Dosimetry Research Of Injury Of Hearts And Lungs In Patients With Esophageal Cancer Treated With IMRT

Objective To observe the influence of the doses of organs at risk such as hearts and lungs to their functions in patients with esophageal cancer with intensity-modulation radiatedtherapyMethods Intensity-modulation radiated therapy (IMRT) plan was designed on Topslane Venus TPS for 29 patients with untreated esophageal cancer which were 23 males and 6 females, Karnofsky performance status(KPS) was﹥or﹦70.They can have some fluid or semifluid .None had phymatosis medical records and mortal disease .Everyone had not troisier sign and metastasis .The length of tumor was 4cm～7cm by barium meal before radiotherapy was accepted and it was 3.2cm-6.1cm by chest computer tomography ( we think pathological changes exist if the thick of esophagus wall≧0.5cm). age distribution was 32-70y,the median age was 61y.The type of pathology was all squamous cell carcinoma.They were immobilized with vacuum bag from MED-TEC in the dorsal position under simulator, the body marks and its coordinate parameters were made by positioning technology of multipoint fixed ,then they were scanned by spiral computer tomography ,the selected region which included focus of infection was successive scanned by 3-5mm each layer .then these imaging information was transmitted to treatment planning system (TPS) through local area network. Target and normal organ would be draw gross tumor volume(GTV).Clinical target volume (CTV) was enlarged 0.5 cm on the base of GTV and planning target volume (PTV) was enlarged 1 cm on the base of clinical target volume. Several IMRT treatment plans were designed for each patients by doctor in charge and physicist and prescription dose was 60-68Gy. the relationship of injury of lungs and hearts and the irradiated volume of them with Dose volume Histogram(DVH) and clinical factor on the conditions of 95% prescription dose covers PTV would be analyzed.Results V20 of lung has significant difference for radioactivity injury of lungs in these pertinent factors such as Dmax,Dmean,V10,V20,V30 , V45and V10 of heart have significant difference for radioactivity injury of hearts in these pertinent factors such as Dmax,Dmean,V10,V20,V30.Conclusion dosimetry factor can predict well the occurrence of injure of hearts and lungs.V20 of lung is important factor for injury of lung.V45 and V60 of heart are important factors for injury of heart.