Virtual patient technology got its start in 1989, when the National Library of Medicine initiated the Visible Human Project with the goal of creating anatomically detailed, 3D representations of...
Virtual patient technology got its start in 1989, when the National Library of Medicine initiated the Visible Human Project with the goal of creating anatomically detailed, 3D representations of the male and female bodies for computer use. In 1993, the first model was found in 38-year-old death row convict Joseph Paul Jernigan, who had donated his body to science. University of Colorado scientists froze Jernigan’s body and sliced six blocks of the body into 1-millimeter increments, producing more than 1,800 cross-sectional, digitized color images. Two years later, the female model was made from a heart failure victim, whose body was sliced—using more-advanced technology—into 1/3-millimeter increments. In the following two years, the pictures were released on the Internet and are still available for download. Once the images were available, computer-assisted drawing programs were used to put them together to depict specific organs or regions of the body, allow for manipulation, and reflect the body’s properties. From these models were derived several types of virtual patients, mainly consisting of computer-based images of humans or human anatomy; some can accurately simulate patient—physician interactions with the computer-based “patient” displaying facial expressions and offering verbal information about symptoms, some can be used to study anatomy as virtual cadavers that display realistic tissues and organs, while still others can be used during training to simulate medical and surgical procedures. While the technology exists to combine the latter two applications—the two we will focus on in this article—to create one virtual patient that can be used to simulate numerous procedures or study any anatomical feature, such a system would be prohibitively expensive; virtual patient tools used to practice one specific virtual medical or surgical procedure, such as a colonoscopy, or to study one organ or region of the body are much more affordable.
In addition to depicting very detailed virtual models of organs and tissues—compiled from hundreds of patients representing all body sizes, shapes, ages, races, etc—creating a realistic and useful virtual patient “really consists of collecting data, creating patient models, creating sense of touch, simulating how the skin would move [and] how the tissues would move if something touches the skin, creating something to make it look very realistic visually, like textures [or] colors on the surface of a model so it looks like an interior organ, simulating blood flow, and simulating incisions,” explains Thenkurussi Kesavadas, PhD, Associate Professor and Director, University at Buffalo Virtual Reality Lab, the State University of New York at Buffalo. The ideal virtual patient might also require the incorporation of haptic devices (explained below) to emulate touch and pressure.
The latest virtual patients are unbelievably realistic, a trait that advances year by year. When performing a simulated procedure on one of these 21st-century tools, what the physician, surgeon, or medical student sees is practically the same in terms of resolution and definition as viewing a video image of a live patient.
It’s important to note at this point that this technology certainly is not meant to replace real-life situations or patient contact; it does, however, possess numerous benefits and strong potential for the clinical world.
What Makes Them So Good?
Appearances and expectations to the contrary, virtual patient technology is actually pretty straightforward and very easy to use, according to Dr. Kesavadas. “As a matter of fact,” he adds, “the students will find it easier and more fun to switch [from text and dissection] to these kinds of technologies, especially those who are fond of playing computer and video games.” In fact, he notes that even students with very minimal knowledge of how to use a computer and similar devices should be able to easily use this technology. Beyond ease of use, virtual technology has several additional advantages over using cadavers and mannequins to teach and learn about anatomy and over practicing procedures on live patients.
Virtual Patients Vs. Cadavers and Mannequins
While it is true that the realism and irreplaceable tactile sensations only possible in a true hands-on environment, such as the one encountered in the gross anatomy classroom during cadaver dissection, can never be surpassed, there are several drawbacks that can add to the attractiveness of virtual patients. For example, the opportunity to deal with such tissue can be quite limited, cadaveric tissue doesn’t always represent live tissue well, and live functioning of organs or the human body system cannot be captured with cadavers, explains Marc Triola, MD, Assistant Professor of Medicine, Chief, Section of Medical Informatics, Division of General Internal Medicine, New York University School of Medicine. With the use of virtual patients, simulations can be created that much more closely approximate live tissue. Virtual patients are cheaper and more reproducible than cadavers, and also possess the additional benefits of being interactive, reprogrammable, and reusable. Further, long periods of anatomy training can be carried out using virtual patient technology without requiring the continual presence of an instructor.
Also, with a virtual patient, a student can be made instantly aware of his or her mistake and start over an endless number of times until he or she gets it right. Plus, with volumetric models available, students would be able to see with the same perspective as if they were cutting into the tissues of a cadaver. Further, virtual patients go beyond cadavers and mannequins with their ability to change any number of features and characteristics with the click of a button, including age, weight, ethnicity, height, and disease/condition of the patient. With the speed of PC graphics cards—even those that are quite cheap—millions of calculations can be performed instantly, allowing for highly detailed models of patients to be moved and rotated on the computer screen at very fast speeds on a relatively cheap PC. With cadavers and mannequins, these features are fixed, and 20 mannequins are needed to simulate the 20 different body types that could be represented by just one virtual patient.
