Assessment and performance evaluation of photon optimizer (PO) vs. dose volume optimizer (DVO) for IMRT and progressive resolution optimizer (PRO) for RapidArc planning using a virtual phantom

Ravindra Shende, Gourav Gupta, Ganesh Patel, Shenthil Kumar


Purpose: The purpose of the study was to present the quantitative and qualitative evaluation of newly incorporated photon optimizer (PO) versus previously was used independent dose volume optimizer (DVO) for intensity modulated radiation therapy (IMRT) and progressive resolution optimizer (PRO) for Rapid-arc/ volumetric modulated arc therapy (VMAT) in version 13.5 of Eclipse treatment planning system (ETPS).

Methods: We accomplished this study with the help of cylindrical virtual phantom created in the ETPS. Six individual phantoms study sets (PSS) were generated and different material density value was assigned in order to evaluate the behavior optimizers in the presence of tissue heterogeneity. Several independent plans were generated for IMRT and Rapid-arc by changing optimizer module PO, DVO, and PRO for 6 MV, 15 MV flattened beam and 6 MV-flattening filter free (FFF) beam.

Results: The self-governing evaluations of PO versus DVO for IMRT plan and PO versus PRO for Rapid-arc/VMAT plans were performed. We estimated and compared various distinct parameters such as maximum dose, minimum dose, mean dose, conformity index (CI), quality index (QI), homogeneity index (HI), integral plan monitor unit (MU) and dose volume histogram (DVH). The percentages of the average variation over all PSS and beam energy between PO versus DVO optimized plan quality parameters such as planning target volume (PTV) maximum, minimum, mean doses, CI, QI and HI were 0.23%, 1.67%, 0.09%, 20.4%, 0.77% and 0.52% , respectively, whereas for PO versus PRO were 1.18%, 3.38%, 0.19%, 8.11%, 2.78%, and 1.28%, respectively.

Conclusion: The results presented in this study showed that PO generates plans with better quality in shorter time compared to DVO and PRO for both IMRT and Rapid-arc/VMAT, respectively.


Optimization, Dose Volume Optimizer, Progressive Resolution Optimizer, Photon Optimizer, IMRT, Rapid-arc

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