Economic analysis of computed tomography units.

All operating CT installations in the United States were surveyed in January 1976; data were obtained from 98 of 140 installations. Although the respondents represented 80 head units and 18 head and body units, the overwhelming experience was with head CT studies. CT equipment was installed in an average of 1.3 months, operated 64 hr per week and examined 50-55 patients per week. A downtime of 7 hr per week was reported. Radiologists are responsible for 92 of 98 installations, and 90% of installations are in a hospital. The scheduling delay averages 1.6 days for inpatients and 11.5 days for outpatients. The delay is increasing in many installations. The estimated total yearly technical cost is +325,000-+371,000 per installation, depending upon patient volume. The estimated technical cost per patient (when 50 patients per week are studied) compares favorably with the estimated net revenue per patient from the average basic technical charge (+130 compared to +138). A separate billing method is used by 59% of installations, and 76% have an extra charge for contrast injection and additional studies; 60% of patients receive contrast. The reported total charges during the last 3 months were higher in installations that (1) charged additionally for contrast, (2) were located in outpatient settings, and (3) had nonradiologists as the responsible physician. It should be emphasized that most CT installations are not independent activities and should be considered an integral part of a diagnostic radiology department or office.