ABSTRACT
Quality Control .......................................................................................... 106 4.4.1 Beam Control Parameters Investigated ...................................... 107 4.4.2 Satisfactory and Unsatisfactory Periods of Machine
Performance .................................................................................... 109 4.4.2.1 Possible Major Machine Replacements ........................ 109
4.4.3 Studies to Predict Faults from Short-Term Data Logging ........ 110 4.4.3.1 Variation of Parameters with Gantry Angle ............... 110 4.4.3.2 Determination of 2R Standard Deviation and
Action Level Cut-Off Point ............................................ 111 4.4.3.3 Ratio of Daily Run-Up and Logged Value ................... 114
4.4.4 Conclusion ...................................................................................... 114 4.5 A Cyber Assistant: Long-Term Monitoring Quality Control .............. 115
4.5.1 System Description ........................................................................ 115 4.5.2 Methodology .................................................................................. 115 4.5.3 System Design ................................................................................ 116 4.5.4 Program Flow ................................................................................. 118
4.5.4.1 Test Selection ................................................................... 119 4.5.4.2 Test Execution .................................................................. 120
4.5.5 Program Modules .......................................................................... 120 4.5.5.1 The User Interface ........................................................... 121 4.5.5.2 The Database Module ..................................................... 121
4.5.6 System Operation ........................................................................... 121 4.5.7 Conclusion ...................................................................................... 123
4.6 The Future Potential .................................................................................. 123 References ............................................................................................................ 124
Quality control (QC) in radiotherapy has become increasingly signifi cant over the past 15 years. It has been recognized that to achieve and maintain high standards of safe and effective dose delivery there is a need for both quality assurance systems and quality control checks. The international committee for radiation protection (ICRP) [1] recognized the need for protection of the patient in radiotherapy and the role that QC played in this. The hazards of radiation to normal tissue were well known and the risk of oncogenesis [2-4] further complicates the use of radiation in cancer treatment. These concerns were reinforced by accidents [5], some of which were due to safety failures, others due to performance failures, and of course some due to human error. It has been clear that the absence or defi ciencies of QC had an adverse effect in some of these accidents. Many accidents highlighted the need for standards to be established in both safety and performance.
