One of the major advances to medicine as been the ability to non invasively peer inside the human body through the use of imaging techniques including X rays of dense tissues and magnetic resonance imaging (MRI) or to understand physiological processes using positron emission tomography (PET). Therefore, most advancement to medicine has been technological, and health care professionals as well as society as a whole have become dependent on technology. Simply stated, the ability of technology and computing to further modernize and change healthcare and its delivery is limitless.

At present the bulk of healthcare applications deal with information systems that consist mostly of administrative applications such as strategic decision-support, enterprise wide networks or with clinical support applications. With clinical support applications, the patient's medical record that contains temporal physiological information and treatment modalities is the basis for the system. The incorporation and retention of patient information using information technology such as distributed computer-based patient record databases and clinical support systems enhances the overall quality of care as well as constraining medical costs.

"Most healthcare organizations and integrated delivery systems operate separate clinical services information systems, particularly in areas such as pharmacy, clinical laboratory and radiology" (1). The laboratory information system is the most common type of application system. Broadly speaking, these system are concerned with automation of routine laboratory practices and fall into two categories, those involved in actually automating the testing process itself and those involved in the processing of laboratory data. Another category is the pharmacy information system. "This type of application has been used to check prescriptions, monitor medications administered to patients as well as monitoring drug therapies for possible adverse reactions" (2). One of the more advanced systems concerns the viewing and storage of radiological data. These systems are used by radiologists to view and interpret actual patient data in the form of images. These images have been acquired through radiological procedures such as X ray or magnetic resonance imaging. It is this category of clinical application that is leading the way in the use of virtual environments because it deals extensively with three-dimensional volumes and the rendering of surfaces.

Virtual Environments

The dependence of our society on computer technology has lead to the blending of reality with the silicon world. The use of virtual reality, a computer-generated illusion of three-dimensional space, can be found in many aspects of business and science. The technology itself are varied, what is specific about shared-space technology is that user exploits spatial properties such as movement and containment in order to carry out a particular task or for communication. For instance, virtual reality systems can be used as a mode of simulation, where that simulation represents an aircraft control system, a theater where poetry is read, or a three-dimensional sectioned human body. Most of these systems are networked enabling multiple users to participate, manipulate objects and share experiences within a proxy of reality. "More precisely, virtual environments involve the merging of the numerically modeled space in the computer with the user's experiential three-dimensional space" (3).

There are five basic types of virtual reality categories these include media-spaces, spatial video-conferencing, collaborative virtual environments, telepresence systems and collaborative augmented environments (4). Media-spaces are often used in offices and are used to enhance the existing workspace. This type of system makes use of integrated audio and visual technology. The basis for this category is the placement of various cameras in a room so as to give the users different views of the activities of others. Media-spaces can be best described as social systems where individuals located at distant sites may collaborate on long term projects. The drawbacks to these systems include difficulty in sharing text documents, the manipulation of objects and only modest peripheral awareness.

Spatial video conferences can be considered an advancement to the media-spaces category. This type of conferencing also makes use of integrated audio and visual technology however it improves on peripheral awareness and instead relies on gaze- direction. "Gaze-direction has been identified as a major element of conversation management and helps in understanding the viewpoints of others when engaged in collaborative work" (4). This principle of gaze-direction is what separates this technology from that of media-spaces. Many spatial video conferencing systems have the ability to manipulate documents and make use of shared drawing surfaces. There are limitations to this system as far as the number of individuals that may participate must remain low and participates can not dynamically enter and leave the space.

Up to this point, both systems use mixed audio and visual technology as a proxy for face- to-face communication. The intention of virtual reality is to bring individuals together over great distances and could be best described as a means of reducing time involved in travel. The above systems do not attempt to augment or replace reality with actual or modified representations of the real world. However, collaborative virtual environments (CVE) attempt to do exactly that, the replacement of reality. Collaborative virtual environments make use of networked virtual reality systems to support group work and activities. The main concept behind the use of a virtual environment is the users are replaced with alternate representations, or avatars. The users in the space can change their locations and view perspectives, interact with others in the space as well as manipulate data represented as objects unlike other systems where data and communications are located in separate windows. Additionally, collaborative virtual environments aim to provide an integrated, explicit, and persistent context for cooperation that combines both the participants and their information into a common display space (4, 5). Because of these reasons the category of virtual reality lends itself to certain medical situations, especially surgical applications.

