The Research Of Setup Errors In Nasopharymgeal Carcinoma Precise Radiotherapy Based On CTVision

Objective:Research the setup errors of NPC and experimental mold by CTVision system.Preliminary discussion CTVision treatment planning system of PTV margin, to guide clinical precise radiotherapy.Methods:The case group were collected from 2014 January to guide during 2014 June in our department full use of IIGRT for NPC patients with a total of 21 cases.For CTVision image guided system comes with a large aperture CT scan, 1 times per week for image guided, an average of 6 times for each patient image guided, received a total of 132 pieces of CT image authentication.The experimental group by using a self designed and simulated head neck and body of the experimental production of the mold, a total of 10 times CT scanning and positioning, design and complete the 10 radiotherapy plan, test 7 times each image guided radiotherapy plan, a total of 70 scans.Analysis of a swing error will get the case group and experimental group three directions, a preliminary discussion on PTV margin in NPC.Results:The case group under a total of 132 CT images in the CTVision image-guided radiotherapy system,the setup errors on x,y,z were(0.19±1.24)mm,(0.15±1.35)mm,(0.25±1.12)mm.The experimental group under a total of 70 CT images in the CTVision image-guided radiotherapy system,the setup errors on x,y,z(0.23±1.29)mm,(0.23±1.45)mm,(0.40±1.29)mm.The case group and the experimental group setup errors data in X, Y, Z direction is no statistical significance(P = 0.833, 0.707, 0.400). Conclusions:1.Setup errors in the three directions of all the CT scans were detected.2.NPC patients setup error were small, little difference in three directions.3.IGRT of NPC patients in our department, CTV extended 3mm can guarantee the accuracy of treatment.4.This experiment used CTVision system performs the experimental mold radiotherapy treatment plan verification intuitive and convenient data acquisition, to NPC placed the variation of position error.