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What Is the Impact of Specific Vs. Combined Purpose Model Library in Knowledge Based Planning?

E Bossart

E Bossart*, M Duffy , G Simpson , M Abramowitz , A Pollack , N Dogan , Univ Miami, Miami, FL


SU-I-GPD-T-320 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: To determine if a single purpose knowledge based planning model library (KBP) will outperform a combined model library when planning.

Methods: Three KBP model libraries were created in Varian’s Eclipse version 13.7: (a) a model library for patients treated to prostate alone (P, 66 patients), (b) a model library for patients treated to the prostate and pelvic lymph nodes (PPLN, 31 patients), and (c) a model library combining the patients in model libraries 1 and 2 (97 patients). Five patients with prostate alone plans and five patients with prostate plus lymph node, each planned by an expert planner with a plan considered to be clinically treatable by a physician, were replanned using a single run of the optimizer utilizing each of the appropriate KBP model libraries. The P cases were replanned using library (a) and (c) while the PPLN cases were replanned using model libraries (b) and (c). All plans were normalized such that 96% of the prostate planning target volume (PPTV) received 100% of the planned dose. The KBP plans were compared against each other and against the expert plan.

Results: All plans created were considered clinically acceptable for treatment within the guidelines set out by our department. There were only minor variations between the single purpose model libraries and the combined purpose model library, with some critical organs being slightly better for one or the other model library but no consistency as to which model library was better for any particular plan.

Conclusion: This study indicates that a combined KBP model library may perform as well as a single purpose KBP in planning for prostate. This has some implications for more complex sites such as head and neck.

Funding Support, Disclosures, and Conflict of Interest: This research was funded by a Varian Research Grant.

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