Spinal cord tolerance to single-session uniform irradiation in pigs: Implications for a dose-volume effect

Paul M. Medin, Ryan D. Foster, Albert J. Van Der Kogel, James W. Sayre, William H. McBride, Timothy D. Solberg

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Background and purpose: This study was performed to test the hypothesis that spinal cord radiosensitivity is significantly modified by uniform versus laterally non-uniform dose distributions. Materials and methods: A uniform dose distribution was delivered to a 4.5-7.0 cm length of cervical spinal cord in 22 mature Yucatan minipigs for comparison with a companion study in which a laterally non-uniform dose was given [1]. Pigs were allocated into four dose groups with mean maximum spinal cord doses of 17.5 ± 0.1 Gy (n = 7), 19.5 ± 0.2 Gy (n = 6), 22.0 ± 0.1 Gy (n = 5), and 24.1 ± 0.2 Gy (n = 4). The study endpoint was motor neurologic deficit determined by a change in gait within one year. Spinal cord sections were stained with a Luxol fast blue/periodic acid Schiff combination. Results: Dose-response curves for uniform versus non-uniform spinal cord irradiation were nearly identical with ED 50's (95% confidence interval) of 20.2 Gy (19.1-25.8) and 20.0 Gy (18.3-21.7), respectively. No neurologic change was observed for either dose distribution when the maximum spinal cord dose was ≤17.8 Gy while all animals experienced deficits at doses ≥21.8 Gy. Conclusion: No dose-volume effect was observed in pigs for the dose distributions studied and the endpoint of motor neurologic deficit; however, partial spinal cord irradiation resulted in less debilitating neurologic morbidity and histopathology.

Original languageEnglish (US)
Pages (from-to)101-105
Number of pages5
JournalRadiotherapy and Oncology
Volume106
Issue number1
DOIs
Publication statusPublished - Jan 2013

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Keywords

  • Dose-volume effect
  • Normal tissue tolerance
  • Spinal cord tolerance
  • Stereotactic spinal radiosurgery
  • Swine

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Hematology

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