Do auto-planning intensity modulated radiotherapy treatment plans for central lung cancer have improved quality over manual plans?

Background : To investigate the performance of Auto - Planning intensity modulated radiation therapy (IMRT) plans for patients with central lung cancer and to determine whether Auto - Planning improves the quality of IMRT plans. Materials and Methods : Thirty patients treated with IMRT for central lung cancer were replanned with the Pinnacle 3 Auto - Planning module. The dose distribution at the target, organ at risk (OAR) sparing, dose falloff in the five rings outside of target, monitor units (MUs), planning time, and dosimetric verification in terms of the γ passing rate were evaluated. A Wilcoxon signed - rank test was performed to assess differences between groups (p<0.05). Results : The target homogeneity in the Auto - Planning were significantly better than that in the manual plans, the target conformity in both groups were similar. The Auto - Planning plans yielded lower V 5 , V 10 , V 13 , V 20 , V 30 , V 40 values, mean lung dose of total lung (p<0.01), and D max of spinal cord (p<0.01) and V 30 of heart (p<0.01). No significant difference was found for the V 40 of the heart (p=0.203). The Auto - Planning module reduced the D mean , D 2 and D 5 values in all rings outside of PTV. The planning time was 52.5% shorter for Auto - Planning plans than for manual plans (p<0.01), and 4.4% additional MUs were required with Auto - Planning. No difference was observed for the γ passing rate. Conclusion : Auto - Planning for central lung cancer could improve homogeneity of target volumes, significantly delivery lower dose to OARs and steeper dose falloff outside of tumors while reducing the planning time.