National survey of computed tomography unit capacity.

Data from 521 computed tomography (CT) units show that 61% do not have the capacity to meet the current national guideline of 2,500 examinations per year. Capacity is primarily determined by study mix, such as head or body, without and/or with contrast agent. A new guideline accommodating this finding, using a scale of head equivalent CT (HECT) units, is proposed. The recommended annual level of 3,000 HECT units is based on the capacity of two-thirds of the 441 responding hospitals, whose units are staffed 52.4 hrs/wk, 75% of which are actually available for examinations. Twenty-five per cent of scans on body units are body studies, 39% of which are double studies and 35% only contrast enhanced studies; 70% of the head studies are double studies, and 16% are done with contrast agent alone. On head units the corresponding values are 58% and 20%.