Beyond not wanting to smell like formaldehyde for months on end, medical students and physicians may also not want to work with cadavers due to ethical considerations and other reasons. Also, universities and institutions need not receive permission to work with virtual patients, as is needed with cadavers. “There is always an issue of ethics when using cadavers,” notes Dr. Kesavadas. “The virtual patient is very clean, in the sense that everything is software. I think it is much friendlier for the user than using cadavers.”
As noted, there currently is no technology-driven substitute on the market that could completely replicate and replace the benefits of performing procedures on a cadaver, but with the increasing accuracy of virtual patients and the tremendous progress made in the last few years in the field of haptic devices, a full model patient with complete, detailed anatomy that can be manipulated and performed upon just as with a cadaver is expected to be available within the next five years say some experts.
The most recent advances of major prominence in virtual patient technology have been in the area of haptics, which are handheld tools that create tactile sensations that can mimic the “feel” of the resistance, tension, elasticity, and resilience of human tissue, thereby allowing “incisions” and pressure application during procedures on virtual patients in exactly the same manner as on cadavers or real, live patients. Such devices can act as virtual stand-ins for a wide variety of medical instruments; it can be used, for example, as a virtual scalpel to cut a 3D image in which the “skin” actually opens to a depth that corresponds with the pressure applied and allows the user to feel the difference between bone and muscle. Haptics have been around for years, but the technology has become more affordable, enabling more institutions to afford their use. According to Dr. James Mayrose, Research Assistant Professor, Department of Emergency Medicine, The State University of New York at Buffalo, Erie County Medical Center, the price of haptics will continue to decline to the point that they’ll be as affordable as PCs, while at the same time becoming more technologically sophisticated and performing a greater range of tasks and procedures in an increasingly realistic manner.
With the benefits and advances discussed above, “virtual patients have the potential to greatly prepare students and house staff for…real-life encounters and really bring them to a much higher level [of preparedness and competence] by the time they get into an actual clinical situation,” states Dr. Triola. “There’s certainly a significant cost associated with these devices, but that cost, considering that these devices are reusable and can be used across many students, is probably insignificant compared to the costs of actual medical care or real anatomic samples.”
Potential in Clinical Medicine
Although most of the work in virtual patient technology has been dedicated to surgery preparation and medical education, “virtual patients also have a strong potential in clinical medicine, where they can be used as visual interfaces to knowledge-based systems in various simulation and training applications,” write Simo et al. in Studies in Health Technology and Informatics. The technology also has a part to play in clinical training, not only for medical students, but also for practicing physicians and surgeons. A surgeon would benefit greatly by practicing, prior to performing the actual surgery, on the patient on which he or she will be operating; by creating a virtual replica of this patient, this ideal state, impossible in practical terms, could become a reality.
Family physicians and general practitioners could use virtual patients to stay updated on conditions and diseases they may not see on a daily basis by reviewing how they affect the body or by simulating a technique they may not use that often. “It could be almost like continuing medical education,” says Dr. Mayrose.
Family physicians and general practitioners might also one day be able to replace their bulky patient files with a computerized virtual patient record that has all of a given patient’s information programmed into it. “You could do a full body scan and keep a 3D model of the patient, and that can be correlated with digital X-rays and such things,” notes Dr. Kesavadas, who feels this technology will be available for use on PCs within five years.
The virtual patient will also have a strong role in the area of diagnostics. For example, the clinical impact of virtual colonoscopy is already well documented; it enables physicians to scan and create a virtual colon that provides more information than traditional colonoscopy. It also allows the treating physician to better develop a differential diagnosis, make decisions about diagnostic testing, therapies, and management, follow the patient over time, and learn more about the natural history of the patient’s disease. The information gleaned through this application is also able to easily move with the patient throughout their care by other members of a multidisciplinary team. However, “it’s a little further away before you’ll see a general practitioner using it,” says Dr. Kesavadas. “You’ll start seeing virtual technology in the clinical applications of hospitals in 4-5 years.”
So, given the obvious benefits to be derived from this technology, what’s keeping it from widespread adoption throughout the healthcare system? Virtual patient technology is currently in the research and development stage, mostly at major universities and teaching hospitals and within various federal governmental institutes and organizations. This isn’t to say that virtual patient technology is completely unavailable on the market. Physicians can visit tradeshows and medical conferences such as Medicine Meets Virtual Reality and talk with vendors and see this technology in person. For practices that can afford it, companies such as Entelos, Inc and Simbionix are beginning to commercialize virtual patient products. And as the costs of this technology drop due to increasing availability and reproducibility, more and more physicians will take the natural step toward utilizing it in their daily practice.
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