| Background:Cervical cancer is one of the most common malignant tumors in female reproductive system,and its incidence ranks fourth in the world of female cancer.At present,the treatment of cervical cancer includes surgery,radiotherapy,chemotherapy and biotherapy,and radiotherapy plays an important role both in the early postoperative period and in the later treatment.2016 NCCN guidelines recommend preoperative radiotherapy for patients who include stageⅡA,which can prolonge the progression free survival and overall survival.Concurrent chemoradiotherapy for patients with stageⅡB,However,radiotherapy can improve the survival rate of patients and prolong the survival time of patients,Including radiation proctitis,radiation cystitis,increasing blood toxicity,and especially white blood cells and neutrophils.In recent years,with the progress of radiation therapy technology,In particular,the development and application of three dimensional conformal radiotherapy(IMRT),volume modulated arc intensity(VMAT)and intracavitary interpolation for intracavitary radiotherapy for cervical cancer has reached an unprecedented height.At present,if there is a superiority about the dose,comparing intensity-modulated radiotherapy(IMRT),in the target area and the protection of the small intestine,rectum and bladder for volumetric modulated arc therapy(VMAT)is uncertain,and less research on bone marrow protection.Therefore,we performed a dosimetric study of cervical cancer(IMRT)and volume modulated intensity(VMAT).Objective:Objective to compare the dose,conformal index,homogeneity index and the dose of organ protection in patients with cervical cancer treated with intensity-modulated radiotherapy(IMRT)scheme and volumetric modulated arc therapy(VMAT)scheme,to determine a more appropriate way of radiotherapy for cervical cancer.Methods:Methods the clinical data of 8 patients with cervical cancer treated in our hospital from January 2015 to January 2016 were retrospectively analyzed,positioning in the CT simulation,and by the same physics division application Varian Eclipse planning system.8 patients were treated with intensity-modulated radiotherapy(IMRT)and volumetric modulated arc therapy(VMAT)for the treatment of two patients.The prescription dose of the target area: 50.4 Gy /28f/1.8Gy.In order to avoid the difference of the number of the field,the intensity-modulated radiotherapy(IMRT)plan was seven field irradiation,the volumetric modulated arc therapy(VMAT)using double arc irradiation.The two plans require 100% equal dose curve wrapped around 95% PTV.Limit organ dose according to RTOG standard: rectum V40<40%,bladder V40<30%,small intestine V30<40%,spinal cord Dmax<40 Gy.According to the specific conditions of the physics of the weight optimization.After the completion of the plan,the target area uniformity index,fitness index and the dose distribution difference of the two organs were statistically analyzed,Statistical analysis of SPSS19.0 system was used to compare the differences between the two treatments in the treatment of cervical cancer.Results:1.The volumetric modulated arc therapy(VMAT)is better than the intensity-modulated radiotherapy(IMRT)in the shape index and the uniformity index of the target area.2.The volumetric modulated arc therapy(VMAT)is more effective than the intensity-modulated radiotherapy(IMRT)to reduce the low dose area of clinical target area.3.The volumetric modulated arc therapy(VMAT)than the intensity-modulated radiotherapy(IMRT)in the rectum,bladder dose distribution on the same,each has advantages,no significant difference.4.In the protection of bone marrow,volumetric modulated arc therapy(VMAT)in V20 and above the high dose area has the advantage,but in V10 and below the intensity-modulated radiotherapy(IMRT)has the advantage.Concusion:IMRT has some advantages over the VMAT in terms of shape,evenness,MU and treatment time.VMAT increased the volume of low dose and low volume of high dose area.Therefore,the protection of VMAT in the serial organ is more meaningful. |
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