Room: AAPM ePoster Library
Purpose: To implement a novel method using kV and MV imaging of a linear accelerator to improve the positional accuracy of metal and MRI compatible HDR applicator source simulation and delivery.
Methods: A Varian Novalis Tx was used to image 2 MRI compatible cylinder sets, 2 MRI compatible tandem and ovoid sets, 1 metal tandem and ovoid set, and 3 tandem and ring sets. Each set was imaged with the source position simulator (SPS) set to the treatment position, and their respective dummy sources. The SPS and actual source was compared using a connected ruler and camera system. The coincidence of the SPS and the dummy sources were compared. The time to take the measurements and user variation with six different users evaluating images were also recorded.
Results: Applicator positional accuracy showed to be within 0.5mm with an average accuracy of 0.2mm of the expected position. The new method proved to be independent of user and showed an efficiency improvement up to 53.75 minutes for 3 applicators and up to 125.5 minutes for 10 applicators. There was no user dependence found.
Conclusion: The proposed method using kV and MV imaging of a linear accelerator proved to be a feasible method of measuring the positional accuracy of HDR applicators. There was no user dependence found, and the accuracy and time to perform the test were improved when compared to a traditional method using film and a CT scanner.
Not Applicable / None Entered.