医用回旋加速器束流引出位置对液体靶工作效率的影响

目的探讨医用回旋加速器引出束流轰靶的位置对液体靶生产正电子同位素能力的影响。方法选择最佳磁场电流范围;固定轰靶的束流强度（30μA）、靶室压力（350±10Psi）、核反应时间（T=30min）及靶水体积（1.5mL H2O18）,利用18O（p,n）18F核反应生产18F同位素;以圆形靶膜正中为坐标原点,建立直角坐标平面,调整回旋加速器加速粒子的引出位置,分别使2/3束流截面面积位于不同的两个相邻象限内,测量不同条件下反应结束后获得的18F的放射性活度。结果束流中心定位于靶膜正中位置时获得的18F的放射性活度为（710±30）mCi（n=15）;束流中心定位于靶膜正中位置垂直偏下,且2/3束流截面积位于圆形靶膜的第三、四象限内时,获得的18F的放射性活度为（860±50）mCi（n=15）;束流中心定位于靶膜正中位置偏左或偏右,且2/3束流截面积位于第二、三象限或第一、四象限时,获得的18F的放射性活度都为（640±35）mCi（n=15）;束流中心定位于靶膜正中位置偏上,且2/3束流截面积位于第一、二象限时,获得的18F的放射性活度为（550±40）mCi（n=15）。结论轰靶束流的引出位置的改变会直接影响液体靶的工作效率;当束流中心定位于靶膜正中位置偏下通过时,液体靶的工作效率最好。

Impact of Medical Cyclotron Beam Extraction Position on the Liquid Target Efficiency

Objective To investigate the impact of medical cyclotron beam extraction position on the liquid target efficiency.Methods Selected the best magnetic field current range,and fixed target beam intensity of the H（30μA）,target chamber pressure（350±10Psi）,the nuclear reaction time（t = 30min） and the target water volume（1.5mL H2O18）,the use of 18O（p,n） 18F nuclear reaction 18F isotope production;in the middle of a circular target membrane origin for the coordinates of the establishment of rectangular coordinate plane,adjust the cyclotron to accelerate particles leads to positions,respectively,so that 2/3 of the beam cross-sectional area of two adjacent located in different quadrants,the measurement of reaction under different conditions,18F radioactivity is measured in the end.Results The beam center located in the middle of the target membrane the location of 18F radioactivity is measured in obtained for the 710±30mCi（n=15）;beam center located in the middle position of the target membrane under the vertical side,and 2/3 of the beam cross-sectional area is located in a circular target membrane the third and fourth quadrant when radioactivity is measured with the 18F 860±50 mCi（n=15）;beam center located in the middle of the target membrane with the location of left or right,and 2/3 of the beam cross-sectional area is located in the second and third quadrant or the first,four quadrant and limit access to the 18F radioactivity is measured in both the 640±35 mCi（n=15）;beam center located in the middle position of the target membrane on the side,and 2/3 of the beam cross-sectional area located in One,two quadrant when it was measured as the 550±40 mCi（n=15）.Conclusion The location of the target changes will directly affect the efficiency of the liquid target;when the beam center located in the target membrane side through the middle position,the liquid target,the efficiency of the best.