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Title: Effect of various methods for rectum delineation on relative and absolute dose-volume histograms for prostate IMRT treatment planning

Abstract

Several reports have dealt with correlations of late rectal toxicity with rectal dose-volume histograms (DVHs) for high dose levels. There are 2 techniques to assess rectal volume for reception of a specific dose: relative-DVH (R-DVH, %) that indicates relative volume for a vertical axis, and absolute-DVH (A-DVH, cc) with its vertical axis showing absolute volume of the rectum. The parameters of DVH vary depending on the rectum delineation method, but the literature does not present any standardization of such methods. The aim of the present study was to evaluate the effects of different delineation methods on rectal DVHs. The enrollment for this study comprised 28 patients with high-risk localized prostate cancer, who had undergone intensity-modulated radiation therapy (IMRT) with the prescription dose of 78 Gy. The rectum was contoured with 4 different methods using 2 lengths, short (Sh) and long (Lg), and 2 cross sections, rectum (Rec) and rectal wall (Rw). Sh means the length from 1 cm above the seminal vesicles to 1 cm below the prostate and Lg the length from the rectosigmoid junction to the anus. Rec represents the entire rectal volume including the rectal contents and Rw the rectal volume of the area with a wallmore » thickness of 4 mm. We compared dose-volume parameters by using 4 rectal contour methods for the same plan with the R-DVHs as well as the A-DVHs. For the high dose levels, the R-DVH parameters varied widely. The mean of V{sub 70} for Sh-Rw was the highest (19.4%) and nearly twice as high as that for Lg-Rec (10.4%). On the contrary, only small variations were observed in the A-DVH parameters (4.3, 4.3, 5.5, and 5.5 cc for Sh-Rw, Lg-Rw, Sh-Rec, and Lg-Rec, respectively). As for R-DVHs, the parameters of V{sub 70} varied depending on the rectal lengths (Sh-Rec vs Lg-Rec: R = 0.76; Sh-Rw vs Lg-Rw: R = 0.85) and cross sections (Sh-Rec vs Sh-Rw: R = 0.49; Lg-Rec vs Lg-Rw: R = 0.65). For A-DVHs, however, the parameters of Sh rectal A-DVHs hardly changed regardless of differences in rectal length at all dose levels. Moreover, at high dose levels (V{sub 70}), the parameters of A-DVHs showed less dependence on rectal cross sections (Sh-Rec vs Sh-Rw: R = 0.66; Lg-Rec vs Lg-Rw: R = 0.59). This study showed that A-DVHs were less dependent on the delineation methods than R-DVHs, especially for evaluating the rectal dose at higher dose levels. It can therefore be assumed that, in addition to R-DVHs, A-DVHs can be used for evaluating rectal toxicity.« less

Authors:
 [1];  [1];  [2];  [1];  [1];  [2];  [1];  [1]
  1. Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka (Japan)
  2. (Japan)
Publication Date:
OSTI Identifier:
22577874
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Dosimetry; Journal Volume: 41; Journal Issue: 2; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; 62 RADIOLOGY AND NUCLEAR MEDICINE; CROSS SECTIONS; HEALTH HAZARDS; NEOPLASMS; PATIENTS; PLANNING; PROSTATE; RADIATION DOSES; RADIOTHERAPY; RECTUM; STANDARDIZATION; THICKNESS; TOXICITY

