应用Matrixx验证活动挡铅形成的电子束照射野

To Investigate the Dose Distribution of Electron Beam Irradiation Filed Removable Lead Block Technique with Matrixx Measurement

目的:验证活动挡铅形成的电子束照射野的剂量分布,讨论其所形成的照射野对临床照射的影响。方法:一体式挡铅组成的电子束照射野由一块规则的、对称的10 cm×8 cm空心挡铅形成,照射野大小:10 cm×8 cm;活动式挡铅组成的电子束照射野由一块长方形的14 cm×4 cm实心挡铅和一块规则、对称、一体式10 cm×10 cm空心挡铅组成,形成的照射野大小:10 cm×8 cm。使用IBA的I’mRT Matrixx分别测量一体式挡铅的电子束照射野和活动式挡铅形成的形状、面积一样的电子束照射野。用OmniPro I’mRT软件得出两种方法形成的照射野在X轴方向上的剂量分布曲线。结果:活动挡铅形成的照射野与一体式挡铅照射野的面积大小一样。但是,一体式挡铅照射野的对称轴与X轴方向上的剂量分布曲线的对称轴相一致,即剂量分布曲线以照射野x=0处的Y轴对称分布。活动挡铅照射野的对称轴是x=0处的Y轴,与X轴方向上的剂量分布曲线的对称轴x=-1处的纵轴不一致,即剂量曲线不以照射野的对称轴对称分布,剂量分布不均。结论:技师在使用高能电子束对患者进行照射治疗时,要严格按照计划和医嘱,使用与计划相匹配的一体式挡铅。

Objective： To verify the dose distribution of electron beam radiation fields what formed by activities lead block,diss cuss the radiation field that effect on the clinical exposure.Methods：Electron beam irradiation field formed by integrative lead blockthat consists of a regular、symmetrical hollow block 10 cm x8 cm lead formation, Radiation field size： 10 cmx8 cm.Elec tron beam irradiation field formed by a removable lead block that consists of a rectangular piece of 14 cmx 4 cm solid lead block and a regular,symmetrical hollow block 10 cmxl0 cm lead formation,Radiation field size： 10 cmx8 cm.Using IBA I ＇mRT Matrixx measured integrative lead block and activities lead block to form the area of the same size of electron beam radiation field.Results： A removable lead block in the area of the formation of the radiation field and an integrative lead block formation of the radiation field, the area of the same size.But, electron beam irradiation field formed by integrative lead block on the axis of symmetry and the X axis dose distribution curve of the axis of syrnmetry is the same.The dose distribution curve with radiation field ofX=O, Y axisymrnetric distributions.Electron beam irradiation field formed by a removable lead block exposure axis of symmetry is X = O, Y axis. With the X axis dose distribution curve of the axis of symrnetry on X = 1, Y axis is not the same. Dose curve is not according to the radiation field of symmetrical distribution of axial symmetry. Uneven distribution of dose. Conclusions：Technicians in the use of high energy electron beam irradiation therapy on the patients, they must be in strict accor- dance with the plan and the doctor＇s advice, use integrative lead block match the plan.