Study on the significance of consistency of preoperative and postoperative bladder filling in patients with cervical cancer for target area and organ at risk in IMRT / 中华放射肿瘤学杂志

ABSTRACT

Objective Bladder filling in patients with cervical cancer before and after operation during intensity-modulated radiotherapy (IMRT) was controlled by using bladder volume measurement instrument (BVI 9400).The displacement errors of the target area and the changes of the irradiation dose and the morphology of the filling bladder were compared.The significance of consistency of preoperative and postoperative bladder filling in IMRT for cervical cancer was investigated.Methods Forty-five patients with cervical cancer treated with radiotherapy in our hospital in 2018 were recruited and divided into A,B and C groups (n=15).In group A,patients did not undergo surgery,patients in group B received radical resection of cervical cancer (bladder volume measurement (BVI 9400) was utilized to monitor the bladder urine volume in both A and B groups before treatment).In group C,patients who self-controlled urination without monitoring bladder urine volume before treatment were randomly selected.All patients in three groups underwent KV-CBCT scan before treatment for online registration analysis.The displacement errors in the x-(left and right),y-(head and foot),z-axis directions (ventral and dorsal),PTV coverage volume percentage (V10o) and percentage difference (△ V100) of the prescription dose were calculated.Results The average displacement errors in the x-,y-,z-axis directions were as follows1.67 mm,1.55 mm and 1.67 mm in group A,1.43 mm,1.58 mm and 1.84 mm in group B,and 2.27 mm,2.30 mm and 2.08 mm in group C,respectively.In group A,the V1oo was calculated as 96.96％ and △ V1oo was 1.17％.In group B,V1oo was 9 5.9 ％ and △ V10o was 1.2 9 ％.In group C,V10o was 9 4.0 2 ％ and △ V100 was 2.1 7 ％.Conclusions Controlling the consistency of bladder filling can reduce the effect of inconsistency of bladder filling upon the displacement errors to certain extent,which can guarantee the accuracy of the target location and the irradiation dose of the target,protect the bladder,small intestine and rectum,and alleviate the radiation-induced response of cervical cancer patients.