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 language | English (US) |
---|---|
Pages (from-to) | 101-105 |
Number of pages | 5 |
Journal | Radiotherapy and Oncology |
Volume | 106 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2013 |
Keywords
- Dose-volume effect
- Normal tissue tolerance
- Spinal cord tolerance
- Stereotactic spinal radiosurgery
- Swine
ASJC Scopus subject areas
- Hematology
- Oncology
- Radiology Nuclear Medicine and imaging