Study On The Use Of Ultrasound To Monitor Bladder Volume To Reduce The Volume Of Normal Tissue Irradiation In Pelvic Radiotherapy

Objective:Explore the application of conventional B-ultrasound equipment to monitor the change of bladder volume and provide technical support for accurate radiation therapy of pelvic tumors to reduce the dose of normal tissues such as intestines.Materials and Methods: This study collected 40 patients who were admitted to the First People’s Hospital of chen zhou City from March 2019 to August 2019 and were diagnosed with pelvic tumors.These patients were trained for urinary urination and applied conventional B-ultrasound at different time periods(15-30 min,30-45 min,45-60 min,60-75 min,75-90min)monitor the bladder volume to obtain the best time window for bladder filling;randomly select 10 patients from40 patients to use the best time for bladder filling Window to monitor the bladder volume weekly during radiotherapy and compare it with the initial CT scan to verify the reproducibility of the optimal bladder filling time window during actual radiotherapy;5 patients were randomly selected from 40 patients in The bladder filling and bladder emptying are used in the radiotherapy plan.DVH is used to compare the radiation dose of bladder filling and normal tissues under bladder emptying to evaluate the acute toxicity during radiotherapy.Result:1.After urinary training,the conventional B-ultrasound measurement of bladder volume is in good agreement with the CT scan to determine the bladder volume.2.The bladder volume was measured at different time periods(15-30 min,30-45 min,45-60 min,60-75 min,75-90min)and a scatter plot was drawn.The results showed that the predicted value and measured value of the bladder volume of the patient were between The correlation coefficient was 0.705(P> 0.6),and the correlation was the best.It was determined that 60-75 min was the best time window for bladder volume filling.3.There was no significant difference in bladder volume measurement among patients with urination using the best time window in different genders,different tumor types,and with or without a history of pelvic surgery(P> 0.05).4.Ten patients were randomly selected for repeated monitoring of bladder volume.The initial CT scan of the bladder filling volume was very close to the bladder volume during treatment,and there was no significant difference between the two(P> 0.05).5.Five patients were randomly selected from 40 patients to make a bladder filling and emptying bladder radiotherapy plan.The dose-volume histogram(DVH)showed that the intestinal and bladder irradiation volumes in the bladder filling state were significantly reduced compared to the empty state.6.Monitor the occurrence of acute side effects during radiotherapy.The incidence of acute side effects in the gastrointestinal tract and urinary system is low and the symptoms are mild.Conclusion:1.The best time window for bladder filling was determined using B-mode monitoring at 60-75 min after drinking.2.During the course of radiotherapy,the irradiation volume of normal pelvic organs is significantly reduced when the bladder is full,compared with the empty state;the acute toxicity is less and light.