Dosimetric Advantage Of Volumetric Rotation Intensity Modulation And Static Fixed-field Intensity Modulation In Radiotherapy For Stage ?b Cervical Cancer

Objective:The purpose of this study was to investigate the dosimetric differences between VMAT and 5F-IMRT?7F-IMRT in stage?b cervical cancer radiotherapy.Methods:By collecting select 10 patients who underwent radical radiotherapy?b period of primary cervical cancer patients?both by pathological diagnosis of squamous cell carcinomas?as the research object,use the Pinnacle³ 9.6 treatment planning system,for all patients,line 5f-imrt,7f-imrt,and design of the double arc VMAT three kinds of radiation,according to the special CT radiotherapy simulation location machine scanning image,clinical target area?CTV?and the surrounding organs?OAR?threatening the sketch.The target target area of the three groups of treatment plans and the dosimetry differences of the organs at risk were compared,the total number of hoppers?MU?and Time?S?of the treatment were compared.Results:1.The dose distribution of three kinds of treatment plan are accord with the requirement of target prescription dose,VMAT plan of CI is?1.17±0.08?slightly higher than 5f-imrt?1.07±0.11?and 7f-imrt?1.08±0.08?,7f-imrt slightly higher than5f-imrt,statistically significant difference?P<0.05?;However,there was no significant difference in prescription dose distribution and HI?P>0.05?.2.The MU of the VMAT plan is?553.2±111.5?,which is significantly lower than 5f-imrt?627.8±119.1?and 7f-imrt?640.5±109.9?;In the treatment time?Times?,the VMAT plan?164.9±47.7?S was significantly lower than 5f-imrt?407.0±52.8?S and 7f-imrt?458.7±92.5?S,and 5f-imrt was slightly lower than 7f-imrt?P<0.05?.3.To the protection of the bladder,VMAT V₃₀0 is?85.6±11.4?%slightly less than5f-imrt?91.9±8.8?%,while V₄₀0 is?57.2±15.8?is slightly lower than 5f-imrt?70.4±16.8?and 7f-imrt?62.0±13.6?,the above differences are statistically significant?P<0.05?.4.For the protection of the small intestine,VMAT's V₃₀?35.6±10.4?%was slightly less than 5f-imrt?40.5±9.9?%and 7f-imrt?38.4±11.1?%,V₄₀0 as?9.9±7.0?%slightly less than 5f-imrt?16.5±10.2?%and 7f-imrt?13.0±8.2%?%;At the same time,the V₁₅5 of 5f-imrt?84.9±7.1?was slightly lower than that of VMAT?90.4±6.6?%and 7f-imrt?88.7±6.1?%.All the above differences were statistically significant?P<0.05?.5.There was no statistically significant difference in the dose volume comparison between the rectum and bilateral femoral head of the three treatment plans?P>0.05?.Conclusion:Compared to IMRT,VMAT for the treatment of stage IIIb cervical cancer:1.The dose distribution characteristics of the target target area are comparable,but the target area of VMAT is better than IMRT.2.Treatment time is significantly shorter.3.To some extent,the irradiation volume of the small intestine and bladder is reduced.4.For the protection of the rectum and bilateral femoral head,no obvious advantage was seen.5.IMRT is preferably 7F-IMRT from the standpoint of dosimetry.