Study on dosimetric verification of VMAT treatment planning for chest esophageal carcinoma / 中华放射肿瘤学杂志

ABSTRACT

Objective To study the dosimetry characteristics of VMAT plan in the esophageal carcinoma radiotherapy.Methods Application of 0.6 cm3 ionization chamber and COMPASS threedimensional dose verification system,20 cases of upper and middle chest esophageal carcinoma on the VMAT plans for absolute dose and relative dose verification.Dose volume histogram (DVH) comparison treatment target,lungs,heart,and differences in the spinal cord irradiation dose and volume,and analyses γpass rate of GTV,CTV,PTV and organs at risks.Results The center dose of upper and middle chest esophageal carcinoma accurate rates were above 99％.Thoracic segment esophagealGTV,PTV and organs at risks of γ pass rate above 97％.D95％ and Dmean of GTV,CTV and PTV were relatively undervalued within 3％.D1％ of spinal cord is 2.21％ overvalued.Left and right pulmonary V5 were slightly overvalued by about 0.5％,V10-D30,Dmean undervalued within 2％.In period of middle chest esophageal carcinomathe gamma passed rate of GTV,CTV,PTV and organs at risks of above 97％,GTV,CTV,PTV D95％,Dmean were relatively undervalued within 2％.Spinal cord D1％ is 2.04％ overvalued.Left and right pulmonary V5-D30 to V10 as a trend of gradually to be underestimated,at 1.5％.Heart Dmean was undervalued by 2.68％.Conclusion VMAT technology is applicable in the chest esophageal carcinoma radiotherapy.