What remains similar in many virtual reality systems is the creation and utilization of avatars. Avatars, derived from the Indian word for one regarded as an incarnation, serve as a physical proxy for the user. The avatars fall into several categories based on appearance. Some of the more common avatar classes include animal representations, cartoon characters and abstract avatars which may have shocking or unusual form. The users of these types of avatars usually wish to remain anonymous another intent is that they may attempt to adopt some or all of the character's qualities. "Therefore, in many cases there is a psychological relationship between the user and their avatar" (6). Some users who are not concerned with anonymity prefer to utilize actual user images and are known as real-face avatars.

In virtual environments people may communicate and setup social spaces through the utilization of avatar proxies. "As with humans, avatars have defined areas of perception the closest being the manipulation range where objects can be moved or inspected, next is the audio perception range and finally the visual perception range" (7). Communication in this three-dimensional environment can take place using text messaging or voice additionally, this communication must take place synchronously (8). Voice is the preferred method of communication because it is the most natural form associated with human behavior (9). When voice communication is used facial animation can be added to the avatar. So the character can visually project emotion with a smile or a frown and thus adding to the realism of the experience.

Two examples of sophisticated collaborative virtual environments include MASSIVE (Model, Architecture and System for Spatial Interaction in Virtual Environment). Other systems include DIVE (Distributed Interactive Virtual Environment) and the large-scale military system known as NPSNET. "MASSIVE allows for the complete implementation of spatial model of interactions and includes network-supported communication of up to twenty users" (10). It also possesses an advanced interaction model that allows users to generate and manipulate objects within the virtual world. The most current version of the system strives for data consistency and the ability to build or structure worlds.

World structuring in as system such as MASSIVE is based on the concept of locales. This is a technique, which allow for the formation of appropriately sized "chucks" of information. Locales provide a means of structuring and composing a virtual world according to spatial characteristics. The locale is the fundamental unit of the virtual world, it could represent a distinct region such as a room or surgical suite (7, 10, 11). The locale may also contain virtual objects as varied as a table, a wall or a surgeon's scalpel. With the locale representation of space there is no global coordinate system instead each locale contains its own independent coordinate system. The complete virtual world and associated objects are linked together using inter-locale links.

Many examples of low cost virtual reality systems can be found on the World Wide Web. Two of most familiar are Activeworld and Onlive Traveler; however, both differ in their metaphors. Activeworld is intended as an actual replacement of civilization with towns, streets and buildings, with the system operating in a modified browser. Whereas, Onlive Traveler is a communication based system that requires a downloadable client (Figure 1).

Still other systems are based on open technologies such as virtual reality modeling language (VRML) and open GL. This is the case with the DeepMatrix system, which is a web based three-dimensional multi-user system. The significance of this system is that it focuses on e-commerce and it is the first system that utilizes Java on all levels to achieve full platform independence on client as well as the server side. Therefore, as a system, it is highly applicable in areas that rely on high user accessibility as is required in B2C e-commerce.

Another category of virtual environments is telepresence systems. These systems allow users to experience and manipulate objects in remote physical space through computer and communication technology (4, 11). Telepresence applications typically involve the creation of a physical proxy of the remote person in the form of a robot which has cameras attached to it and which can move through the physical environment (4). This technology also provides the same immersion as found in the collaborative virtual environment.

The final category of virtual environments is what is termed the collaborative augmented environment. This type of system attempts to mix virtual environments and reality therefore they are called shared-space systems. "The advantage of this virtual environment is the ability to overlay graphical objects onto a real world scene with some degree of dynamic registration between the two" (4). As an example, in shared-space systems, multiple users may manipulate a virtual object from across a physical space (4). An alternate approach to the use of mixed spaces includes the ability to augment real objects with specific digital information to enhance the user interaction with the physical object. Peripheral information such as sound and light further add to the enhancement. The long-term goal of collaborative augmented environments is to provide the natural integration of digital and physical information.

When dealing with systems utilizing telepresence, collaborative virtual environments or shared-spaced environments all must include dimensions of artificiality transportation, and spatiality. All the above must work together at various levels to provide some degree of user immersion. Transportation is the dimension that deals with the extent to which a group of users and objects leave behind their local space and enter a new remote or virtual space in order to communicate with others or to perform set of tasks. The degree of transportation from the real world can be little to as much as totally immersion as is the case with a CAVE, a room system whose surfaces project multiple synchronized images to completely simulate abstract reality. At an intermediate levels of transportation participants find split levels of involvement, where users attend to aspects of both their immediate physical environment and that of virtual reality (4).

