Abstract: Objective The Objective of this study was to explore the application value of ultrasonic bladder volume monitoring technology in intensity modulated radiotherapy(IMRT)after operation of cervical cancer.Methods A total of 56 patients with cervical cancer who underwent IMRT after radical operation in our hospital from October 2018 to October 2019 were selected and divided into the observation and control groups with a random number table method,28 cases in each group.The patients in the observation group were monitored the bladder volume by the ultrasonic bladder volume meter,and the patients in the control group were instructed orally by doctors to feel subjectively the degree of bladder filling.The difference of three-dimensional target displacement error,homogeneity index(HI),conformability index(CI)and the percentage of irradiated volume of bladder,small intestine,rectum and femoral head were compared between patients in the observation and control groups.The intestinal adverse reactions during radiotherapy were also compared between patients in two groups.Results The displacement errors in the head,foot and ventral directions in the observation group were significantly lower than those of the control group,the difference was statistically significant(P＜0.001),but the displacement errors in the left and right directions of the two groups was no differences between patients in the two groups(P＞0.05).The HI in the observation group was significantly lower than that in the control group(P＜0.05),but there was no differences in CI between patients in the two groups(P＞0.05);the percentage of irradiated volume of the bladder and small intestine in the observation group was significantly smaller than that in the control group(P＜0.05),but there was no differences in the percentage of irradiated volume of rectum and femoral head between patients in the two groups(P＞0.05).There was no difference in the incidence of diarrhea between patients in the two groups(P＞0.05),but the time of diarrhea in the control group was earlier than that in the observation group.Conclusion The use of ultrasonic bladder volume monitoring technology to maintain the consistency of bladder filling in IMRT after cervical cancer surgery can reduce the displacement error of target area,increase the accuracy of target area delineation,ensure the effective radiation dose of the target area,protect the physiological function of endangered organs at a certain extent,and reduce the response to radiotherapy,it should be promoted and applied in clinical practice.

Key words: Ultrasound bladder volume monitoring, Cervical cancer, Intensity modulated radiotherapy, Target area, Organ at risk