Therac-25

Therac-25 Rotation

Therac-25 was a computer-controlled radiation therapy machine, developed and manufactured by the Atomic Energy of Canada Limited (AECL) in 1982, following the earlier Therac-6 and Therac-20 models.

Overview

The Therac-25 was a sophisticated machine designed to provide radiation treatment for cancer patients. It could deliver two types of radiation: direct high-energy electron beams (up to 25 MeV) and X-rays produced by directing the electron beam onto a metal target. The machine was controlled by a computer that allowed the operator to select the type and intensity of radiation according to the specific treatment plan for each patient.

Development and Production

The development of the Therac-25 was a significant step forward in radiation therapy technology. Unlike its predecessors, the Therac-6 and Therac-20, which were developed in collaboration with French companies, the Therac-25 was fully designed and manufactured by AECL.

Safety Incidents

While the Therac-25 was a technological advancement, it was also associated with a series of safety incidents in which patients received massive overdoses of radiation. These accidents, which occurred between 1985 and 1987, were due to software errors that allowed the machine to deliver extremely high doses of radiation.

These incidents led to extensive investigations, resulting in significant changes in the standards and regulations for the development and use of medical software devices.

Legacy

Despite the safety issues associated with the Therac-25, the lessons learned from its use have had a profound impact on the fields of radiation therapy and medical device software development. It has led to a greater emphasis on software testing, risk assessment, and the importance of incorporating fail-safe mechanisms in medical devices.

See Also

• Medical radiation
• Medical device
• Software testing
• Risk assessment