碳离子治疗计划系统中CT-WEPL校正曲线的测量研究

Study on the measurement of CT-WEPL calibration curve in carbon ion treatment planning system

目的通过实验测量建立一个计算机断层扫描-水等效路径长度(CT-WEPL)校正曲线,应用于碳离子放射治疗计划(ciPlan)系统。方法使用几个组织等效材料测量WEPL系数,在这些数据基础上,根据分布拟合出CT-WEPL校正曲线。结果通过实验测得CT-WEPL=1.075×10-3 CT+1.068(CT<-85);CT-WEPL=4.247×10-4 CT+1.014(CT≥-85)。结论在实验基础上,CT值与WEPL系数之间没有固定通用的曲线,对于特定的CT机,应该建立一个专用的CT-WEPL校正曲线。

Objective To establish a computerized-tomography water equivalent penetration length(CT-WEPL)calibration curve for the carbon ion treatment planning(ciPlan)system.Methods Several tissue-equivalent materials were adopted for measuring the WEPL coefficients.The CT-WEPL was acquired by fitting the corresponding curve according to the experiment data.Results CT-WEPL=1.075×10^(-3) CT+1.068(CT<-85);CT-WEPL=4.247×10^(-4) CT+1.014(CT≥-85).Conclusion On the experimental basis,there is no fixed general calibration curve between CT number and WEPL coefficient in carbon ion beams.For a specific CT machine,a dedicated CT-WEPL calibration curve should be established.