Dosimetric comparison of two algorithms in intensity-modulated radiation therapy for NSCLC

Objective: To evaluate the dose distribution of two algorithms in intensity-modulated radiation therapy (IMRT) for a basis for treatment planning of non-small cell lung cancer (NSCLC). Methods: Ten NSCLC patients were selected in this analysis. IMRT plans were created with Sliding Wnd (SLD) algorithm and Smart Sequence (SMT) algorithm. The dose distribution, MU, treatment time and result of 2 D dose verification were the parameters for comparison between those two plans. Results: D_2%, D_98%, D_mean, CI and HI of PTV from SLD algorithm were superior than that with SMT algorithm (P < 0.05). D_mean, V₂₀, V₃₀, V₄₀, V₅₀ of lungs with SLD algorithm were better than that with SMT algorithm (P < 0.05), and no significant difference in other parameters was observed between the two algorithms. The MU of SMT algorithm was reduced by 48 and the treatment time was shortened by 0.12 min compared to SLD algorithm. The dosimetry of 3%/3 mm γ passing rate of SLD and SMT were (99.2 ± 0.5)% and (99.3 ± 0.6)%;, and 2%/2 mm γ passing rate of SLD and SMT were (95.8 ± 2.3)% and (95.7 ± 2.5)%. Conclusion: The dose distribution of target, radiation dose to OAR and dosimetry passing rate of two algorithms can meet the clinical requirements, all of them can apply in IMRT for NSCLC. The dose distribution of target and protection of lungs with SLD algorithm were better than that with SMT algorithm. Our study reveals that SLD algorithm favors a more precise IMRT planning for NSCLC. (authors)