Citation Formats

Kusumoto, Chiaki, Ohira, Shingo, Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Miyazaki, Masayoshi, Ueda, Yoshihiro, Department of Radiation Oncology, Graduate School of Medicine, Osaka University, Suita, Isono, Masaru, and Teshima, Teruki, E-mail: teshima-te@mc.pref.osaka.jp. Effect of various methods for rectum delineation on relative and absolute dose-volume histograms for prostate IMRT treatment planning. United States: N. p., 2016. Web. doi:10.1016/J.MEDDOS.2015.11.001.
Kusumoto, Chiaki, Ohira, Shingo, Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Miyazaki, Masayoshi, Ueda, Yoshihiro, Department of Radiation Oncology, Graduate School of Medicine, Osaka University, Suita, Isono, Masaru, & Teshima, Teruki, E-mail: teshima-te@mc.pref.osaka.jp. Effect of various methods for rectum delineation on relative and absolute dose-volume histograms for prostate IMRT treatment planning. United States. doi:10.1016/J.MEDDOS.2015.11.001.
Kusumoto, Chiaki, Ohira, Shingo, Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Miyazaki, Masayoshi, Ueda, Yoshihiro, Department of Radiation Oncology, Graduate School of Medicine, Osaka University, Suita, Isono, Masaru, and Teshima, Teruki, E-mail: teshima-te@mc.pref.osaka.jp. Fri . "Effect of various methods for rectum delineation on relative and absolute dose-volume histograms for prostate IMRT treatment planning". United States. doi:10.1016/J.MEDDOS.2015.11.001.
@article{osti_22577874,
title = {Effect of various methods for rectum delineation on relative and absolute dose-volume histograms for prostate IMRT treatment planning},
author = {Kusumoto, Chiaki and Ohira, Shingo and Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita and Miyazaki, Masayoshi and Ueda, Yoshihiro and Department of Radiation Oncology, Graduate School of Medicine, Osaka University, Suita and Isono, Masaru and Teshima, Teruki, E-mail: teshima-te@mc.pref.osaka.jp},
abstractNote = {Several reports have dealt with correlations of late rectal toxicity with rectal dose-volume histograms (DVHs) for high dose levels. There are 2 techniques to assess rectal volume for reception of a specific dose: relative-DVH (R-DVH, %) that indicates relative volume for a vertical axis, and absolute-DVH (A-DVH, cc) with its vertical axis showing absolute volume of the rectum. The parameters of DVH vary depending on the rectum delineation method, but the literature does not present any standardization of such methods. The aim of the present study was to evaluate the effects of different delineation methods on rectal DVHs. The enrollment for this study comprised 28 patients with high-risk localized prostate cancer, who had undergone intensity-modulated radiation therapy (IMRT) with the prescription dose of 78 Gy. The rectum was contoured with 4 different methods using 2 lengths, short (Sh) and long (Lg), and 2 cross sections, rectum (Rec) and rectal wall (Rw). Sh means the length from 1 cm above the seminal vesicles to 1 cm below the prostate and Lg the length from the rectosigmoid junction to the anus. Rec represents the entire rectal volume including the rectal contents and Rw the rectal volume of the area with a wall thickness of 4 mm. We compared dose-volume parameters by using 4 rectal contour methods for the same plan with the R-DVHs as well as the A-DVHs. For the high dose levels, the R-DVH parameters varied widely. The mean of V{sub 70} for Sh-Rw was the highest (19.4%) and nearly twice as high as that for Lg-Rec (10.4%). On the contrary, only small variations were observed in the A-DVH parameters (4.3, 4.3, 5.5, and 5.5 cc for Sh-Rw, Lg-Rw, Sh-Rec, and Lg-Rec, respectively). As for R-DVHs, the parameters of V{sub 70} varied depending on the rectal lengths (Sh-Rec vs Lg-Rec: R = 0.76; Sh-Rw vs Lg-Rw: R = 0.85) and cross sections (Sh-Rec vs Sh-Rw: R = 0.49; Lg-Rec vs Lg-Rw: R = 0.65). For A-DVHs, however, the parameters of Sh rectal A-DVHs hardly changed regardless of differences in rectal length at all dose levels. Moreover, at high dose levels (V{sub 70}), the parameters of A-DVHs showed less dependence on rectal cross sections (Sh-Rec vs Sh-Rw: R = 0.66; Lg-Rec vs Lg-Rw: R = 0.59). This study showed that A-DVHs were less dependent on the delineation methods than R-DVHs, especially for evaluating the rectal dose at higher dose levels. It can therefore be assumed that, in addition to R-DVHs, A-DVHs can be used for evaluating rectal toxicity.},
doi = {10.1016/J.MEDDOS.2015.11.001},
journal = {Medical Dosimetry},
number = 2,
volume = 41,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 2016},
month = {Fri Jul 01 00:00:00 EDT 2016}
}