While the limited data collected in the study demonstrated considerable heterogeneity in clinical practice, the study proved a brachytherapy dosimetry audit to be feasible. Future studies should include verification of source strength using a Standard Dosimetry Laboratory calibrated chamber, a phantom that more closely mimics the clinical situation, a more comprehensive review of safety and quality assurance (QA) procedures including source dwell time and position accuracy, and a review of patient treatment QA procedures such as applicator position verification.
For the purpose of dose measurement using a high‐dose rate 192Ir source, four methods of thermoluminescent dosimeter (TLD) calibration were investigated. Three of the four calibration methods used the 192Ir source. Dwell times were calculated to deliver 1 Gy to the TLDs irradiated either in air or water. Dwell time calculations were confirmed by direct measurement using an ionization chamber. The fourth method of calibration used 6 MV photons from a medical linear accelerator, and an energy correction factor was applied to account for the difference in sensitivity of the TLDs in 192Ir and 6 M V. The results of the four TLD calibration methods are presented in terms of the results of a brachytherapy audit where seven Australian centers irradiated three sets of TLDs in a water phantom. The results were in agreement within estimated uncertainties when the TLDs were calibrated with the 192Ir source. Calibrating TLDs in a phantom similar to that used for the audit proved to be the most practical method and provided the greatest confidence in measured dose. When calibrated using 6 MV photons, the TLD results were consistently higher than the 192Ir−calibrated TLDs, suggesting this method does not fully correct for the response of the TLDs when irradiated in the audit phantom.PACS number: 87
Physics quality assurance (QA) is an integral part of a medical physicist's role in the radiotherapy centre. Management of physics QA documents is an issue with a long-term accumulation. Storage space, archive administration and paper consumption are just some of the difficulties faced by physicists. Plotting trends and drawing meaningful conclusions from these results can be challenging using traditional QA methods. Remote checking of QA within a hospital network can also be problematic. The aim of this project is introduce a paperless QA system that will provide solutions to many of these issues.
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