Abstract

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Title:: Effect of setup errors on dosimetric distribution in intracranial stereotactic radiotherapy

Author(s):: CUI Xiangli1; 2; ZHANG Liwei1; FEI Zhenle1; WANG Hongzhi1; 1. Cancer Hospital, Chinese Academy of Sciences, Hefei 230031, China; 2. Anhui Province Key Laboratory of Medical Physics and Technology/Center of Medical Physics and Technology/Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China

Keywords:: ; Keywords: intracranial stereotactic radiotherapy; setup error; dose distribution; image-guided

Abstract:: Abstract: Objective To investigate the effect of setup errors on dose distribution in intracranial stereotactic radiotherapy (SRT) for improving positioning scheme. Methods Ten patients receiving intracranial SRT was randomly enrolled in the study. The cone beam CT before and after radiotherapy was acquired by XVI and then was registered with planning CT to obtain the setup errors before and during radiotherapy. Moreover, Xio planning system was used to investigate the effects of setup errors on the conformity, mean dose and maximum dose of planning target areas. Results The setup errors before and during intracranial SRT were (3.40±1.14) and (0.36±0.12) mm, respectively. The relative conformity index of planning target areas was reduced from 1.00±0.00 to 0.81±0.17 (P=0.007, t=-3.494). The relative mean dose was increased by 1.56%±1.15 % (P=0.002, t=4.304). The effect of setup errors during radiotherapy on dose distribution was negligible. Conclusion Using image-guided frameless intracranial SRT with online correction of setup errors can achieve high geometric and dosimetric accuracies.