Dose Calculation Comparisons between Three Modern Treatment Planning Systems

Courtney Bosse; Ganesh Narayanasamy; Daniel Saenz; Pamela Myers; Neil Kirby; Karl Rasmussen; Panayiotis Mavroidis; Niko Papanikolaou; Sotirios Stathakis

doi:10.4103/jmp.JMP_111_19

Dose Calculation Comparisons between Three Modern Treatment Planning Systems

J Med Phys. 2020 Jul-Sep;45(3):143-147. doi: 10.4103/jmp.JMP_111_19. Epub 2020 Oct 13.

Authors

Courtney Bosse¹, Ganesh Narayanasamy², Daniel Saenz³, Pamela Myers³, Neil Kirby³, Karl Rasmussen³, Panayiotis Mavroidis⁴, Niko Papanikolaou³, Sotirios Stathakis³

Affiliations

¹ Radiation Oncology, Colorado Associates in Medical Physics, Colorado Springs, CO 80907, USA.
² Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
³ Mays Cancer Center, MD Anderson Cancer Center, University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
⁴ Department of Radiation Oncology, University of North Carolina, Chapel Hill, NC, USA.

Abstract

Purpose: Monaco treatment planning system (TPS) version 5.1 uses a Monte-Carlo (MC)-based dose calculation engine. The aim of this study is to verify and compare the Monaco-based dose calculations with both Pinnacle³ collapsed cone convolution superposition (CCCS) and Eclipse anisotropic analytical algorithm (AAA) calculations.

Materials and methods: For this study, 18 previously treated lung and head-and-neck (HN) cancer patients were chosen to compare the dose calculations between Pinnacle, Monaco, and Eclipse. Plans were chosen from those that had been treated using the Elekta VersaHD or a Novalis Tx linac. All of the treated volumetric-modulated arc therapy plans used 6 MV or 10 MV photon beams. The original plans calculated with CCCS or AAA along with the recalculated ones using MC from the three TPS were exported into Velocity software for intercomparison.

Results: To compare the dose calculations, Planning target volume (PTV) heterogeneity indexes and conformity indexes were calculated from the dose volume histograms (DVH) of all plans. While mean lung dose (MLD), lung V5 and V20 values were recorded for lung plans, the computed dose to parotids, brainstem, and mandible were documented for HN plans. In plan evaluation, percent differences of the above dosimetric values in Monaco computation were compared against each of the other TPS computations.

Conclusion: It could be concluded through this research that there can be differences in the calculation of dose across different TPSs. Although relatively small, these differences could become apparent when compared using DVH. These differences most likely arise from the different dose calculation algorithms used in each TPS. Monaco employs the MC allowing it to have much more detailed calculations that result in it being seen as the most accurate and the gold standard.

Keywords: Radiation dose comparison; radiotherapy plan similarity; treatment planning system comparison.