Current studies demonstrated efficacy of PET/CT/(MRI) with [18F]TFAHA for imaging HDACs class IIa expression-activity in 9L and U87-MG brain glioma models in rats, and for non-invasive monitoring of MC1568 induced inhibition of HDAC class IIa activity in 9L gliomas. The gene discussed is HDAC9; the disease is central nervous system cancer.