CT引导穿刺点计算方法的研究

A study on methodology for calculating the CT-guided puncture point

目的研究 CT 引导穿刺点的计算方法。方法用几何学原理,经201例临床病例的验证,证实 GE Prospeed FⅡCT 机床坐标与图层坐标之间的函数关系。结果当机架角度为0时,床坐标与图层坐标之间的函数关系为 TWM=S190+M,T_(WM)是对应图层移动到外定位点的床坐标值,M为图层坐标值;当机架角度不为0(角度变量为0)时,床坐标与图层坐标之间的函数关系为T_(WM-1)=S190/Cosθ+M。误差与机架角度的函数关系为 X=|190(1/Cosθ—1)|。结论通过上述公式引入机架角度变量,完全符合 GE Prospeed FⅡCT 机定位的几何原理,能精确计算出目标图层的床坐标值,快速作出穿刺点定位。

Objective To study the methodology for calculating the CT-guided puncture point. Methods The functions between bed coordinates and scan section coordinates was calculated on 201 cases using a GE Prospeed F Ⅱ CT. Results When the gantry had no angulation, the function between bed coordinates and scan section coordinates was as followed： TWM = S190 ＋ M;when the gantry had some angulation, the function between bed coordinates and scan section coordinates was as followed： TWM-1 = S190/Cosθ ＋ M. The function between the error and the angulation of gantry was as followed： X = ｜ 190（1/Cosθ-1） ｜. Conclusion With the introduction of the gantry angulation according to the funcion set up as above, the bed coordinates and the punction point could be calculated accurately and quickly.