Monte Carlo-based software for 3D personalized dose calculations in image-guided radiotherapy

Coralie Le Deroff; Lucie Berger; Julien Bellec; Guillaume Boissonnat; Héléna Chesneau; Sophie Chiavassa; Julie Desrousseaux; Stéphanie Gempp; Olivier Henry; Jimmy Jarril; Delphine Lazaro; Ronan Lefeuvre; Vincent Passal; Fanny Solinhac; Caroline Lafond; Gregory Delpon

doi:10.1016/j.phro.2022.02.004

Monte Carlo-based software for 3D personalized dose calculations in image-guided radiotherapy

Phys Imaging Radiat Oncol. 2022 Feb 26:21:108-114. doi: 10.1016/j.phro.2022.02.004. eCollection 2022 Jan.

Authors

Coralie Le Deroff¹, Lucie Berger², Julien Bellec¹, Guillaume Boissonnat³, Héléna Chesneau¹, Sophie Chiavassa⁴, Julie Desrousseaux⁵, Stéphanie Gempp⁵, Olivier Henry¹, Jimmy Jarril², Delphine Lazaro³, Ronan Lefeuvre¹, Vincent Passal⁴, Fanny Solinhac⁵, Caroline Lafond^{1

6}, Gregory Delpon⁴

Affiliations

¹ Centre Eugène Marquis (Unicancer), Rennes, France.
² Centre Jean Perrin (Unicancer), Clermont Ferrand, France.
³ Université Paris-Saclay, CEA, List, F-91120 Palaiseau, France.
⁴ Institut de Cancérologie de l'Ouest (Unicancer), Saint-Herblain, France.
⁵ Assistance Publique - Hôpitaux de Marseille, Marseille, France.
⁶ Université de Rennes, Inserm, LTSI - UMR 1099, Rennes, France.

Abstract

Background and purpose: Image-guided radiotherapy (IGRT) involves frequent in-room imaging sessions contributing to additional patient irradiation. The present work provided patient-specific dosimetric data related to different imaging protocols and anatomical sites.

Material and methods: We developed a Monte Carlo based software able to calculate 3D personalized dose distributions for five imaging devices delivering kV-CBCT (Elekta and Varian linacs), MV-CT (Tomotherapy machines) and 2D-kV stereoscopic images from BrainLab and Accuray. Our study reported the dose distributions calculated for pelvis, head and neck and breast cases based on dose volume histograms for several organs at risk.

Results: 2D-kV imaging provided the minimum dose with less than 1 mGy per image pair. For a single kV-CBCT and MV-CT, median dose to organs were respectively around 30 mGy and 15 mGy for the pelvis, around 7 mGy and 10 mGy for the head and neck and around 5 mGy and 15 mGy for the breast. While MV-CT dose varied sparsely with tissues, dose from kV imaging was around 1.7 times higher in bones than in soft tissue. Daily kV-CBCT along 40 sessions of prostate radiotherapy delivered up to 3.5 Gy to the femoral heads. The dose level for head and neck and breast appeared to be lower than 0.4 Gy for every organ in case of a daily imaging session.

Conclusions: This study showed the dosimetric impact of IGRT procedures. Acquisition parameters should therefore be chosen wisely depending on the clinical purposes and tailored to morphology. Indeed, imaging dose could be reduced up to a factor 10 with optimized protocols.

Keywords: Breast; CBCT, Cone Beam Computed Tomography; Head-and-neck; IGRT; IGRT, Image Guided Radiotherapy; MC, Monte Carlo; Monte Carlo dose calculation; Personalized dose; Prostate.