RESUMO
Objective To evaluate the dosimetric characteristics of base dose plan compensation (BDPC) optimization method applied on the intensity-modulated radiotherapy (IMRT) for upper esophageal carcinoma,based on the Eclipse treatment planning system.Methods Nineteen patients were included.For each case initial IMRT plan was generated and further optimized respectively by the two following methods:the BDPC method and hot and cold spot control (HCSC) method.Then the BDPC and HCSC plans were compared concerning planning-target-volume (PTV) coverage,conformity index (CI),and homogeneity index (HI),as well as organ-at-risk (OAR) sparing,planning time,monitor unit (MU) and delivery time.Results Compared with the HCSC plans,the BDPC plans provided superior CI and HI (Z =-3.662,-3.745,P ＜ 0.05),as well as lower D2％ (near-maximum dose) (Z =-3.823,P ＜ 0.05) and comparable D98％ (near-minimum dose) (P ＞ 0.05) for PTV64 (high-risk PTV),and provided superiorCI (Z=-3.340,P＜0.05),lower D95％ and D98％ (Z=-3.582,-2.616,P＜0.05) for PTV54 (low-risk PTV).The BDPC plans also provided slightly lower doses to the spinal cord and lung compared with the HCSC plans (Z =-3.625--3.369,P ＜ 0.05).Moreover,the planning time [(26.05 ±0.88) min] for BDPC plans was less than that of the HCSC plans [(33.73 ± 3.24) min] (Z =-3.823,P ＜0.05).The MU of the BDPC plans (1 019 ± 167) was higher than that of the HCSC plans (1 003 ±159) (Z=-2.616,P＜0.05),while the delivery time [(3.52 ±0.29) min] was more than that of the HCSC plans [(3.50±0.28) min] (Z=-2.548,P＜0.05).Conclusions The BDPC optimization method can significantly improve target dose homogeneity and conformity with effective reduction of the dose to OARs for upper esophageal carcinoma.Moreover,it is simple and can improve the treatment planning efficiency.