The increasing importance of X-ray computed tomography as a source of medical exposure

Computed tomography (CT) has continued to expand steadily throughout the world since the technique was introduced into clinical practice in 1972. It has, of course, made a substantial impact on patient care, although national surveys have established the increasing importance of CT as a source of medical exposure. Information for the UK in 1993 suggests that the contribution from CT to collective dose from X rays may have risen to about a third. It is essential that there should be a continuing review of CT practice so as to take advantage of all opportunities for reducing exposure without loss of benefit to patients. A survey in the UK has indicated potential scope for improvement in the optimisation of protection for patients undergoing CT examinations and the National Radiological Protection Board has made general recommendations aimed at ensuring better control of patient dose and, in particular, advocating the development of reference doses for CT. (Author)