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Title: Local Hypothermia as a Radioprotector of the Rectal Wall During Prostate Stereotactic Body Radiation Therapy

Abstract

Purpose: To compare the single-fraction dose-related incidence of rectal obstruction and/or bleeding in normothermic and hypothermic rectums of a rat model. Methods and Materials: A 1.9-cm length of rectum was irradiated with a single fraction in 57 Sprague-Dawley rats using a dedicated image-guided small animal irradiator and Monte Carlo–based treatment planning system. All rats had a rectal temperature control apparatus placed during irradiation and were stratified to achieve either a normothermic (37°C) or hypothermic (15°C) rectal wall temperature. Radiation was delivered to a 1-cm-diameter cylindrical volume about the cooling device and rectal wall. The radiation dose was escalated from 16 Gy up to 37 Gy to assess the dose response in each arm. The primary endpoint of this study was rectal obstruction and/or bleeding during a follow-up of 180 to 186 days. Histologic scoring was performed on all study rats. Results: Probit analysis showed a dose associated with a 50% incidence of rectal obstruction of 24.6 Gy and 40.8 Gy for normothermic and hypothermic arms, respectively. The occurrence of obstruction and/or bleeding correlated with the posttreatment histologic score for normothermic rats; however, there was no difference in histologic score between normothermic and hypothermic rats at the highest dose levels evaluated. Conclusions: A significant radioprotective effect wasmore » observed using local hypothermia during a single large dose of radiation for the functional endpoint of rectal obstruction and/or bleeding. A confirmatory study in a large animal model with anatomic and physiologic similarities to humans is suggested.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [4]; ; ;  [1]
  1. Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas (United States)
  2. Department of Radiology, UT Southwestern Medical Center, Dallas, Texas (United States)
  3. Department of Biostatistics, University of California, Los Angeles, Los Angeles, California (United States)
  4. (United States)
  5. Department of Pathology, UT Southwestern Medical Center, Dallas, Texas (United States)
Publication Date:
OSTI Identifier:
22649909
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 98; Journal Issue: 1; Other Information: Copyright (c) 2017 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:
62 RADIOLOGY AND NUCLEAR MEDICINE; CYLINDRICAL CONFIGURATION; GY RANGE 10-100; HYPOTHERMIA; RADIATION DOSES; RADIOTHERAPY; RATS; RECTUM; TEMPERATURE CONTROL

Citation Formats

Hrycushko, Brian A., E-mail: Brian.Hrycushko@utsouthwestern.edu, Chopra, Rajiv, Sayre, James W., Department of Radiology, University of California, Los Angeles, Los Angeles, California, Richardson, James A., Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas, Folkert, Michael R., Timmerman, Robert D., and Medin, Paul M.. Local Hypothermia as a Radioprotector of the Rectal Wall During Prostate Stereotactic Body Radiation Therapy. United States: N. p., 2017. Web. doi:10.1016/J.IJROBP.2017.01.017.
Hrycushko, Brian A., E-mail: Brian.Hrycushko@utsouthwestern.edu, Chopra, Rajiv, Sayre, James W., Department of Radiology, University of California, Los Angeles, Los Angeles, California, Richardson, James A., Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas, Folkert, Michael R., Timmerman, Robert D., & Medin, Paul M.. Local Hypothermia as a Radioprotector of the Rectal Wall During Prostate Stereotactic Body Radiation Therapy. United States. doi:10.1016/J.IJROBP.2017.01.017.
Hrycushko, Brian A., E-mail: Brian.Hrycushko@utsouthwestern.edu, Chopra, Rajiv, Sayre, James W., Department of Radiology, University of California, Los Angeles, Los Angeles, California, Richardson, James A., Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas, Folkert, Michael R., Timmerman, Robert D., and Medin, Paul M.. Mon . "Local Hypothermia as a Radioprotector of the Rectal Wall During Prostate Stereotactic Body Radiation Therapy". United States. doi:10.1016/J.IJROBP.2017.01.017.
@article{osti_22649909,
title = {Local Hypothermia as a Radioprotector of the Rectal Wall During Prostate Stereotactic Body Radiation Therapy},
author = {Hrycushko, Brian A., E-mail: Brian.Hrycushko@utsouthwestern.edu and Chopra, Rajiv and Sayre, James W. and Department of Radiology, University of California, Los Angeles, Los Angeles, California and Richardson, James A. and Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas and Folkert, Michael R. and Timmerman, Robert D. and Medin, Paul M.},
abstractNote = {Purpose: To compare the single-fraction dose-related incidence of rectal obstruction and/or bleeding in normothermic and hypothermic rectums of a rat model. Methods and Materials: A 1.9-cm length of rectum was irradiated with a single fraction in 57 Sprague-Dawley rats using a dedicated image-guided small animal irradiator and Monte Carlo–based treatment planning system. All rats had a rectal temperature control apparatus placed during irradiation and were stratified to achieve either a normothermic (37°C) or hypothermic (15°C) rectal wall temperature. Radiation was delivered to a 1-cm-diameter cylindrical volume about the cooling device and rectal wall. The radiation dose was escalated from 16 Gy up to 37 Gy to assess the dose response in each arm. The primary endpoint of this study was rectal obstruction and/or bleeding during a follow-up of 180 to 186 days. Histologic scoring was performed on all study rats. Results: Probit analysis showed a dose associated with a 50% incidence of rectal obstruction of 24.6 Gy and 40.8 Gy for normothermic and hypothermic arms, respectively. The occurrence of obstruction and/or bleeding correlated with the posttreatment histologic score for normothermic rats; however, there was no difference in histologic score between normothermic and hypothermic rats at the highest dose levels evaluated. Conclusions: A significant radioprotective effect was observed using local hypothermia during a single large dose of radiation for the functional endpoint of rectal obstruction and/or bleeding. A confirmatory study in a large animal model with anatomic and physiologic similarities to humans is suggested.},
doi = {10.1016/J.IJROBP.2017.01.017},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 1,
volume = 98,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}