Electronic Design

Telepresence In Medicine

One form of telepresence is telemedicine, the remote diagnosis, evaluation, and treatment of a patient by a physician or health organization via data transmitted wirelessly or via the Internet. Directed by medical doctors located offsite, medical technicians perform tests on patients and administer care in real time. Cameras and other instruments let doctors view the patient so they can accurately guide technicians during treatment.

Telemedicine is a multi-dimensional application domain involving four major functional blocks: sensors and instruments, information content, data processing and storage, and data transmission. Each requires a careful evaluation of what technology to use. Often, OEMs are called upon to bundle telemedicine systems with all of these functional blocks in mind.

Telemedicine systems require a wide range of sensors to monitor various physiological components, such as respiration rate, temperature, blood pressure, heart rate, glucose levels, urine flow and content, autonomic nervous activity, and metabolism rates. These sensors must be small, rugged, miserly when using power, highly accurate, and reliable with long operating lifetimes. Microelectromechanical-systems (MEMS) technology enables many of these sensors.

Sensor ergonomics with respect to the patient and the care provider are crucial. Such sensors also face biocompatibility and safety issues, especially since many of them are implanted in the body. Some sensors are designed as fabrics to be worn on a patient’s arm, waist, or whatever part of the body is being tested. Others could be disposable, such as image sensors that are swallowed. These sensors also must be able to work with wireless transceivers. Certain sensors, like a lab-on-a-chip, are extensions of larger systems that analyze and display the biological and chemical contents of a body’s fluids, enzymes, and blood.

Equipment can include TV monitors, personal computers, PDAs, mobile phones, and various dedicated scopes like dermascopes, otoscopes, stethoscopes, and ophthalmoscopes. Scanners and video and photo cameras are also needed. In fact, the cameras that are widely available on today’s mobile phones may soon gain enough bandwidth and resolution to enable the transmission of telemedical information via the phone. Some mobile phones already include vital-sign monitoring sensors that wirelessly transmit output data to external medical locations (see “Bluetooth EMS Units Streamline Cardiovascular Intervention” at ED Online 15935).

Once you’ve assessed the hardware required, you then need to decide what kind of content will to be transmitted: video, video conferencing, 2D and 3D gray-level and color images, X-ray images, gray-level and color videos, physiological signals and values, and haptic signals. Next, you need to know how to capture and store this massive amount of information in a database and process it for diagnostic support. Then there’s the issue of privacy, which means a secure database of information with restricted access. Multimedia standards also must be chosen (encoding/decoding, compression/decompression, and manipulating data), and they should be compatible with telemedicine applications.

Transmission technologies include GPRS-EDGE, 2G, 3G, 4G, DSL, ISDN, ATM lease lines, optical networks, and the Internet. One key issue is the availability of low-cost broadband technologies like WiMAX to facilitate the expansion of telemedicine services.

Another critical issue is the software. Flexible and easily maintainable open-source software platforms are essential for telemedicine to grow. The dependence on proprietary software architectures should be avoided if the object is to make telemedicine more practical and pervasive.

Fortunately, some good examples of open-architecture software platforms come in the form of operating systems, application development programs, Web servers, relational databases, visualization tools, and image segmentation and registration software like Linux, Java, MySQL, VTK, ITK, and PHP.

The technology exists to enable the successful development and implementation of telemedicine systems. Yet technical challenges remain when it comes to seamlessly integrating all of the major functional blocks.

Ambitious plans, however, are on the drawing boards of many government agencies and medical associations to overcome these problems. For example, the American Telemedicine Association (ATA) has been developing an inventory of existing medical-center-based telemedicine networks. To date, approximately 200 such networks operate in the U.S., linking over 2500 institutions nationwide.
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