Assessment criteria for diagnostic imaging technologies.

Expensive diagnostic imaging technologies need to be assessed. Assessment is most difficult with new technologies. Rapid technical change creates pressure for widespread provision because of apparently self-evident advantages. For the health care provider, technology assessment is of central importance. Timing is crucial; economic and clinical studies have to be carried out simultaneously; and studies must be broadly based. Assessment should be carried out only on properly selected technologies. Apart from picture archiving and communication systems, existing expensive diagnostic imaging technologies are now so mature that assessment is concerned mainly with costs and benefits. To be provided, a technology needs to be effective, economic, appropriate and needed. The history of computed tomography illustrates technology assessment from innovation to routine application. Technology assessment also provides essential guidance for equipment selection. Different regulations and controls, explicit or implicit, exist in different countries. There are special requirements for technology assessment in each country according to overall health requirements and policies. The main contemporary challenges are the correct selection of equipment for assessment, and the development of predictive methods of assessment.