SU-F-T-614: Comparison of Pinnacle and Monaco Dose Calculations of SBRT Treatments

Authors


Abstract

Purpose:

The purpose of this study was to evaluate, compare and investigate the differences of SBRT treatment plans on dose calculation and plan metrics between Pinnacle and Monaco treatment planning systems (TPS).

Methods:

14 previously treated patients’ files were exported from the Pinnacle treatment planning system to Monaco. All of the treatment plans were created in Pinnacle and delivered on a Varian Novalis with the HD120 multi-leaf collimator. The plans were recalculated within Monaco using a Monte-Carlo algorithm. From the calculated dose distributions, the PITV, R50, conformity and homogeneity indices were computed and used for SBRT plan evaluation. Dose volume histogram comparison and OAR dose statistics were also used for the comparison.

Results:

The mean PITV for Monaco increased 7% over Pinnacle, while the standard deviation increased from 0.047 to 0.076. The Homogeneity Index increased from 1.32 to 1.35. The Target Coverage decreased slightly from 0.98 to 0.97. The standard deviations for Homogeneity Index and Target coverage varied insignificantly by less than 0.2%.

Conclusion:

The PITV increasing shows that the prescription dose volume increases, since the PTV will not change between treatment planning systems. This indicates that the more accurate dose near density change interfaces from Monaco shows the original planning has the dose shifted away from the isocenter. The homogeneity index increases shows that there is more of a change between the minimum and maximum doses within the PTV so the target coverage decreases.

Ancillary