ABSTRACT
INTRODUCTION Radiotherapy (RT) is one of the most effective treatment modalities for both primary and metastatic brain tumors. However, RT is limited by the narrow therapeutic index between the effective treatment dose and the sensitivity of normal nervous tissue. For example, the dose of RT required to kill gliomas can also destroy normal glial tissue. The total RT dose, volume of tissue irradiated, dose per fraction, energy type (e.g., gamma, proton), and the duration of treatment, all play a role in determining the relative risk of RT-related neurotoxicity. In addition, age, comorbid illness, genetic predisposition, and chemotherapy are external factors that impact the risk of RT-related neurotoxicity (1-3).
