Effect Of Bladder And Rectum Dose Induced By Bladder Filling Condition In Brachytherapy Of Uteirne Cervical Cancer

Objective: To analyze the effect of bladder and rectum dose when thebladder is filled and emptied in brachytherapy（BT） of uterine cervical cancer,which provide evidence in reducing complications of cystitis and proctitis afterthis treatment.Methods: Select20cervical cancer patients staging from FIGO IIa to FIGOIIIb,giving them three-tube brachytherapy using Holland Fletcher system. andthen choose another20cervical cancer patients staging from FIGO Ib to FIGOIIa who have undergone radical hysterectomy, giving them two-tubebrachytherapy using Holland Fletcher system. The use of CT simulation werescanned respectively after voiding bladder immediately and filling more than50ml after half an hour. Normal tissues of the bladder and rectum are outlined inthe CT images at bladder emptying and filling state. Treatment plans weredeveloped at the bladder emptyting and filling state, plan prescription dose is600cGy/fraction. According to DVH map, choose brachytherapy plan on betternormal tissue dose distribution.Results:1.In three-tube brachytherapy, the bladder irradiation dose B-D1400±70(cGy) in bladder filling condition was significantly larger than that thebladder irradiation dose B-D1332±65(cGy) in bladder emptying condition,with statistics significance (P＜0.05); the filling dose B-D2362±63(cGy) wassignificantly larger than the emptying dose B-D2296±94(cGy), with statisticalsignificance (P＜0.05); rectal radiation dose was no significant difference in the two states of bladder.2.In two-tube brachytherapy, the bladder irradiation dose b-D1395±55(cGy) in bladder filling condition was significantly larger than that the bladderirradiation dose b-D1350±76(cGy) in bladder emptying condition, withstatistics significance (P＜0.05); the filling dose b-D2368±59(cGy) wassignificantly larger than the emptying dose b-D2315±63(cGy), with statisticalsignificance (P＜0.05); rectal radiation dose was no significant difference in thetwo states of bladder.Conclutions: When cervical cancer patients underwent brachytherapy, bladderfilling condition affected bladder dose exists. Empty the bladder can protect thebladder better, reduce bladder dose. The bladder filling condition affects therectum dose not much.