Quantification of the impact of electrons transport model on DVH metrics and radiobiological indices for lung radiotherapy plans. (September 2016)

• Record Type: Journal Article
• Authors: Chaikh, Abdulhamid; Balosso, Jacques
• Is Part Of: Physica medica. Volume 32(2016)Supplement 3
• Page Start: 268
• Publication Date: 2016-09
• Subjects: Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2016.07.585
• Languages: English
• ISSNs: 1120-1797

Abstract

Abstract : Introduction and purpose: to evaluate and quantify the impact of the calculation of electrons transport on dose distribution and radiobiological predictions for lung radiotherapy. Materials and methods: The dose was calculated using the former Modified Batho (PB-MB) method and the Anisotropic Analytical Algorithm (AAA). Data derived from DVH, for target and lung, were compared. To compare dose distribution, 2D gamma ( γ ) index was applied. The radiobiological indices, TCP and NTCP, were compared using Lyman and EUD models. Spearman's rank test was used to explore the best correlation coefficient ( ρ ) predicting the dose difference. The bootstrap method was used to estimate the 95% confidence intervals, and Wilcoxon paired test to calculate p -values. Results: For the same prescribed dose, the plans generated with AAA predicted less dose and a more heterogeneous dose distribution inside the target, with p < 0.05 MB predicted a better coverage of the target, overestimating the TCP while underestimating the NTCP, with p < 0.05. The γ analysis showed that the difference between MB and AAA could reach up to ±10% confirming the results obtained from TCP/NTCP. The data showed a good correlation between TCP with D95%, as well as NTCP with mean dose, V20 and V30, with ρ > 0.7. Conclusion: The electrons transport, taken into account by AAA, showed a significant impact on delivered dose, dose distribution and TCP/NTCP. Readjusting the prescribed dose and a better optimization to protect the organs at risks should be considered and discussed when using new algorithms as AAA type. Disclosure: None.