Timing of postseed imaging influences rectal dose-volume parameters for cesium-131 prostate seed implants

Research output: Contribution to journalArticle

Abstract

Purpose: To study the influence of timing of postseed implant imaging on rectal dose-volume parameters for cesium-131 (131Cs) seed prostate implants. Methods and Materials: Fifteen patients were treated in our institution with combination 131Cs brachytherapy followed by pelvic external beam radiation therapy for intermediate to high-risk prostate cancers. For all patients, CT scans were scheduled at 7 days (CT7) and again at 2 months for external beam radiation therapy simulation purpose (CT60) postseed implantation. Comprehensive postseed implant dosimetry was performed for both CT7 and CT60 scans. In each case, dose-volume histogram parameters, rectal separation (the distance between the center of posterior most seed and most anterior rectal wall), and posterior row activity (the total activity implanted within 2-4mm anterior to the posterior wall of the prostate) data were collected. The absolute rectal volumes receiving 100% and 110% prescription dose were also collected. Results: Rectal dose correlated strongly with rectal separation (p<0.001). The mean change in rectal separation between CT7 and CT60 scans was 1.1 (±1.7) mm, and the corresponding change in 0.1-cc rectal dose was 18 (±26.5) Gy. Posterior row activity did not correlate with rectal dose (p=0.51). The mean volume of rectum that receives between 100% and 110% of the prescription dose (RV100 and RV110) increased twofold, between CT7 and CT60 evaluations (0.03 [±0.06] cc vs. 0.07 (±0.05) cc, respectively, p=0.06). Conclusions: Our study has demonstrated that rectal doses after 131Cs seed implants are influenced by the timing of postseed imaging. This may be a consequence of prostatic and periprostatic edema resolution.

Original languageEnglish (US)
Pages (from-to)489-494
Number of pages6
JournalBrachytherapy
Volume11
Issue number6
DOIs
StatePublished - Nov 2012

Fingerprint

Cesium
Prostate
Seeds
Prescriptions
Radiotherapy
Brachytherapy
Rectum
Edema
Prostatic Neoplasms

Keywords

  • Cs
  • Imaging
  • Post-seed
  • Rectum

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

Cite this

@article{bbf5bdfee91a4139a68f15ddcd960541,
title = "Timing of postseed imaging influences rectal dose-volume parameters for cesium-131 prostate seed implants",
abstract = "Purpose: To study the influence of timing of postseed implant imaging on rectal dose-volume parameters for cesium-131 (131Cs) seed prostate implants. Methods and Materials: Fifteen patients were treated in our institution with combination 131Cs brachytherapy followed by pelvic external beam radiation therapy for intermediate to high-risk prostate cancers. For all patients, CT scans were scheduled at 7 days (CT7) and again at 2 months for external beam radiation therapy simulation purpose (CT60) postseed implantation. Comprehensive postseed implant dosimetry was performed for both CT7 and CT60 scans. In each case, dose-volume histogram parameters, rectal separation (the distance between the center of posterior most seed and most anterior rectal wall), and posterior row activity (the total activity implanted within 2-4mm anterior to the posterior wall of the prostate) data were collected. The absolute rectal volumes receiving 100{\%} and 110{\%} prescription dose were also collected. Results: Rectal dose correlated strongly with rectal separation (p<0.001). The mean change in rectal separation between CT7 and CT60 scans was 1.1 (±1.7) mm, and the corresponding change in 0.1-cc rectal dose was 18 (±26.5) Gy. Posterior row activity did not correlate with rectal dose (p=0.51). The mean volume of rectum that receives between 100{\%} and 110{\%} of the prescription dose (RV100 and RV110) increased twofold, between CT7 and CT60 evaluations (0.03 [±0.06] cc vs. 0.07 (±0.05) cc, respectively, p=0.06). Conclusions: Our study has demonstrated that rectal doses after 131Cs seed implants are influenced by the timing of postseed imaging. This may be a consequence of prostatic and periprostatic edema resolution.",
keywords = "Cs, Imaging, Post-seed, Rectum",
author = "Ravindra Yaparpalvi and Raquibul Hannan and Evan Landau and Kahan, {Norman Z.} and Bodner, {William R.} and Hsiang-Chi Kuo and Lloyd Minsky and Mehta, {Keyur J.} and Garg, {Madhur K.} and Shalom Kalnicki and Chandan Guha",
year = "2012",
month = "11",
doi = "10.1016/j.brachy.2011.07.004",
language = "English (US)",
volume = "11",
pages = "489--494",
journal = "Brachytherapy",
issn = "1538-4721",
publisher = "Elsevier Inc.",
number = "6",

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TY - JOUR

T1 - Timing of postseed imaging influences rectal dose-volume parameters for cesium-131 prostate seed implants

AU - Yaparpalvi, Ravindra

AU - Hannan, Raquibul

AU - Landau, Evan

AU - Kahan, Norman Z.

