'astatized' originates from the element name 'astatine' plus the verb-forming suffix '-ize' (from Greek-derived '-izein'), where 'astatine' itself was coined from Greek 'astatos' meaning 'unstable'.

'astatine' was coined in the 20th century from Greek 'astatos' ('unstable'); English formed the verb 'astatize' by adding the productive suffix '-ize' to 'astatine', and the modern past participle form became 'astatized'.

Initially the root referred to the notion of 'unstable' (the meaning behind the element name), but in modern technical use 'astatize/astatized' specifically means 'to label or incorporate astatine' (especially in radiochemistry).