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

Kunogi H, Yamaguchi N, Wakumoto Y, Sasai K - J Contemp Brachytherapy (2015)

Bottom Line: We compared the rectal and bladder doses in 18 patients on each CT series.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology.

ABSTRACT

Purpose: 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.

Material and methods: 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.

Results: 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).

Conclusions: 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.

No MeSH data available.


Related in: MedlinePlus

Projection image of the source in the transverse dimension. In the upper image, the red source images are seed source positions without a catheter, and the bright images are source positions with the catheter. The shifts on the ventrodorsal and crosswise directions are apparent in this image. The lower image is the reference image as a comparison with the upper image to understand the source shift. In the lower image, the red source images and bright images are seed source positions with a catheter
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Figure 0002: Projection image of the source in the transverse dimension. In the upper image, the red source images are seed source positions without a catheter, and the bright images are source positions with the catheter. The shifts on the ventrodorsal and crosswise directions are apparent in this image. The lower image is the reference image as a comparison with the upper image to understand the source shift. In the lower image, the red source images and bright images are seed source positions with a catheter

Mentions: The mean source location difference in 1,200 sources among 18 patients between the CT series with and without a catheter in place was 1.3 mm (standard deviation (SD): 0.3 mm). Figures 1 and 2 show the displacements in the source positions and dose distributions, respectively. The estimated prostate volumes and results of the analysis of dose-volume histograms (DVHs) were compared with and without the catheter (Table 1). The D90 and V100 values for the post-implant prostate in all 18 patients were significantly different on CT with versus without the catheter (D90 (mean ± SD): 164 (95%) ± 20 Gy vs. 162 (94%) ± 20 Gy, p = 0.012; V100 (mean ± SD): 113 ± 14% vs. 111 ± 14%, p = 0.023). The UD10 and UD30 values in 18 patients were significantly different on CT with versus without the catheter (UD10 (mean ± SD): 152 ± 19% vs. 157 ± 19%, p < 0.001; UD30 (mean ± SD): 139 ± 14% vs. 143 ± 13%, p = 0.001).


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

Kunogi H, Yamaguchi N, Wakumoto Y, Sasai K - J Contemp Brachytherapy (2015)

Projection image of the source in the transverse dimension. In the upper image, the red source images are seed source positions without a catheter, and the bright images are source positions with the catheter. The shifts on the ventrodorsal and crosswise directions are apparent in this image. The lower image is the reference image as a comparison with the upper image to understand the source shift. In the lower image, the red source images and bright images are seed source positions with a catheter
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499521&req=5

Figure 0002: Projection image of the source in the transverse dimension. In the upper image, the red source images are seed source positions without a catheter, and the bright images are source positions with the catheter. The shifts on the ventrodorsal and crosswise directions are apparent in this image. The lower image is the reference image as a comparison with the upper image to understand the source shift. In the lower image, the red source images and bright images are seed source positions with a catheter
Mentions: The mean source location difference in 1,200 sources among 18 patients between the CT series with and without a catheter in place was 1.3 mm (standard deviation (SD): 0.3 mm). Figures 1 and 2 show the displacements in the source positions and dose distributions, respectively. The estimated prostate volumes and results of the analysis of dose-volume histograms (DVHs) were compared with and without the catheter (Table 1). The D90 and V100 values for the post-implant prostate in all 18 patients were significantly different on CT with versus without the catheter (D90 (mean ± SD): 164 (95%) ± 20 Gy vs. 162 (94%) ± 20 Gy, p = 0.012; V100 (mean ± SD): 113 ± 14% vs. 111 ± 14%, p = 0.023). The UD10 and UD30 values in 18 patients were significantly different on CT with versus without the catheter (UD10 (mean ± SD): 152 ± 19% vs. 157 ± 19%, p < 0.001; UD30 (mean ± SD): 139 ± 14% vs. 143 ± 13%, p = 0.001).

Bottom Line: We compared the rectal and bladder doses in 18 patients on each CT series.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology.

ABSTRACT

Purpose: 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.

Material and methods: 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.

Results: 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).

Conclusions: 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.

No MeSH data available.


Related in: MedlinePlus