Doctor telling niece to get dope (12)
I believe the answer is:
intelligence
'dope' is the definition.
(both can mean information)
'doctor telling niece' is the wordplay.
'doctor' is an anagram indicator.
'telling'+'niece'='tellingniece'
'tellingniece' with letters rearranged gives 'INTELLIGENCE'.
'to get' is the link.
(Other definitions for intelligence that I've seen before include "Dope" , "Mind; news" , "Spy reports" , "Covert information" , "Covertly-gathered info" .)