X Zhong*, Y Park, Y Zhang, Z Trivedi, J Wu, L Chen, S Kazemifar, A Godley, S Jiang, M Lin, UT Southwestern Medical Center, Dallas, TX

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  X Zhong

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TH-E-TRACK 5-5 (Thursday, 7/29/2021) 3:30 PM - 4:30 PM [Eastern Time (GMT-4)]

Purpose: Accurate dose calculation algorithms, such as AcurosXB(AXB) and Monte Carlo(MC), have become the only dose calculation engine available for some new adaptive therapy systems and accelerated the need to transition to AXB/MC. In this work, we describe the approach to transition from AAA to AXB in a large institution.

Methods: Phase1 implementation is in physics side, a large scale AAA plan recalculation and reoptimization study was performed with AXB for total of 205 cases covering seven disease sites. Gamma analysis of 1%/1mm, 2%/2mm and 3%/3mm and dose-volume-histogram(DVH) metric comparisons were performed to quantify the systematic dosimetric impact for the individual disease sites and develop the proposal to handle the dosimetric impacts. In phase2 implementation, the representative cases in each disease site were replanned with AXB. The treated AAA plan recalculated with AXB, representing prior practice in AXB-scale; the AXB plan recalculated with AAA, representing the future practice in AAA-scale; along with the statistics from phase 1 were presented to the physicians, planners, and therapists of each disease-oriented-team(DOT). New guidelines and workflows were developed based on the feedback obtained.

Results: Breast plans demonstrated the lowest gamma passing rate followed by bone and lung. Gamma failure was observed in lung, cortical bone, and heterogeneity interfaces. In the DVH and replan studies, higher D0.03cc and heterogeneity on PTV was found for all sites, and no significant impact was found in OAR doses. Planning timeline was adjusted for case suffering from AXB planning such as larynx and lung SBRT. Metal object handling starts from the physician consulting phase and added into the physician consultation questionnaire to allow time to obtain the material information.

Conclusion: Transition of dose calculation engine requires team effort. The site specific findings and the implementation process presented in this work can be used as reference for other institution.

Handouts

Keywords

Not Applicable / None Entered.

Taxonomy

TH- External Beam- Photons: Computational dosimetry engines- deterministic

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