RELATIONSHIP BETWEEN DOSE AND THE LATENT PERIOD FOR RADIATION MYELOPATHY IN RATS

Citation
Jp. Geraci et Ms. Mariano, RELATIONSHIP BETWEEN DOSE AND THE LATENT PERIOD FOR RADIATION MYELOPATHY IN RATS, Radiation research, 140(3), 1994, pp. 340-346
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Radiology,Nuclear Medicine & Medical Imaging
Journal title
ISSN journal
0033-7587
Volume
140
Issue
3
Year of publication
1994
Pages
340 - 346
Database
ISI
SICI code
0033-7587(1994)140:3<340:RBDATL>2.0.ZU;2-V
Abstract
A l-cm segment of rat cervical spinal cord was irradiated (16-150 Gy) and the animals were followed for 16 months to determine the dose-resp onse relationship for the latent period for radiation myelopathy. The latent period was found to be dependent on dose in the ED(0) to ED(100 ) dose range, independent of dose in the range ED(100) to 1.5 times th e ED(100) dose and dependent on dose for doses more than 1.5 times the ED(100) dose. Histologically, some vascular injury and demyelinizatio n were observed in the irradiated cord segment of all paretic animals. In the first dose-dependent region there was a bimodal distribution o f latent periods, suggesting two mechanisms for paralysis in this dose region. A hypothesis based on glial and vascular injury is presented which explains the triphasic dose-response relationship for the latent period. The 95% confidence limits for the dose location of both of th e dose-dependent regions were less than 10% of the administered dose. Therefore, if used correctly, the latent period as an end point should be able to be used to detect dose-modifying parameters (i.e. RBE and OER) that are greater than 20%.