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A Decision Support Tool for Adaptive Replanning Implemented in a Commercial Treatment Planning System

S Svensson1*, K Eriksson2 , B Godyn3 , T Kanehira4 , J Sonke5 , (1) RaySearch Laboratories, Stockholm, N/A, (2) RaySearch Laboratories, Stockholm, N/A, (3) RaySearch Laboratories, Stockholm, N/A, (4) The Netherlands Cancer Institute, Amsterdam, CX, (5) Netherlands Cancer Institute, Amsterdam,


(Sunday, 7/29/2018) 3:00 PM - 6:00 PM

Room: Exhibit Hall

Purpose: To implement a decision support tool for adaptive replanning based on selection criteria found in the literature as part of an existing commercial treatment planning system (TPS), which includes dose tracking and adaptive replanning functionality. Furthermore, to apply the tool in a retrospective study for comparison of selection criteria with respect to timing of replanning.

Methods: Through the scripting language of TPS RayStation (RaySearch Laboratories), a user interface for adaptive replanning decision support was implemented. Selection criteria found in a review article, [1], were included as well as criteria based on target dose deviation and user defined clinical goals. Five H&N patients were used to test the decision support tool. The patients were treated using a dual-arc VMAT plan in 35fx. For each fraction, a CBCT image was acquired. Using RayStation, daily dose was computed for each fraction. Through deformable image registration (DIR), contours were propagated onto the daily image to allow for anatomic and dosimetric evaluation. DIR was also used to map the daily doses back to the planning image to estimate delivered accumulated dose throughout the treatment.

Results: Volume loss and mean dose increase to the parotid glands was evaluated following a majority of the studies included in [1]. For all patients, mean dose was within the limits (less than 1Gy accumulated) while volume loss suggested replanning for two patients (more than 25%).

Conclusion: It is feasible to implement tailored decision support tools in TPS RayStation. Furthermore, the decision support tool can be used to translate published results into clinical practice.[1] C. L. Brouwer, et al., “Identifying patients who may benefit from adaptive radiotherapy: Does the literature on anatomic and dosimetric changes in head and neck organs at risk during radiotherapy provide information to help?,� Radiother. Oncol., 115(3): 285–294, 2015.


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