A dosimetery study on different irradiation technique for esophageal carcinoma by 3 dimensional treatment planning system(3D-TPS)
- VernacularTitle:用三维放射治疗计划系统评估食管癌常规放射治疗计划
- Author:
Wei LI
;
Kuai-Le ZHAO
;
Guo-Liang JIANG
;
Li-Jun ZHOU
;
Lan-Fei CHEN
;
Xue-Hui SHI
;
- Publication Type:Journal Article
- Keywords:
esophageal carcinoma;
3D-TPS;
conventional radiotherapy;
dose-volume histogram
- From:China Oncology
2006;0(11):-
- CountryChina
- Language:Chinese
-
Abstract:
Background and purpose:Coventional radiation has been used for decades,but the 3D dose distribution has not been studied as yet.In this study,different treatment plans of conventional irradiation technique for esophageal carcinoma have been evaluated by 3-D TPS.Methods:Five patients with esophageal carcinoma at upper-thoracic and five patients at middle-thoracic were enrolled in this study.Three conventional treatment plans were created for each patient,with a prescribed dose of 70 Gy.For tumor at upper-thoracic,plan 1 consisted of one anterior field and bilateral posterior oblique fields with wedges,plan 2 consisted of anterior bilateral oblique fields with wedges ,plan 3 consisted of a pair of AP-PA portals,then followed by right anterior oblique portals and left posterior oblique portals to spare spine cord.For tumor at middle thoracic,plan 1 consisted of one anterior field and bilateral posterior oblique fields.Plan 2 consisted of a pair of AP-PA portals and followed by another pair of parallel-opposed lateral off- cord fields as boost.Plan 3 used the same plan as for the lesion at upper-thoracic.The evaluation of each treatment plan was carried out by dose-volume histogram(DVH).Results:For tumor at upper-thoracic,on average,the maximum dose to spinal-cord in plan 3 was (57.1?4.9)Gy,and was higher than that in plan 1 and plan 2.Plan 1 increased mean lung dose from (12.8?2.1)Gy to (18.2?4.1)Gy(P=0.045)compared with plan 2,but it improved the homogenous dose of PTV2,especially in the patient with long tumor.For tumor at middle-thoracic,on average,plan 2 increased mean lung dose from (11.9?1.1)Gy to (13.0?0.6)Gy(P=0.045) compared with plan 3.Plan 2 increased V_(20) and V_(30) from (23.6?2.3)% to (29.2?1.9)%(P=0.004) and (13.9?2.3)% to (20.9?1.3)%(P=0.006) compared with plan 1.The trachea volume of(?)70 Gy(V_(70))in plan 3 was larger than that in plan 1[(20.3?15.9)% VS (10.5?9.8)%,P=0.058].Conclusion:For tumor at upper-thoracic,plan 1 and 2 were superior to plan 3.Irradiation to lung in plan 2 was lower than that in plan 1,but plan 1 improved the homogenous dose of PTV2 compared with plan 2,especially for patient with longer lesion.For tumor at upper-thoracic,plan 2 increased irradiation dose to lung compared with plan 1 and plan 3.Plan 1 was comparable with plan 3,but the dose of trachea in plan 1 may lower than that in plan 3.
