open access

Vol 24, No 2 (2019)
Original research articles
Published online: 2019-03-01
Submitted: 2017-12-13
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Investigation of the changes in the prostate, bladder, and rectal wall sizes during external beam radiotherapy

Osamu Tanaka, Kensaku Seike, Takuya Taniguchi, Kousei Ono, Masayuki Matsuo
DOI: 10.1016/j.rpor.2019.02.005
·
Rep Pract Oncol Radiother 2019;24(2):204-207.

open access

Vol 24, No 2 (2019)
Original research articles
Published online: 2019-03-01
Submitted: 2017-12-13

Abstract

Aim and background

The change in the prostate size for radiotherapy has not yet been elucidated. The coverage of radiation dose is affected by changes in the prostate size. We evaluated the changes in the prostate, rectum, and bladder wall sizes during IMRT of fraction 2Gy/day using MRI.

Materials and methods

Twenty-four patients with prostate cancer were enrolled in this study. MRI was performed at three time points. While the initial MRI was performed before the start of radiotherapy (RT), the second MRI was performed at 38Gy (range: 36–40Gy), which represented the halfway point of the RT course. The last MRI was performed on the day of completion of the RT course (76Gy; range: 74–78Gy). We estimated the prostate, rectum, and bladder wall sizes at three time points.

Results

We observed no significant difference between the estimated sizes of the prostate during RT in all three phases. In addition, the volume of the rectal wall remained unchanged in all phases. However, the volume of the bladder wall significantly decreased from the initial to the last time points. Furthermore, the standard deviation (SD) obtained by subtracting the final size from the initial one was large (mean, 30.1; SD, 10.1).

Conclusions

The volume of the bladder wall decreased during IMRT. The range of subtraction of the volume of the bladder wall was extensive. Thus, the estimation of the bladder wall may be useful to reduce the inter-fraction variation.

Abstract

Aim and background

The change in the prostate size for radiotherapy has not yet been elucidated. The coverage of radiation dose is affected by changes in the prostate size. We evaluated the changes in the prostate, rectum, and bladder wall sizes during IMRT of fraction 2Gy/day using MRI.

Materials and methods

Twenty-four patients with prostate cancer were enrolled in this study. MRI was performed at three time points. While the initial MRI was performed before the start of radiotherapy (RT), the second MRI was performed at 38Gy (range: 36–40Gy), which represented the halfway point of the RT course. The last MRI was performed on the day of completion of the RT course (76Gy; range: 74–78Gy). We estimated the prostate, rectum, and bladder wall sizes at three time points.

Results

We observed no significant difference between the estimated sizes of the prostate during RT in all three phases. In addition, the volume of the rectal wall remained unchanged in all phases. However, the volume of the bladder wall significantly decreased from the initial to the last time points. Furthermore, the standard deviation (SD) obtained by subtracting the final size from the initial one was large (mean, 30.1; SD, 10.1).

Conclusions

The volume of the bladder wall decreased during IMRT. The range of subtraction of the volume of the bladder wall was extensive. Thus, the estimation of the bladder wall may be useful to reduce the inter-fraction variation.

Get Citation

Keywords

Radiotherapy; Prostate; Size change; MRI

About this article
Title

Investigation of the changes in the prostate, bladder, and rectal wall sizes during external beam radiotherapy

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 24, No 2 (2019)

Pages

204-207

Published online

2019-03-01

DOI

10.1016/j.rpor.2019.02.005

Bibliographic record

Rep Pract Oncol Radiother 2019;24(2):204-207.

Keywords

Radiotherapy
Prostate
Size change
MRI

Authors

Osamu Tanaka
Kensaku Seike
Takuya Taniguchi
Kousei Ono
Masayuki Matsuo

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