Lesion evolution after gamma knife irradiation observed by magnetic resonance imaging |
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| Authors: | D Jirák K Náměstková V Herynek R Liščák J Vymazal V Mareš |
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| Institution: | 1. MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague;2. Center for Cell Therapy and Tissue Repair, Prague;3. Center for Cell Therapy and Tissue Repair, Prague;4. Institute of Experimental Medicine ASCR, Prague;5. Department of Stereotactic and Radiation Neurosurgery, Na Homolce Hospital, Prague;6. Institute of Physiology ASCR, Prague, Czech Republic;7. Faculty of Science, University of J. E. Purkinje, ústí nad Labem, Czech Republic |
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| Abstract: | Purpose: Our study is focused on the magnetic resonance imaging (MRI) observation of lesion development and hippocampus related functional impairments in rats after irradiation with a Leksell Gamma knife (LGK).Materials and methods: We exposed 32 three-month-old Long-Evans rats to various radiation doses (25 Gy, 50 Gy or 75 Gy). The rats were scanned by a 4.7 T magnetic resonance (MR) spectrometer at several timepoints (1 – 18 months) after irradiation. The lesion size was evaluated by manual segmentation; the animals were behaviorally tested in a Morris water maze and examined histologically.Results: We found that a dose of 25 Gy induced no edema, necrosis or behavioral change. The response of the rats to higher doses was not uniform; the first occurrence of lesions in the rat brains irradiated with 50 and 75 Gy was detected six months post-irradiation. Functional impairment correlated well with the lesion size and histology.Conclusions: Rat brains showed the development of expanding delayed lesions after 50 or 75 Gy doses from the LGK during the first year after irradiation. |
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| Keywords: | Gamma knife rat brain magnetic resonance imaging Morris water maze |
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