肛管排气术对子宫颈癌腔内近距离放疗剂量学的影响OA

Objective To compare the dosimetric differences in the target volumes and organs at risk(OARs)of intracavitary brachyther-apy for cervical cancer patients with rectal distension before and after rectal gas evacuation,and to evaluate the protective effect of rectal gas evacuation on these patients.Methods Ten typical cervical cancer cases with rectal distension were collected from the First Affiliated Hospital of Ningbo University from June 2023 to January 2025.These patients had positive or close surgical margins after cervical cancer surgery,received external beam radiotherapy followed by intracavitary brachytherapy,and developed rectal distension due to rectal gas during treatment.Intracavitary brachytherapy plans were designed for the patients with rectal distension and after rectal gas evacuation,and dosimetric differences between the target volumes and OARs were compared.Results Both plans met the requirement for 90%target volume dose coverage.After rectal gas evacuation,D98[(5.27±0.17)Gy vs(5.51±0.31)Gy],V150[(56.05±5.32)%vs(65.18±4.72)%],and V200[(29.98±5.36)%vs(38.92±6.99)%]all decreased(all P<0.05),while D100 showed a decreasing trend[(3.99±0.39)Gy vs(4.37±0.35)Gy,P=0.052].After rectal gas evacuation,the D1cc,D2cc,and D5cc of the rectum were significantly reduced(all P<0.05).There were no significant differences in the bladder's D1cc,D2cc,and D5cc between the two plans(all P>0.05).Conclusions Rectal gas evacuation significantly reduces the radiation dose to the rectum with less effect on the bladder.While there is a slight decrease in target dose cover-age,it still maintains a high level of coverage.