Room: AAPM ePoster Library
Purpose: Stereotactic body radiation therapy (SBRT) is a new promising option for treating patients with refractory ventricular tachycardia. The purpose of this study is to investigate if planning for such cases can be automated.
Methods: Based on our clinical experience in treating 13 patients with this novel technique, we designed a script that incorporates our planning strategy, namely designing the avoidance/ring structures, choosing the arc angles and selecting the appropriate optimization objectives and weights, and performing the optimization and dose calculation tasks to present the dosimetrist with an initial plan generated by automation. Scripted settings have been devised by finding common options in clinical plans, followed by a trial-and-error comparing scripted results against clinically-accepted plans to find the strategy minimizing differences.
Results: The script creates a treatment plan from the approved structures in about 30 minutes without any user interaction. While the physician and dosimetrists may tweak the automatically generated plan to fit trade-offs of a specific case, plans generated by the script met clinical endpoints and incorporate planning settings that are unlikely to change between patients. Without any alteration of the automated plans, the mean minimum target dose was 22.64 Gy (21.58 to 24.07), while for the clinical plans it was 18.89 (10.36 to 22.68). Similarly, the maximum dose was 31.98 ( 30.76 to 33.01) and 31.37 (29.50 to 34.27) respectively. Dose to critical structures was also comparable between automated and clinical plans, for example, a mean maximum of 26.83 and 25.87 for the right ventricle and 31.28 and 31.72 for the left ventricle respectively.
Conclusion: A customized script incorporating our department’s experience in treating tachycardia patients was created to aid with the acceptance of this new application into community practice as it incorporates in one package our institution’s experience in designing treated plans for cases treated with this modality.