Comparison of positioning accuracy between optical positioning system and cone beam CT in nasopharyngeal carcinoma radiotherapy
Objective To evaluate the application value of optical positioning system(OPS)in radiotherapy positioning of nasopharyngeal carcinoma.Methods 36 patients with nasopharyngeal carcinoma receiving radiotherapy were studied.Personalized head pillow and head,neck and shoulder thermoplastic film were used for body position fixation,and 6 infrared light reflection positioning balls were fixed on the thermoplastic film before CT scan.Cone beam CT(CBCT)(kV level)was used for position verification and shift bed correction during the first treatment.Based on CBCT tumor center positioning values,OPS and indoor laser positioning system tumor center positioning values were compared and analyzed.The alignment and positioning time of OPS and CBCT were recorded,and the stability of the OPS positioning error was analyzed.Results The alignment of OPS and CBCT in left and right direction(X-axis),abdominal and dorsal direction(Y-axis)and head and foot direction(Z-axis)were 94.4%,75.0%and 97.2%,and those of the indoor laser positioning system in X-axis,Y-axis and Z-axis were 69.4%,72.2%and 44.4%.The alignment in X-axis and Z-axis of OPS and CBCT was significantly higher than that of indoor laser positioning system,and the difference was statistically significant(P＜0.05),and the alignment in Y axis was not statistically significant(P＞0.05).There was no statistically significant difference(P＞0.05)in translation errors of the X-axis(Bone-T-LR),Y-axis(Bone-T-AP),Z-axis(Bone-T-CC),and rotation errors of X-axis(Bone-R-LR),Y-axis(Bone-R-AP),and Z-axis(Bone-R-CC)during the first and second OPS positioning.The average time of OPS positioning was(1.8±0.6)min,which was significantly shorter than(9.4±3.1)min of CBCT positioning(t=14.442,P=0.000＜0.05).Conclusion In nasopharyngeal carcinoma radiotherapy,OPS positioning has good consistency with CBCT,with good stability and significantly shortened positioning time,which can avoid additional radiation caused by CBCT,improve the safety and operation efficiency of nasopharyngeal carcinoma radiotherapy,and have high application value.
NETL
NSTL
万方数据
维普
