In computers, medical software is a significant branch of software engineering

Software engineering

Software Engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software...

. Many medical device

Medical device

A medical device is a product which is used for medical purposes in patients, in diagnosis, therapy or surgery . Whereas medicinal products achieve their principal action by pharmacological, metabolic or immunological means. Medical devices act by other means like physical, mechanical, thermal,...

s that monitor or control patients are predominantly controlled by software. Medical devices are frequently regulated and must comply with local and regional laws. In the European Union

European Union

The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

, these includes the Medical Devices Directive

Medical Devices Directive

The Medical Device Directive is intended to harmonise the laws relating to medical devices within the European Union...

. In the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the Food and Drug Administration

Food and Drug Administration

The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...

 has increased its involvement in reviewing the development of medical device software starting in the mid-1980s, where coding errors in a radiation therapy device (Therac-25

Therac-25

The Therac-25 was a radiation therapy machine produced by Atomic Energy of Canada Limited after the Therac-6 and Therac-20 units ....

) resulted in the overdose of patients.