AU - Bodner, William R.

AU - Kuo, Hsiang-Chi

AU - Minsky, Lloyd

AU - Mehta, Keyur J.

AU - Garg, Madhur K.

AU - Kalnicki, Shalom

AU - Guha, Chandan

PY - 2012/11

Y1 - 2012/11

N2 - Purpose: To study the influence of timing of postseed implant imaging on rectal dose-volume parameters for cesium-131 (131Cs) seed prostate implants. Methods and Materials: Fifteen patients were treated in our institution with combination 131Cs brachytherapy followed by pelvic external beam radiation therapy for intermediate to high-risk prostate cancers. For all patients, CT scans were scheduled at 7 days (CT7) and again at 2 months for external beam radiation therapy simulation purpose (CT60) postseed implantation. Comprehensive postseed implant dosimetry was performed for both CT7 and CT60 scans. In each case, dose-volume histogram parameters, rectal separation (the distance between the center of posterior most seed and most anterior rectal wall), and posterior row activity (the total activity implanted within 2-4mm anterior to the posterior wall of the prostate) data were collected. The absolute rectal volumes receiving 100% and 110% prescription dose were also collected. Results: Rectal dose correlated strongly with rectal separation (p<0.001). The mean change in rectal separation between CT7 and CT60 scans was 1.1 (±1.7) mm, and the corresponding change in 0.1-cc rectal dose was 18 (±26.5) Gy. Posterior row activity did not correlate with rectal dose (p=0.51). The mean volume of rectum that receives between 100% and 110% of the prescription dose (RV100 and RV110) increased twofold, between CT7 and CT60 evaluations (0.03 [±0.06] cc vs. 0.07 (±0.05) cc, respectively, p=0.06). Conclusions: Our study has demonstrated that rectal doses after 131Cs seed implants are influenced by the timing of postseed imaging. This may be a consequence of prostatic and periprostatic edema resolution.

AB - Purpose: To study the influence of timing of postseed implant imaging on rectal dose-volume parameters for cesium-131 (131Cs) seed prostate implants. Methods and Materials: Fifteen patients were treated in our institution with combination 131Cs brachytherapy followed by pelvic external beam radiation therapy for intermediate to high-risk prostate cancers. For all patients, CT scans were scheduled at 7 days (CT7) and again at 2 months for external beam radiation therapy simulation purpose (CT60) postseed implantation. Comprehensive postseed implant dosimetry was performed for both CT7 and CT60 scans. In each case, dose-volume histogram parameters, rectal separation (the distance between the center of posterior most seed and most anterior rectal wall), and posterior row activity (the total activity implanted within 2-4mm anterior to the posterior wall of the prostate) data were collected. The absolute rectal volumes receiving 100% and 110% prescription dose were also collected. Results: Rectal dose correlated strongly with rectal separation (p<0.001). The mean change in rectal separation between CT7 and CT60 scans was 1.1 (±1.7) mm, and the corresponding change in 0.1-cc rectal dose was 18 (±26.5) Gy. Posterior row activity did not correlate with rectal dose (p=0.51). The mean volume of rectum that receives between 100% and 110% of the prescription dose (RV100 and RV110) increased twofold, between CT7 and CT60 evaluations (0.03 [±0.06] cc vs. 0.07 (±0.05) cc, respectively, p=0.06). Conclusions: Our study has demonstrated that rectal doses after 131Cs seed implants are influenced by the timing of postseed imaging. This may be a consequence of prostatic and periprostatic edema resolution.

KW - Cs

KW - Imaging

KW - Post-seed

KW - Rectum

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U2 - 10.1016/j.brachy.2011.07.004

DO - 10.1016/j.brachy.2011.07.004

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