THE INFLUENCE OF FULL BLADDER ON DOSE DISTRIBUTION DURING INTRACAVITARY BRACHYTHERAPY

In the present study, the difference in dose distributions at reference points due to the bladder fullness were evaluated in 61 intracavitary applications for 51 patients with carcinoma of the uterine cervix or endometrium. Also the differences between two intracavitary applications in 10 patients who had more than one application were evaluated. The mean doses at the bladder neck, bladder base, vagina and rectum were alike both for the empty or full bladder. The greatest dose difference was at the bladder chain point both in operated and inoperable cases however this difference did not follow a special pattern. In operated cases the bladder base received a higher dose than the bladder neck (p=0.000, p=0.001 respectively) whereas the opposite was observed in inoperable patients (p=0.001, p=0.017 respectively). There was no statistically significant difference at the reference points between the first and second applications in patients who had two brachytherapy applications. During treatment planning it would be more helpful to determine the dose to the bladder both at the bladder neck and bladder base. Although no difference was observed at the reference points due to empty or full bladder it would be more appropriate to give the treatment with full bladder in order to displace the intestines away from the radioactive sources.

Keywords: gynecological cancer, intracavitary brachytherapy