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Validation of Automatic Planning Scripts for Prostate SBRT with and Without Lymph Nodes

C Venencia*, M Almada, O Apaza Blanco, I Marquez, O Muriano, P Murina, Instituto Zunino -Fundacion Marie Curie, Cordoba, ARGENTINA

Presentations

PO-GePV-T-402 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

ePoster Forums

Purpose: Validate an automatic planning (AP) for prostate SBRT with and without lymph nodes against manual plans using and not using RapidPlan

Methods: ESAPI and Microsoft Visual Studio were used to create an Scripts (C#) executable in Eclipse v15.6 (Varian). It included VMAT plan generation, optimization based on RapidPlan (PO_15606), dose calculation and plan evaluation (data extraction from ARIA database). TrueBeam STx with 10MV and HDMLC were used. RapidPlan models (SBRT_36.25Gy and SBRT_40/25Gy) were created and validated using 40 planse. 50 patients for each SBRT modality were selected. Each patient was replanned by an experienced physicist manually (MP), using RapidPlan tool during the optimization (MP_w/RP), and executing the AP Script. A comparison was done using PTVs D98% and D2%, CI (conformity index), GI (gradient index), HI (homogeneity index), MU (monitor units) and OARs (rectum and bladder) dose volume constraints compliance. For a subgroup of plans (20 patients for each treatment modality), patient specific QA using portal dosimetry (gamma criterion of 2%/1mm and Th10%) were compared. Statistical analysis was done using ANOVA with Turkey-Kramer comparison test. A p-value ≤ 0.05 was considered statically significant.

Results: For prostate SBRT_36.25Gy, no differences for D98%, GI, HI and OARs dose volume constraints. MP showed higher D2% and MU were found. AP improves CI and portal dosimetry passing rate compared to MP and MP_w/RP. For prostate SBRT_40/25Gy no differences for D98% (PTV_High_4000!), D95% (PTV_Low_2500!), GI and HI were found. MP showed higher D2%. AP showed less MU. There were no differences for OARs dose volume constraints except for bladder V20Gy where MP have higher values. AP improves CI and reduce the MU compared to MP and MP_w/RP. There were no differences in portal dosimetry results

Conclusion: AP generate identical or better plan results than MP and MP_w/RP for prostate SBRT with and without lymph nodes.

Keywords

Not Applicable / None Entered.

Taxonomy

TH- External Beam- Photons: Treatment planning using machine learning/Knowledge Based Planning/automation

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