Systematic Testing of Radiotherapy Accelerators

The nature of radiotherapy accelerators is briefly explained. It is argued that these complex safety-critical systems need a systematic basis for testing their software. The paper describes a novel application of protocol specification and testing methods to radiotherapy accelerators. It is explained that the accelerator control system is specified using LOTOS (Language Of Temporal Ordering Specification). It is completely infeasible to use the LOTOS directly for test generation. Instead, specification inputs are restricted using annotations in a Parameter Constraint Language. This is automatically translated into LOTOS and combined with the accelerator specification. It then becomes manageable to generate tests of the actual accelerator to check that it agrees with its specification according to the relation ioconf (input-output conformance). Test annotations and a sample test are described.