50. What can be expected of quality controls performed by analysing the dynamic LOG files produced by "traditional" external radiotherapy treatment machines (Linacs)?. (December 2017)

• Record Type: Journal Article
• Authors: Beaumont, S.
• Is Part Of: Physica medica. Volume 44(2017)Supplement 1
• Page Start: 24
• Page End: 25
• Publication Date: 2017-12
• Subjects: Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2017.10.075
• Languages: English
• ISSNs: 1120-1797

Abstract

Abstract : Introduction: The dynamic LOG files contain the radiation parameters of the beam delivered at a higher or lower frequency and, in the best of cases, the identity of the patient who was treated and of the beam. They can hopefully provide the means for a convenient quality control of the treated beam integrated into patient treatment workflow. However all dynamic LOG files are not of equal quality, therefore their respective structures must be thoroughly examined to be able to correctly interpret the results of the quality controls performed using these files and to be able to set the tolerances around these results in a pertinent manner. And finally, dynamic LOG files do not always reflect the reality of the irradiation conditions. It is therefore important to be familiar with these artefacts and with what must be implemented in order to minimise their consequences for patients. Methods: The treatment machines produce different types of dynamic LOG files: VARIAN machines: DynaLogs by the Clinac and TrajectoryLogs by the Truebeam. ELEKTA machines: 2 types in service mode (.xml and.prf), 1 type in clinical mode (.dat), however ELEKTA only authorises the Icom-VX path to retrieve the radiation parameters in clinical mode. Several recent articles in relevant scientific journals describe the shortcomings in the capability of dynamic LOG files to always accurately reflect the actual radiation. Results: The author presents: A comparison of the different types of dynamic LOG files. Two ways in which to use these files, the respective pros and cons for each, emphasising the importance of never over-interpreting statistical data. A few revealing examples of the value of analysing dynamic LOG files to perform a Linac quality control integrated in the patient treatment workflow. The articles written that have defeated the data contained in the dynamic LOG files. Conclusions: The author again underlines the power of the Linac quality controls performed using the dynamic LOG files which they generate, but also stresses the precautions that need to be taken to ensure that this methodology remains pertinent.