How Much Surplus Capacity is Required to Maintain Low Waiting Times?

Multi-institutional Analysis of Computed and Direct Radiography

PURPOSE

To compare economic aspects of equipment configurations, productivity levels, and patient waiting times in the performance of computed radiography (CR) and direct radiography (DR).

MATERIALS AND METHODS

The study received internal review board exemption status, without the need for informed patient consent. Data from four study sites were used to calculate the CR-DR crossover point (defined as the point at which the cost-effectiveness of DR equals that of CR) and CR-DR annual cost differentials. Analyzed variables included equipment and operating costs, examination volumes, and productivity. A program was developed to simulate patient arrival times, number of patient examinations, and patient waiting times on the basis of average annualized parameters for each of the four clinics. Sensitivity analyses were conducted to assess utilization rates and determine cost optimization. Utilization rates were compared with the number of excess long-stay CR patients (ie, patients who spent more than 30 minutes waiting in the radiology department prior to CR examination) and with the cost (per excess long-stay CR patient who waited more than 60 minutes) averted by using DR.

RESULTS

Excess annual costs for DR over CR at the four sites ranged from $50,757 to $75,303. At extrapolated levels of economic penalties for long waiting times, the crossover point at which the DR cost became justifiable was when CR capacity utilization rates approached or exceeded 80%.

CONCLUSION

In the current practice environment, with capacity utilization rates well below 80%, CR is likely to be a more cost-effective technology for the majority of general radiography providers.