Study on the correlation between bladder volume and dose distribution in intensity modulated radiotherapy for cervical cancer
Objective To explore the effect of bladder volume changes on bladder dosimetry in intensity modulated radiation therapy(IMRT)for cervical cancer.Methods A total of 10 cases of cervical cancer patients who underwent concomitant radiochemotherapy at Beijing Obstetrics and Gynecology Hospital,Capital Medical University from January 2020 to December 2021 were selected.All patients were treated with IMRT technol-ogy combined with 192 Ir high-dose rate brachytherapy.In the first week of external irradiation,cone beam computed tomography(CBCT)was per-formed once before each radiotherapy for the first five times,and once a week thereafter.Based on CBCT images,the bladder structure was redrawn and transplanted into the planned CT images to obtain the actual bladder volume and dose distribution during treatment,and the correlation be-tween standardized bladder volume(CBCT bladder volume/CT bladder volume)and standardized bladder dose(CBCT bladder dose/CT bladder dose)was analyzed.Results The bladder volume in CBCT image was smaller than that in planning CT image,and the standardized bladder average volume was(0.96±0.31).Due to the effects of volume changes,the bladder dose in CBCT image was higher than that in planning CT image.The standardized bladder average dose and standardized average V45 were(1.01±0.03)and(1.03±0.12),respectively.There was no correlation between standardized bladder volume and standardized bladder average dose(P＞0.05).Standardized bladder volume was positively correlated with standardized V45(r=0.870,P=0.001).Conclusion In the treatment of IMAT for cervical cancer,the consistency of bladder filling degree is poor.The larger the bladder volume,the greater the bladder dose V45.Based on image-guided radiotherapy,the patient's bladder volume should be kept as consistent as possible with the bladder volume during localization to avoid excessive dose to the bladder.
Cervical cancerIntensity modulated radiotherapyCone beam computed tomographyBladder volumeDose distribution
NETL
NSTL
万方数据
