Room: Exhibit Hall
Purpose: LINACs can break down, leading to unintended treatment breaks and potential undesirable clinical outcome. To mitigate treatment interruption, a patient may be transferred to another machine for treatment during machine down. A tool is available in a commercial treatment planning system (TPS), which allows automatic conversion of a plan from one machine to another based on the dose volume histogram (DVH) of the original plan. The objective of the study is to evaluate the quality of the plan created by the tool and the feasibility of its clinical application.
Methods: In total 10 patients were selected for this study. The patients were originally treated on a Siemen Artiste LINAC, but manually replanned for and transferred to a Varian Truebeam when Artiste was down. DVH based plan conversion (Auto) was applied retrospectively to generate corresponding plans for Truebeam. Varian Eclipse TPS was used for all plans. The quality of the auto converted plan, including target coverage and normal tissue sparing, was evaluated and compared to the original and the manually re-planned plan. The time and effort were also evaluated for auto plan conversion against the manual replanning.
Results: A manual replanning typically took up to two hours to complete, while a DVH based plan conversion took less than half hour. The quality of Auto plan was adequate for treatment for about half of the patients, but poor for others, which needed either minor adjustment or a total replanning to achieve acceptable dosimetric distribution.
Conclusion: The DVH based plan converter can be used to quickly generate alternative plans for another machine during machine down, leading to minimal treatment interruption. However, the quality of the auto plan varies from case to case, and manual adjustment may be needed to achieve clinically acceptable planning quality.