Abstract：Objective To study the relationship between tumor size,source intensity,prescription dose and source dwell time in the after-loading treatment plan,and to establish a method that can be used for rapid quality control of after-loading plans.Methods The all of gynecological cancer patients treated in this hospital were selected:84 cases of all three tubes of Fletcher applicator,58 cases of uterine alone and 39 cases of vaginal applicator. Each patient was scanned with CT before treatment. Contouring the target and organs at risk,the treatment plan was optimized using IPSA. Record the source strength,prescription dose,source dwell time,and tumor volume of the prescribed dose for each case. Calculate CI values and Rv. The k-value analyzes the CI distribution characteristics and the correlation with the Rv value. In addition,46 cases of gynecologic tumor patients were used to verify the method.Results The fitting index of the after-loading scheme of the three applicators showed a normal distribution. The mean value of the Fletcher applicator CI was 0.720±0.067,the k value was 1 394,Rvalue was 0.894. The mean value of the uterine alone CI was 0.697±0.076,the k value was 1 428,R=0.940,the mean value of the vaginal applicator CI was 0.742±0.067,the k value was 1 362,and R=0.909.Conclusions Using this method,it can quickly assess whether the planned target volume,radiation source intensity,prescription dose and treatment time match,and find the cause of deviation based on the feedback Results to ensure that the after-loading treatment plan can be quickly,accurately,and efficiently implemented according to clinical requirements.
Ji Tianlong,Zhao Jing,Shen Hao et al. A fast quality assurance method for three-dimensional Afterloading treatment plan[J]. Chinese Journal of Radiation Oncology, 2019, 28(7): 543-546.
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