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Objective To analyze the difference of dosimetry and evaluate clinical efficacy and acute toxicity reaction between RapidArc and fixed gantry angle dynamic intensity modulated radiotherapy (IMRT) in advanced cervical carcinoma.Methods A total of 43 patients with locally advanced cervical cancer were studied,including 22 patients treated with RapidArc and 21 patients with IMRT.All plans were prescribed 50.4 Gy in 28 fractions.The conformity index and homogeneity index of the targets,the monitor units(MUs) and delivery time were compared.Incidence of acute intestinal and bladder side effects and rates of efficacy were calculated.Results The conformity index of RapidArc was better compared to IMRT.The V40 and V50 of bladder and V30,V40 and V50 of rectum planned by RapidArc was significantly lower than that by IMRT(t =-2.386,-2.397,P ＜0.05;t =-5.525,-2.883,-2.686,P ＜0.05).The mean dose of femoral head planned by RapidArc was also significantly lower (t =-2.395,P ＜ 0.05).For RapidArc,mean MU and treatment time were reduced by 53.15％,and 62.14％,respectively.There was no difference in the incidence of acute intestinal and bladder toxicity and rates of complete remission and efficacy between the two groups.Conclusions In dosimetric analysis,RapidArc showed advantage in protecting organs at risk and reducing treatment time in radical radiotherapy for locally advanced cervical carcinoma.
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Objective To compare the planning quality and acute toxicity between RapidArc and fixed gantry angle dynamic intensity modulated radiotherapy (IMRT) in the postoperative radiotherapy for cervical cancer patients.Methods All 35 patients with cervical cancer who had received postoperative radiotherapy were studied,including 17 patients with RapidArc and 18 patients with IMRT.All plans were prescribed 50 Gy in 25 fractions.The dose-volume histogram data,the conformity index and homogeneity index of the targets,the monitor units (MUs) and delivery time were compared.During the treatment,the incidence of acute intestinal and bladder side effects were also compared.Results Compared to IMRT,the conformity index of RapidArc was better(t =3.13,P ＜ 0.05),but the homogeneity index was slightly worse (t =-4.25,P ＜ 0.05).The V20 and V30 of femoral head planned by RapidArc was significantly lower than that by IMRT (t =2.56,2.34,P ＜ 0.05).The mean MU for RapidArc was reduced by 52.1％ compared with IMRT.The mean treatment time for RapidArc was decreased by 46.8％ compared with IMRT.There was no difference in the incidence of acute intestinal and bladder toxicity between the two groups.Conclusion For patients with cervical cancer who need prophylactic postoperative radiotherapy,both RapidArc and IMRT plan can achieve equal target coverage and organs at risk(OAR) sparing.There is no significant difference in dosimetric parameters and acute toxicity between the two groups.Compared with IMRT,RapidArc plan has fewer MUs and less treatment time and significantly improves the treatment efficiency.
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ObjectiveTo discuss dosimetric characteristics of an intensity-modulated radiotherapy (IMRT) technique for treating the chest wall and regional nodes as an integrated volume after modified radical mastectomy ( MRM ),and observe acute side-effects following irradiation.Methods From June 2009 to August 2010,75 patients were randomly enrolled.Of these,41 had left-sided breast cancer.Each eligible patient had a planning CT in treatment position,on which the chest wall,supraclavicular,and infraclavicular nodes,+/-internal mammary region,were contoured as an integrated volume.A muhi-beam IMRT plan was designed with the target either as a whole or two segments divided at below the clavicle head.A dose of 50 Gy in 25 fractions was prescribed to cover at least 90％ of the PTV.Internal mammary region was included in 31 cases.Dose volume histograms were used to evaluate the IMRT plans.The acute side effects were followed up regularly during and after irradiation.The independent two-sample t-test was used to compare the dosimetric parameters between integrated and segmented plans.ResultsPlanning design was completed for all patients,including 55 integrated and 20 segmented plans,with median number of beams of 8.The conformity index and homogeneity index was 1.43 ± 0.15 and 0.14 ± 0.02,respectively.Patients with internal mammary region included in PTV had higher homogeneity index PT.The percent volume of PTV receiving ＞ 110％ prescription dose was ＜ 5％.None of the dose constraints to normal structures was violated.There were statistically significant differences in the means of dosimetric parameters of PTV,such as Dmax,DmeanV107％,and V110％,between integrated and segmented plans (t=2.19 -2.53,P=0.013-0.031 ).≥ grade 2 radiation dermatitis was identified in 3 2 patients ( grade 2 in 2 2 patients,grade 3 in 10 patients ),mostly occurred within 1 - 2 weeks after treatment.The sites of moist desquamation were anterior axillary fold (27/37) and chest wall (10/37).Only 2 patients developed grade 2 radiation pneumonitis.Conclusions The IMRT technique applied after MRM with integrated locoregional target volume is dosimetrically feasible,and the treatment was proved to be well-tolerated by most patients.