Artificiality is the dimension concerned with the degree to which a virtual space is either synthetic or based on the physical world. With synthetic artificiality, deals with spaces that are totally independent or devoid of human external reality and synthetic information may include electronic synthesized sounds and three-dimensional geometric representations. Actual physical information may be represented as an image of a face or body as well as electronic documents.

The last dimension that concerns shared-space virtual environments is the concept of spatiality. The fundamental attributes of this dimension include containment, topology, distance, orientation and movement (4, 10). Of the above attributes movement of participants is considered necessary and lends itself to the development of distance and orientation. Movement also allows for the exploration of digital spaces and also plays a role in dynamic group formation (5).

Medical Applications and Virtual Environments

Medicine is in a state of transition whereby virtual environments and scientific visualization has furthered patient care and medical education. Virtual reality is being used to enhance medicine in four main areas: education and training, medical disaster planning and casualty care, virtual prototyping and rehabilitation and psychiatric therapy (12). The use of virtual environments is being applied to a wide range of medical disciplines, including remote and local surgery, surgical planning as well as treatment of phobias and other causes of psychological distress. It is also used for the visualization of data intensive medical record set.

Today, surgery remains mostly a visual and manual discipline. What this amount to is that many aspects of medicine require dexterous work, or the ability match hand-eye coordination with the specific task at hand. Therefore, the use of virtual environments, especial those involved in actual surgical procedures or training in virtual simulators must mimic physical interactions with instruments, eye coordination and medical planning.

The concept that medicine is a dexterous task is central to the development of virtual medical environments. These systems must allow for delicate work of actual surgical representations that can be performed for hours on end without strain. Such systems already exist for brain and heart surgery, certain minimally invasive techniques and craniofacial repair. "Therefore, the approach of medical simulations is to bring the computer-modeled work object such as a three-dimensional medical image, a scalpel, cutting tool or laser into the user's natural work volume" (13). Additionally, as a surgeon performs dexterous work he is usually within one foot or so of his work, this affords good depth perception and reduces arm strain. So when one attempts to develop system to replace reality the above concerns must be taken into account.

The key to dexterity is hand eye coordination. "In the abstract, a mouse cursor seems far better than a finger, pointing more precisely at a point in the monitor screen" (13). However, in three-dimensional systems stereo vision as well as the position of the user's body is of importance. Therefore, it is both the physical state of the user's body, the position of the head and the arms as well as vision that must come together in the accomplish a given task.

When merging the user's workspace with that of the computers it is of importance that the user must be able to perceive an objects relative location and to have some sort of tactile sense for the object. The sense of touching can be accomplished through the use of a generalized tool handle this is what the user actually manipulates. The virtual tool becomes the "working end" and it may portray various surgical instruments such as a scalpel blade or a laser. "It is generally understood that if the user can see the tool and feel the tool then the perception matches" (13).

Medical virtual environments augment vision and dexterity in various ways. The most common setup for these types of systems makes use of a virtual workbench metaphor. The virtual workbench is composed of a mix of physical items and computer-generated objects (Figure 2). The physical items include a tool handle or some other type of input device. The mouse is a poor metaphor for a scalpel handle and must be replaced using specialized devices with electro-magnetic and mechanically linked three-dimensional input sensors. Other equipment that is required for realism and to match user perception includes stereo glasses, high-resolution monitor and workstation (13, 14).

Current Surgical Aspects

Until recently, it has been considered by many physicians and laymen alike that surgery was extreme, exploratory in some instances, and fraught with complications due to the lack exact patient data. However, with the advent of computer technology and specifically the use of this technology coupled to imaging systems has expanded and enhance medical procedures.

Today, image-guided surgery has been used to help guide surgeons to targets during actual operations. In this method virtual reality is augmented with actual patient data in the form of surface and volume renderings as well as the simulation of tissue behavior. This form of augmented virtual reality is used in conjunction with an interventional imaging system and surgical suite in order to perform minimally invasive techniques leading to fewer infections and more rapid recovery (14). The system makes use of dynamic visual feedback used to create intraoperative three-dimensional representations as opposed to standard radiography or two-dimensional volume reconstructions

(Figure 3).

