The Influence of Different Target Margin Parameters on the Quality of Volumetric Modulated Arc Therapy Plan after Radical Surgery for Breast Cancer
Objective To explore the influence of different target edge parameters on the quality of volume arc intensity modulated radiotherapy(VMAT)plan after radical surgery for breast cancer.Methods With the retrospective analysis of the clinical data of 14 patients with breast cancer who underwent VMAT in hospital from January 2021 to December 2022,three sets of VMAT plans with different target area margin parameters were designed using the Monaco planning system for each patient.The dosimetric indices of the three target areas[average dose of PTV(Dmean),maximum dose(Dmax),2%volume exposure dose of PTV(D2%),98%volume exposure dose of PTV(D98%),50%volume exposure dose of PTV(D50%),Conformity Index(CI),Heterogeneity Index(HI),dose gradient index(GI)],organ at risk(OARs)dosimetry index[percentage of lung volume on the affected side(V5,V20,V30)and mean dose(Dmean),percentage of lung volume on the healthy side(V5)and mean dose(Dmean),Percentage of cardiac volume(V5)and mean dose(Dmean),maximum dose of spinal cord(Dmax)and mean dose of healthy mammary gland(Dmean),and planning parameters[planned control points(CP),monitor unit(MU)and beam exit time(T)]were compared.Results The Dmean,Dmax,D2%,D50%,HI,and GI of the Tight group were lower than those of the Narrow group and the Normal group,and the Dmean,D2%,D50%,HI,and GI of the Narrow group were lower than those of the Normal group,with statistical significance(P<0.05);There was no statistically significant difference in Dmax between the Narrow group and the Normal group(P>0.05);The D98%and CI of the Tight group were higher than those of the Narrow group and the Normal group,and the D98%of the Narrow group was higher than that of the Normal group,with statistical significance(P<0.05);There was no statistically significant difference in CI between the Narrow group and the Normal group(P>0.05).The cardiac V5,Dmean,and spinal Dmax of the Tight group were lower than those of the Narrow group and the Normal group,and the Narrow group was lower than the Normal group,with statistical significance(P<0.05);The Dmean of the healthy breast in the Tight and Narrow groups was lower than that in the Narrow group,and the difference was statistically significant(P<0.05);There were no statistically significant differences in the dosimetric indicators of other OARs among the three groups(P<0.05).The CP,MU,and T of the Tight group were higher than those of the Narrow and Normal groups,and the Narrow group was higher than the Normal group,with statistical significance(P<0.05);The MU of the Tight group was higher than that of the Narrow and Normal groups,and the differences were statistically significant(P<0.05);There was no statistically significant difference in MU between the Narrow group and the Normal group(P>0.05).Conclusion When the VMAT plan is designed after radical surgery for breast cancer,the reasonable setting of target edge parameters can improve the dosimetry characteristics and help to improve the accuracy and therapeutic effect of radiotherapy.
Radiation therapyRadical surgeg breast cancerVolumetric modulated arc therapyMargin parameters of the target areaDosimetry
万方数据
维普
