====== Radiation necrosis ======

{{ ::radiationnecrosis.jpeg?300|}}

===== Pathophysiology =====

As radiation is selectively toxic to more rapidly dividing cells, the two normal cell types within the CNS most vulnerable to RN are vascular [[endothelium]] (which have a turnover time of ≈ 6–10 mos)
and [[oligodendroglia]]l cells. Vascular injury may be the primary limiting factor to the tolerance of cranial XRT
((O'Connor MM, Mayberg MR. Effects of Radiation on Cerebral Vasculature: A Review. Neurosurgery. 2000; 46:138–151)).
Injury from XRT occurs at lower doses when given concurrently with chemotherapy (especially [[methotrexate]]).

===== Etiology of side effects =====

The mechanism(s) by which XRT causes side effects is not known with certainty, but may be due to: 

1. damage to vascular endothelium: effects on cerebral vasculature may differ substantially from
effects on systemic vessels
((O'Connor MM, Mayberg MR. Effects of Radiation on Cerebral Vasculature: A Review. Neurosurgery. 2000; 46:138–151)).

2. glial injury

3. immune system effect

===== Clinical features =====

[[Radiation necrosis clinical features]].

===== Diagnosis =====

[[Radiation necrosis diagnosis]].

===== Treatment =====

see [[Radiation necrosis treatment]]

===== References =====