Objective To investigate the dosimetric effects of tumor treating fields(TTFields)patches on different radiotherapy modes for glioblastoma(GBM)patients who wear TTFields patches during radiotherapy,thereby providing dosimetric guidance for determining the appropriate radiotherapy mode.Methods With the TTFields data from GBM patients,artifact-free radiotherapy CT images were obtained utilizing 3D-printed TPU TTFields patches(3D-Print-TTFields)and anthropomorphic phantoms,and then a TTFields-synchronized radiotherapy image model was constructed.Furthermore,the treatment planning system was used to construct a dosimetric calculation model for TTFields-synchronized radiotherapy by simulating and fitting the ray attenuation rate of TTFields patches measured by accelerators.Using these models,3 kinds of radiotherapy plans were simulated and developed.Specifically,P1 simulated the conventional radiotherapy mode;P2 simulated the TTFields-combined radiotherapy mode(TTF-Com-RT),in which patients underwent radiotherapy using the P1 plan while wearing TTFields patches;and P3 simulated the TTFields-synchronized radiotherapy(TTF-Syn-RT)mode where the TTFields patches were worn throughout the entire radiotherapy process.The paired t-test was used to analyze dosimetric parameters such as target dose(D95),average scalp dose(D-skin),conformity index(CI)and homogeneity index(HI)in 3 plans(P1,P2,and P3),as well as the D95 and D-skin parameters for intensity-modulated radiotherapy(IMRT)and volumetric modulated arc therapy(VMAT)techniques in the P3 plan.Results The D95 simulated by P2 decreased by 1.35%as compared with P1(P<0.05),and the D95 simulated by P3 was 1.31%higher than that in P2(P<0.05).Compared with P1,P2 and P3 increased the D-skin by 12.56%and 14.30%,respectively(P<0.05),and the D-skin simulated by P3 increased by 1.55%as compared with P2(P<0.05).However,there were trivial differences in D95 between P3 and P1,CI and HI among all plans,D95 and D-skin between IMRT and VMAT techniques in P3 plan(P>0.05).Conclusion Based on GBM patient data,CT simulation images obtained from 3D-Print-TTFields combined with anthropomorphic phantom are artifact-free and meet radiotherapy requirements.The target and scalp dose differences between TTF-Com-RT and TTF-Syn-RT are less than 2%,and the dosimetric difference of TTF-Syn-RT using IMRT/VMAT techniques is insignificant.Therefore,clinicians can choose radiotherapy modes and techniques according to actual needs.

Objective To investigate the dosimetric effects of tumor treating fields(TTFields)patches on different radiotherapy modes for glioblastoma(GBM)patients who wear TTFields patches during radiotherapy,thereby providing dosimetric guidance for determining the appropriate radiotherapy mode.Methods With the TTFields data from GBM patients,artifact-free radiotherapy CT images were obtained utilizing 3D-printed TPU TTFields patches(3D-Print-TTFields)and anthropomorphic phantoms,and then a TTFields-synchronized radiotherapy image model was constructed.Furthermore,the treatment planning system was used to construct a dosimetric calculation model for TTFields-synchronized radiotherapy by simulating and fitting the ray attenuation rate of TTFields patches measured by accelerators.Using these models,3 kinds of radiotherapy plans were simulated and developed.Specifically,P1 simulated the conventional radiotherapy mode;P2 simulated the TTFields-combined radiotherapy mode(TTF-Com-RT),in which patients underwent radiotherapy using the P1 plan while wearing TTFields patches;and P3 simulated the TTFields-synchronized radiotherapy(TTF-Syn-RT)mode where the TTFields patches were worn throughout the entire radiotherapy process.The paired t-test was used to analyze dosimetric parameters such as target dose(D95),average scalp dose(D-skin),conformity index(CI)and homogeneity index(HI)in 3 plans(P1,P2,and P3),as well as the D95 and D-skin parameters for intensity-modulated radiotherapy(IMRT)and volumetric modulated arc therapy(VMAT)techniques in the P3 plan.Results The D95 simulated by P2 decreased by 1.35%as compared with P1(P<0.05),and the D95 simulated by P3 was 1.31%higher than that in P2(P<0.05).Compared with P1,P2 and P3 increased the D-skin by 12.56%and 14.30%,respectively(P<0.05),and the D-skin simulated by P3 increased by 1.55%as compared with P2(P<0.05).However,there were trivial differences in D95 between P3 and P1,CI and HI among all plans,D95 and D-skin between IMRT and VMAT techniques in P3 plan(P>0.05).Conclusion Based on GBM patient data,CT simulation images obtained from 3D-Print-TTFields combined with anthropomorphic phantom are artifact-free and meet radiotherapy requirements.The target and scalp dose differences between TTF-Com-RT and TTF-Syn-RT are less than 2%,and the dosimetric difference of TTF-Syn-RT using IMRT/VMAT techniques is insignificant.Therefore,clinicians can choose radiotherapy modes and techniques according to actual needs.