Telemedicine: New Application of Communications Technology

Telemedicine may be defined as the practice of medicine at long distance by means of telecommunications, in particular, closed-circuit television and telemetry. Two-way television enables physicians to establish a nominal doctor-patient relationship with patients at a remote location, while providing the means for visual examination of patients. Biomedical telemetry transmits patients´ vital signs, detected by standard medical bioelectric sensors and physiological function transducers. In a telemedicine simulation experiment, a test group of physicians deemed black-and-white television adequate for most diagnostic purposes, but expressed a preference for color. The group evidenced little interest in picture resolution greater than that provided by the standard U.S. 525-line system. The Plumbicon camera was said to provide better pictures for medical purposes than the vidicon. In either color or black-and-white television, lighting is a critical factor in the proper rendition of flesh tones as well as in providing the necessary illusion of depth for the observation of detail. Commercial television lighting practices are directly applicable. The inclusion of certain colored items in the televised scene aid in the interpretation of color television pictures. Designing the biomedical portion of a telemedicine system requires knowledge of the various electrical characteristics of the vital signs to be transmitted. These cover a wide range of frequencies and amplitudes. Most bioelectric potentials are so small that special care must be taken to avoid artifacts produced by electrical interference.