Dosimetric impact of fluence smoothing levels on radiotherapy planning for nasopharyngeal carcinoma
LUO Yi
HU Xiang-ying
LIAO Zhi-chun
He Ya-di
LI Zheng-huan
Abstract：Objective To investigate the dosimetric effects of different fluence smoothing(FS)levels in the Monaco treatment planning system(TPS)on intensity-modulated radiotherapy(IMRT)plans for nasopharyngeal carci-noma(NPC).Methods CT data from 26 patients with NPC were used to generate IMRT plans using the Monaco TPS under identical optimization conditions.The FS levels were set to High,Medium,Low,and Off.The plans were evaluated based on conformity index(CI)and homogeneity index(HI)for the planning target volume(PTV),mean dose(Dmean),maximum dose(Dmax),and dose-volume metrics for organs at risk(OARs),as well as plan delivery time(PDT)and monitor units(MU).Results Among the four FS levels,there were no significant differences in PTV dosim-etric parameters(TC,HI,CI)(P＞0.05).For OARs,significant differences were observed in the Dmean of the thyroid and larynx between the H&M and H&O comparisons(P＜0.05),while other OAR parameters showed no statistically sig-nificant differences(P＞0.05).The average MU values from High to Off were 826.38,807.26,833.57,and 824.1,respectively,with corresponding plan delivery times of 382.88 s,354.92 s,375.56 s,and 368.96 s.The Medium FS level yielded the lowest MU and PDT,with reductions of 3.12％and 7.31％,respectively,compared to the highest val-ues(P＜0.05).Conclusion All FS levels in Monaco 5.11 TPS produced clinically acceptable IMRT plans for NPC.However,considering overall target coverage,OAR sparing,and delivery efficiency,the Medium FS level was found to be the most optimal.
Keywords：fluence smoothingintensity-modulated planningnasopharyngeal carcinomatreatment planning systemdosimetry
Publication Date：2025-08-15
Online Publishing Date：2025-11-06(First online date of this platform, not the publication date of the document)
Pages：5( 1212-1216 )