PET evaluation of late cerebral effect in advanced radiation therapy techniques for cranial base tumors

Background and Objective: Even though the benefits of radiation therapy are well established, it is important to recognize the broad spectrum of radiation-induced changes, particularly in the central nervous system. The possible damage to the brain parenchyma may have clinical consequences and in particular cognitive impairment might be one of the major complications of radiotherapy. To date, no studies have investigated the effects of focal radiation therapy on brain structure and function together with the assessment of their clinical outcomes at a long follow-up. Methods: In this prospective study, we evaluated in six patients the possible brain late effects after radiation therapy, using a standardized neuropsychological battery, MRI and18F-FDG PET using SPM and semi-quantitative methods, in patients affected by cranial base tumors who underwent gamma knife or tomotherapy. Results: Neuropsychological examinations showed no cognitive impairment after the treatment. In all patients, both MRI assessment and18F-FDG-PET did not reveal any local or distant anatomical and metabolic late effects. Conclusion: The present study support the safety of advanced radiation therapy techniques.18F-FDG-PET, using SPM and semi-quantitative methods, might be a valuable tool to evaluate the cerebral ra-diotoxicity in patients treated for brain neoplasms.