Dosimetric comparison in 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy with 5-field for thoracic middle esophageal carcinoma / 肿瘤研究与临床

ABSTRACT

Objective To compare the difference of dosimetric results between 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) with 5-field for thoracic middle esophageal carcinoma.Methods Ten patients with thoracic middle esophageal carcinoma were involved in this study.Four treatment plans were designed for each patient,including one 3D-CRT plan and three IMRT plans with 5-field and all evaluation contents were compared.Results There were no significant differences of cord Dmax,total-lung mean dose (Dmean),L-lung Dmean and R-lung V25,V30.Significant differences of heart V30,V40 and Dmean were obtained among the plans,with the lowest of 5IMRT2 (V3028.67±15.97,V4013.04±7.28,Dmean2097.76±718.26) and 5IM RT3(27.39±14.96,13.00±7.32,2096.16±718.85),the highest of 5CRT (43.27±18.69,26.83±19.18,2393.48±896.12) and 5IMRT1 (41.81±17.16,23.08±11.17,2403.77±834.73).There were significant differences of L-lung V5,V10,V15,V20 V25 and V30.All IMRT plans reduce V20,V25 and V30.5IMRT1 did not increase V5 (54.39±7.58) and V10 (44.76±6.30),but reducesd V15 (20.86±5.16),5IMRT2 (V570.89±7.95,V1050.94±8.71,V1534.20±6.62) and 5IMRT3 (V570.26±7.94,V1049.80±7.62,V1534.60±5.40)increased V5,V10 and V15.There were also significant differences of R-lung V5.V10,V10,V20 and Dmean.All IMRT plans reduced V20,but increased Vs and V10.5IMRT1 did not increase V15 (23.67±5.73) and Dmean (923.49±182.34); 5IMRT2 did not increases V15 (26.72±±6.79) but increases Dmean (1060.34±205.02); 5IMRT3 increased both V15 (32.40±6.59) and Dmean (1100.54±197.84).Significant differences were found in Dmean,homogeneity index (HI) and conformity index (CI) of PTV,with the best Dmean of 5IMRT1 (6219.80±37.90),the second of 5IMRT3 (6268.91±56.26); the best HI of 5IMRT1 (0.0870±0.0219) and 5IMRT3 (0.0990±0.0219);the best CI of 5IRT2 (0.8682±0.0172) and 5IMRT3 (0.8667±0.0183).Conclusion 5-field IMRT plans have the advantages in the treatment of thoracic middle esophageal carcinoma with better HI,CI of target volume and sparing of lung (V20,V25 and V30) compared to 3D-CRT.5IMRT1 plan has the advantages in reducing low-dose volume (V5,V10,V15 and Dmean) of lung.