Objective To propose a method for obtaining the Portal Dosimetry(hereinafter referred to as PD)splicing field(hereinafter referred to as PD splicing field)through matrix concatenation for split fields,and to analyze data of PD splicing field for cervical cancer planning.Methods Seven fields of intensity modulated therapy were selected for 20 patients with cervical cancer.Each field was divided into one pair of fields.First,a PD dose verification plan containing only the separation field was prepared,and then the linear accelerator beam was used to execute it.By means of matrix splicing and matrix superposition,PD splicing field and PD large field corresponding to each pair of PD division field were obtained respectively.Using the PD software module,the gamma pass rates of the PD splicing field and the PD large field were obtained,which were denoted as Gp and Gd respectively.Gm was used to represent the average gamma pass rate value for each pair of PD divisions.The statistical analysis and comparative study of Gp,Gd and Gm were carried out.Results The values of Gp,Gd,and Gm for all 140 large fields were 98.78％±0.70％,97.34％±1.25％and 98.87％±0.51％,respectively.Pairwise comparison results showed that there was a significant statistical difference(P＜0.05)between Gp and Gd.Overall the difference between Gp and Gm was relatively small.For each PD verification plan,the plan verification pass rate(Gplan)was calculated for all fields of the same type.Statistical analysis results of Gplan showed that there was a significant statistical difference between PD splicing field(P＜0.05)and PD large field,the difference between PD splicing field and PD split field was relatively small.Conclusion The concept of PD splicing field proposed in this study provides useful reference information for evaluating the dose verification results of PD.
维普
万方数据