Normal lung tissue complication probability in MR-Linac and conventional radiotherapy

Somayeh Gholami; Francesco Longo; Sara Shahzadeh; Hassan Ali Nedaie; Ryan Sharp; Ali S Meigooni

doi:10.1016/j.rpor.2020.09.002

Normal lung tissue complication probability in MR-Linac and conventional radiotherapy

Rep Pract Oncol Radiother. 2020 Nov-Dec;25(6):961-968. doi: 10.1016/j.rpor.2020.09.002. Epub 2020 Sep 29.

Authors

Somayeh Gholami^{1

2}, Francesco Longo³, Sara Shahzadeh⁴, Hassan Ali Nedaie^{1

2}, Ryan Sharp⁵, Ali S Meigooni⁶

Affiliations

¹ Radiation Oncology Research Centre, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.
² Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
³ Department of Physics, University of Trieste and INFN Trieste, Italy.
⁴ Department of Medical Radiation Engineering, Shahid Beheshti University, Tehran, Iran.
⁵ Department of Health Physics and Diagnostic Sciences, University of Nevada, Las Vegas, Nevada, United States.
⁶ Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada, United States.

Abstract

Purpose: To study normal lung tissue (NLT) complications in magnetic resonance (MR) image based linac and conventional radiotherapy (RT) techniques.

Materials and methods: The Geant4 toolkit was used to simulate a 6 MV photon beam. A homogenous magnetic field of 1.5 Tesla (T) was applied in both perpendicular and parallel directions relative to the radiation beam.Analysis of the NLT complications was assessed according to the normal lung tissue complication probability (NTCP), the mean lung dose (MLD), and percentage of the lung volume receiving doses greater than 20 Gy (V₂₀), using a sample set of CT images generated from a commercially available 4D-XCAT digital phantom.

Results: The results show that the MLD and V₂₀ were lower for MR-linac RT. The largest reduction of MLD and V₂₀ for MR-linac RT configurations were 5 Gy and 29.3%, respectively.

Conclusion: MR-linac RT may result in lower NLT complications when compared to conventional RT.

Keywords: Geant4 toolkit; MR-linac; Normal lung tissue complications; XCAT digital phantom.