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Evaluation of a Pencil Beam Scanning Proton Dose Model for a Commercial Treatment Planning System

D Patel1*, F Poenisch1 , N Sahoo1 , X Zhu1 , M Gillin1 , M Janson2 , R Mohan1 , U Titt1 , (1) MD Anderson Cancer Center, Houston, TX, (2) RaySearch Laboratories, Stockholm, Stockholm


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

Room: Exhibit Hall

Purpose: To evaluate a pencil spot scanning (PBS) proton dose models for the Hitachi proton machine at proton therapy center, Houston (PTC-H) in a commercial treatment planning system (TPS), RayStation.

Methods: The modeling of the PBS beam line required input data including in-air lateral profiles, integral depth doses, measured field-size factors and measured absolute dose per MU. This input data set consisted of Monte Carlo (MC) simulations and measured data. The input data from MC simulations had been validated by measurements. To validate RayStation, first an MU definition plan was delivered to a water phantom and measurements were performed using a Farmer Chamber. The plan used for this measurement was then imported into RayStation. The dose was calculated using an analytical and a MC models in RayStation and compared against the measured data.

Results: The PBS proton machine at PTC-H was modeled to reproduce the input data at all energies and for both dose calculation models. Dose measurements for the MU definition plan in water were made and the preliminary calculations performed using the same dose delivery plan in RayStation show good agreement with the measured data.

Conclusion: The dose validation for RayStation is under progress. First stage analysis show good agreement between dose models (analytical and MC) of RayStation and the measured data. The dose plans with heterogeneous phantom and more complex patient plans will be computed using RayStation dose computation models for further validation.


Absolute Dosimetry, Treatment Planning


TH- External Beam- Particle therapy: Proton therapy - computational dosimetry-deterministic

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