Dosimetric effects of boundary range scattering dose planning mode on Cyberknife treatment of lung cancer brain metastases / 医疗卫生装备

ABSTRACT

Objective To explore the dosimetric effects of a self-developed planning mode of boundary range scattering dose(BRSD)on Cyberknife treatment of lung cancer brain metastases.Methods The positioning images of 15 patients with lung cancer brain metastases treated in the radiotherapy department of some institution from January 1,2021 to December 31,2021 were selected and introduced into Cyberknife Multiplan 4.0.3 treatment planning system.A fractionated stereotactic radiotherapy(FSRT)plan(as the FSRT planning group)and a BRSD plan(as the BRSD planning group)were developed for each patient.The FSRT planning group developed a plan for the planning target volume(PTV)in the conventional way,so that V100 covered more than 95％of the PTV;the BRSD planning group prepared a plan for the gross tumor volume(GTV)with the same parameter conditions as the FSRT planning group and the prescription dose was normalized to the PTV so that V100 covered more than 95％of the PTV.The dosimetric parameters of the target area and normal tissue of the 2 groups were compared by dose-volume histograms and isodose curves.Statistical analysis was performed using SPSS 24.0 software.Results The D98,Dmax and Dmean in the target area of the BRSD planning group were significantly higher than those of the FSRT planning group,and the differences were statistically significant(P<0.05);the differences in the conformity index,dose gradient index,and Dmean,V30,V24 and D3cc in normal tissue of the 2 groups were not statistically significant(P>0.05);the BRSD planning group gained a denser dose distribution when compared with the FSRT planning group.Conclusion The BRSD planning mode gains significant dosimetric advantage by enhancing the absorbed dose to the target area without increasing or decreasing the dose to normal tissue.