Program Information

Creation of a Comprehensive Head and Model Using Knowledge Based Planning

J ALPUCHE AVILES*, D Sasaki , K Sutherland , B Kane , CancerCare Manitoba, Winnipeg, Manitoba

Presentations

SU-E-T-92 Sunday 3:00PM - 6:00PM Room: Exhibit Hall

Purpose: The purpose of this study was to evaluate if a commercial implementation of Knowledge Based Planning (KBP) software can be used to estimate Dose Volume Histogram (DVHs) on a comprehensive data set of Head and Neck (HN) patients.

Methods: KBP is a tool capable of estimating DVHs for Organs At Risk (OARs) based on the DVHs of plans of similar patients treated in the past. This study used a newly developed commercial implementation of KBP to create a HN model. The model was trained using a database of retrospectively treated HN patients. This database covered the spectrum of cases expected to be found in the clinic, including multiple targets and 18 different dose prescription combinations. A set of independent validation patients was used to quantify the accuracy of DVHs estimated using the model and covered the same spectrum of HN cases.

Results: The accuracy of the model was calculated by comparing the volumes of the estimated and clinical DVHs at doses equal to 50%, 85% and 99% of the maximum OAR dose. This allowed us to quantify the accuracy of the estimated DVHs even in cases when the OAR was receiving a low dose. The highest accuracy was obtained in the estimation of the DVHs for the Brain (<1% on average). The accuracy for the Brainstem, Cord, Mandible, Oral Cavity, Parotids and the Pharyngeal Constrictor ranged from -2% to 9% on average.

Conclusion: This study shows the feasibility to estimate DVHs in a wide range of HN cases using a novel KBP algorithm. The use of a comprehensive set of patients results in a robust HN model which can be used in a wide range of clinical cases. Further planning is required to confirm if the current accuracy is sufficient to guide the planning process.

Funding Support, Disclosures, and Conflict of Interest: The authors are Clinical Evaluators/Consultants for Varian Medical Systems. This study was partially funded by Varian Medical Systems.

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