ABSTRACT
Objective To establish a rapid synchrony tracking precision detection method for the CyberKnife system by comparing the data between experimental measurements and end to end (E2E) result.Methods The auto quality assurance (AQA) phantom was placed on the synchrony motion plat and irradiated by two orthogonal beams.The concentricity of the beam projection center on the film and the wolfram center were analyzed through AQA software to detect tracking precision.The planning implement time of experimental measurements and E2E was then compared.Results No significant difference was found between the measurement and E2E data (P ＞ 0.05).The time for setting up and modeling in two approaches was identical and the average time for planning implement was 144 and 723 s,respectively.Conclusions The method in our analysis could reduce the procedure time and supplement the AQA and synchrony E2E test,which might be conducted in the morning quality assurance (QA) or weekly QA for CyberKnife system.
ABSTRACT
Objective To analyze the differences between CyberKnife radiotherapy with different numbers of gold markers.Methods A total of 424 patients undergoing CyberKnife with gold markers from 2013 to 2014 were enrolled and analyzed.In these patients,330 patients with no less than 3 gold markers were assigned to observation group and 94 patients with less than 3 gold markers were assigned to control group.The setup error and treatment error were recorded and analyzed for each patient.Results The mean setup error and mean treatment error were 0.031 mm and 0.314 mm in the observation group and 0.057 mm and 1.122 mm in the control group,respectively.Conclusion Tracking no less than 3 gold markers can substantially improve the accuracy and quality of treatment.
ABSTRACT
Objective To investigate the impacts of fiducial tracking and X-sight tracking on the short-term therapeutic effect of cybernikife in the treatment of lung cancer.Methods Retrospective analysis was performed on 64 lung cancer patients (72 lesions),including 40 primary tumor patients (41 lesions) and 24 metastatic tumor patients (31 lesions),who were treated with cyberknife.Fiducial tracking was used for 45 lesions,while X-sight tracking was used for 27 lesions.The planning target volume was covered by 70％-94％ (median 80％) isodose contour.The irradiation dose was 60 Gy/3 fractions.The relationship between short-term therapeutic effect and tracking method was determined.Results Overall,the lesions undergoing fiducial tracking showed significantly higher response rate than those undergoing X-sight tracking (93％ vs.74％,x2 =6.84,P=0.033),and so was in lower lung lesions (15％ vs.7％,x2 ＝7.18,P=0.028).But the two tracking methods achieved similar effects in upper lung lesions (28％ vs.12％,x2 =2.36,P =0.310).In the lesions with treatment volumes smaller than 15 cm3,the fiducial tracking achieved significantly higher response rate than the X-sight tracking (25 ％ vs.12％,x2 =6.53,P =0.038),but the two tracking methods achieved similar effects in the lesions with treatment volumes not smaller than 15 cm3 (17％ vs 8％,x2 =1.57,P =0.460).Overall,the lesions undergoing X-sight tracking had significantly highertreatment failure rate than fiducial tracking (1 9 ％ vs.2 ％,x2 =6.33,P =0.021).Conclusions Different tracking methods may lead to different therapeutic effects of cyberknife in the treatment of lung cancer,which are related to lesion location and treatment volume.