Chlorotoxin (CTX) is a 36-amino-acid disulfide-containing peptide derived from 
the venom of the scorpion Leiurus quinquestriatus. CTX alters physiology in 
numerous ways. It interacts with voltage gated chloride channels, Annexin-2, and 
matrix metalloproteinase-2 (MMP-2). CTX-based bioconjugates have been widely 
subjected to phase I/II clinical trials and have shown substantial promise. Many 
studies have demonstrated that CTX preferentially binds to neuroectodermal 
tumors, such as glioblastoma, without cross-reactivity to normal brain cells. 
With its ability to penetrate the blood-brain-barrier (BBB) and its tyrosine 
residue allows covalent conjugation with functional moieties, CTX is an 
attractive platform to explore development of diagnostic and therapeutic agents 
for gliomas. In this review, we outline CTX structure and its molecular targets, 
summarize molecular variations of CTX developed for glioma imaging, and discuss 
future trends and perspectives for CTX conjugates as a theranostic agent.