Diffusion of new technologies: rational and irrational.

The diffusion of medical technology, the process by which new clinical procedures and devices come into use in the health care system, is an historical topic, as old as medicine itself. Hospitals, physicians, manufacturers, third-party payers, and patients all are factors in the demand for, and adoption and diffusion of, new medical technologies. The federal government also plays a role both in furthering technology diffusion through federally financed health programs and in attempting to control diffusion by stimulating state certificate of need and other regulatory programs. The history of the CT scanner's diffusion illustrates the problems that can result from the lack of a coherent strategy to control the diffusion of major medical technologies. Some of these same problems are now appearing in the diffusion of magnetic resonance imaging (MRI) devices. In the current health care environment, prospective payment and the continuing period of remarkable technological innovation are major influences on technology diffusion and on initiatives for technology assessment. The diffusion of technology can be made more rational by instituting a formal process to identify technologies (both old and new) that require assessment, by financial support for assessment efforts, by selective reimbursement for clinical trials, and by regionalization of costly procedures.