Analysis of positioning error of within batch and between batches of HyperArc stereotactic radiotherapy for intracranial tumors
10.3969/j.issn.1672-8270.2025.02.003
- VernacularTitle:HyperArc立体定向放射治疗颅内肿瘤分次内及分次间摆位误差分析
- Author:
Nan LI
1
;
Lang YU
1
;
Xiansong SUN
1
;
Huiying QU
1
;
Yijun WANG
1
;
Bo YANG
1
;
Xin LIAN
1
Author Information
1. 中国医学科学院北京协和医院放疗科 北京 100730
- Publication Type:Journal Article
- Keywords:
Positioning error;
Stereotactic radiotherapy(SRT);
6-dimensional free bed;
Intracranial tumor
- From:
China Medical Equipment
2025;22(2):15-19
- CountryChina
- Language:Chinese
-
Abstract:
Objective:Based on HyperArc stereotactic radiotherapy(SRT)technique,six-dimensional free bed combined with double mask fixation was used to treat intracranial tumors,and the positioning errors of within batch and between batches were analyzed,so as to provide basis for the accuracy of clinical treatment of this technique.Methods:A total of 13 patients with intracranial tumors who admitted to Peking Union Medical College Hospital from March to July 2023 were retrospectively selected,and they were treated by using HyperArc SRT technique.The validation images of cone-beam computed tomography(CBCT)of within batch and between batches during treatment were analyzed.The positioning errors of three translational direction[left and right(x),head and foot(y)and abdominal and dorsal(z)]and rotational direction were analyzed.The each positioning error was set as group A,and the remaining error after the positioning error was corrected through six-dimensional free bed was set as group B,and the error post treatment was set as group C.The difference between group B and group C was defined as the change of within batch.According to the margin formula,the positioning error of within batch was used to calculate the required range of margin.Results:Under the mode of six-dimensional free bed correction combined with double mask fixation,a total of 59 times of HyperArc SRT on head were performed.In the comparison of the average errors on the six-dimensional direction among groups A,B and C,the errors of group A on x direction and y direction were respectively(0.119±0.039)and(-0.133±0.047)cm,and the differences of them between group A and group B[(0.004±0.002)and(0.018±0.005)cm]were significant(t=2.890,-3.224,P<0.05).There were no significant differences on other directions between the two groups(P>0.05).The error of RX direction of group B was(0.033±0.021)°,and the difference of that between group B and group C[(0.122±0.045)°]was significant(t=-2.306,P<0.05),while there were no significant differences on other directions(P>0.05).In the margin of the design of the plan of intracranial tumors,the x,y and z directions were respectively 0.6,0.9 and 0.4 mm.Conclusion:In the radiotherapy of using HyperArc SRT technique for intracranial tumors,the use of six-dimensional free bed combined with double mask treatment can significantly shorten the margin,and ensure accurate irradiation for gross tumor volume(GTV)and simultaneously reduce the irradiation volume and dose of surrounding normal tissue.
