医用回旋加速器Saturated Yields参数选择的实验研究校正时

Study on the parameters selection during saturated yields calibration of medical cyclotron

【摘要】目的医用回旋加速器的活度指示校正是针对SaturatedYields进行校正，使其可以准确显示所生产药物的活度，以免造成不必要的资源浪费，因此对SaturatedYields进行校正时参数的选择显得至关重要。方法为了选择合理的参数对SaturatedYields进行校正，本研究以生产合成18F-氟脱氧葡萄糖（18F-FDG）为例，分别采用150、300、600、750、900、1200、1500μA·min进行药物合成，测量最终18F-FDG的产量；并分别对SaturatedYields进行校正，比较理论计算值和实际测量值的区别，从而找出对SaturatedYields进行校正时的合理参数。结果在300～900μA·min之间，正电子药物产量实际测量值和理论计算值呈现良好的线性关系；但是在低于300μA·min或者大于900μA·min时，并不呈现良好的线性关系。结论选择合理的参数，一般在300～900μA·min之间（粒子束流15～30μA，轰击时间20～60min），对SaturatedYields进行校正，可以使回旋加速器准确显示所生产药物的活度，降低运行成本，减少对工作人员的辐射；而对于选择小于300μA·min或大于900μA·min的参数进行校正时，不仅会造成资源浪费，而且会增加对工作人员的辐射，因此不建议使用其对SaturatedYields进行校正。

Objective In order to indicate the positron drug activity exactly in medical cyclotron, radioactivity indication must be calibrated through saturated yields, so parameters selection during saturated yields calibration plays an important role during positron drug production. Methods In order to choose parameters during saturated yields calibration 18F-FDG was took as an example in this study, parameters such as 150, 300, 600, 750, 900, 1 200, 1 500 μA·min were applied respectively during positron drug production, the yields of 18F- FDG were measured and the differences between the theoretical calculation values and practical measured values were compared. Results Experiments showed that the relation of yields between the theoretical calculation values and practical measured values was in good linear relationship when the parameters are from 300-900 μA·min, whereas out of this range, the relation was not in good linear relationship. Conclusion The parameters should be chosen appropriately during saturated yields calibration, and the range was between 300-900 μA·min,（irradiation current 15-30 μA, irradiation time 20-60 min） which wiU make medical cyclotron radioactivity indicate exactly, reduce operating cost and personal radiation dose. On the contrary, if out of this range, which will increase operating cost and personal radiation dose, so it was not recommended.