Benefits and cost of computerized tomography in radiation therapy

The use of computerized tomography (CT) to guide the radiation therapy of cancer has been shown in several studies to have a major impact on the treatment process. The implications of these observations for the likely outcome of treatment provide two indications of the cost-effectiveness of CT in this application. First, the cost of CT relative to that of therapy is compared with the estimated increment in benefit due to CT relative to the benefit of therapy without CT. In this comparison, CT is found to be cost-effective by a factor of 5.5. Second, the cost of CT is compared with an estimate of the averge increased cost of treatment when initial therapy has failed. This comparison favors CT by a factor of 4.6. These estimates are conservative and do not take into account possible reductions in morbidity for which CT may be responsible.