External audit is a crucial element in QA programmes for clinical dosimetry in radiotherapy. The proposed CRP will extend the scope of activities by national TLD-based networks from dosimetry audit for rectangular radiation fields to audit of irregular and small fields relevant to modern radiotherapy.
To ensure the quality of the dosimetric chain in Member States through an independent means of verification of the calibration of radiation beams used for treatment of cancer patients. To assist Member States in developing national quality audit programmes for radiotherapy dosimetry.
To develop and make available a methodology and procedures for national EAGs for dose measurement of complex radiotherapy parameters used for cancer treatment. This included TLD based dosimetry for irregular MLC fields for conformal radiotherapy, for heterogeneous situations, and for small MLC shaped fields relevant to stereotactic radiotherapy and applicable to dosimetry for IMRT. In addition it included a new development of film-based 2D dosimetry for testing dose distributions, specifically beam penumbra, in small field geometry.
The results of the CRP have contributed to the overall increase in the radiation dosimetry expertise in the participating countries. Direct experience has been gained by the countries involved in the CRP, on the practical methods and procedures to extend TLD measurements to conditions closer to those used for patient treatments in more complex geometries. Secondly, the network structures, extended to include these new auditing activities, will be available as examples of how to develop the infrastructure and implement new auditing methods and procedures. The expertise acquired in this CRP can be disseminated and adapted, using suitable methodology and structures, by national audit systems in any country operating dosimetry audits for radiotherapy based on mailed TLD, or wishing to do so.
The ultimate benefit of this CRP is to potentially large numbers of patients requiring radiotherapy who will receive improved quality treatment with reduced likelihood for potential misadministration of the dose.