Commissioning of GPU-based multi-criteria optimizer combined with plan navigation tools for high-dose-rate brachytherapy

Cédric Bélanger; Sylviane Aubin; Luc Beaulieu; Éric Poulin

doi:10.5114/jcb.2022.118995

Commissioning of GPU-based multi-criteria optimizer combined with plan navigation tools for high-dose-rate brachytherapy

J Contemp Brachytherapy. 2022 Aug;14(4):379-389. doi: 10.5114/jcb.2022.118995. Epub 2022 Aug 23.

Authors

Cédric Bélanger^{1

2}, Sylviane Aubin², Luc Beaulieu^{1

2}, Éric Poulin²

Affiliations

¹ Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer de l'Université Laval, CHU de Québec, Québec, Canada.
² Service de physique médicale et de radioprotection, Centre intégré de cancérologie, CHU de Québec - Université Laval et Centre de recherche du CHU de Québec, Québec, Canada.

Abstract

Purpose: Recently, our GPU-based multi-criteria optimization (gMCO) algorithm has been integrated in a graphical user interface (gMCO-GUI) that allows real-time plan navigation through a gMCO-generated set of Pareto-optimal plans for high-dose-rate (HDR) brachytherapy. This work reports on the commissioning of the gMCO algorithm into clinical workflow.

Material and methods: Our MCO workflow was validated against Oncentra Prostate v. 4.2.2 (OcP) and Oncentra Brachy v. 4.6.0 (OcB). 40 HDR prostate brachytherapy patients (20 with OcP and 20 with OcB) were retrospectively re-planned with gMCO algorithm by generating 2,000 Pareto-optimal plans. A single gMCO treatment plan was exported using gMCO-GUI plan navigation tools. The optimized dwell positions and dwell times of gMCO plans were exported via DICOM RTPLAN files to OcP/OcB, where final dosimetry was calculated. TG43 implementation in gMCO was validated against the consensus data of flexisource. Five analytical shapes were used as the ground truth for volume calculations. Dose-volume histogram (DVH) curves generated by gMCO were compared with the ones generated by OcP/OcB. 3D dose distributions (and isodose lines) were validated against OcP/OcB using dice similarity coefficient (DSC), 95% undirected Hausdorff distance (95% HD), and γ analysis.

Results: Differences between -0.4% and 0.3% were observed between gMCO calculated dose rates and the flexisource consensus data. gMCO volumes were within ±2% agreement in 3/5 volumes (deviations within -2.9% and 0.1%). For 9 key DVH indices, the differences between gMCO and OcP/OcB were within ±1.2%. Regarding the accuracy of key isodose lines, the mean DSC was greater than 0.98, and the mean 95% HD was below 0.4 mm. The fraction of voxels with γ ≤ 1 was greater than 99% for all cases with 1%/1 mm threshold.

Conclusions: The GPU-based MCO workflow was successfully integrated into the clinical workflow and validated against OcP and OcB.

Keywords: GPU; commissioning; high-dose-rate brachytherapy; interactive planning; multi-criteria optimization; plan navigation.