Résumé
Objective To investigate dose characteristics of megavoltage cone-beam CT in the low MU and rotation way for imaging,and to improve the quality assuraflce. Methods Dose linearity,a parameter describing beam characteristics,was measured for different numbers of MUs on megavoltage conebeam CT accelerator.Dose stability was measured 5 times using exposure of 7 MUs,which was repeated another 5 times 6 hours after. Results Dose linearity was good using exposure between 5 and 20 MUs.The average dose among the first and second 5 measurements was(5.74±0.01)Gy and(5.76±0.01)Gy while exposure of the accelerator was 7 MU.The difference between the two doses was 0.41%. he dose was stability while megavoltage cone-beam CT image was in the low MU and rotation way. Conclusion Dose characteristics of megavoltage cone-beam CT in the low MU and rotation way for imaging can qualify clinically application.