As with most disciplines, surgery requires practice. This may present itself even to a skilled practitioner due to the complications of unique cases. Virtual environments have been used under these circumstances as a means of preoperative planning. Preoperative planning allow the surgeon to review a particular case in a virtual setting making use of actual patient data. This then allows for the view and implement of alternative procedures. Since this occurs prior to patient involvement, costs, time and hopefully complications are reduced.

Telemedicine is the application of computer and communication technologies to support the facilitation of healthcare to patients at remote locations. These types of systems have been used with much success when assisting in remote operations. This usually takes the form of a medical specialist at one site and a trained general practitioner or surgeon by the patient's side. Telemedicine requires audio and video equipment, fiber optics, interfaces to surgical instrumentation as well as the ability to transmit radiological information. Telemedicine has yet to integrate virtual reality.

Although telemedicine does not support the virtual environment, it has set a milestone for the penetration into the medical community. In particular, these systems have been incorporated into military usage. An example of this technology is the Joint Medical Operations - Telemedicine or JMO-T (15). This system was designed to transmit and receive near real time, far-forward medical data under battlefield conditions. "It makes use of digital scopes, digital blood and urine laboratories, physiological monitors, digital radiography and ultrasound" (15). The use of medical information technology in austere theaters of operations was implemented by the military to expand resources and to reduce medical personnel to enemy fire.

Medical Education

The field of medical education was the first medical discipline to exploit the power of virtual environments (3). The use of virtual environments provides a unique education resource for the study of anatomical structure and medical procedures. One of the central issues in medical education is to provide a realistic sense of the inter-relation of anatomical structures in three-dimensional space. Using virtual environments, the student of medicine can repeatedly explore the anatomical structures of interest in both normal and diseased states. The user of the system may then visualize various anatomical features in exploded view for better comprehension of complex morphologies and the underlying physiological processes. The above becomes impossible and largely unethically with human subjects and is economically unrealistic or cumbersome at the laboratory level or with cadavers.

Another advantage of using virtual reality systems for medical education is that the demonstration and exploration of various anatomical systems can be combined with other educational resources (Figure 4). For instance, a predefined medical instructional exercise pertaining to a specific anatomical structure or organ can be created with expert voice annotations as a means of guidance. The student may then further explore using the above exercise and then use the simulation as a study guide for a possible class examination. The value of virtual environment simulators is in the teaching of cognitive as well as manual skills. That is individuals who practice the discipline of surgery must become dexterous and continually practice hand-eye coordination.

The Medical College of Georgia and the Georgia Institute of Technology have developed an example of a working medical surgery simulation. The stimulator enables ophthalmic surgeons to practice delicate procedures using a virtual eye a stereoscopic microscope and force feedback surgical instrument that continuously report orientation and position. The system functionality is modifiable and allows for the substitution of instruments and evaluation of training record and playback functions. The virtual component of the simulator is the computer-generated eye and the interaction of the eye with the surgical instrumentation. The eye, itself, is represented by a series of deformable three-dimensional models. The model represents various anatomical structures such as the sclera, iris, zonules and retina. All the above tissues are textured with actual human eye images. As in the living state, both the lens and the cornea were modeled as semi-transparent objects. When the virtual eye makes contact with an associated surgical instrument, the eye deforms and a proportional amount of tactile feedback is registered by the user.

This example serves to explain the basis of hybrid model systems, which are currently in wide use. The virtual objects, especially smooth surface organs and related structures are currently composed of polygonal surfaces using the two-dimensional textures or images "mapped" onto them. This can produce a realistic effect as far as representing actual tissue; however inaccuracies can be ascertained when object are viewed from various angles (15).

Presently, evaluation and testing protocols are being developed to determine how the virtual environment simulators can contribute to surgical education. For example, it must be demonstrated that there is a measurable improvement through outcome analysis. In other words, there must be an improvement in a relevant dimension such as shorter surgical time, shorter training periods to train learners, lower the complication rate or simply lower overall costs.

Training of doctors in the surgical theater itself brings increased risk to the patient due to inexperience and longer surgical procedures. The result is to cause an increase stress on the already constrained healthcare system because new surgical procedures require training by other doctors, who are already inundated by their own clinical schedules. The continued training of healthcare professionals regarding new procedures in rural or remote settings is difficult and surgical training opportunities present themselves on a case-by-case basis (1, 2). The best solution to this problem depends on the development and acceptance of medical training simulators that offer sufficient transportation and artificiality. This enables a surgeon a degree of "practice time", under computer control, to perfect ones technique as part of a preoperative planning method. This concept of precise computer monitored training stems from the analogy of flight simulator training where a pilot learns aircraft instrumentation and flight characteristics prior to real-time flight responsibilities.

