Effect of a urinary catheter on seed position and rectal and bladder doses in CT-based post-implant dosimetry for prostate cancer brachytherapy.

To assess the variability in rectal and bladder dosimetric parameters determined according to post-implant computed tomography (CT) images in patients with or without a urethral catheter.

Patients with prostate cancer who were scheduled to undergo CT after brachytherapy between October 2012 and January 2014 were included.

We obtained CT series with and without a urinary catheter in each patient. We compared the rectal and bladder doses in 18 patients on each CT series.

The shifts in the seed positions between with and without a catheter in place were 1. 3 ± 0. 3 mm (mean ± standard deviation). The radiation doses to the rectum, as determined on the CT series, with a urethral catheter were higher than those on CT without a catheter (p < 0. 001). Radiation doses to the bladder with a catheter were significantly lower than those without a catheter (p = 0. 027).

Post-implant dosimetry (PID) with no catheter showed significantly lower rectal doses and higher bladder doses than those of PID with a catheter. We recommend the PID procedure for CT images in patients without a catheter. Use of CT with a catheter is limited to identifying urethral position.

Journal of contemporary brachytherapy. 2015 Jun 29 [Epub]

Hiroaki Kunogi, Nanae Yamaguchi, Yoshiaki Wakumoto, Keisuke Sasai

Department of Radiation Oncology. , Department of Radiation Oncology. , Department of Urology, Juntendo University, Hongo, Bunkyo-ku, Tokyo, Japan. , Department of Radiation Oncology.

PubMed    Full Text Article