Medical Accelerator Safety Considerations-0D2A917D

Several recent radiation accidents resulting in overexposures of radiotherapy patients have focused attention on the serious consequences of equipment failures in linear accelerator treatment units. Descriptions of these incidents have been reported in American Medical Association (AMA) periodicals.1-5 The potential hazard is particularly great in multimodality treatment units. This task group report discusses the safety considerations stemming from the increased use of computer logic and microprocessors in the control systems of treatment units. It suggests how procedures and operator responses can be improved to lessen or avoid risks associated with hardware and software failures in radiotherapy equipment. Examination of radiation overexposures in general suggests that equipment failures and faulty procedures, as well as poor operator responses, are frequently involved. A report on the 1986 reactor accident at Chernobyl places heavy blame on the reactor staff for six actions identified by Soviet authorities as violations of operating procedures. 6 In an early study of radiation exposure accidents in the U.S. Nuclear Energy Program, Catlin found that the primary cause of accidents was operator error followed by equipment, procedure, and other failures.7 Overexposures can result solely from equipment failures; inadequate, inappropriate, or undocumented procedures; or operator error. Often, two or all three factors are involved. Because humans are fallible, and radiation therapy is carried out in a stressful environment, it is essential to clearly delineate response procedures for operators when radiation safety is involved.