CONFORMED (Conformance Of Radiological/Medical Devices)

Introduction
Work Plan
Publications

Introduction

This project was conducted from October 2000 to September 2003 by Qian Bing under the supervision of Ken Turner. Funding was provided by the National Computing Centre.

The goal of the project was to define a method for specifying, analysing and testing the functional and performance characteristics of radiotherapy equipment used in oncology centres for cancer treatment. The project used LOTOS (Language Of Temporal Ordering Specification) as the specification language. The project studied the characteristics of radiotherapy machines, with a view to formally modelling them and then deriving rigorous tests to evaluate their correct behaviour.

The purpose of the project was to create a safer environment for treatment of patients by radiation machines. The main goals were:

• to define a method for specifying the functional and performance characteristics of radiotherapy equipment
• to develop a method for deriving and applying rigorous tests of radiotherapy equipment based on their specifications
• to develop prototype tool support for the methods
• to demonstrate the methods and tools through realistic case studies.

Work Plan

The overall project approach was as follows:

Task 1. Survey

A literature and tools survey was carried out in the fields of formalising (non-)functional requirements using LOTOS, conformance testing based on LOTOS, radiotherapy equipment, and radiotherapy practices.

Task 2. Requirements Definition for Radiotherapy Machines

Radiotherapy machines are quite different in functionality and characteristics from most computer-controlled systems. It was necessary to identify clearly the functions that radiotherapy machines perform and the performance requirements that they must meet. The outcome of this task was a high-level statement of requirements that can be specialised for any particular radiotherapy machine.

Task 3. Formalisation of Functional and Performance Characteristics

The requirements definition for radiotherapy machines was formalised using LOTOS. The LOTOS community has already gained experience of specifying medical devices. It was important, however, to describe performance aspects of radiotherapy machines. The outcome of this task was a formal specification in LOTOS of the functionality and performance expected of a radiotherapy machine.

Task 4. Development of Testing Theory and Practice

The notion of conformance testing is well developed in data communications. Formal methods for conformance testing have also been investigated, including techniques based on LOTOS. The scientific challenges facing the project are to adapt such approaches to the field of radiotherapy, to devise testing techniques for LOTOS, and to develop a means of testing performance based on LOTOS. The outcome of this task was test suites derived from the formal specification of a radiotherapy machine. Tools were developed for automated test derivation based on the theory.

Publications

The following papers provide technical details of the work:

• Kenneth J. Turner. Formally-Based Testing of Radiotherapy Accelerators. In Robert N. Procter and Mark Rouncefield, editors, Proc. Workshop on Dependability in Healthcare, pages 97-99, Edinburgh, March 2001.

• Kenneth J. Turner and Qian Bing. Systematic Testing of Radiotherapy Accelerators. In Hartmut Ehrig, Berndt J. Krämer and Atilla Ertas, editors, Proc. Integrated Design and Process Technology (IDPT 02), pages 33.1-33.8, Society for Design and Process Science, Grandview, Texas, USA, June 2002.

• Kenneth J. Turner and Qian Bing. Protocol Techniques for Testing Radiotherapy Accelerators. In Moshe Vardi and Doron Peled, editors, Proc. Formal Techniques for Networked and Distributed Systems (FORTE XV), Lecture Notes in Computer Science 2529, 81-96, Copyright Springer, Berlin, November 2002.

• Kenneth J. Turner. Test Generation for Radiotherapy Accelerators, Software Tools for Technology Transfer, 7(4):361-375, Copyright Springer, August 2005.

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