Time Is Money: An Investigation On the Use of Copper and Aluminum Electron Plates for TG-142 Monthly Energy Checks
T Binder1, W Weaver2*, Z Pearson2, (1) University of Kentucky- Alyzen Medical Physics, Jonesboro, AR, (2) Alyzen Medical Physics, Jonesboro, AR
Presentations
PO-GePV-T-100 (Sunday, 7/10/2022) [Eastern Time (GMT-4)]
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Purpose: The evaluation of copper versus aluminum for a four-step electron cone plate in TG-142 monthly electron energy checks.
Methods: Copper and aluminum plates were milled to fit a Varian 20x20 electron cone. Each plate has four quadrants, each of an increasing thickness. Crossline and inline profiles were taken in a 3D water tank to characterize the plates. In addition, PDDs were taken under each of the quadrants. This information was then analyzed to determine the approximate photon contamination component. Finally, a comparison of the PDDs converted into water was created to further analyze photon contamination at proposed measurement depths.
Results: Comparisons were made between the data taken for the copper and aluminum plates. Initial results seem to suggest that while in copper there is a small reduction in the edge effects from the changing quadrants, the overall change is rather small in both. In addition, results seem to initially suggest that the copper plate has a larger photon contamination component than the aluminum plate. The level of photon contamination does not appear to be to a level that would make the use of either plate problematic.
Conclusion: This project has shown the clinical feasibility of using both a copper and aluminum plate as an electron TG-142 energy check device. The aluminum plate appears to suffer more edge effects than copper but has a reduced photon contamination component. The use of devices of this nature has the potential to improve the efficiency of monthly electron energy checks.
Keywords
Quality Assurance, Electron Therapy
Taxonomy
TH- External Beam- Electrons: Quality Assurance - Linear accelerator
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