ABSTRACT
Objective To evaluate the clinical feasibility of localization CT enhanced image replacing plain CT scan image for target delineation and dose calculation.Methods Forty cases of NPC were collected and divided into two groups with different concentrations of contrast agents.The contours of planning target volume (PTV) and organs at risk (OARs) of each case were delineated in the plain scan image,and the contours of PTV and OARs were copied to the enhanced image.Two plans based on the plain scan image and the enhanced image were designed in the planning system of Eclipse.The dose distribution and OARs and MU were compared between the groups.Results No statistical differences were found in the dosimetry of PTV,OARs and MU (P＞0.05).Conclusion The image intensifier has little effect on the dose calculation of Eclipse for NPC.In the radiotherapy for NPC,the localization CT enhanced image can be used to replace the plain CT scan image for target delineation and dose calculation.