Reducing radiation dose to pelvic small bowel in cervical cancer patients treated with Ir-192 intracavitary brachytherapy by using urinary bladder distension.

ABSTRACT

OBJECTIVES: Several techniques and devices have been used in an attempt to minimize radiation dose to gastrointestinal tract while giving pelvic radiation. We evaluated the effect of urinary bladder distension to displace pelvic small bowel out of intracavitary brachytherapy field to minimize radiation dose to small bowel in cervical cancer patients. MATERIAL AND METHOD: Eleven cervical cancer patients who received Ir-192 intracavitary brachytherapy with tandem and transverse ovoids were included in this study. Oral contrast material was used to visualize pelvic small bowel. Urinary bladder was distended by injection 125-200 ml. normal saline solution. Pelvic radiograph, anteroposterior and lateral view, was performed before and after bladder distention for brachytherapy treatment planning and comparing radiation dose at small bowel. RESULTS: The average maximum radiation dose at small bowel before and after bladder distension were 3123 cGy and 1998 cGy respectively. The summation of small bowel dose was reduced 54.17% (p = 0.002). CONCLUSION: Urinary bladder distension could effectively displace pelvic small bowel and reduce the radiation dose to small bowel from Ir-192 intracavitary brachytherapy in cervical cancer patients.