Collaborative Medical Environments

As in other professions, the medical community participates in conferences and other forms of collaboration. Meetings may also involve professional or technical consultations regarding patient cases leading to improved care. The normal practice has included the traditional face-to-face meetings or phone communication. "The use of computer media communication and in particular collaborative virtual environments can be used to enhance collaboration and to change and extend the medical knowledge base" (16).

Within a collaborative environment or workspace several issues regarding user descriptions must be recognized. The most apparent is a sense of location within the virtual world, next is identity, which leads to the ability to distinguish other participates and to retain individual identifies over time. Since much of human communication is visual other issues such as facial expressions and gestures need to be considered when using virtual environments in computer mediated communication (6).

The conference has played a long-standing tradition in professional circles, playing a central role in informal and formal knowledge building and social network maintenance (). It has been through the use of networked computer technology that has led to changes in the meeting planning and social experiences of the participants. In particular, on line computer conferences show a great promise for changing methods of collaboration. This technology has the ability to reduce logistics and other organizational factors as well as quickly representing data in various formats. However, more importantly the peer collaboration can include a larger pool of users thereby adding content and also allowing for horizontal communication (16).

A major problem that needs to be addressed in using virtual environments as a means of computer mediated communication are the problems of coping with inconsistencies due to network delays in collaborative virtual environments. The cause of these delays may be attributed to low bandwidth, network distance or geographical distance. Since these shared environments involve participants are remote sites any delay in communication may potentially break the consistency between users and their replicated environments (5, 16). The issue of a temporal delay causing latency in voice data or decrease object response would be considered a nuisance in normal computer media communication however, some medical collaboration may be simultaneous with patient procedures. The use of collaborative environment in life-critical systems therefore necessitates that latency be reduced through dedicated high-speed connections.

Conclusion

The widespread use of computer technology in our society has led to changes in many aspects of business, science and education. This has led to the development and exploration new problems, changed workflow, altered data representations and made available vast amounts of information. Furthermore, the ability of computer systems to present information as either descriptive or prescriptive has empowered individuals and generated social ramifications (18).

The next step in enabling computer system users is the ability to replace reality with a virtual environment. That is, the incorporation of a shared-space where users can collaborate, investigate complex objects, or train for complex tasks. There are five basic types of virtual reality categories these are media-spaces, spatial video-conferencing, collaborative virtual environments, telepresence systems and collaborative augmented environments. Each has specific attributes that have been tailored based on task or on an aspect of computer mediated communication.

At present, medical virtual environments deal mainly with the presentation of gross anatomical structures for educational purposes or for the augmentation of surgical techniques using intraoperative three-dimensional imaging. In these systems, real-time patient data is incorporated and then used for preoperative planning and medical training. Telemedicine is the application of computer and communication technologies to support the facilitation to healthcare to patients at remote locations has yet to incorporate virtual reality.

The delivery of healthcare is a team effort with many individuals possessing various skills contributing to successful patient outcomes. However, the ability to use virtual environments in team training has not been explored up to this point. For instance, a surgical team is a group generally consisting of a surgeon, an anesthetist and one or more technicians. The emphasis in the development of virtual reality systems so far has emphasized either education of a signal member or the presentation of patient data. Future work needs to include virtual environments for the training of entire teams allowing for collaboration.

There are challenges to be overcome in order to augment and further increase the realism of virtual environments. For instance some medical disorders present themselves to the healthcare professional as a malodor or as frictional sounds as is the case with various joint abnormalities. At this time, there is no technology incorporated into these systems to simulate odor or sound feedback. Additionally, force feedback of instruments is crude and in particular tactile feedback especially of soft tissues is lacking.

The ultimate goal of medicine is to enter a new era of understanding of disease at the molecular level. Computer technology along with molecular techniques has enabled researchers to sequence the entire human genome. As the biochemical and genetic causes of basic human disorders are elucidated new individually tailored therapeutics will be developed. In the future what will be needed is the ability to link genetic database information, real-time patient pathology at the microscopic level coupled with augmented virtual reality treatment systems used by expert teams as a means of collaboration and ultimately successful patient treatment.

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