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Objective:To evaluate the accuracy and stability of stereotactic radiosurgery (SRS) algorithm in optical surface imaging (OSI) system in non-coplanar radiotherapy.Methods:Three OSI imaging systems were used to measure the phantom repeatedly at different couch rotation angles to analyze the accuracy and stability of OSI system. Seven patients with multiple brain metastases who underwent single-center non-coplanar radiotherapy were randomly selected, and the accuracy and stability of OSI for patient imaging were analyzed. Stability is defined as the difference between the two OSI measurements when the couch is turned from 0° to a non 0° angle, and then back to 0°, using the 0° cone beam CT (CBCT) as the "gold standard". Accuracy is defined as the difference between OSI and CBCT (at 0° couch angle) measurement data. The measurement data with normal distribution were described as Mean ± SD. The data with non-normal distribution were expressed as M (Q). The difference of the former data was compared by one-way ANOVA, and the difference of the latter data was assessed by Kruskal-Wallis H nonparametric test. Results:For non-coplanarity, the translation accuracy of the phantom and the patient was ≤ 1.30 mm and ≤ 1.00 mm, and the rotation accuracy was ≤ 0.50° and ≤ 0.60°, respectively. The translation errors mainly occurred in the left-right and head-foot directions. In terms of stability, the maximum standard deviation of phantom coplanar translation and rotation was 0.06 mm and 0.06°. The maximum standard deviation of patient translation and rotation was 0.17 mm and 0.19°.Conclusions:Although the new SRS algorithm improves the non-coplanar accuracy, it still cannot meet the precise requirements of non-coplanar single isocenter radiotherapy for multiple brain metastases, especially in the left-right and head-foot directions. When the couch rotation angle is large, OSI is not recommended for image-guided radiotherapy. However, its high stability can be used to monitor the intrafractional motion of patients.
RESUMO
Objective To provide a representative,objective and operable evaluation tool for agsessing tlle quality of clinical internship of nursing students,and through fuzzy evaluation and feeding back information scientmcauy to improve clinical teaching quality comprehensively.Methods Employing the method of"sorting of experts contrast"to score assessing indicators according to the importance in the undergraduate nursing internship by 10 experts,using mathematical methods to calculate the index weight,and applying fuzzy mathematics to the quality evaluation of nursing internship. Results The project had appropriate indicators and objective and reasonable weight.By applying this system,the general state of intemship students asessod by the clinical teachers and the head nurses was evaluated fuzzily,which was in accordance with the actual performance of students.Conclusions The index system with the characteristics of modern practice teaching concepts combines comprehensiveness with innovation,importance with completeness,accords with the teaching goals of nursing students,and the fuzzy evaluation of that will be better to evaluate the internship quality of nursing students comprehensively and objectively.