不同参数设置对双侧乳腺癌螺旋断层放疗计划的影响研究OA

Objective To investigate the effects of varying parameters—such as jaw width,pitch and modulation factor—on helical tomotherapy(HT)plans for bilateral breast cancer(BBC).Methods Totally 17 BBC patients undergoing radiotherapy at some hospital from October 2013 to July 2023 had their data selected retrospectively.Different HT plans were designed with the jaw width(1.0,2.5 or 5.0 cm),pitch(0.215,0.287 or 0.430)and modulation factor(2.0,2.5,3.0,3.5 or 4.0),with the other parameters kept constant.The HT plans with different parameter settings were compared in terms of treatment time and dosimetric parameters including the maximum dose(D2),minimum dose(D98),target volume coverage(D95),V105,conformity index(CI)and homogeneity index(HI)to the planned target volume(PTV),dosimetric indexes of organs at risk(OAR)such as V5,V20,V30 and Dmean of the bilateral lungs,V5,V20,V30 and Dmean of the heart and Dmean of the liver.SPSS 20.0 software was used for statistical analysis.Results Reduced jaw width improved PTV dosimetric parameters including D98、D95、D2、D105、V105、HI and decreased doses to OARs significantly(P<0.05),but the differences in CI were not statistically significant(P>0.05);however,the treatment time increased exponentially as the jaw width decreased,with the differences being statistically significant(P<0.05).Reduced pitches resulted in modestly improved exposure doses to PTVs and OARs,with the differences being statistically significant(P<0.05),while the reduction of pitches had a minor impact on the treatment time.Increased modulation factors contributed to improving the dosimetric parameters of PTVs and OARs,with the differences being statistically significant(P<0.05).There were minor differences between the dosimetric parameters of the plans with modulation factors of 3.5 and 4.0,and for every 0.5 increase in the modulation factor the average treatment time increased by approximately 15%,with the differences being statistically significant(P<0.05).Conclusion Generally the BBC HT plan with a jaw width of 5.0 cm,a pitch of 0.215 and a modulation factor of 3.5 gains superior performance.[Chinese Medical Equipment Journal,2026,47(1):56-62].