Study On Impacts Of Bladder Filling Consistency In Radiotherapy For Pelvic Malignant Tumor

ObjectiveThis present study was to verify the reliability of the bladder ultrasound scanner.In order to explore the relationship between the interval after drinking water and the change of bladder volume,the stability of the patient's bladder was trained before radiotherapy.At the same time,the impacts of bladder filling consistency in radiotherapy for pelvic malignant tumor were explored.So as to maintain the same bladder volume during the radiotherapy and reduce the influence of bladder volume changes on the organs at risk(OAR)during the radiotherapy for pelvic cancer.Materials and methodsOur study design was a prospective study.To verify the reliability of the bladder ultrasound scanner,15 cases were choosen with pelvic malignant tumors which confirmed by pathology,the bladder ultrasound scanner was used to measure the bladder capacity before treatment.When the predetermined bladder volume was reached,planning CT was performed to calculate the bladder volume.Independent sample t-test and Pearson correlation analysis were performed on the two measurement methods to verify the accuracy of the bladder ultrasound scanner.A total of 106 patients with histologically documented pelvic malignant tumor who treated with radiotherapy in Shandong Tumor Hospital between October 2016 and July 2018 were included.In order to explore the impacts affecting the consistency of bladder filling,the stability training of bladder was carried out.Empty the bladder and drink 500 ml of water at one time.The bladder volume changed with time was recorded and repeated measurement was performed.The relationship between the bladder volume and the interval time was analyzed according.Univariate analysis was conducted on the factors that may affect bladder volume,such as gender,age,alcohol consumption,BMI and pelvic surgery,and independent sample t-test was applied.The patient's bladder volume during radiotherapy was determined,and the paired sample t-test was performed.ResultsThe mean volume of planning CT was(512.60±200.01)ml,and the bladder ultrasound scanner was(502.73±202.00)ml.There was no significant difference between the measurement results of the two devices,P>0.05.Statistical analyze showed there was a correlation between the two groups,r=0.998,P < 0.01.There was a certain correlation between bladder volume and time when the water intake of the patients was 500 ml,and the correlation coefficient was 0.693,P < 0.05.Pelvic surgery and BMI had influence on bladder volume during treatment(447.66 ml vs.545.29 ml,436.54 ml vs.473.43ml),P < 0.05.Statistical analyze showed there was a statistically significant difference in bladder volume for time except V1(P < 0.05).Pelvic surgery was a relevant factor affecting the consistency of bladder filling.There was no significantly difference between gender,age,alcohol consumption and BMI index and bladder filling,P > 0.05.Compared with the bladder volume at the beginning of treatment,the bladder volume decreased(113.78 55.74)ml,or about 24.7%,throughout the treatment.The difference was statistically significant(P < 0.05),indicating that the bladder volume decreased during radiotherapy,and the bladder volume after treatment was significantly smaller than that before treatment.Conclusions1 There was a significant correlation between the bladder volume measured by bladder ultrasound scanner and the planning CT.2 Surgery is the main influencing factor of bladder filling.BMI index and whether or not pelvic surgery has an effect on bladder volume during positioning.3 The bladder volume decreased gradually during radiotherapy,and the bladder ultrasound scanner was used to monitor the bladder volume during the treatment,which could reduce the decrease of the bladder volume during radiotherapy.