Dosimetry study on conformal radiation therapy, intensity modulated radiation therapy and intensity modulated arc radiotherapy in middle thoracic esophageal cancer / 肿瘤研究与临床

ABSTRACT

Objective To compare the dosimetry of three different radiation therapy plans [threedimensional conformal radiation therapy (3DCRT),intensity modulated radiation therapy (IMRT),intensity modulated arc radiotherapy (IMAT)].Methods Selected 15 cases with middle thoracic esophageal cancer,Varian Eclipse 8.6 planning systems were designed with 3DCRT,IMRT,IMAT,3DCRT using 5-8 coplanar radiation fields,IMRT using 7 coplanar radiation fields,IMAT using 2 radians.Three planned dose difference were compared.Results Compared with 3DCRT,IMRT and IMAT were better with heterogeneity index (HI),conformality index (CI),VPTV 95 ％,V5,V20,V35 of total lung,and V30 of heart (t =2.531,P＜ 0.05).There was no statistically significant difference for the V10,V15,V25,V30 mean dose of total lung,the mean dose of heart,the maximum dose of spinal cord,and the minimum dose of PTV among the three plans (t =1.325,P ＞0.05).Conclusion IMAT and IMRT are similar in the middle thoracic esophageal cancer radiotherapy target volume dose coverage and organs at risk protection,they are better than 3DCRT.IMAT in the monitor units and delivery time are less than IMRT.