[Hemodynamic and pathological changes in the normal rabbit brain after linac stereotactic irradiation]

Area of Science:

• Neurosurgery
• Radiology
• Pathology

Context:

• Clinical reports on stereotactic radiosurgery (SRS) are available, but basic animal studies are limited.
• Understanding the long-term effects of high-dose SRS on brain tissue and hemodynamics is crucial.

Purpose:

• To investigate the cerebral hemodynamic and pathohistological changes in rabbits following stereotactic, high-dose irradiation using a linear accelerator.

Summary:

• Rabbits received a single 100 Gy dose of SRS. Dynamic CT scans and histopathological analyses (H&E, GFAP) were performed at various intervals up to two years.
• Early findings (day 3) included cerebral hemorrhage and astrocyte proliferation. By day 180, brain necrosis was evident, with capillary fibrinoid degeneration.
• Regional cerebral blood flow (r-CBF) exhibited a biphasic pattern: an initial decrease, followed by an increase at 3 weeks, and a subsequent decline to unmeasurable levels by two years.

Impact:

• This study provides critical insights into the temporal dynamics of brain injury and vascular changes after high-dose SRS in an animal model.
• Findings suggest that early edema and later vascular wall changes contribute to the observed biphasic r-CBF alterations.
• The results can inform clinical SRS protocols and the management of potential side effects.