ABSTRACT
Objective To analyze the discrepancies between position adjustments obtained with the stereoscopic 2DKV XGS-10 system and the Varian OBI system for head-and-neck region IMRT treatments,and to compare for image acquisition and registration time.Methods CBCT images were obtained with OBI system and 2DKV images were acquired by XGS-10 system for 30 head-and-neck patients prior to Varian21EX IMRT treatment.The images were registered with planning image for localization,and position adjustments were given in LR,SI and AP directions,then the discrepancies between them were analyzed.On the comparison of the two different systems,the Pearson coefficient was used to analyzed the correlation and 95％ CI analysis to discern the consistence.Results Analysis of images acquired for the 30 patients yielded the following results:position adjustments with XGS-10 system were (-1.03 ± 2.15) mm,(0.86 ± 2.59) mm,(0.42 ± 1.66) mm in LR,SI and AP directions,whereas (0.00 ± 1.68) mm,(1.53 ± 2.12) mm,(0.10 ± 1.54) mm with CBCT in LR,SI and AP directions.The discrepancies were (-1.03 ± 1.24) mm,(-0.68 ± 1.78) mm and (0.32±1.61) mm in LR,SI and AP directions.The correlation coefficients between them were 0.817,0.731 and 0.495 in LR,SI and AP directions.95％ CI were (-1.47--0.59),(-1.32-0.04),(-0.26-0.90) mm.The average image acquisition and registration time were 10 s and ＜ 15 s in XGS-10 system,with 3 min and 8 min in OBI system.Conclusions Both of XGS-10 system and OBI system could be used to improve patient position accuracy,but XGS-10 system could cut down the total time.